ref: 6cd07cf340af12356ca4558cb8fad5ed3ebc41d1
dir: /sys/src/9/imx8/i2cimx.c/
#include "u.h"
#include "../port/lib.h"
#include "../port/error.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "../port/i2c.h"
enum {
Moduleclk = 25*Mhz,
I2C_IADR = 0x00,
I2C_IFDR = 0x04,
I2C_I2CR = 0x08,
I2CR_IEN = 1<<7,
I2CR_IIEN = 1<<6,
I2CR_MSTA = 1<<5,
I2CR_MTX = 1<<4,
I2CR_TXAK = 1<<3,
I2CR_RSTA = 1<<2,
I2C_I2SR = 0x0C,
I2SR_ICF = 1<<7,
I2SR_IAAS = 1<<6,
I2SR_IBB = 1<<5,
I2SR_IAL = 1<<4,
I2SR_SRW = 1<<2,
I2SR_IIF = 1<<1,
I2SR_RXAK = 1<<0,
I2C_I2DR = 0x10,
};
typedef struct Ctlr Ctlr;
struct Ctlr
{
void *regs;
int irq;
Rendez;
};
static void
interrupt(Ureg*, void *arg)
{
I2Cbus *bus = arg;
Ctlr *ctlr = bus->ctlr;
wakeup(ctlr);
}
static int
haveirq(void *arg)
{
uchar *regs = arg;
return regs[I2C_I2SR] & (I2SR_IAL|I2SR_IIF);
}
static int
waitsr(Ctlr *ctlr, int inv, int mask)
{
uchar *regs = ctlr->regs;
int sr;
for(;;){
sr = regs[I2C_I2SR];
if(sr & I2SR_IAL){
regs[I2C_I2SR] = sr & ~(I2SR_IAL|I2SR_IIF);
break;
}
if(sr & I2SR_IIF)
regs[I2C_I2SR] = sr & ~I2SR_IIF;
if((sr ^ inv) & mask)
break;
/* polling mode */
if(up == nil || !islo())
continue;
tsleep(ctlr, haveirq, regs, 1);
}
return sr ^ inv;
}
static uchar dummy;
static int
io(I2Cdev *dev, uchar *pkt, int olen, int ilen)
{
I2Cbus *bus = dev->bus;
Ctlr *ctlr = bus->ctlr;
uchar *regs = ctlr->regs;
int cr, sr, alen, o, i;
cr = regs[I2C_I2CR];
if((cr & I2CR_IEN) == 0)
return -1;
o = 0;
if(olen <= 0)
goto Stop;
alen = 1;
if((pkt[0] & 0xF8) == 0xF0 && olen > alen)
alen++;
regs[I2C_IADR] = (pkt[0]&0xFE)^0xFE; /* make sure doesnt match */
/* wait for bus idle */
waitsr(ctlr, I2SR_IBB, I2SR_IBB);
/* start */
cr |= I2CR_MSTA | I2CR_MTX | I2CR_TXAK | I2CR_IIEN;
regs[I2C_I2CR] = cr;
/* wait for bus busy */
if(waitsr(ctlr, 0, I2SR_IBB) & I2SR_IAL)
goto Err;
if(olen > alen)
pkt[0] &= ~1;
for(o=0; o<olen; o++){
regs[I2C_I2DR] = pkt[o];
sr = waitsr(ctlr, 0, I2SR_IIF);
if(sr & I2SR_IAL)
goto Err;
if(sr & I2SR_RXAK)
goto Stop;
}
if(ilen <= 0)
goto Stop;
if((pkt[0]&1) == 0){
regs[I2C_I2CR] = cr | I2CR_RSTA;
pkt[0] |= 1;
for(i=0; i<alen; i++){
regs[I2C_I2DR] = pkt[i];
sr = waitsr(ctlr, 0, I2SR_IIF);
if(sr & I2SR_IAL)
goto Err;
if(sr & I2SR_RXAK)
goto Stop;
}
}
cr &= ~(I2CR_MTX | I2CR_TXAK);
if(ilen == 1) cr |= I2CR_TXAK;
regs[I2C_I2CR] = cr;
dummy = regs[I2C_I2DR]; /* start the next read */
for(i=1; i<=ilen; i++){
sr = waitsr(ctlr, I2SR_ICF, I2SR_IIF);
if(sr & I2SR_IAL)
