WiringPi/wiringPi/wiringPi.c

/*
 * wiringPi:
 *	Arduino look-a-like Wiring library for the Raspberry Pi
 *	Copyright (c) 2012-2024 Gordon Henderson and contributors
 *	Additional code for pwmSetClock by Chris Hall <chris@kchall.plus.com>
 *
 *	Thanks to code samples from Gert Jan van Loo and the
 *	BCM2835 ARM Peripherals manual, however it's missing
 *	the clock section /grr/mutter/
 ***********************************************************************
 * This file is part of wiringPi:
 *    https://github.com/WiringPi/WiringPi
 *
 *    wiringPi is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as
 *    published by the Free Software Foundation, either version 3 of the
 *    License, or (at your option) any later version.
 *
 *    wiringPi is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public
 *    License along with wiringPi.
 *    If not, see <http://www.gnu.org/licenses/>.
 ***********************************************************************
 */

// Revisions:
//	19 Jul 2012:
//		Moved to the LGPL
//		Added an abstraction layer to the main routines to save a tiny
//		bit of run-time and make the clode a little cleaner (if a little
//		larger)
//		Added waitForInterrupt code
//		Added piHiPri code
//
//	 9 Jul 2012:
//		Added in support to use the /sys/class/gpio interface.
//	 2 Jul 2012:
//		Fixed a few more bugs to do with range-checking when in GPIO mode.
//	11 Jun 2012:
//		Fixed some typos.
//		Added c++ support for the .h file
//		Added a new function to allow for using my "pin" numbers, or native
//			GPIO pin numbers.
//		Removed my busy-loop delay and replaced it with a call to delayMicroseconds
//
//	02 May 2012:
//		Added in the 2 UART pins
//		Change maxPins to numPins to more accurately reflect purpose


#include <stdio.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>
#include <ctype.h>
#include <poll.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <asm/ioctl.h>
#include <byteswap.h>
#include <sys/utsname.h>
#include <linux/gpio.h>

#include "softPwm.h"
#include "softTone.h"

#include "wiringPi.h"
#include "../version.h"
#include "wiringPiLegacy.h"

// Environment Variables

#define	ENV_DEBUG	"WIRINGPI_DEBUG"
#define	ENV_CODES	"WIRINGPI_CODES"
#define	ENV_GPIOMEM	"WIRINGPI_GPIOMEM"


// Extend wiringPi with other pin-based devices and keep track of
//	them in this structure

struct wiringPiNodeStruct *wiringPiNodes = NULL ;

// BCM Magic

#define	BCM_PASSWORD		0x5A000000


// The BCM2835 has 54 GPIO pins.
//	BCM2835 data sheet, Page 90 onwards.
//	There are 6 control registers, each control the functions of a block
//	of 10 pins.
//	Each control register has 10 sets of 3 bits per GPIO pin - the ALT values
//
//	000 = GPIO Pin X is an input
//	001 = GPIO Pin X is an output
//	100 = GPIO Pin X takes alternate function 0
//	101 = GPIO Pin X takes alternate function 1
//	110 = GPIO Pin X takes alternate function 2
//	111 = GPIO Pin X takes alternate function 3
//	011 = GPIO Pin X takes alternate function 4
//	010 = GPIO Pin X takes alternate function 5
//
// So the 3 bits for port X are:
//	X / 10 + ((X % 10) * 3)

// Port function select bits

#define	FSEL_INPT		0b000
#define	FSEL_OUTP		0b001
#define	FSEL_ALT0		0b100
#define	FSEL_ALT1		0b101
#define	FSEL_ALT2		0b110
#define	FSEL_ALT3		0b111
#define	FSEL_ALT4		0b011
#define	FSEL_ALT5		0b010

//RP1 chip (@Pi5) - 3.1.1. Function select
#define RP1_FSEL_ALT0			0x00
#define RP1_FSEL_GPIO			0x05  //SYS_RIO
#define RP1_FSEL_NONE			0x09
#define RP1_FSEL_NONE_HW	0x1f  //default, mask

//RP1 chip (@Pi5) RIO address
const unsigned int RP1_RIO_OUT = 0x0000;
const unsigned int RP1_RIO_OE  = (0x0004/4);
const unsigned int RP1_RIO_IN  = (0x0008/4);

//RP1 chip (@Pi5) RIO offset for set/clear value
const unsigned int RP1_SET_OFFSET = (0x2000/4);
const unsigned int RP1_CLR_OFFSET = (0x3000/4);

//RP1 chip (@Pi5) PDE/PDU pull-up/-down enable
const unsigned int RP1_PUD_UP = (1<<3);
const unsigned int RP1_PUD_DOWN = (1<<2);
const unsigned int RP1_INV_PUD_MASK = ~(RP1_PUD_UP | RP1_PUD_DOWN); //~0x0C

//RP1 chip (@Pi5) pin level, status register
const unsigned int RP1_STATUS_LEVEL_LOW  = 0x00400000;
const unsigned int RP1_STATUS_LEVEL_HIGH = 0x00800000;
const unsigned int RP1_STATUS_LEVEL_MASK = 0x00C00000;

const unsigned int RP1_DEBOUNCE_DEFAULT_VALUE = 4;
const unsigned int RP1_DEBOUNCE_MASK    = 0x7f;
const unsigned int RP1_DEBOUNCE_DEFAULT = (RP1_DEBOUNCE_DEFAULT_VALUE << 5);

const unsigned int RP1_IRQRESET = 0x10000000; //CTRL Bit 28

const unsigned int RP1_PAD_DEFAULT_0TO8      = (0x0B | 0x70);  //Slewfast, Schmitt, PullUp,   | 12mA, Input enable
const unsigned int RP1_PAD_DEFAULT_FROM9     = (0x07 | 0x70);  //Slewfast, Schmitt, PullDown, | 12mA, Input enable
const unsigned int RP1_PAD_IC_DEFAULT_0TO8  = 0x9A; //pull-up, Schmitt
const unsigned int RP1_PAD_IC_DEFAULT_FROM9 = 0x96; //pull-down, Schmitt

const unsigned int RP1_PAD_DRIVE_MASK   = 0x00000030;
const unsigned int RP1_INV_PAD_DRIVE_MASK = ~(RP1_PAD_DRIVE_MASK);

//RP1 chip (@Pi5) address
const unsigned long long RP1_64_BASE_Addr = 0x1f000d0000;
const unsigned int RP1_BASE_Addr     = 0x40000000;
const unsigned int RP1_PWM0_Addr     = 0x40098000;  // Adress is not mapped to gpiomem device!
const unsigned int RP1_IO0_Addr      = 0x400d0000;
const unsigned int RP1_SYS_RIO0_Addr = 0x400e0000;
const unsigned int RP1_PADS0_Addr    = 0x400f0000;


// Access from ARM Running Linux
//	Taken from Gert/Doms code. Some of this is not in the manual
//	that I can find )-:
//
// Updates in September 2015 - all now static variables (and apologies for the caps)
//	due to the Pi v2, v3, etc. and the new /dev/gpiomem interface

const char* gpiomem_global    = "/dev/mem";
const char* gpiomem_BCM       = "/dev/gpiomem";
const char* gpiomem_RP1       = "/dev/gpiomem0";
const int   gpiomem_RP1_Size  = 0x00030000;
// PCIe Memory access, static define - maybe needed to detect in future
//dmesg: rp1 0000:01:00.0: bar1 len 0x400000, start 0x1f00000000, end 0x1f003fffff, flags, 0x40200
const char* pciemem_RP1_path  = "/sys/bus/pci/devices/0000:01:00.0";
const char* pciemem_RP1       = "/sys/bus/pci/devices/0000:01:00.0/resource1";
const int   pciemem_RP1_Size  = 0x00400000;
const unsigned short pciemem_RP1_Ventor= 0x1de4;
const unsigned short pciemem_RP1_Device= 0x0001;

static volatile unsigned int GPIO_PADS ;
static volatile unsigned int GPIO_CLOCK_BASE ;
static volatile unsigned int GPIO_BASE ;
static volatile unsigned int GPIO_TIMER ;
static volatile unsigned int GPIO_PWM ;
static volatile unsigned int GPIO_RIO ;

#define	PAGE_SIZE		(4*1024)
#define	BLOCK_SIZE		(4*1024)

static unsigned int usingGpioMem    = FALSE ;
static          int wiringPiSetuped = FALSE ;

// PWM
//	Word offsets into the PWM control region

#define	PWM_CONTROL 0
#define	PWM_STATUS  1
#define	PWM0_RANGE  4
#define	PWM0_DATA   5
#define	PWM1_RANGE  8
#define	PWM1_DATA   9

//	Clock regsiter offsets

#define	PWMCLK_CNTL	40
#define	PWMCLK_DIV	41

#define	PWM0_MS_MODE    0x0080  // Run in MS mode
#define	PWM0_USEFIFO    0x0020  // Data from FIFO
#define	PWM0_REVPOLAR   0x0010  // Reverse polarity
#define	PWM0_OFFSTATE   0x0008  // Ouput Off state
#define	PWM0_REPEATFF   0x0004  // Repeat last value if FIFO empty
#define	PWM0_SERIAL     0x0002  // Run in serial mode
#define	PWM0_ENABLE     0x0001  // Channel Enable

#define	PWM1_MS_MODE    0x8000  // Run in MS mode
#define	PWM1_USEFIFO    0x2000  // Data from FIFO
#define	PWM1_REVPOLAR   0x1000  // Reverse polarity
#define	PWM1_OFFSTATE   0x0800  // Ouput Off state
#define	PWM1_REPEATFF   0x0400  // Repeat last value if FIFO empty
#define	PWM1_SERIAL     0x0200  // Run in serial mode
#define	PWM1_ENABLE     0x0100  // Channel Enable

// Timer
//	Word offsets

#define	TIMER_LOAD	(0x400 >> 2)
#define	TIMER_VALUE	(0x404 >> 2)
#define	TIMER_CONTROL	(0x408 >> 2)
#define	TIMER_IRQ_CLR	(0x40C >> 2)
#define	TIMER_IRQ_RAW	(0x410 >> 2)
#define	TIMER_IRQ_MASK	(0x414 >> 2)
#define	TIMER_RELOAD	(0x418 >> 2)
#define	TIMER_PRE_DIV	(0x41C >> 2)
#define	TIMER_COUNTER	(0x420 >> 2)

// Locals to hold pointers to the hardware

static volatile unsigned int *base ;
static volatile unsigned int *gpio ;
static volatile unsigned int *pwm ;
static volatile unsigned int *clk ;
static volatile unsigned int *pads ;
static volatile unsigned int *timer ;
static volatile unsigned int *timerIrqRaw ;
static volatile unsigned int *rio ;

// Export variables for the hardware pointers

volatile unsigned int *_wiringPiBase ;
volatile unsigned int *_wiringPiGpio ;
volatile unsigned int *_wiringPiPwm ;
volatile unsigned int *_wiringPiClk ;
volatile unsigned int *_wiringPiPads ;
volatile unsigned int *_wiringPiTimer ;
volatile unsigned int *_wiringPiTimerIrqRaw ;
volatile unsigned int *_wiringPiRio ;

// Data for use with the boardId functions.
//	The order of entries here to correspond with the PI_MODEL_X
//	and PI_VERSION_X defines in wiringPi.h
//	Only intended for the gpio command - use at your own risk!

// piGpioBase:
//	The base address of the GPIO memory mapped hardware IO

#define	GPIO_PERI_BASE_OLD  0x20000000
#define	GPIO_PERI_BASE_2835 0x3F000000
#define	GPIO_PERI_BASE_2711 0xFE000000
#define	GPIO_PERI_BASE_2712 0x00  //unknown - 32-bit mapped global mem access not supported for now

static volatile unsigned int piGpioBase = 0 ;

const char *piModelNames [24] =
{
  "Model A",	//  0
  "Model B",	//  1
  "Model A+",	//  2
  "Model B+",	//  3
  "Pi 2",	//  4
  "Alpha",	//  5
  "CM",		//  6
  "Unknown07",	// 07
  "Pi 3",	// 08
  "Pi Zero",	// 09
  "CM3",	// 10
  "Unknown11",	// 11
  "Pi Zero-W",	// 12
  "Pi 3B+",	// 13
  "Pi 3A+",	// 14
  "Unknown15",	// 15
  "CM3+",	// 16
  "Pi 4B",	// 17
  "Pi Zero2-W",	// 18
  "Pi 400",	// 19
  "CM4",	// 20
  "CM4S",	// 21
  "Unknown22",	// 22
  "Pi 5",	// 23
} ;

const char *piProcessor [5] =
{
  "BCM2835",
  "BCM2836",
  "BCM2837",
  "BCM2711",
  "BCM2712",
} ;

const char *piRevisionNames [16] =
{
  "00",
  "01",
  "02",
  "03",
  "04",
  "05",
  "06",
  "07",
  "08",
  "09",
  "10",
  "11",
  "12",
  "13",
  "14",
  "15",
} ;

const char *piMakerNames [16] =
{
  "Sony",	//	 0
  "Egoman",	//	 1
  "Embest",	//	 2
  "Unknown",//	 3
  "Embest",	//	 4
  "Stadium",//	 5
  "Unknown06",	//	 6
  "Unknown07",	//	 7
  "Unknown08",	//	 8
  "Unknown09",	//	 9
  "Unknown10",	//	10
  "Unknown11",	//	11
  "Unknown12",	//	12
  "Unknown13",	//	13
  "Unknown14",	//	14
  "Unknown15",	//	15
} ;

const int piMemorySize [8] =
{
   256,		//	 0
   512,		//	 1
  1024,		//	 2
  2048,		//	 3
  4096,		//	 4
  8192,		//	 5
     0,		//	 6
     0,		//	 7
} ;

// Time for easy calculations

static uint64_t epochMilli, epochMicro ;

// Misc

static int wiringPiMode = WPI_MODE_UNINITIALISED ;
static volatile int    pinPass = -1 ;
static pthread_mutex_t pinMutex ;

static int RaspberryPiModel  = -1;
static int RaspberryPiLayout = -1;

// Debugging & Return codes

int wiringPiDebug       = FALSE ;
int wiringPiReturnCodes = FALSE ;

// Use /dev/gpiomem ?

int wiringPiTryGpioMem  = FALSE ;

static unsigned int lineFlags [64] =
{
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
} ;

static int lineFds [64] =
{
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
} ;

static int isrFds [64] =
{
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
} ;

// ISR Data
static int chipFd = -1;
static void (*isrFunctions [64])(void) ;
static pthread_t isrThreads[64];
static int isrMode[64];

// Doing it the Arduino way with lookup tables...
//	Yes, it's probably more innefficient than all the bit-twidling, but it
//	does tend to make it all a bit clearer. At least to me!

