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Fix GPIO pull up/down for Pi4B 

Based on this raspi-gpio commit[1] the 2711 chip uses a different method
for pull up/down. This change implements that same method.

With this change, wiringPi now works for the Pi4B with the subset of
functionality used by zynthian.

[1] 80fa7d04ea?diff=unified
This commit is contained in:
Steve Baker 2019-12-14 20:42:06 +00:00
parent a49f696232
commit 41f941a78e
1 changed files with 42 additions and 6 deletions
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48
wiringPi/wiringPi.c
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@ -214,7 +214,7 @@ volatile unsigned int *_wiringPiTimerIrqRaw ;
// The base address of the GPIO memory mapped hardware IO
#define GPIO_PERI_BASE_OLD 0x20000000
#define GPIO_PERI_BASE_2708 0x3F000000
#define GPIO_PERI_BASE_2835 0x3F000000
#define GPIO_PERI_BASE_2711 0xFE000000
static volatile unsigned int piGpioBase = 0 ;
@ -543,6 +543,14 @@ static uint8_t gpioToFEN [] =
#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
@ -1509,11 +1517,36 @@ void pullUpDnControl (int pin, int pud)
else if (wiringPiMode != WPI_MODE_GPIO)
return ;
*(gpio + GPPUD) = pud & 3 ; delayMicroseconds (5) ;
*(gpio + gpioToPUDCLK [pin]) = 1 << (pin & 31) ; delayMicroseconds (5) ;
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;
*(gpio + GPPUD) = 0 ; delayMicroseconds (5) ;
*(gpio + gpioToPUDCLK [pin]) = 0 ; delayMicroseconds (5) ;
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
{
@ -2270,14 +2303,17 @@ int wiringPiSetup (void)
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:
piGpioBase = GPIO_PERI_BASE_2711 ;
piGpioPupOffset = GPPUPPDN0 ;
break ;
default:
piGpioBase = GPIO_PERI_BASE_2708 ;
piGpioBase = GPIO_PERI_BASE_2835 ;
piGpioPupOffset = GPPUD ;
break ;
}