goto Err;
if(sr & I2SR_ICF)
goto Stop;
if(i == ilen){
cr &= ~(I2CR_MSTA|I2CR_IIEN);
regs[I2C_I2CR] = cr;
}
else if(i == ilen-1){
cr |= I2CR_TXAK;
regs[I2C_I2CR] = cr;
}
pkt[o++] = regs[I2C_I2DR];
}
return o;
Err:
o = -1;
Stop:
cr &= ~(I2CR_MTX|I2CR_MSTA|I2CR_RSTA|I2CR_IIEN);
regs[I2C_I2CR] = cr;
return o;
}
static int
divindex(int v)
{
static int tab[] = {
/* 0x00 */ 30, 32, 36, 42, 48, 52, 60, 72,
/* 0x08 */ 80, 88, 104, 128, 144, 160, 192, 240,
/* 0x10 */ 288, 320, 384, 480, 576, 640, 768, 960,
/* 0x18 */1152,1280,1536,1920,2304,2560,3072,3840,
/* 0x20 */ 22, 24, 26, 28, 32, 36, 40, 44,
/* 0x28 */ 48, 56, 64, 72, 80, 96, 112, 128,
/* 0x30 */ 160, 192, 224, 256, 320, 384, 448, 512,
/* 0x38 */ 640, 768, 896,1024,1280,1536,1792,2048,
};
int i, x = -1;
for(i = 0; i < nelem(tab); i++){
if(tab[i] < v)
continue;
if(x < 0 || tab[i] < tab[x]){
x = i;
if(tab[i] == v)
break;
}
}
return x;
}
static void
clkenable(char *name, int on)
{
char clk[32];
snprint(clk, sizeof(clk), "%s.ipg_clk_patref", name);
setclkgate(clk, 0);
if(on) {
setclkrate(clk, "osc_25m_ref_clk", Moduleclk);
setclkgate(clk, 1);
}
}
static int
init(I2Cbus *bus)
{
Ctlr *ctlr = bus->ctlr;
uchar *regs = ctlr->regs;
clkenable(bus->name, 1);
regs[I2C_IFDR] = divindex(Moduleclk / bus->speed);
regs[I2C_IADR] = 0;
regs[I2C_I2CR] = I2CR_IEN;
delay(1);
intrenable(ctlr->irq, interrupt, bus, BUSUNKNOWN, bus->name);
return 0;
}
static Ctlr ctlr1 = {
.regs = (void*)(VIRTIO + 0xA20000),
.irq = IRQi2c1,
};
static Ctlr ctlr2 = {
.regs = (void*)(VIRTIO + 0xA30000),
.irq = IRQi2c2,
};
static Ctlr ctlr3 = {
.regs = (void*)(VIRTIO + 0xA40000),
.irq = IRQi2c3,
};
static Ctlr ctlr4 = {
.regs = (void*)(VIRTIO + 0xA50000),
.irq = IRQi2c4,
};
void
i2cimxlink(void)
{
static I2Cbus i2c1 = { "i2c1", 400000, &ctlr1, init, io };
static I2Cbus i2c3 = { "i2c3", 400000, &ctlr3, init, io };
static I2Cbus i2c4 = { "i2c4", 400000, &ctlr4, init, io };
iomuxpad("pad_i2c1_sda", "i2c1_sda", "SION ~LVTTL ~HYS PUE ODE MAX 40_OHM");
iomuxpad("pad_i2c1_scl", "i2c1_scl", "SION ~LVTTL ~HYS PUE ODE MAX 40_OHM");
addi2cbus(&i2c1);
iomuxpad("pad_i2c3_sda", "i2c3_sda", "SION ~LVTTL ~HYS PUE ODE MAX 40_OHM");
iomuxpad("pad_i2c3_scl", "i2c3_scl", "SION ~LVTTL ~HYS PUE ODE MAX 40_OHM VSEL_0");
addi2cbus(&i2c3);
iomuxpad("pad_i2c4_sda", "i2c4_sda", "SION ~LVTTL ~HYS PUE ODE MAX 40_OHM");
iomuxpad("pad_i2c4_scl", "i2c4_scl", "SION ~LVTTL ~HYS PUE ODE MAX 40_OHM");
addi2cbus(&i2c4);
}