// pinToGpio:
//	Take a Wiring pin (0 through X) and re-map it to the BCM_GPIO pin
//	Cope for 3 different board revisions here.

static int *pinToGpio ;

// Revision 1, 1.1:

static int pinToGpioR1 [64] =
{
  17, 18, 21, 22, 23, 24, 25, 4,	// From the Original Wiki - GPIO 0 through 7:	wpi  0 -  7
   0,  1,				// I2C  - SDA1, SCL1				wpi  8 -  9
   8,  7,				// SPI  - CE1, CE0				wpi 10 - 11
  10,  9, 11, 				// SPI  - MOSI, MISO, SCLK			wpi 12 - 14
  14, 15,				// UART - Tx, Rx				wpi 15 - 16

// Padding:

      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 31
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 47
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 63
} ;

// Revision 2:

static int pinToGpioR2 [64] =
{
  17, 18, 27, 22, 23, 24, 25, 4,	// From the Original Wiki - GPIO 0 through 7:	wpi  0 -  7
   2,  3,				// I2C  - SDA0, SCL0				wpi  8 -  9
   8,  7,				// SPI  - CE1, CE0				wpi 10 - 11
  10,  9, 11, 				// SPI  - MOSI, MISO, SCLK			wpi 12 - 14
  14, 15,				// UART - Tx, Rx				wpi 15 - 16
  28, 29, 30, 31,			// Rev 2: New GPIOs 8 though 11			wpi 17 - 20
   5,  6, 13, 19, 26,			// B+						wpi 21, 22, 23, 24, 25
  12, 16, 20, 21,			// B+						wpi 26, 27, 28, 29
   0,  1,				// B+						wpi 30, 31

// Padding:

  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 47
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 63
} ;


// physToGpio:
//	Take a physical pin (1 through 26) and re-map it to the BCM_GPIO pin
//	Cope for 2 different board revisions here.
//	Also add in the P5 connector, so the P5 pins are 3,4,5,6, so 53,54,55,56

static int *physToGpio ;

static int physToGpioR1 [64] =
{
  -1,		// 0
  -1, -1,	// 1, 2
   0, -1,
   1, -1,
   4, 14,
  -1, 15,
  17, 18,
  21, -1,
  22, 23,
  -1, 24,
  10, -1,
   9, 25,
  11,  8,
  -1,  7,	// 25, 26

                                              -1, -1, -1, -1, -1,	// ... 31
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 47
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,	// ... 63
} ;

static int physToGpioR2 [64] =
{
  -1,		// 0
  -1, -1,	// 1, 2
   2, -1,
   3, -1,
   4, 14,
  -1, 15,
  17, 18,
  27, -1,
  22, 23,
  -1, 24,
  10, -1,
   9, 25,
  11,  8,
  -1,  7,	// 25, 26

// B+

   0,  1,
   5, -1,
   6, 12,
  13, -1,
  19, 16,
  26, 20,
  -1, 21,

// the P5 connector on the Rev 2 boards:

  -1, -1,
  -1, -1,
  -1, -1,
  -1, -1,
  -1, -1,
  28, 29,
  30, 31,
  -1, -1,
  -1, -1,
  -1, -1,
  -1, -1,
} ;


int piBoard() {
  if (RaspberryPiModel<0) { //need to detect pi model
    int   model, rev, mem, maker, overVolted;
    piBoardId (&model, &rev, &mem, &maker, &overVolted);
  }
  return RaspberryPiModel<0 ? 0 : 1;
}

int GetMaxPin() {
  return PI_MODEL_5 == RaspberryPiModel ? 27 : 63;
}


#define RETURN_ON_MODEL5 if (PI_MODEL_5 == RaspberryPiModel) { if (wiringPiDebug) printf("Function not supported on Pi5\n");  return; }

int FailOnModel5() {
  if (PI_MODEL_5 == RaspberryPiModel) {
    return wiringPiFailure (WPI_ALMOST, "Function not supported on Raspberry Pi 5.\n"
  "  Unable to continue. Keep an eye of new versions at https://github.com/wiringpi/wiringpi\n") ;
  }
  return 0;
}

// gpioToGPFSEL:
//	Map a BCM_GPIO pin to it's Function Selection
//	control port. (GPFSEL 0-5)
//	Groups of 10 - 3 bits per Function - 30 bits per port

static uint8_t gpioToGPFSEL [] =
{
  0,0,0,0,0,0,0,0,0,0,
  1,1,1,1,1,1,1,1,1,1,
  2,2,2,2,2,2,2,2,2,2,
  3,3,3,3,3,3,3,3,3,3,
  4,4,4,4,4,4,4,4,4,4,
  5,5,5,5,5,5,5,5,5,5,
} ;


// gpioToShift
//	Define the shift up for the 3 bits per pin in each GPFSEL port

static uint8_t gpioToShift [] =
{
  0,3,6,9,12,15,18,21,24,27,
  0,3,6,9,12,15,18,21,24,27,
  0,3,6,9,12,15,18,21,24,27,
  0,3,6,9,12,15,18,21,24,27,
  0,3,6,9,12,15,18,21,24,27,
  0,3,6,9,12,15,18,21,24,27,
} ;


// gpioToGPSET:
//	(Word) offset to the GPIO Set registers for each GPIO pin

static uint8_t gpioToGPSET [] =
{
   7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
} ;

// gpioToGPCLR:
//	(Word) offset to the GPIO Clear registers for each GPIO pin

static uint8_t gpioToGPCLR [] =
{
  10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
  11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
} ;


// gpioToGPLEV:
//	(Word) offset to the GPIO Input level registers for each GPIO pin

static uint8_t gpioToGPLEV [] =
{
  13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,
  14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,
} ;


#ifdef notYetReady
// gpioToEDS
//	(Word) offset to the Event Detect Status

static uint8_t gpioToEDS [] =
{
  16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
  17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,
} ;

// gpioToREN
//	(Word) offset to the Rising edge ENable register

static uint8_t gpioToREN [] =
{
  19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,
  20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,
} ;

// gpioToFEN
//	(Word) offset to the Falling edgde ENable register

static uint8_t gpioToFEN [] =
{
  22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,
  23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,
} ;
#endif


// GPPUD:
//	GPIO Pin pull up/down register

#define	GPPUD	37

/* 2711 has a different mechanism for pin pull-up/down/enable  */
#define GPPUPPDN0                57        /* Pin pull-up/down for pins 15:0  */
#define GPPUPPDN1                58        /* Pin pull-up/down for pins 31:16 */
#define GPPUPPDN2                59        /* Pin pull-up/down for pins 47:32 */
#define GPPUPPDN3                60        /* Pin pull-up/down for pins 57:48 */

static volatile unsigned int piGpioPupOffset = 0 ;

// gpioToPUDCLK
//	(Word) offset to the Pull Up Down Clock regsiter

static uint8_t gpioToPUDCLK [] =
{
  38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,38,
  39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,39,
} ;


// gpioToPwmALT
//	the ALT value to put a GPIO pin into PWM mode

static uint8_t gpioToPwmALT [] =
{
          0,         0,         0,         0,         0,         0,         0,         0,	//  0 ->  7
          0,         0,         0,         0, FSEL_ALT0, FSEL_ALT0,         0,         0, 	//  8 -> 15
          0,         0, FSEL_ALT5, FSEL_ALT5,         0,         0,         0,         0, 	// 16 -> 23
          0,         0,         0,         0,         0,         0,         0,         0,	// 24 -> 31
          0,         0,         0,         0,         0,         0,         0,         0,	// 32 -> 39
  FSEL_ALT0, FSEL_ALT0,         0,         0,         0, FSEL_ALT0,         0,         0,	// 40 -> 47
          0,         0,         0,         0,         0,         0,         0,         0,	// 48 -> 55
          0,         0,         0,         0,         0,         0,         0,         0,	// 56 -> 63
} ;


// gpioToPwmPort
//	The port value to put a GPIO pin into PWM mode

static uint8_t gpioToPwmPort [] =
{
          0,         0,         0,         0,         0,         0,         0,         0,	//  0 ->  7
          0,         0,         0,         0, PWM0_DATA, PWM1_DATA,         0,         0, 	//  8 -> 15
          0,         0, PWM0_DATA, PWM1_DATA,         0,         0,         0,         0, 	// 16 -> 23
          0,         0,         0,         0,         0,         0,         0,         0,	// 24 -> 31
          0,         0,         0,         0,         0,         0,         0,         0,	// 32 -> 39
  PWM0_DATA, PWM1_DATA,         0,         0,         0, PWM1_DATA,         0,         0,	// 40 -> 47
          0,         0,         0,         0,         0,         0,         0,         0,	// 48 -> 55
          0,         0,         0,         0,         0,         0,         0,         0,	// 56 -> 63

} ;

// gpioToGpClkALT:
//	ALT value to put a GPIO pin into GP Clock mode.
//	On the Pi we can really only use BCM_GPIO_4 and BCM_GPIO_21
//	for clocks 0 and 1 respectively, however I'll include the full
//	list for completeness - maybe one day...

#define	GPIO_CLOCK_SOURCE	1

// gpioToGpClkALT0:

static uint8_t gpioToGpClkALT0 [] =
{
          0,         0,         0,         0, FSEL_ALT0, FSEL_ALT0, FSEL_ALT0,         0,	//  0 ->  7
          0,         0,         0,         0,         0,         0,         0,         0, 	//  8 -> 15
          0,         0,         0,         0, FSEL_ALT5, FSEL_ALT5,         0,         0, 	// 16 -> 23
          0,         0,         0,         0,         0,         0,         0,         0,	// 24 -> 31
  FSEL_ALT0,         0, FSEL_ALT0,         0,         0,         0,         0,         0,	// 32 -> 39
          0,         0, FSEL_ALT0, FSEL_ALT0, FSEL_ALT0,         0,         0,         0,	// 40 -> 47
          0,         0,         0,         0,         0,         0,         0,         0,	// 48 -> 55
          0,         0,         0,         0,         0,         0,         0,         0,	// 56 -> 63
} ;

// gpioToClk:
//	(word) Offsets to the clock Control and Divisor register

static uint8_t gpioToClkCon [] =
{
         -1,        -1,        -1,        -1,        28,        30,        32,        -1,	//  0 ->  7
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1, 	//  8 -> 15
         -1,        -1,        -1,        -1,        28,        30,        -1,        -1, 	// 16 -> 23
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 24 -> 31
         28,        -1,        28,        -1,        -1,        -1,        -1,        -1,	// 32 -> 39
         -1,        -1,        28,        30,        28,        -1,        -1,        -1,	// 40 -> 47
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 48 -> 55
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 56 -> 63
} ;

static uint8_t gpioToClkDiv [] =
{
         -1,        -1,        -1,        -1,        29,        31,        33,        -1,	//  0 ->  7
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1, 	//  8 -> 15
         -1,        -1,        -1,        -1,        29,        31,        -1,        -1, 	// 16 -> 23
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 24 -> 31
         29,        -1,        29,        -1,        -1,        -1,        -1,        -1,	// 32 -> 39
         -1,        -1,        29,        31,        29,        -1,        -1,        -1,	// 40 -> 47
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 48 -> 55
         -1,        -1,        -1,        -1,        -1,        -1,        -1,        -1,	// 56 -> 63
} ;


/*
 * Functions
 *********************************************************************************
 */


/*
 * wiringPiFailure:
 *	Fail. Or not.
 *********************************************************************************
 */

int wiringPiFailure (int fatal, const char *message, ...)
{
  va_list argp ;
  char buffer [1024] ;

  if (!fatal && wiringPiReturnCodes)
    return -1 ;

  va_start (argp, message) ;
    vsnprintf (buffer, 1023, message, argp) ;
  va_end (argp) ;

  fprintf (stderr, "%s", buffer) ;
  exit (EXIT_FAILURE) ;

  return 0 ;
}


/*
 * setupCheck
 *	Another sanity check because some users forget to call the setup
 *	function. Mosty because they need feeding C drip by drip )-:
 *********************************************************************************
 */

static void setupCheck (const char *fName)
{
  if (!wiringPiSetuped)
  {
    fprintf (stderr, "%s: You have not called one of the wiringPiSetup\n"
	"  functions, so I'm aborting your program before it crashes anyway.\n", fName) ;
    exit (EXIT_FAILURE) ;
  }
}

