Hi :
I am using the 3.14.52 sdk for platform imx6ul, i meet a issue,
when i2c clk is disable, reading i2c register cause the cpu stopping, it
mean the cpu don't get any instruction, like cpu is stopped.
i don't know why, it is soc hw issue? summary information as follow:
at the file: drivers/i2c/busses/i2c-imx.c, add a workround patch for
ls1/ls2:
static int i2c_imx_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs, int num)
{
unsigned int i, temp;
int result;
bool is_lastmsg = false;
struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
+ /* workround for ERR010027: ensure that the I2C BUS is idle
+ * before switching to master mode and attempting a Start cycle
+ */
+ result = i2c_imx_bus_busy(i2c_imx, 0); -
> it will call
the imx_i2c_read_reg, and stop in the code "return readb(i2c_imx->base +
(reg << i2c_imx->hwdata->regshift));"
+ if (result) no any calltrace, like cpu stop here. if you remove
these add code, then it work well, or enable the i2c clk and control
before the add code.
+ goto fail0;
/* Start I2C transfer */
result = i2c_imx_start(i2c_imx);
if (result)
goto fail0;
/* read/write data */
for (i = 0; i < num; i++) {
if (i == num - 1)
is_lastmsg = true;
...........
}
attach is the booting log.
Regards,
czou
Original Attachment has been moved to: imx6ul-i2c-read-failed-.zip
