ref: 595fbddb1c9e152d9080d7b0faa301709fa6466d
dir: /sys/src/9/bcm/gpio.c/
/* * Raspberry Pi GPIO support */ #include "u.h" #include "../port/lib.h" #include "../port/error.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "io.h" #define GPIOREGS (VIRTIO+0x200000) /* GPIO regs */ enum { Fsel0 = 0x00>>2, FuncMask= 0x7, Set0 = 0x1c>>2, Clr0 = 0x28>>2, Lev0 = 0x34>>2, Evds0 = 0x40>>2, Redge0 = 0x4C>>2, Fedge0 = 0x58>>2, Hpin0 = 0x64>>2, Lpin0 = 0x70>>2, ARedge0 = 0x7C>>2, AFedge0 = 0x88>2, PUD = 0x94>>2, Off = 0x0, Pulldown= 0x1, Pullup = 0x2, PUDclk0 = 0x98>>2, PUDclk1 = 0x9c>>2, }; void gpiosel(uint pin, int func) { u32int *gp, *fsel; int off; gp = (u32int*)GPIOREGS; fsel = &gp[Fsel0 + pin/10]; off = (pin % 10) * 3; *fsel = (*fsel & ~(FuncMask<<off)) | func<<off; } void gpiopull(uint pin, int func) { u32int *gp, *reg; u32int mask; gp = (u32int*)GPIOREGS; reg = &gp[PUDclk0 + pin/32]; mask = 1 << (pin % 32); gp[PUD] = func; microdelay(1); *reg = mask; microdelay(1); *reg = 0; } void gpiopulloff(uint pin) { gpiopull(pin, Off); } void gpiopullup(uint pin) { gpiopull(pin, Pullup); } void gpiopulldown(uint pin) { gpiopull(pin, Pulldown); } void gpioout(uint pin, int set) { u32int *gp; int v; gp = (u32int*)GPIOREGS; v = set? Set0 : Clr0; gp[v + pin/32] = 1 << (pin % 32); } int gpioin(uint pin) { u32int *gp; gp = (u32int*)GPIOREGS; return (gp[Lev0 + pin/32] & (1 << (pin % 32))) != 0; } void gpioselevent(uint pin, int falling, int enable) { u32int *gp, *field; int reg; enable = enable != 0; if(falling) reg = Fedge0; else reg = Redge0; gp = (u32int*)GPIOREGS; field = &gp[reg + pin/32]; *field = (*field & ~(enable<<pin)) | (enable<<pin); } int gpiogetevent(uint pin) { u32int *gp, *reg, val; gp = (u32int*)GPIOREGS; reg = &gp[Evds0 + pin/32]; val = *reg & (1 << (pin % 32)); *reg |= val; return val != 0; } void gpiomeminit(void) { Physseg seg; memset(&seg, 0, sizeof seg); seg.attr = SG_PHYSICAL; seg.name = "gpio"; seg.pa = GPIOREGS; seg.size = BY2PG; addphysseg(&seg); }