/*
 * gpioMemCheck:
 *	See if we're using the /dev/gpiomem interface, if-so then some operations
 *	can't be done and will crash the Pi.
 *********************************************************************************
 */

static void usingGpioMemCheck (const char *what)
{
  if (usingGpioMem)
  {
    fprintf (stderr, "%s: Unable to do this when using /dev/gpiomem. Try sudo?\n", what) ;
    exit (EXIT_FAILURE) ;
  }

}


void PrintSystemStdErr () {
  struct utsname sys_info;
  if (uname(&sys_info) == 0) {
    fprintf (stderr, "      WiringPi    : %d.%d\n", VERSION_MAJOR, VERSION_MINOR);
    fprintf (stderr, "      system name : %s\n", sys_info.sysname);
    //fprintf (stderr, "  node name   : %s\n", sys_info.nodename);
    fprintf (stderr, "      release     : %s\n", sys_info.release);
    fprintf (stderr, "      version     : %s\n", sys_info.version);
    fprintf (stderr, "      machine     : %s\n", sys_info.machine);
    if (strstr(sys_info.machine, "arm") == NULL && strstr(sys_info.machine, "aarch")==NULL) {
      fprintf (stderr, " -> This is not an ARM architecture; it cannot be a Raspberry Pi.\n") ;
    }
  }
}


void piFunctionOops (const char *function, const char* suggestion, const char* url)
{
  fprintf (stderr, "Oops: Function %s is not supported\n", function) ;
  PrintSystemStdErr();
  if (suggestion) {
    fprintf (stderr, " -> Please %s\n", suggestion) ;
  }
  if (url) {
    fprintf (stderr, " -> See info at %s\n", url) ;
  }
  fprintf (stderr, " -> Check at https://github.com/wiringpi/wiringpi/issues.\n\n") ;
  exit (EXIT_FAILURE) ;
}

void ReportDeviceError(const char *function, int pin, const char *mode, int ret) {
  fprintf(stderr, "wiringPi: ERROR: ioctl %s of %d (%s) returned error '%s' (%d)\n", function, pin, mode, strerror(errno), ret);
}


/*
 * piGpioLayout:
 *	Return a number representing the hardware revision of the board.
 *	This is not strictly the board revision but is used to check the
 *	layout of the GPIO connector - and there are 2 types that we are
 *	really interested in here. The very earliest Pi's and the
 *	ones that came after that which switched some pins ....
 *
 *	Revision 1 really means the early Model A and B's.
 *	Revision 2 is everything else - it covers the B, B+ and CM.
 *		... and the Pi 2 - which is a B+ ++  ...
 *		... and the Pi 0 - which is an A+ ...
 *
 *	The main difference between the revision 1 and 2 system that I use here
 *	is the mapping of the GPIO pins. From revision 2, the Pi Foundation changed
 *	3 GPIO pins on the (original) 26-way header - BCM_GPIO 22 was dropped and
 *	replaced with 27, and 0 + 1 - I2C bus 0 was changed to 2 + 3; I2C bus 1.
 *
 *	Additionally, here we set the piModel2 flag too. This is again, nothing to
 *	do with the actual model, but the major version numbers - the GPIO base
 *	hardware address changed at model 2 and above (not the Zero though)
 *
 *********************************************************************************
 */
 const char* revfile = "/proc/device-tree/system/linux,revision";

void piGpioLayoutOops (const char *why)
{
  fprintf (stderr, "Oops: Unable to determine Raspberry Pi board revision from %s and from /proc/cpuinfo\n", revfile) ;
  PrintSystemStdErr();
  fprintf (stderr, " -> %s\n", why) ;
  fprintf (stderr, " -> WiringPi is designed for Raspberry Pi and can only be used with a Raspberry Pi.\n\n") ;
  fprintf (stderr, " -> Check at https://github.com/wiringpi/wiringpi/issues.\n\n") ;
  exit (EXIT_FAILURE) ;
}

int piGpioLayout (void)
{
  piBoard();
  return RaspberryPiLayout;
}

/*
 * piBoardRev:
 *	Deprecated, but does the same as piGpioLayout
 *********************************************************************************
 */

int piBoardRev (void)
{
  return piGpioLayout () ;
}

const char* GetPiRevision(char* line, int linelength, unsigned int* revision) {

  const char* c = NULL;
  uint32_t Revision = 0;
  _Static_assert(sizeof(Revision)==4, "should be unsigend integer with 4 byte size");

	FILE* fp = fopen(revfile,"rb");
	if (!fp) {
    if (wiringPiDebug)
		  perror(revfile);
		return NULL; // revision file not found or no access
	}
	int result = fread(&Revision, sizeof(Revision), 1, fp);
	fclose(fp);
	if (result<1) {
    if (wiringPiDebug)
		  perror(revfile);
		return NULL; // read error
	}
	Revision = bswap_32(Revision);
	snprintf(line, linelength, "Revision\t: %04x", Revision);
  c =  &line[11];
  *revision = Revision;
  if (wiringPiDebug)
	  printf("GetPiRevision: Revision string: \"%s\" (%s) - 0x%x\n", line, c, *revision);
	return c;
}

/*
 * piBoardId:
 *	Return the real details of the board we have.
 *
 *	This is undocumented and really only intended for the GPIO command.
 *	Use at your own risk!
 *
 *	Seems there are some boards with 0000 in them (mistake in manufacture)
 *	So the distinction between boards that I can see is:
 *
 *		0000 - Error
 *		0001 - Not used
 *
 *	Original Pi boards:
 *		0002 - Model B,  Rev 1,   256MB, Egoman
 *		0003 - Model B,  Rev 1.1, 256MB, Egoman, Fuses/D14 removed.
 *
 *	Newer Pi's with remapped GPIO:
 *		0004 - Model B,  Rev 1.2, 256MB, Sony
 *		0005 - Model B,  Rev 1.2, 256MB, Egoman
 *		0006 - Model B,  Rev 1.2, 256MB, Egoman
 *
 *		0007 - Model A,  Rev 1.2, 256MB, Egoman
 *		0008 - Model A,  Rev 1.2, 256MB, Sony
 *		0009 - Model A,  Rev 1.2, 256MB, Egoman
 *
 *		000d - Model B,  Rev 1.2, 512MB, Egoman	(Red Pi, Blue Pi?)
 *		000e - Model B,  Rev 1.2, 512MB, Sony
 *		000f - Model B,  Rev 1.2, 512MB, Egoman
 *
 *		0010 - Model B+, Rev 1.2, 512MB, Sony
 *		0013 - Model B+  Rev 1.2, 512MB, Embest
 *		0016 - Model B+  Rev 1.2, 512MB, Sony
 *		0019 - Model B+  Rev 1.2, 512MB, Egoman
 *
 *		0011 - Pi CM,    Rev 1.1, 512MB, Sony
 *		0014 - Pi CM,    Rev 1.1, 512MB, Embest
 *		0017 - Pi CM,    Rev 1.1, 512MB, Sony
 *		001a - Pi CM,    Rev 1.1, 512MB, Egoman
 *
 *		0012 - Model A+  Rev 1.1, 256MB, Sony
 *		0015 - Model A+  Rev 1.1, 512MB, Embest
 *		0018 - Model A+  Rev 1.1, 256MB, Sony
 *		001b - Model A+  Rev 1.1, 256MB, Egoman
 *
 *	A small thorn is the olde style overvolting - that will add in
 *		1000000
 *
 *	The Pi compute module has an revision of 0011 or 0014 - since we only
 *	check the last digit, then it's 1, therefore it'll default to not 2 or
 *	3 for a	Rev 1, so will appear as a Rev 2. This is fine for the most part, but
 *	we'll properly detect the Compute Module later and adjust accordingly.
 *
 * And then things changed with the introduction of the v2...
 *
 * For Pi v2 and subsequent models - e.g. the Zero:
 *
 *   [USER:8] [NEW:1] [MEMSIZE:3] [MANUFACTURER:4] [PROCESSOR:4] [TYPE:8] [REV:4]
 *   NEW          23: will be 1 for the new scheme, 0 for the old scheme
 *   MEMSIZE      20: 0=256M 1=512M 2=1G
 *   MANUFACTURER 16: 0=SONY 1=EGOMAN 2=EMBEST
 *   PROCESSOR    12: 0=2835 1=2836
 *   TYPE         04: 0=MODELA 1=MODELB 2=MODELA+ 3=MODELB+ 4=Pi2 MODEL B 5=ALPHA 6=CM
 *   REV          00: 0=REV0 1=REV1 2=REV2
 *********************************************************************************
 */

void piBoardId (int *model, int *rev, int *mem, int *maker, int *warranty)
{
  const int maxlength = 120;
  char line [maxlength+1] ;
  const char *c ;
  unsigned int revision = 0x00 ;
  int bRev, bType, bProc, bMfg, bMem, bWarranty ;

  //piGpioLayoutOops ("this is only a test case");

  c = GetPiRevision(line, maxlength,  &revision); // device tree
  if (NULL==c) {
    c = GetPiRevisionLegacy(line, maxlength, &revision); // proc/cpuinfo
  }
  if (NULL==c) {
    piGpioLayoutOops ("GetPiRevision failed!") ;
  }

  if ((revision &  (1 << 23)) != 0)	// New style, not available for Raspberry Pi 1B/A, CM
  {
    if (wiringPiDebug)
      printf ("piBoardId: New Way: revision is: %08X\n", revision) ;

    bRev      = (revision & (0x0F <<  0)) >>  0 ;
    bType     = (revision & (0xFF <<  4)) >>  4 ;
    bProc     = (revision & (0x0F << 12)) >> 12 ;	// Not used for now.
    bMfg      = (revision & (0x0F << 16)) >> 16 ;
    bMem      = (revision & (0x07 << 20)) >> 20 ;
    bWarranty = (revision & (0x03 << 24)) != 0 ;

    // Ref: https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-revision-codes
    *model    = bType ;
    *rev      = bRev ;
    *mem      = bMem ;
    *maker    = bMfg  ;
    *warranty = bWarranty ;
    RaspberryPiLayout = GPIO_LAYOUT_DEFAULT ; //default

    if (wiringPiDebug)
      printf ("piBoardId: rev: %d, type: %d, proc: %d, mfg: %d, mem: %d, warranty: %d\n",
		bRev, bType, bProc, bMfg, bMem, bWarranty) ;
  }
  else					// Old way
  {
    if (wiringPiDebug)
      printf ("piBoardId: Old Way: revision is: %s\n", c) ;

    if (!isdigit (*c))
      piGpioLayoutOops ("Bogus \"Revision\" line (no digit at start of revision)") ;

// Make sure its long enough

    if (strlen (c) < 4)
      piGpioLayoutOops ("Bogus \"Revision\" line (not long enough)") ;

// If longer than 4, we'll assume it's been overvolted

    *warranty = strlen (c) > 4 ;

// Extract last 4 characters:

    c = c + strlen (c) - 4 ;

// Fill out the replys as appropriate
    RaspberryPiLayout = GPIO_LAYOUT_DEFAULT ; //default
    /**/ if (strcmp (c, "0002") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1   ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; RaspberryPiLayout = GPIO_LAYOUT_PI1_REV1; }
    else if (strcmp (c, "0003") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_1 ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; RaspberryPiLayout = GPIO_LAYOUT_PI1_REV1; }

    else if (strcmp (c, "0004") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_2 ; *mem = 0 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "0005") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_2 ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; }
    else if (strcmp (c, "0006") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_2 ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; }

    else if (strcmp (c, "0007") == 0) { *model = PI_MODEL_A  ; *rev = PI_VERSION_1_2 ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; }
    else if (strcmp (c, "0008") == 0) { *model = PI_MODEL_A  ; *rev = PI_VERSION_1_2 ; *mem = 0 ; *maker = PI_MAKER_SONY ;  ; }
    else if (strcmp (c, "0009") == 0) { *model = PI_MODEL_A  ; *rev = PI_VERSION_1_2 ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; }

    else if (strcmp (c, "000d") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_EGOMAN  ; }
    else if (strcmp (c, "000e") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "000f") == 0) { *model = PI_MODEL_B  ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_EGOMAN  ; }

    else if (strcmp (c, "0010") == 0) { *model = PI_MODEL_BP ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "0013") == 0) { *model = PI_MODEL_BP ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_EMBEST  ; }
    else if (strcmp (c, "0016") == 0) { *model = PI_MODEL_BP ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "0019") == 0) { *model = PI_MODEL_BP ; *rev = PI_VERSION_1_2 ; *mem = 1 ; *maker = PI_MAKER_EGOMAN  ; }

    else if (strcmp (c, "0011") == 0) { *model = PI_MODEL_CM ; *rev = PI_VERSION_1_1 ; *mem = 1 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "0014") == 0) { *model = PI_MODEL_CM ; *rev = PI_VERSION_1_1 ; *mem = 1 ; *maker = PI_MAKER_EMBEST  ; }
    else if (strcmp (c, "0017") == 0) { *model = PI_MODEL_CM ; *rev = PI_VERSION_1_1 ; *mem = 1 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "001a") == 0) { *model = PI_MODEL_CM ; *rev = PI_VERSION_1_1 ; *mem = 1 ; *maker = PI_MAKER_EGOMAN  ; }

    else if (strcmp (c, "0012") == 0) { *model = PI_MODEL_AP ; *rev = PI_VERSION_1_1 ; *mem = 0 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "0015") == 0) { *model = PI_MODEL_AP ; *rev = PI_VERSION_1_1 ; *mem = 1 ; *maker = PI_MAKER_EMBEST  ; }
    else if (strcmp (c, "0018") == 0) { *model = PI_MODEL_AP ; *rev = PI_VERSION_1_1 ; *mem = 0 ; *maker = PI_MAKER_SONY    ; }
    else if (strcmp (c, "001b") == 0) { *model = PI_MODEL_AP ; *rev = PI_VERSION_1_1 ; *mem = 0 ; *maker = PI_MAKER_EGOMAN  ; }

    else                              { *model = 0           ; *rev = 0              ; *mem =   0 ; *maker = 0 ;               }
  }

