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backported support for /dev/gpiomem #4

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backported support for /dev/gpiomem #4

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32 changes: 28 additions & 4 deletions wiringPi/wiringPi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,7 @@

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


// Mask for the bottom 64 pins which belong to the Raspberry Pi
Expand Down Expand Up @@ -250,6 +251,10 @@ static pthread_mutex_t pinMutex ;
int wiringPiDebug = FALSE ;
int wiringPiReturnCodes = FALSE ;

// Use /dev/gpiomem ?

int wiringPiTryGpioMem = FALSE ;

// sysFds:
// Map a file descriptor from the /sys/class/gpio/gpioX/value

Expand Down Expand Up @@ -1866,8 +1871,8 @@ int wiringPiSetup (void)
if (getenv (ENV_CODES) != NULL)
wiringPiReturnCodes = TRUE ;

if (geteuid () != 0)
(void)wiringPiFailure (WPI_FATAL, "wiringPiSetup: Must be root. (Did you forget sudo?)\n") ;
if (getenv (ENV_GPIOMEM) != NULL)
wiringPiTryGpioMem = TRUE ;

if (wiringPiDebug)
printf ("wiringPi: wiringPiSetup called\n") ;
Expand All @@ -1889,8 +1894,27 @@ int wiringPiSetup (void)

// Open the master /dev/memory device

if ((fd = open ("/dev/mem", O_RDWR | O_SYNC | O_CLOEXEC) ) < 0)
return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: Unable to open /dev/mem: %s\n", strerror (errno)) ;
if (wiringPiTryGpioMem)
{
if ((fd = open ("/dev/gpiomem", O_RDWR | O_SYNC | O_CLOEXEC) ) < 0)
return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: Unable to open /dev/gpiomem: %s\n", strerror (errno)) ;
BCM2708_PERI_BASE = 0;
}

// ... otherwise fall back to the original /dev/mem which requires root level access

else
{
// This check is here because people are too stupid to check for themselves or read
// error messages.

if (geteuid () != 0)
(void)wiringPiFailure (WPI_FATAL, "wiringPiSetup: Must be root. (Did you forget sudo?)\n") ;

if ((fd = open ("/dev/mem", O_RDWR | O_SYNC | O_CLOEXEC) ) < 0)
return wiringPiFailure (WPI_ALMOST, "wiringPiSetup: Unable to open /dev/mem: %s\n", strerror (errno)) ;
}


// GPIO:

Expand Down