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fsl_i2c: generate nine pulses on SCL if the I2C bus is hung

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When the code detected that the bus is hung (e.g. SDA stuck low),
send 9 pulses on SCL to try to fixup the bus.

Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Chunhe Lan <Chunhe.Lan@freescale.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Heiko Schocher <hs@denx.de>
This commit is contained in:
Chunhe Lan 2013-08-16 15:10:36 +08:00 • committed by Heiko Schocher
parent 40a60c6e8b
commit b8ce3343b6
1 changed files with 57 additions and 2 deletions
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59
drivers/i2c/fsl_i2c.c
View file

@ -206,9 +206,50 @@ static unsigned int get_i2c_clock(int bus)
return gd->arch.i2c1_clk; /* I2C1 clock */
}
static int fsl_i2c_fixup(const struct fsl_i2c *dev)
{
const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
unsigned long long timeval = 0;
int ret = -1;
writeb(I2C_CR_MEN | I2C_CR_MSTA, &dev->cr);
timeval = get_ticks();
while (!(readb(&dev->sr) & I2C_SR_MBB)) {
if ((get_ticks() - timeval) > timeout)
goto err;
}
if (readb(&dev->sr) & I2C_SR_MAL) {
/* SDA is stuck low */
writeb(0, &dev->cr);
udelay(100);
writeb(I2C_CR_MSTA, &dev->cr);
writeb(I2C_CR_MEN | I2C_CR_MSTA, &dev->cr);
}
readb(&dev->dr);
timeval = get_ticks();
while (!(readb(&dev->sr) & I2C_SR_MIF)) {
if ((get_ticks() - timeval) > timeout)
goto err;
}
ret = 0;
err:
writeb(I2C_CR_MEN, &dev->cr);
writeb(0, &dev->sr);
udelay(100);
return ret;
}
static void fsl_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
{
const struct fsl_i2c *dev;
const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT);
unsigned long long timeval;
#ifdef CONFIG_SYS_I2C_INIT_BOARD
/* Call board specific i2c bus reset routine before accessing the
@ -226,6 +267,18 @@ static void fsl_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
writeb(0x0, &dev->sr); /* clear status register */
writeb(I2C_CR_MEN, &dev->cr); /* start I2C controller */
timeval = get_ticks();
while (readb(&dev->sr) & I2C_SR_MBB) {
if ((get_ticks() - timeval) < timeout)
continue;
if (fsl_i2c_fixup(dev))
debug("i2c_init: BUS#%d failed to init\n",
adap->hwadapnr);
break;
}
#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
/* Call board specific i2c bus reset routine AFTER the bus has been
* initialized. Use either this callpoint or i2c_init_board;
@ -394,8 +447,10 @@ fsl_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr, int alen,
int i = -1; /* signal error */
u8 *a = (u8*)&addr;
if (i2c_wait4bus(adap) >= 0 &&
i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0 &&
if (i2c_wait4bus(adap) < 0)
return -1;
if (i2c_write_addr(adap, dev, I2C_WRITE_BIT, 0) != 0 &&
__i2c_write(adap, &a[4 - alen], alen) == alen) {
i = __i2c_write(adap, data, length);
}