  RaspberryPiModel = *model;

  switch (RaspberryPiModel){
    case PI_MODEL_A:
    case PI_MODEL_B:
    case PI_MODEL_AP:
    case PI_MODEL_BP:
    case PI_ALPHA:
    case PI_MODEL_CM:
    case PI_MODEL_ZERO:
    case PI_MODEL_ZERO_W:
      piGpioBase = GPIO_PERI_BASE_OLD ;
      piGpioPupOffset = GPPUD ;
      break ;

    case PI_MODEL_4B:
    case PI_MODEL_400:
    case PI_MODEL_CM4:
      piGpioBase = GPIO_PERI_BASE_2711 ;
      piGpioPupOffset = GPPUPPDN0 ;
      break ;

    case PI_MODEL_5:
      piGpioBase = GPIO_PERI_BASE_2712 ;
      piGpioPupOffset = 0 ;
      break ;

    default:
      piGpioBase = GPIO_PERI_BASE_2835 ;
      piGpioPupOffset = GPPUD ;
      break ;
  }
}



/*
 * wpiPinToGpio:
 *	Translate a wiringPi Pin number to native GPIO pin number.
 *	Provided for external support.
 *********************************************************************************
 */

int wpiPinToGpio (int wpiPin)
{
  return pinToGpio [wpiPin & 63] ;
}


/*
 * physPinToGpio:
 *	Translate a physical Pin number to native GPIO pin number.
 *	Provided for external support.
 *********************************************************************************
 */

int physPinToGpio (int physPin)
{
  return physToGpio [physPin & 63] ;
}


/*
 * setPadDrive:
 *	Set the PAD driver value
 *********************************************************************************
 */
void setPadDrivePin (int pin, int value) {
  if (PI_MODEL_5 != RaspberryPiModel) return;
  if (pin < 0 || pin > GetMaxPin()) return ;

  uint32_t wrVal;
  value = value & 3; // 0-3 supported
  wrVal = (value << 4); //Drive strength 0-3
  pads[1+pin] = (pads[1+pin] & RP1_INV_PAD_DRIVE_MASK) | wrVal;
  if (wiringPiDebug) {
    printf ("setPadDrivePin: pin: %d, value: %d (%08X)\n", pin, value, pads[1+pin]) ;
  }
}


void setPadDrive (int group, int value)
{
  uint32_t wrVal, rdVal;

  if ((wiringPiMode == WPI_MODE_PINS) || (wiringPiMode == WPI_MODE_PHYS) || (wiringPiMode == WPI_MODE_GPIO))
  {
    value = value & 7; // 0-7 supported
    if (PI_MODEL_5 == RaspberryPiModel) {
      if (-1==group) {
        printf ("Pad register:\n");
        for (int pin=0, maxpin=GetMaxPin(); pin<=maxpin; ++pin) {
          unsigned int drive = (pads[1+pin] & RP1_PAD_DRIVE_MASK)>>4;
          printf ("  Pin %2d: 0x%08X drive: 0x%d = %2dmA\n", pin, pads[1+pin], drive, 0==drive ? 2 : drive*4) ;
        }
      }
      if (group !=0) { // only GPIO range @RP1
        return ;
      }
      switch(value) {
        default:
                /* bcm*/                 // RP1
        case 0: /* 2mA*/ value=0; break; // 2mA
        case 1: /* 4mA*/
        case 2: /* 6mA*/ value=1; break; // 4mA
        case 3: /* 8mA*/
        case 4: /*10mA*/ value=2; break; // 8mA
        case 5: /*12mA*/
        case 6: /*14mA*/
        case 7: /*16mA*/ value=3; break; //12mA
      }
      wrVal = (value << 4); //Drive strength 0-3
      //set for all pins even when it's avaiable for each pin separately
      for (int pin=0, maxpin=GetMaxPin(); pin<=maxpin; ++pin) {
        pads[1+pin] = (pads[1+pin] & RP1_INV_PAD_DRIVE_MASK) | wrVal;
      }
      rdVal = pads[1+17]; // only pin 17 readback, for logging
    } else {
      if (-1==group) {
        printf ("Pad register: Group 0: 0x%08X, Group 1: 0x%08X, Group 2: 0x%08X\n", *(pads + 0 + 11), *(pads + 1 + 11), *(pads + 2 + 11)) ;
      }

      if ((group < 0) || (group > 2))
        return ;

      wrVal = BCM_PASSWORD | 0x18 | value; //Drive strength 0-7
      *(pads + group + 11) = wrVal ;
      rdVal = *(pads + group + 11);
    }

    if (wiringPiDebug)
    {
      printf ("setPadDrive: Group: %d, value: %d (%08X)\n", group, value, wrVal) ;
      printf ("Read : %08X\n", rdVal) ;
    }
  }
}


/*
 * getAlt:
 *	Returns the ALT bits for a given port. Only really of-use
 *	for the gpio readall command (I think)
 *********************************************************************************
 */

int getAlt (int pin)
{
  int fSel, shift, alt ;

  pin &= 63 ;

  /**/ if (wiringPiMode == WPI_MODE_PINS)
    pin = pinToGpio [pin] ;
  else if (wiringPiMode == WPI_MODE_PHYS)
    pin = physToGpio [pin] ;
  else if (wiringPiMode != WPI_MODE_GPIO)
    return 0 ;

  if (PI_MODEL_5 == RaspberryPiModel) {
    alt = (gpio[2*pin+1] & RP1_FSEL_NONE_HW); //0-4  function

  /*
  BCM:
  000b = GPIO Pin 9 is an input
  001b = GPIO Pin 9 is an output
  100b = GPIO Pin 9 takes alternate function 0
  101b = GPIO Pin 9 takes alternate function 1
  110b = GPIO Pin 9 takes alternate function 2
  111b = GPIO Pin 9 takes alternate function 3
  011b = GPIO Pin 9 takes alternate function 4
  010b = GPIO Pin 9 takes alternate function 5
  RP1:
   8 = alternate function 6
   9 = alternate function 7
  10 = alternate function 8
  11 = alternate function 9
  */
    switch(alt) {
      case 0: return 4;
      case 1: return 5;
      case 2: return 6;
      case 3: return 7;
      case 4: return 3;
      case RP1_FSEL_GPIO: {
          unsigned int outputmask = gpio[2*pin] & 0x3000;   //Bit13-OETOPAD + Bit12-OEFROMPERI
          return (outputmask==0x3000) ? 1 : 0; //1=OUT 0=IN
        }
      case 6: return 8;
      case 7: return 9;
      case 8: return 10;
      case 9: return 11;
      default:return alt;
    }

  } else {
    fSel    = gpioToGPFSEL [pin] ;
    shift   = gpioToShift  [pin] ;

    alt = (*(gpio + fSel) >> shift) & 7 ;
  }
  return alt ;
}


enum WPIPinAlt getPinModeAlt(int pin) {
  return (enum WPIPinAlt) getAlt(pin);
}


/*
 * pwmSetMode:
 *	Select the native "balanced" mode, or standard mark:space mode
 *********************************************************************************
 */

void pwmSetMode (int mode)
{
  if ((wiringPiMode == WPI_MODE_PINS) || (wiringPiMode == WPI_MODE_PHYS) || (wiringPiMode == WPI_MODE_GPIO))
  {
    FailOnModel5();
    if (mode == PWM_MODE_MS)
      *(pwm + PWM_CONTROL) = PWM0_ENABLE | PWM1_ENABLE | PWM0_MS_MODE | PWM1_MS_MODE ;
    else
      *(pwm + PWM_CONTROL) = PWM0_ENABLE | PWM1_ENABLE ;
  }
}


/*
 * pwmSetRange:
 *	Set the PWM range register. We set both range registers to the same
 *	value. If you want different in your own code, then write your own.
 *********************************************************************************
 */

void pwmSetRange (unsigned int range)
{
  FailOnModel5();
  if ((wiringPiMode == WPI_MODE_PINS) || (wiringPiMode == WPI_MODE_PHYS) || (wiringPiMode == WPI_MODE_GPIO))
  {
    *(pwm + PWM0_RANGE) = range ; delayMicroseconds (10) ;
    *(pwm + PWM1_RANGE) = range ; delayMicroseconds (10) ;
  }
}


/*
 * pwmSetClock:
 *	Set/Change the PWM clock. Originally my code, but changed
 *	(for the better!) by Chris Hall, <chris@kchall.plus.com>
 *	after further study of the manual and testing with a 'scope
 *********************************************************************************
 */

void pwmSetClock (int divisor)
{
  uint32_t pwm_control ;

  FailOnModel5();
  if (piGpioBase == GPIO_PERI_BASE_2711)
  {
    divisor = 540*divisor/192;
  }
  divisor &= 4095 ;

  if ((wiringPiMode == WPI_MODE_PINS) || (wiringPiMode == WPI_MODE_PHYS) || (wiringPiMode == WPI_MODE_GPIO))
  {
    if (wiringPiDebug)
      printf ("Setting to: %d. Current: 0x%08X\n", divisor, *(clk + PWMCLK_DIV)) ;

    pwm_control = *(pwm + PWM_CONTROL) ;		// preserve PWM_CONTROL

// We need to stop PWM prior to stopping PWM clock in MS mode otherwise BUSY
// stays high.

    *(pwm + PWM_CONTROL) = 0 ;				// Stop PWM

// Stop PWM clock before changing divisor. The delay after this does need to
// this big (95uS occasionally fails, 100uS OK), it's almost as though the BUSY
// flag is not working properly in balanced mode. Without the delay when DIV is
// adjusted the clock sometimes switches to very slow, once slow further DIV
// adjustments do nothing and it's difficult to get out of this mode.

    *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x01 ;	// Stop PWM Clock
      delayMicroseconds (110) ;			// prevents clock going sloooow

    while ((*(clk + PWMCLK_CNTL) & 0x80) != 0)	// Wait for clock to be !BUSY
      delayMicroseconds (1) ;

    *(clk + PWMCLK_DIV)  = BCM_PASSWORD | (divisor << 12) ;

    *(clk + PWMCLK_CNTL) = BCM_PASSWORD | 0x11 ;	// Start PWM clock
    *(pwm + PWM_CONTROL) = pwm_control ;		// restore PWM_CONTROL

    if (wiringPiDebug)
      printf ("Set     to: %d. Now    : 0x%08X\n", divisor, *(clk + PWMCLK_DIV)) ;
  }
}


/*
 * gpioClockSet:
 *	Set the frequency on a GPIO clock pin
 *********************************************************************************
 */

void gpioClockSet (int pin, int freq)
{
  int divi, divr, divf ;

  FailOnModel5();
  pin &= 63 ;

  /**/ if (wiringPiMode == WPI_MODE_PINS)
    pin = pinToGpio [pin] ;
  else if (wiringPiMode == WPI_MODE_PHYS)
    pin = physToGpio [pin] ;
  else if (wiringPiMode != WPI_MODE_GPIO)
    return ;

  divi = 19200000 / freq ;
  divr = 19200000 % freq ;
  divf = (int)((double)divr * 4096.0 / 19200000.0) ;

  if (divi > 4095)
    divi = 4095 ;

  *(clk + gpioToClkCon [pin]) = BCM_PASSWORD | GPIO_CLOCK_SOURCE ;		// Stop GPIO Clock
  while ((*(clk + gpioToClkCon [pin]) & 0x80) != 0)				// ... and wait
    ;

  *(clk + gpioToClkDiv [pin]) = BCM_PASSWORD | (divi << 12) | divf ;		// Set dividers
  *(clk + gpioToClkCon [pin]) = BCM_PASSWORD | 0x10 | GPIO_CLOCK_SOURCE ;	// Start Clock
}


/*
 * wiringPiFindNode:
 *      Locate our device node
 *********************************************************************************
 */

struct wiringPiNodeStruct *wiringPiFindNode (int pin)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  while (node != NULL)
    if ((pin >= node->pinBase) && (pin <= node->pinMax))
      return node ;
    else
      node = node->next ;

  return NULL ;
}


/*
 * wiringPiNewNode:
 *	Create a new GPIO node into the wiringPi handling system
 *********************************************************************************
 */

static         void pinModeDummy             (UNU struct wiringPiNodeStruct *node, UNU int pin, UNU int mode)  { return ; }
static         void pullUpDnControlDummy     (UNU struct wiringPiNodeStruct *node, UNU int pin, UNU int pud)   { return ; }
//static unsigned int digitalRead8Dummy        (UNU struct wiringPiNodeStruct *node, UNU int UNU pin)            { return 0 ; }
//static         void digitalWrite8Dummy       (UNU struct wiringPiNodeStruct *node, UNU int pin, UNU int value) { return ; }
static          int digitalReadDummy         (UNU struct wiringPiNodeStruct *node, UNU int UNU pin)            { return LOW ; }
static         void digitalWriteDummy        (UNU struct wiringPiNodeStruct *node, UNU int pin, UNU int value) { return ; }
static         void pwmWriteDummy            (UNU struct wiringPiNodeStruct *node, UNU int pin, UNU int value) { return ; }
static          int analogReadDummy          (UNU struct wiringPiNodeStruct *node, UNU int pin)            { return 0 ; }
static         void analogWriteDummy         (UNU struct wiringPiNodeStruct *node, UNU int pin, UNU int value) { return ; }

struct wiringPiNodeStruct *wiringPiNewNode (int pinBase, int numPins)
{
  int    pin ;
  struct wiringPiNodeStruct *node ;

