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 --- drivers/i2c/fsl_i2c.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 56 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c index 5d7e010..ef0004d 100644 --- a/drivers/i2c/fsl_i2c.c +++ b/drivers/i2c/fsl_i2c.c @@ -222,9 +222,50 @@ static unsigned int get_i2c_clock(int bus) return gd->arch.i2c1_clk; /* I2C1 clock */ }
+static int 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; +} + void i2c_init(int speed, int slaveadd) { + const unsigned long long timeout = usec2ticks(CONFIG_I2C_MBB_TIMEOUT); + unsigned long long timeval; const struct fsl_i2c *dev; unsigned int temp; int bus_num, i; @@ -252,6 +293,17 @@ i2c_init(int speed, int slaveadd) writeb(slaveadd << 1, &dev->adr);/* write slave address */ 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 (i2c_fixup(dev)) + debug("i2c_init: BUS#%d failed to init\n", i); + + break; + } }
#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT @@ -412,8 +464,10 @@ i2c_write(u8 dev, uint addr, int alen, u8 *data, int length) int i = -1; /* signal error */ u8 *a = (u8*)&addr;
- if (i2c_wait4bus() >= 0 - && i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 + if (i2c_wait4bus() < 0) + return -1; + + if (i2c_write_addr(dev, I2C_WRITE_BIT, 0) != 0 && __i2c_write(&a[4 - alen], alen) == alen) { i = __i2c_write(data, length); }