// Minimum pin base is 64

  if (pinBase < 64)
    (void)wiringPiFailure (WPI_FATAL, "wiringPiNewNode: pinBase of %d is < 64\n", pinBase) ;

// Check all pins in-case there is overlap:

  for (pin = pinBase ; pin < (pinBase + numPins) ; ++pin)
    if (wiringPiFindNode (pin) != NULL)
      (void)wiringPiFailure (WPI_FATAL, "wiringPiNewNode: Pin %d overlaps with existing definition\n", pin) ;

  node = (struct wiringPiNodeStruct *)calloc (sizeof (struct wiringPiNodeStruct), 1) ;	// calloc zeros
  if (node == NULL)
    (void)wiringPiFailure (WPI_FATAL, "wiringPiNewNode: Unable to allocate memory: %s\n", strerror (errno)) ;

  node->pinBase          = pinBase ;
  node->pinMax           = pinBase + numPins - 1 ;
  node->pinMode          = pinModeDummy ;
  node->pullUpDnControl  = pullUpDnControlDummy ;
  node->digitalRead      = digitalReadDummy ;
//node->digitalRead8     = digitalRead8Dummy ;
  node->digitalWrite     = digitalWriteDummy ;
//node->digitalWrite8    = digitalWrite8Dummy ;
  node->pwmWrite         = pwmWriteDummy ;
  node->analogRead       = analogReadDummy ;
  node->analogWrite      = analogWriteDummy ;
  node->next             = wiringPiNodes ;
  wiringPiNodes          = node ;

  return node ;
}


#ifdef notYetReady
/*
 * pinED01:
 * pinED10:
 *	Enables edge-detect mode on a pin - from a 0 to a 1 or 1 to 0
 *	Pin must already be in input mode with appropriate pull up/downs set.
 *********************************************************************************
 */

void pinEnableED01Pi (int pin)
{
  pin = pinToGpio [pin & 63] ;
}
#endif


const char DEV_GPIO_PI[] ="/dev/gpiochip0";
const char DEV_GPIO_PI5[]="/dev/gpiochip4";

int wiringPiGpioDeviceGetFd() {
  if (chipFd<0) {
    piBoard();
    const char* gpiochip = PI_MODEL_5 == RaspberryPiModel ? DEV_GPIO_PI5 : DEV_GPIO_PI;
    chipFd = open(gpiochip, O_RDWR);
    if (chipFd < 0) {
      fprintf(stderr, "wiringPi: ERROR: %s open ret=%d\n", gpiochip, chipFd);
    } else if (wiringPiDebug) {
      printf ("wiringPi: Open chip %s succeded, fd=%d\n", gpiochip, chipFd) ;
    }
  }
  return chipFd;
}

void releaseLine(int pin) {

  if (wiringPiDebug)
    printf ("releaseLine: pin:%d\n", pin) ;
  lineFlags[pin] = 0;
  close(lineFds[pin]);
  lineFds[pin] = -1;
}

int requestLine(int pin, unsigned int lineRequestFlags) {
  struct gpiohandle_request rq;

   if (lineFds[pin]>=0) {
    if (lineRequestFlags == lineFlags[pin]) {
      //already requested
      return lineFds[pin];
    } else {
      //different request -> rerequest
      releaseLine(pin);
    }
  }

  //requested line
  if (wiringPiGpioDeviceGetFd()<0) {
    return -1;  // error
  }
  rq.lineoffsets[0] = pin;
  rq.lines = 1;
  rq.flags = lineRequestFlags;
  int ret = ioctl(chipFd, GPIO_GET_LINEHANDLE_IOCTL, &rq);
  if (ret || rq.fd<0) {
    ReportDeviceError("get line handle", pin, "RequestLine", ret);
    return -1;  // error
  }

  lineFlags[pin] = lineRequestFlags;
  lineFds[pin] = rq.fd;
  if (wiringPiDebug)
    printf ("requestLine succeeded: pin:%d, flags: %u, fd :%d\n", pin, lineRequestFlags, lineFds[pin]) ;
  return lineFds[pin];
}

/*
 *********************************************************************************
 * Core Functions
 *********************************************************************************
 */

/*
 * pinModeAlt:
 *	This is an un-documented special to let you set any pin to any mode
 *********************************************************************************
 */

void pinModeAlt (int pin, int mode)
{
  int fSel, shift ;

  RETURN_ON_MODEL5
  setupCheck ("pinModeAlt") ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-board pin
  {
    /**/ if (wiringPiMode == WPI_MODE_PINS)
      pin = pinToGpio [pin] ;
    else if (wiringPiMode == WPI_MODE_PHYS)
      pin = physToGpio [pin] ;
    else if (wiringPiMode != WPI_MODE_GPIO)
      return ;

    if (PI_MODEL_5 == RaspberryPiModel) {

      //confusion! diffrent to to BCM!  this is taking directly the value for the register
    /*
    "alt0" 0b100
    "alt1" 0b101
    "alt2" 0b110
    "alt3" 0b111
    "alt4" 0b011
    "alt5" 0b010
    */
      gpio[2*pin+1] = (mode & RP1_FSEL_NONE_HW) | RP1_DEBOUNCE_DEFAULT; //0-4  function, 5-11 debounce time
    } else {
      fSel  = gpioToGPFSEL [pin] ;
      shift = gpioToShift  [pin] ;

      *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | ((mode & 0x7) << shift) ;
    }

  }
}


/*
 * pinMode:
 *	Sets the mode of a pin to be input, output or PWM output
 *********************************************************************************
 */

//Default: rp1_set_pad(pin, 0, 1, 0, 1, 1, 1, 0);
void rp1_set_pad(int pin, int slewfast, int schmitt, int pulldown, int pullup, int drive, int inputenable, int outputdisable) {

  pads[1+pin] = (slewfast != 0) | ((schmitt != 0) << 1) | ((pulldown != 0) << 2) | ((pullup != 0) << 3) | ((drive & 0x3) << 4) | ((inputenable != 0) << 6) | ((outputdisable != 0) << 7);
}

void pinModeFlagsDevice (int pin, int mode, unsigned int flags) {
  unsigned int lflag = flags;
  if (wiringPiDebug)
      printf ("pinModeFlagsDevice: pin:%d mode:%d, flags: %u\n", pin, mode, flags) ;

  lflag &= ~(GPIOHANDLE_REQUEST_INPUT | GPIOHANDLE_REQUEST_OUTPUT);
  switch(mode) {
    default:
      fprintf(stderr, "pinMode: invalid mode request (only input und output supported)\n");
      return;
    case INPUT:
      lflag |= GPIOHANDLE_REQUEST_INPUT;
      break;
    case OUTPUT:
      lflag |= GPIOHANDLE_REQUEST_OUTPUT;
      break;
    case PM_OFF:
      pinModeFlagsDevice(pin, INPUT, 0);
      releaseLine(pin);
      return;
  }

  requestLine(pin, lflag);
}

void pinModeDevice (int pin, int mode) {
  pinModeFlagsDevice(pin, mode, lineFlags[pin]);
}

void pinMode (int pin, int mode)
{
  int    fSel, shift, alt ;
  struct wiringPiNodeStruct *node = wiringPiNodes ;
  int origPin = pin ;

  if (wiringPiDebug)
    printf ("pinMode: pin:%d mode:%d\n", pin, mode) ;

  setupCheck ("pinMode") ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-board pin
  {
    switch(wiringPiMode) {
      default: //WPI_MODE_GPIO_SYS
        fprintf(stderr, "pinMode: invalid mode\n");
        return;
      case WPI_MODE_PINS:
        pin = pinToGpio [pin];
        break;
      case WPI_MODE_PHYS:
        pin = physToGpio [pin];
        break;
      case WPI_MODE_GPIO_DEVICE_BCM:
        pinModeDevice(pin, mode);
        return;
      case WPI_MODE_GPIO_DEVICE_WPI:
        pinModeDevice(pinToGpio[pin], mode);
        return;
      case WPI_MODE_GPIO_DEVICE_PHYS:
        pinModeDevice(physToGpio[pin], mode);
        return;
      case WPI_MODE_GPIO:
        break;
    }

    if (wiringPiDebug)
      printf ("pinMode: bcm pin:%d mode:%d\n", pin, mode) ;

    softPwmStop  (origPin) ;
    softToneStop (origPin) ;

    fSel    = gpioToGPFSEL [pin] ;
    shift   = gpioToShift  [pin] ;

    if (INPUT==mode  || PM_OFF==mode) {
      if (PI_MODEL_5 == RaspberryPiModel) {
        if (INPUT==mode) {
          pads[1+pin] = (pin<=8) ? RP1_PAD_DEFAULT_0TO8 : RP1_PAD_DEFAULT_FROM9;
          gpio[2*pin+1] = RP1_FSEL_GPIO | RP1_DEBOUNCE_DEFAULT; // GPIO
          rio[RP1_RIO_OE + RP1_CLR_OFFSET] = 1<<pin;            // Input
        } else  { //PM_OFF
          pads[1+pin] = (pin<=8) ? RP1_PAD_IC_DEFAULT_0TO8 : RP1_PAD_IC_DEFAULT_FROM9;
          gpio[2*pin+1] = RP1_IRQRESET | RP1_FSEL_NONE_HW | RP1_DEBOUNCE_DEFAULT; // default but with irq reset
        }
      } else {
        *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) ; // Sets bits to zero = input
      }
    } else if (mode == OUTPUT) {
      if (PI_MODEL_5 == RaspberryPiModel) {
        pads[1+pin] = (pin<=8) ? RP1_PAD_DEFAULT_0TO8 : RP1_PAD_DEFAULT_FROM9;
        gpio[2*pin+1] = RP1_FSEL_GPIO | RP1_DEBOUNCE_DEFAULT; // GPIO
        rio[RP1_RIO_OE + RP1_SET_OFFSET] = 1<<pin;            // Output
      } else {
        *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (1 << shift) ;
      }
    } else if (mode == SOFT_PWM_OUTPUT) {
      softPwmCreate (origPin, 0, 100) ;
    } else if (mode == SOFT_TONE_OUTPUT) {
      softToneCreate (origPin) ;
    } else if (mode == PWM_TONE_OUTPUT)
    {
      pinMode (origPin, PWM_OUTPUT) ;	// Call myself to enable PWM mode
      pwmSetMode (PWM_MODE_MS) ;
    }
    else if (mode == PWM_OUTPUT)
    {
      RETURN_ON_MODEL5
      if ((alt = gpioToPwmALT [pin]) == 0)	// Not a hardware capable PWM pin
	      return ;

      usingGpioMemCheck ("pinMode PWM") ;

// Set pin to PWM mode

      *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
      delayMicroseconds (110) ;		// See comments in pwmSetClockWPi

      pwmSetMode  (PWM_MODE_BAL) ;	// Pi default mode
      pwmSetRange (1024) ;		// Default range of 1024
      pwmSetClock (32) ;		// 19.2 / 32 = 600KHz - Also starts the PWM
    }
    else if (mode == GPIO_CLOCK)
    {
      RETURN_ON_MODEL5
      if ((alt = gpioToGpClkALT0 [pin]) == 0)	// Not a GPIO_CLOCK pin
	      return ;

      usingGpioMemCheck ("pinMode CLOCK") ;

// Set pin to GPIO_CLOCK mode and set the clock frequency to 100KHz

      *(gpio + fSel) = (*(gpio + fSel) & ~(7 << shift)) | (alt << shift) ;
      delayMicroseconds (110) ;
      gpioClockSet      (pin, 100000) ;
    }
  }
  else
  {
    if ((node = wiringPiFindNode (pin)) != NULL)
      node->pinMode (node, pin, mode) ;
    return ;
  }
}


/*
 * pullUpDownCtrl:
 *	Control the internal pull-up/down resistors on a GPIO pin.
 *********************************************************************************
 */
void pullUpDnControlDevice (int pin, int pud) {
  unsigned int flag = lineFlags[pin];
  unsigned int biasflags = GPIOHANDLE_REQUEST_BIAS_DISABLE | GPIOHANDLE_REQUEST_BIAS_PULL_UP | GPIOHANDLE_REQUEST_BIAS_PULL_DOWN;

  flag &= ~biasflags;
  switch (pud){
    case PUD_OFF:  flag |= GPIOHANDLE_REQUEST_BIAS_DISABLE;   break;
    case PUD_UP:   flag |= GPIOHANDLE_REQUEST_BIAS_PULL_UP;   break;
    case PUD_DOWN: flag |= GPIOHANDLE_REQUEST_BIAS_PULL_DOWN; break;
    default: return ; /* An illegal value */
  }

  // reset input/output
  if (lineFlags[pin] & GPIOHANDLE_REQUEST_OUTPUT) {
    pinModeFlagsDevice (pin, OUTPUT, flag);
  } else if(lineFlags[pin] & GPIOHANDLE_REQUEST_INPUT) {
    pinModeFlagsDevice (pin, INPUT, flag);
  } else {
    lineFlags[pin] = flag; // only store for later
  }
}


void pullUpDnControl (int pin, int pud)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  setupCheck ("pullUpDnControl") ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-Board Pin
  {
    switch(wiringPiMode) {
      default: //WPI_MODE_GPIO_SYS
        fprintf(stderr, "pinMode: invalid mode\n");
        return;
      case WPI_MODE_PINS:
        pin = pinToGpio [pin];
        break;
      case WPI_MODE_PHYS:
        pin = physToGpio [pin];
        break;
      case WPI_MODE_GPIO_DEVICE_BCM:
        return pullUpDnControlDevice(pin, pud);
      case WPI_MODE_GPIO_DEVICE_WPI:
        return pullUpDnControlDevice(pinToGpio[pin], pud);
      case WPI_MODE_GPIO_DEVICE_PHYS:
        return pullUpDnControlDevice(physToGpio[pin], pud);
      case WPI_MODE_GPIO:
        break;
    }

    if (PI_MODEL_5 == RaspberryPiModel) {
      unsigned int pullbits = pads[1+pin] & RP1_INV_PUD_MASK; // remove bits
      switch (pud){
        case PUD_OFF:  pads[1+pin] = pullbits;                break;
        case PUD_UP:   pads[1+pin] = pullbits | RP1_PUD_UP;   break;
        case PUD_DOWN: pads[1+pin] = pullbits | RP1_PUD_DOWN; break;
        default: return ; /* An illegal value */
      }
    } else {
      if (piGpioPupOffset == GPPUPPDN0)
      {
        // Pi 4B pull up/down method
        int pullreg = GPPUPPDN0 + (pin>>4);
        int pullshift = (pin & 0xf) << 1;
        unsigned int pullbits;
        unsigned int pull;

        switch (pud) {
         case PUD_OFF:  pull = 0; break;
         case PUD_UP:   pull = 1; break;
         case PUD_DOWN: pull = 2; break;
         default: return ; /* An illegal value */
        }

        pullbits = *(gpio + pullreg);
        pullbits &= ~(3 << pullshift);
        pullbits |= (pull << pullshift);
        *(gpio + pullreg) = pullbits;
      }
      else
      {
        // legacy pull up/down method
        *(gpio + GPPUD)              = pud & 3 ;		delayMicroseconds (5) ;
        *(gpio + gpioToPUDCLK [pin]) = 1 << (pin & 31) ;	delayMicroseconds (5) ;

        *(gpio + GPPUD)              = 0 ;			delayMicroseconds (5) ;
        *(gpio + gpioToPUDCLK [pin]) = 0 ;			delayMicroseconds (5) ;
      }
    }
  }
  else						// Extension module
  {
    if ((node = wiringPiFindNode (pin)) != NULL)
      node->pullUpDnControl (node, pin, pud) ;
    return ;
  }
}




/*
 * digitalRead:
 *	Read the value of a given Pin, returning HIGH or LOW
 *********************************************************************************
 */

int digitalReadDevice (int pin) {   // INPUT and OUTPUT should work

   if (lineFds[pin]<0) {
    // line not requested - auto request on first read as input
    pinModeDevice(pin, INPUT);
  }
  if (lineFds[pin]>=0) {
    struct gpiohandle_data data;
    int ret = ioctl(lineFds[pin], GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);
    if (ret) {
      ReportDeviceError("get line values", pin, "digitalRead", ret);
      return LOW;  // error
    }
    return data.values[0];
  }
  return LOW;  // error , need to request line before
}


int digitalRead (int pin)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-Board Pin
  {
    switch(wiringPiMode) {
      default: //WPI_MODE_GPIO_SYS
        fprintf(stderr, "digitalRead: invalid mode\n");
        return LOW;
      case WPI_MODE_PINS:
        pin = pinToGpio [pin];
        break;
      case WPI_MODE_PHYS:
        pin = physToGpio [pin];
        break;
      case WPI_MODE_GPIO_DEVICE_BCM:
        return digitalReadDevice(pin);
      case WPI_MODE_GPIO_DEVICE_WPI:
        return digitalReadDevice(pinToGpio[pin]);
      case WPI_MODE_GPIO_DEVICE_PHYS:
        return digitalReadDevice(physToGpio[pin]);
      case WPI_MODE_GPIO:
        break;
    }

    if (PI_MODEL_5 == RaspberryPiModel) {
      switch(gpio[2*pin] & RP1_STATUS_LEVEL_MASK) {
        default: // 11 or 00 not allowed, give LOW!
        case RP1_STATUS_LEVEL_LOW:  return LOW ;
        case RP1_STATUS_LEVEL_HIGH: return HIGH ;
      }
    } else {
      if ((*(gpio + gpioToGPLEV [pin]) & (1 << (pin & 31))) != 0)
        return HIGH ;
      else
        return LOW ;
    }
  }
  else
  {
    if ((node = wiringPiFindNode (pin)) == NULL)
      return LOW ;
    return node->digitalRead (node, pin) ;
  }
}


/*
 * digitalRead8:
 *	Read 8-bits (a byte) from given start pin.
 *********************************************************************************

unsigned int digitalRead8 (int pin)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-Board Pin
    return 0 ;
  else
  {
    if ((node = wiringPiFindNode (pin)) == NULL)
      return LOW ;
    return node->digitalRead8 (node, pin) ;
  }
}
 */


/*
 * digitalWrite:
 *	Set an output bit
 *********************************************************************************
 */

void digitalWriteDevice (int pin, int value) {

  if (wiringPiDebug)
    printf ("digitalWriteDevice: ioctl pin:%d value: %d\n", pin, value) ;

  if (lineFds[pin]<0) {
    // line not requested - auto request on first write as output
    pinModeDevice(pin, OUTPUT);
  }
  if (lineFds[pin]>=0 && (lineFlags[pin] & GPIOHANDLE_REQUEST_OUTPUT)>0) {
    struct gpiohandle_data data;
    data.values[0] = value;
    if (wiringPiDebug)
      printf ("digitalWriteDevice: ioctl pin:%d cmd: GPIOHANDLE_SET_LINE_VALUES_IOCTL, value: %d\n", pin, value) ;
    int ret = ioctl(lineFds[pin], GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data);
    if (ret) {
      ReportDeviceError("set line values", pin, "digitalWrite", ret);
      return;  // error
    }
  } else {
    fprintf(stderr, "digitalWrite: no output (%d)\n", lineFlags[pin]);
  }
  return; // error
}

void digitalWrite (int pin, int value)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-Board Pin
  {
    switch(wiringPiMode) {
      default: //WPI_MODE_GPIO_SYS
        fprintf(stderr, "digitalWrite: invalid mode\n");
        return;
      case WPI_MODE_PINS:
        pin = pinToGpio [pin];
        break;
      case WPI_MODE_PHYS:
        pin = physToGpio [pin];
        break;
      case WPI_MODE_GPIO_DEVICE_BCM:
        digitalWriteDevice(pin, value);
        return;
      case WPI_MODE_GPIO_DEVICE_WPI:
        digitalWriteDevice(pinToGpio[pin], value);
        return;
      case WPI_MODE_GPIO_DEVICE_PHYS:
        digitalWriteDevice(physToGpio[pin], value);
        return;
      case WPI_MODE_GPIO:
        break;
    }

    if (PI_MODEL_5 == RaspberryPiModel) {
      if (value == LOW) {
        //printf("Set pin %d >>0x%08x<< to low\n", pin, 1<<pin);
        rio[RP1_RIO_OUT + RP1_CLR_OFFSET] = 1<<pin;
      } else {
        //printf("Set pin %d >>0x%08x<< to high\n", pin, 1<<pin);
        rio[RP1_RIO_OUT + RP1_SET_OFFSET] = 1<<pin;
      }
    } else {
      if (value == LOW)
        *(gpio + gpioToGPCLR [pin]) = 1 << (pin & 31) ;
      else
        *(gpio + gpioToGPSET [pin]) = 1 << (pin & 31) ;
    }
  }
  else
  {
    if ((node = wiringPiFindNode (pin)) != NULL)
      node->digitalWrite (node, pin, value) ;
  }
}


/*
 * digitalWrite8:
 *	Set an output 8-bit byte on the device from the given pin number
 *********************************************************************************

void digitalWrite8 (int pin, int value)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-Board Pin
    return ;
  else
  {
    if ((node = wiringPiFindNode (pin)) != NULL)
      node->digitalWrite8 (node, pin, value) ;
  }
}
 */


/*
 * pwmWrite:
 *	Set an output PWM value
 *********************************************************************************
 */

void pwmWrite (int pin, int value)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  FailOnModel5();
  setupCheck ("pwmWrite") ;

  if ((pin & PI_GPIO_MASK) == 0)		// On-Board Pin
  {
    /**/ if (wiringPiMode == WPI_MODE_PINS)
      pin = pinToGpio [pin] ;
    else if (wiringPiMode == WPI_MODE_PHYS)
      pin = physToGpio [pin] ;
    else if (wiringPiMode != WPI_MODE_GPIO)
      return ;

    usingGpioMemCheck ("pwmWrite") ;
    *(pwm + gpioToPwmPort [pin]) = value ;
  }
  else
  {
    if ((node = wiringPiFindNode (pin)) != NULL)
      node->pwmWrite (node, pin, value) ;
  }
}


/*
 * analogRead:
 *	Read the analog value of a given Pin.
 *	There is no on-board Pi analog hardware,
 *	so this needs to go to a new node.
 *********************************************************************************
 */

int analogRead (int pin)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  if ((node = wiringPiFindNode (pin)) == NULL)
    return 0 ;
  else
    return node->analogRead (node, pin) ;
}


/*
 * analogWrite:
 *	Write the analog value to the given Pin.
 *	There is no on-board Pi analog hardware,
 *	so this needs to go to a new node.
 *********************************************************************************
 */

void analogWrite (int pin, int value)
{
  struct wiringPiNodeStruct *node = wiringPiNodes ;

  if ((node = wiringPiFindNode (pin)) == NULL)
    return ;

  node->analogWrite (node, pin, value) ;
}


/*
 * pwmToneWrite:
 *	Pi Specific.
 *      Output the given frequency on the Pi's PWM pin
 *********************************************************************************
 */

void pwmToneWrite (int pin, int freq)
{
  FailOnModel5();

  setupCheck ("pwmToneWrite") ;

  if (freq == 0)
    pwmWrite (pin, 0) ;             // Off
  else
  {
    int range = 600000 / freq ;
    pwmSetRange (range) ;
    pwmWrite    (pin, freq / 2) ;
  }
}



/*
 * digitalWriteByte:
 * digitalReadByte:
 *	Pi Specific
 *	Write an 8-bit byte to the first 8 GPIO pins - try to do it as
 *	fast as possible.
 *	However it still needs 2 operations to set the bits, so any external
 *	hardware must not rely on seeing a change as there will be a change
 *	to set the outputs bits to zero, then another change to set the 1's
 *	Reading is just bit fiddling.
 *	These are wiringPi pin numbers 0..7, or BCM_GPIO pin numbers
 *	17, 18, 22, 23, 24, 24, 4 on a Pi v1 rev 0-3
 *	17, 18, 27, 23, 24, 24, 4 on a Pi v1 rev 3 onwards or B+, 2, 3, zero
 *********************************************************************************
 */

void digitalWriteByte (const int value)
{
  uint32_t pinSet = 0 ;
  uint32_t pinClr = 0 ;
  int mask = 1 ;
  int pin ;

  FailOnModel5();

  if (wiringPiMode == WPI_MODE_GPIO_SYS)
  {
    return ;
  }
  else
  {
    for (pin = 0 ; pin < 8 ; ++pin)
    {
      if ((value & mask) == 0)
	pinClr |= (1 << pinToGpio [pin]) ;
      else
	pinSet |= (1 << pinToGpio [pin]) ;

      mask <<= 1 ;
    }

    *(gpio + gpioToGPCLR [0]) = pinClr ;
    *(gpio + gpioToGPSET [0]) = pinSet ;
  }
}

unsigned int digitalReadByte (void)
{
  int pin, x ;
  uint32_t raw ;
  uint32_t data = 0 ;

  FailOnModel5();

  if (wiringPiMode == WPI_MODE_GPIO_SYS)
  {
    return 0;
  }
  else
  {
    raw = *(gpio + gpioToGPLEV [0]) ; // First bank for these pins
    for (pin = 0 ; pin < 8 ; ++pin)
    {
      x = pinToGpio [pin] ;
      data = (data << 1) | (((raw & (1 << x)) == 0) ? 0 : 1) ;
    }
  }
  return data ;
}


/*
 * digitalWriteByte2:
 * digitalReadByte2:
 *	Pi Specific
 *	Write an 8-bit byte to the second set of 8 GPIO pins. This is marginally
 *	faster than the first lot as these are consecutive BCM_GPIO pin numbers.
 *	However they overlap with the original read/write bytes.
 *********************************************************************************
 */

void digitalWriteByte2 (const int value)
{
  FailOnModel5();

  if (wiringPiMode == WPI_MODE_GPIO_SYS)
  {
  }
  else
  {
    *(gpio + gpioToGPCLR [0]) = (~value & 0xFF) << 20 ; // 0x0FF00000; ILJ > CHANGE: Old causes glitch
    *(gpio + gpioToGPSET [0]) = ( value & 0xFF) << 20 ;
  }
}

unsigned int digitalReadByte2 (void)
{
  uint32_t data = 0 ;

  FailOnModel5();

  if (wiringPiMode == WPI_MODE_GPIO_SYS)
  {
  }
  else
    data = ((*(gpio + gpioToGPLEV [0])) >> 20) & 0xFF ; // First bank for these pins

  return data ;
}


/*
 * waitForInterrupt:
 *	Pi Specific.
 *	Wait for Interrupt on a GPIO pin.
 *	This is actually done via the /dev/gpiochip interface regardless of
 *	the wiringPi access mode in-use. Maybe sometime it might get a better
 *	way for a bit more efficiency.
 *********************************************************************************
 */

int waitForInterrupt (int pin, int mS)
{
  int fd, ret;
  struct pollfd polls ;
  struct gpioevent_data evdata;
  //struct gpio_v2_line_request req2;

  if (wiringPiMode == WPI_MODE_PINS)
    pin = pinToGpio [pin] ;
  else if (wiringPiMode == WPI_MODE_PHYS)
    pin = physToGpio [pin] ;

  if ((fd = isrFds [pin]) == -1)
    return -2 ;

  // Setup poll structure
  polls.fd      = fd;
  polls.events  = POLLIN | POLLERR ;
  polls.revents = 0;

  // Wait for it ...
  ret = poll(&polls, 1, mS);
  if (ret <= 0) {
    fprintf(stderr, "wiringPi: ERROR: poll returned=%d\n", ret);
  } else {
    //if (polls.revents & POLLIN)
    if (wiringPiDebug) {
      printf ("wiringPi: IRQ line %d received %d, fd=%d\n", pin, ret, isrFds[pin]) ;
    }
    /* read event data */
    int readret = read(isrFds [pin], &evdata, sizeof(evdata));
    if (readret == sizeof(evdata)) {
      if (wiringPiDebug) {
        printf ("wiringPi: IRQ data id: %d, timestamp: %lld\n", evdata.id, evdata.timestamp) ;
      }
      ret = evdata.id;
    } else {
      ret = 0;
    }
  }
  return ret;
}

int waitForInterruptInit (int pin, int mode)
{
  const char* strmode = "";

  if (wiringPiMode == WPI_MODE_PINS) {
    pin = pinToGpio [pin] ;
  } else if (wiringPiMode == WPI_MODE_PHYS) {
    pin = physToGpio [pin] ;
  }

  /* open gpio */
  sleep(1);
  if (wiringPiGpioDeviceGetFd()<0) {
    return -1;
  }

  struct gpioevent_request req;
  req.lineoffset = pin;
  req.handleflags = GPIOHANDLE_REQUEST_INPUT;
  switch(mode) {
    default:
    case INT_EDGE_SETUP:
      if (wiringPiDebug) {
        printf ("wiringPi: waitForInterruptMode mode INT_EDGE_SETUP - exiting\n") ;
      }
      return -1;
    case INT_EDGE_FALLING:
      req.eventflags  = GPIOEVENT_REQUEST_FALLING_EDGE;
      strmode = "falling";
      break;
    case INT_EDGE_RISING:
      req.eventflags  = GPIOEVENT_REQUEST_RISING_EDGE;
      strmode = "rising";
      break;
    case INT_EDGE_BOTH:
      req.eventflags  = GPIOEVENT_REQUEST_BOTH_EDGES;
      strmode = "both";
      break;
  }
  strncpy(req.consumer_label, "wiringpi_gpio_irq", sizeof(req.consumer_label) - 1);

  //later implement GPIO_V2_GET_LINE_IOCTL req2
  int ret = ioctl(chipFd, GPIO_GET_LINEEVENT_IOCTL, &req);
  if (ret) {
    ReportDeviceError("get line event", pin , strmode, ret);
    return -1;
  }
  if (wiringPiDebug) {
    printf ("wiringPi: GPIO get line %d , mode %s succeded, fd=%d\n", pin, strmode, req.fd) ;
  }

  /* set event fd nonbloack read */
  int fd_line = req.fd;
  isrFds [pin] = fd_line;
  int flags = fcntl(fd_line, F_GETFL);
  flags |= O_NONBLOCK;
  ret = fcntl(fd_line, F_SETFL, flags);
  if (ret) {
    fprintf(stderr, "wiringPi: ERROR: fcntl set nonblock return=%d\n", ret);
    return -1;
  }

  return 0;
}


int waitForInterruptClose (int pin) {
  if (isrFds[pin]>0) {
    if (wiringPiDebug) {
      printf ("wiringPi: waitForInterruptClose close thread 0x%lX\n", (unsigned long)isrThreads[pin]) ;
    }
    if (pthread_cancel(isrThreads[pin]) == 0) {
      if (wiringPiDebug) {
        printf ("wiringPi: waitForInterruptClose thread canceled successfuly\n") ;
      }
    } else {
     if (wiringPiDebug) {
        fprintf (stderr, "wiringPi: waitForInterruptClose could not cancel thread\n");
      }
    }
    close(isrFds [pin]);
  }
  isrFds [pin] = -1;
  isrFunctions [pin] = NULL;

  /* -not closing so far - other isr may be using it - only close if no other is using - will code later
  if (chipFd>0) {
    close(chipFd);
  }
  chipFd = -1;
  */
  if (wiringPiDebug) {
    printf ("wiringPi: waitForInterruptClose finished\n") ;
  }
  return 0;
}


int wiringPiISRStop (int pin) {
  return waitForInterruptClose (pin);
}

/*
 * interruptHandler:
 *	This is a thread and gets started to wait for the interrupt we're
 *	hoping to catch. It will call the user-function when the interrupt
 *	fires.
 *********************************************************************************
 */

static void *interruptHandler (UNU void *arg)
{
  int pin ;

  (void)piHiPri (55) ;	// Only effective if we run as root

  pin   = pinPass ;
  pinPass = -1 ;

  for (;;) {
    int ret = waitForInterrupt(pin, -1);
    if ( ret> 0) {
      if (wiringPiDebug) {
        printf ("wiringPi: call function\n") ;
      }
      if(isrFunctions [pin]) {
        isrFunctions [pin] () ;
      }
      // wait again - in the past forever - now can be stopped by  waitForInterruptClose
    } else if( ret< 0) {
      break; // stop thread!
    }
  }

  waitForInterruptClose (pin);
  if (wiringPiDebug) {
    printf ("wiringPi: interruptHandler finished\n") ;
  }
  return NULL ;
}


/*
 * wiringPiISR:
 *	Pi Specific.
 *	Take the details and create an interrupt handler that will do a call-
 *	back to the user supplied function.
 *********************************************************************************
 */

int wiringPiISR (int pin, int mode, void (*function)(void))
{
  const int maxpin = GetMaxPin();

  if (pin < 0 || pin > maxpin)
    return wiringPiFailure (WPI_FATAL, "wiringPiISR: pin must be 0-%d (%d)\n", maxpin, pin) ;
  if (wiringPiMode == WPI_MODE_UNINITIALISED)
    return wiringPiFailure (WPI_FATAL, "wiringPiISR: wiringPi has not been initialised. Unable to continue.\n") ;
  if (wiringPiDebug) {
    printf ("wiringPi: wiringPiISR pin %d, mode %d\n", pin, mode) ;
  }
  if (isrFunctions [pin]) {
    printf ("wiringPi: ISR function alread active, ignoring \n") ;
  }

  isrFunctions [pin] = function ;
  isrMode[pin] = mode;
  if(waitForInterruptInit (pin, mode)<0) {
    if (wiringPiDebug) {
      fprintf (stderr, "wiringPi: waitForInterruptInit failed\n") ;
    }
  };

  if (wiringPiDebug) {
    printf ("wiringPi: mutex in\n") ;
  }
  pthread_mutex_lock (&pinMutex) ;
    pinPass = pin ;
    if (wiringPiDebug) {
      printf("wiringPi: pthread_create before 0x%lX\n", (unsigned long)isrThreads[pin]);
    }
    if (pthread_create (&isrThreads[pin], NULL, interruptHandler, NULL)==0) {
      if (wiringPiDebug) {
        printf("wiringPi: pthread_create successed, 0x%lX\n", (unsigned long)isrThreads[pin]);
      }
      while (pinPass != -1)
        delay (1) ;
    } else {
      if (wiringPiDebug) {
        printf("wiringPi: pthread_create failed\n");
      }
    }

    if (wiringPiDebug) {
      printf ("wiringPi: mutex out\n") ;
    }
  pthread_mutex_unlock (&pinMutex) ;

  if (wiringPiDebug) {
    printf ("wiringPi: wiringPiISR finished\n") ;
  }
  return 0 ;
}


/*
 * initialiseEpoch:
 *	Initialise our start-of-time variable to be the current unix
 *	time in milliseconds and microseconds.
 *********************************************************************************
 */

static void initialiseEpoch (void)
{
#ifdef	OLD_WAY
  struct timeval tv ;

  gettimeofday (&tv, NULL) ;
  epochMilli = (uint64_t)tv.tv_sec * (uint64_t)1000    + (uint64_t)(tv.tv_usec / 1000) ;
  epochMicro = (uint64_t)tv.tv_sec * (uint64_t)1000000 + (uint64_t)(tv.tv_usec) ;
#else
  struct timespec ts ;

  clock_gettime (CLOCK_MONOTONIC_RAW, &ts) ;
  epochMilli = (uint64_t)ts.tv_sec * (uint64_t)1000    + (uint64_t)(ts.tv_nsec / 1000000L) ;
  epochMicro = (uint64_t)ts.tv_sec * (uint64_t)1000000 + (uint64_t)(ts.tv_nsec /    1000L) ;
#endif
}


/*
 * delay:
 *	Wait for some number of milliseconds
 *********************************************************************************
 */

void delay (unsigned int howLong)
{
  struct timespec sleeper, dummy ;

  sleeper.tv_sec  = (time_t)(howLong / 1000) ;
  sleeper.tv_nsec = (long)(howLong % 1000) * 1000000 ;

  nanosleep (&sleeper, &dummy) ;
}


/*
 * delayMicroseconds:
 *	This is somewhat intersting. It seems that on the Pi, a single call
 *	to nanosleep takes some 80 to 130 microseconds anyway, so while
 *	obeying the standards (may take longer), it's not always what we
 *	want!
 *
 *	So what I'll do now is if the delay is less than 100uS we'll do it
 *	in a hard loop, watching a built-in counter on the ARM chip. This is
 *	somewhat sub-optimal in that it uses 100% CPU, something not an issue
 *	in a microcontroller, but under a multi-tasking, multi-user OS, it's
 *	wastefull, however we've no real choice )-:
 *
 *      Plan B: It seems all might not be well with that plan, so changing it
 *      to use gettimeofday () and poll on that instead...
 *********************************************************************************
 */

void delayMicrosecondsHard (unsigned int howLong)
{
  struct timeval tNow, tLong, tEnd ;

  gettimeofday (&tNow, NULL) ;
  tLong.tv_sec  = howLong / 1000000 ;
  tLong.tv_usec = howLong % 1000000 ;
  timeradd (&tNow, &tLong, &tEnd) ;

  while (timercmp (&tNow, &tEnd, <))
    gettimeofday (&tNow, NULL) ;
}

void delayMicroseconds (unsigned int howLong)
{
  struct timespec sleeper ;
  unsigned int uSecs = howLong % 1000000 ;
  unsigned int wSecs = howLong / 1000000 ;

  /**/ if (howLong ==   0)
    return ;
  else if (howLong  < 100)
    delayMicrosecondsHard (howLong) ;
  else
  {
    sleeper.tv_sec  = wSecs ;
    sleeper.tv_nsec = (long)(uSecs * 1000L) ;
    nanosleep (&sleeper, NULL) ;
  }
}


/*
 * millis:
 *	Return a number of milliseconds as an unsigned int.
 *	Wraps at 49 days.
 *********************************************************************************
 */

unsigned int millis (void)
{
  uint64_t now ;

#ifdef	OLD_WAY
  struct timeval tv ;

  gettimeofday (&tv, NULL) ;
  now  = (uint64_t)tv.tv_sec * (uint64_t)1000 + (uint64_t)(tv.tv_usec / 1000) ;

#else
  struct  timespec ts ;

  clock_gettime (CLOCK_MONOTONIC_RAW, &ts) ;
  now  = (uint64_t)ts.tv_sec * (uint64_t)1000 + (uint64_t)(ts.tv_nsec / 1000000L) ;
#endif

  return (uint32_t)(now - epochMilli) ;
}


/*
 * micros:
 *	Return a number of microseconds as an unsigned int.
 *	Wraps after 71 minutes.
 *********************************************************************************
 */

unsigned int micros (void)
{
  uint64_t now ;
#ifdef	OLD_WAY
  struct timeval tv ;

  gettimeofday (&tv, NULL) ;
  now  = (uint64_t)tv.tv_sec * (uint64_t)1000000 + (uint64_t)tv.tv_usec ;
#else
  struct  timespec ts ;

  clock_gettime (CLOCK_MONOTONIC_RAW, &ts) ;
  now  = (uint64_t)ts.tv_sec * (uint64_t)1000000 + (uint64_t)(ts.tv_nsec / 1000) ;
#endif


  return (uint32_t)(now - epochMicro) ;
}

/*
 * wiringPiVersion:
 *	Return our current version number
 *********************************************************************************
 */

void wiringPiVersion (int *major, int *minor)
{
  *major = VERSION_MAJOR ;
  *minor = VERSION_MINOR ;
}


int wiringPiUserLevelAccess(void)
{
  struct stat statBuf ;
  const char* gpiomemModule = gpiomem_BCM;

  piBoard();
  if (PI_MODEL_5 == RaspberryPiModel) {
    gpiomemModule = gpiomem_RP1;
  }

  return stat(gpiomemModule, &statBuf) == 0 ? 1 : 0;
}


int wiringPiGlobalMemoryAccess(void)
{
  const char* gpiomemGlobal;
  int fd=-1;
  unsigned int MMAP_size;
  unsigned int BaseAddr, PWMAddr;

  piBoard();
  if (PI_MODEL_5 == RaspberryPiModel) {
    gpiomemGlobal = pciemem_RP1;
    MMAP_size = pciemem_RP1_Size;
    BaseAddr  = 0x00000000;
    PWMAddr	  = 0x00000000;  //not supported so far
  } else {
    gpiomemGlobal = gpiomem_global;
    MMAP_size = BLOCK_SIZE;
    BaseAddr	= piGpioBase + 0x00200000 ;
    PWMAddr	  = piGpioBase + 0x0020C000 ;
  }

  if ((fd = open (gpiomemGlobal, O_RDWR | O_SYNC | O_CLOEXEC)) >0) {
    int returnvalue = 1; // OK

    uint32_t * lgpio = (uint32_t *)mmap(0, MMAP_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, BaseAddr) ;
    if (lgpio == MAP_FAILED) {
      returnvalue = 0;
      if (wiringPiDebug)
        fprintf(stderr,"wiringPiGlobalMemoryAccess: mmap (GPIO 0x%X,0x%X) failed: %s\n", BaseAddr, MMAP_size, strerror (errno)) ;
    } else {
      munmap(lgpio, MMAP_size);
      if (PI_MODEL_5 == RaspberryPiModel) {
        returnvalue = 2;    // GPIO & PWM accessible (same area, nothing to mmap)
      } else {
        //check PWM area
        uint32_t* lpwm = (uint32_t *)mmap(0, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, PWMAddr) ;
        if (lpwm == MAP_FAILED) {
          returnvalue = 1;    // only GPIO accessible
          if (wiringPiDebug)
            fprintf(stderr,"wiringPiGlobalMemoryAccess: mmap (PWM 0x%X,0x%X) failed: %s\n", PWMAddr, MMAP_size, strerror (errno)) ;
        } else {
          returnvalue = 2;  // GPIO & PWM accessible
          munmap(lpwm, BLOCK_SIZE);
        }
      }
    }

    close(fd);
    return returnvalue;
  }
  return 0;  // Failed!
}

/*
 * wiringPiSetup:
 *	Must be called once at the start of your program execution.
 *
 * Default setup: Initialises the system into wiringPi Pin mode and uses the
 *	memory mapped hardware directly.
 *
 * Changed now to revert to "gpio" mode if we're running on a Compute Module.
 *********************************************************************************
 */

int wiringPiSetup (void)
{
  int   fd ;
  int   model, rev, mem, maker, overVolted ;

  if (wiringPiSetuped)
    return 0 ;

  wiringPiSetuped = TRUE ;

  if (getenv (ENV_DEBUG) != NULL)
    wiringPiDebug = TRUE ;

  if (getenv (ENV_CODES) != NULL)
    wiringPiReturnCodes = TRUE ;

  if (wiringPiDebug)
    printf ("wiringPi: wiringPiSetup called\n") ;

// Get the board ID information. We're not really using the information here,
//	but it will give us information like the GPIO layout scheme (2 variants
//	on the older 26-pin Pi's) and the GPIO peripheral base address.
//	and if we're running on a compute module, then wiringPi pin numbers
//	don't really mean anything, so force native BCM mode anyway.

  piBoardId (&model, &rev, &mem, &maker, &overVolted) ;

  if ((model == PI_MODEL_CM) ||
      (model == PI_MODEL_CM3) ||
      (model == PI_MODEL_CM3P))
    wiringPiMode = WPI_MODE_GPIO ;
  else
    wiringPiMode = WPI_MODE_PINS ;

  /**/ if (piGpioLayout () == GPIO_LAYOUT_PI1_REV1)	// A, B, Rev 1, 1.1
  {
     pinToGpio =  pinToGpioR1 ;
    physToGpio = physToGpioR1 ;
  }
  else 					// A2, B2, A+, B+, CM, Pi2, Pi3, Zero, Zero W, Zero 2 W
  {
     pinToGpio =  pinToGpioR2 ;
    physToGpio = physToGpioR2 ;
  }

// Open the master /dev/ memory control device
// Device strategy: December 2016:
//	Try /dev/mem. If that fails, then
//	try /dev/gpiomem. If that fails then game over.

	const char* gpiomemGlobal = gpiomem_global;
  const char* gpiomemModule = gpiomem_BCM;

  if (PI_MODEL_5 == model) {
    gpiomemGlobal = pciemem_RP1;
    gpiomemModule = gpiomem_RP1;
  }

  usingGpioMem = FALSE;
  if (gpiomemGlobal==NULL || (fd = open (gpiomemGlobal, O_RDWR | O_SYNC | O_CLOEXEC)) < 0)
  {
    if (wiringPiDebug) {
      printf ("wiringPi: no access to %s try %s\n", gpiomemGlobal, gpiomemModule) ;
    }
    if (gpiomemModule && (fd = open (gpiomemModule, O_RDWR | O_SYNC | O_CLOEXEC) ) >= 0)	// We're using gpiomem
    {
      piGpioBase   = 0 ;
      usingGpioMem = TRUE ;
    }
    else
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: Unable to open %s or %s: %s.\n"
	"  Aborting your program because if it can not access the GPIO\n"
	"  hardware then it most certianly won't work\n"
	"  Try running with sudo?\n", gpiomemGlobal, gpiomemModule, strerror (errno)) ;
  }
  if (wiringPiDebug) {
    printf ("wiringPi: access to %s succeded %d\n", usingGpioMem ? gpiomemModule : gpiomemGlobal, fd) ;
  }
//	GPIO:
 if (PI_MODEL_5 != model) {
   //Set the offsets into the memory interface.

    GPIO_PADS 	  = piGpioBase + 0x00100000 ;
    GPIO_CLOCK_BASE = piGpioBase + 0x00101000 ;
    GPIO_BASE	  = piGpioBase + 0x00200000 ;
    GPIO_TIMER	  = piGpioBase + 0x0000B000 ;
    GPIO_PWM	  = piGpioBase + 0x0020C000 ;
    GPIO_RIO    = 0x00 ;

// Map the individual hardware components

  //	GPIO:
    base = NULL;
    gpio = (uint32_t *)mmap(0, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_BASE) ;
    if (gpio == MAP_FAILED)
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: mmap (GPIO) failed: %s\n", strerror (errno)) ;

  //	PWM

    pwm = (uint32_t *)mmap(0, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_PWM) ;
    if (pwm == MAP_FAILED)
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: mmap (PWM) failed: %s\n", strerror (errno)) ;

  //	Clock control (needed for PWM)

    clk = (uint32_t *)mmap(0, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_CLOCK_BASE) ;
    if (clk == MAP_FAILED)
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: mmap (CLOCK) failed: %s\n", strerror (errno)) ;

  //	The drive pads

    pads = (uint32_t *)mmap(0, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_PADS) ;
    if (pads == MAP_FAILED)
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: mmap (PADS) failed: %s\n", strerror (errno)) ;

  //	The system timer

    timer = (uint32_t *)mmap(0, BLOCK_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_TIMER) ;
    if (timer == MAP_FAILED)
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: mmap (TIMER) failed: %s\n", strerror (errno)) ;

  // Set the timer to free-running, 1MHz.
  //	0xF9 is 249, the timer divide is base clock / (divide+1)
  //	so base clock is 250MHz / 250 = 1MHz.

    *(timer + TIMER_CONTROL) = 0x0000280 ;
    *(timer + TIMER_PRE_DIV) = 0x00000F9 ;
    timerIrqRaw = timer + TIMER_IRQ_RAW ;

    // Export the base addresses for any external software that might need them
    _wiringPiBase  = base ;
    _wiringPiGpio  = gpio ;
    _wiringPiPwm   = pwm ;
    _wiringPiClk   = clk ;
    _wiringPiPads  = pads ;
    _wiringPiTimer = timer ;
    _wiringPiRio   = NULL ;
  } else {
    unsigned int MMAP_size = (usingGpioMem) ? gpiomem_RP1_Size : pciemem_RP1_Size;

    GPIO_PADS 	= (RP1_PADS0_Addr-RP1_IO0_Addr) ;
    GPIO_CLOCK_BASE = 0x00;
    GPIO_BASE	  = (RP1_IO0_Addr-RP1_BASE_Addr) ;
    GPIO_TIMER	=  0x00;
    GPIO_PWM	  = RP1_PWM0_Addr-RP1_BASE_Addr;
    GPIO_RIO    = (RP1_SYS_RIO0_Addr-RP1_IO0_Addr) ;

    //map hole RP1 memory block from beginning,
    base = (unsigned int *)mmap(0, MMAP_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0x00000000) ;
    if (base == MAP_FAILED)
      return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: mmap failed: %s\n", strerror (errno)) ;
    if (usingGpioMem) {
      gpio = base;              // RP1 start adress of map memory for gpio (same as module memory)
    } else {
      gpio = &base[GPIO_BASE/4];// RP1 start adress of map memory for gpio
    }
    pads = &gpio[GPIO_PADS/4];  // RP1 start adress of map memory for pads
    rio  = &gpio[GPIO_RIO/4];   // RP1 start adress of map memory for rio
    GPIO_PADS += GPIO_BASE;
    GPIO_RIO += GPIO_BASE;

    // Export the base addresses for any external software that might need them
    _wiringPiBase  = base ;
    _wiringPiGpio  = gpio ;
    _wiringPiPwm   = NULL ;
    _wiringPiClk   = NULL ;
    _wiringPiPads  = pads ;
    _wiringPiTimer = NULL ;
    _wiringPiRio   = rio ;
  }
  if (wiringPiDebug) {
    printf ("wiringPi: memory map gpio  0x%x %s\n", GPIO_BASE , _wiringPiGpio ? "valid" : "invalid");
    printf ("wiringPi: memory map pads  0x%x %s\n", GPIO_PADS , _wiringPiPads ? "valid" : "invalid");
    printf ("wiringPi: memory map rio   0x%x %s\n", GPIO_RIO  , _wiringPiRio  ? "valid" : "invalid");
    printf ("wiringPi: memory map pwm   0x%x %s\n", GPIO_PWM  , _wiringPiPwm  ? "valid" : "invalid");
    printf ("wiringPi: memory map clk   0x%x %s\n", GPIO_CLOCK_BASE, _wiringPiClk  ? "valid" : "invalid");
    printf ("wiringPi: memory map timer 0x%x %s\n", GPIO_TIMER,_wiringPiTimer ? "valid" : "invalid");
  }

  initialiseEpoch () ;

  return 0 ;
}


/*
 * wiringPiSetupGpio:
 *	Must be called once at the start of your program execution.
 *
 * GPIO setup: Initialises the system into GPIO Pin mode and uses the
 *	memory mapped hardware directly.
 *********************************************************************************
 */

int wiringPiSetupGpio (void)
{
  (void)wiringPiSetup () ;

  if (wiringPiDebug)
    printf ("wiringPi: wiringPiSetupGpio called\n") ;

  wiringPiMode = WPI_MODE_GPIO ;

  return 0 ;
}


/*
 * wiringPiSetupPhys:
 *	Must be called once at the start of your program execution.
 *
 * Phys setup: Initialises the system into Physical Pin mode and uses the
 *	memory mapped hardware directly.
 *********************************************************************************
 */

int wiringPiSetupPhys (void)
{
  (void)wiringPiSetup () ;

  if (wiringPiDebug)
    printf ("wiringPi: wiringPiSetupPhys called\n") ;

  wiringPiMode = WPI_MODE_PHYS ;

  return 0 ;
}

int wiringPiSetupPinType (enum WPIPinType pinType) {
  if (wiringPiDebug)
    printf ("wiringPi: wiringPiSetupPinType(%d) called\n", (int) pinType) ;
  switch (pinType) {
    case WPI_PIN_BCM:  return wiringPiSetupGpio();
    case WPI_PIN_WPI:  return wiringPiSetup();
    case WPI_PIN_PHYS: return wiringPiSetupPhys();
    default:           return -1;
  }
}


int wiringPiSetupGpioDevice (enum WPIPinType pinType) {
 if (wiringPiSetuped)
    return 0 ;
  if (wiringPiDebug) {
    printf ("wiringPi: wiringPiSetupGpioDevice(%d) called\n", (int)pinType) ;
  }
  if (getenv (ENV_DEBUG) != NULL)
    wiringPiDebug = TRUE ;

  if (getenv (ENV_CODES) != NULL)
    wiringPiReturnCodes = TRUE ;

  if (wiringPiGpioDeviceGetFd()<0) {
    return -1;
  }
  wiringPiSetuped = TRUE ;

  if (piGpioLayout () == GPIO_LAYOUT_PI1_REV1){
    pinToGpio  = pinToGpioR1 ;
    physToGpio = physToGpioR1 ;
  } else {
    pinToGpio  = pinToGpioR2 ;
    physToGpio = physToGpioR2 ;
  }

  initialiseEpoch () ;

  switch (pinType) {
    case WPI_PIN_BCM:
      wiringPiMode = WPI_MODE_GPIO_DEVICE_BCM;
      break;
    case WPI_PIN_WPI:
      wiringPiMode = WPI_MODE_GPIO_DEVICE_WPI;
      break;
    case WPI_PIN_PHYS:
      wiringPiMode = WPI_MODE_GPIO_DEVICE_PHYS;
      break;
    default:
      wiringPiSetuped = FALSE;
      return -1;
  }

  return 0 ;
}

/*
 * wiringPiSetupSys:
 * GPIO Sysfs Interface for Userspace is deprecated
 *   https://www.kernel.org/doc/html/v5.5/admin-guide/gpio/sysfs.html
 *
 * Switched to new GPIO driver Interface in version 3.3
 */

int wiringPiSetupSys (void)
{
  if (wiringPiSetuped)
    return 0 ;
  if (wiringPiDebug)
    printf ("wiringPi: wiringPiSetupSys called\n") ;
  return wiringPiSetupGpioDevice(WPI_PIN_BCM);
}