Hi Alain
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxxxxxxx>
Regards
On 9/20/21 5:21 PM, Alain Volmat wrote:
> While handling an error during transfer (ex: NACK), it could
> happen that the driver has already written data into TXDR
> before the transfer get stopped.
> This commit add TXDR Flush after end of transfer in case of error to
> avoid sending a wrong data on any other slave upon next transfer.
>
> Fixes: aeb068c57214 ("i2c: i2c-stm32f7: add driver")
>
> Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-stm32f7.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index b9b19a2a2ffa..ed977b6f7ab6 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -1696,6 +1696,16 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
> time_left = wait_for_completion_timeout(&i2c_dev->complete,
> i2c_dev->adap.timeout);
> ret = f7_msg->result;
> + if (ret) {
> + /*
> + * It is possible that some unsent data have already been
> + * written into TXDR. To avoid sending old data in a
> + * further transfer, flush TXDR in case of any error
> + */
> + writel_relaxed(STM32F7_I2C_ISR_TXE,
> + i2c_dev->base + STM32F7_I2C_ISR);
> + goto pm_free;
> + }
>
> if (!time_left) {
> dev_dbg(i2c_dev->dev, "Access to slave 0x%x timed out\n",
> @@ -1744,8 +1754,16 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
> timeout = wait_for_completion_timeout(&i2c_dev->complete,
> i2c_dev->adap.timeout);
> ret = f7_msg->result;
> - if (ret)
> + if (ret) {
> + /*
> + * It is possible that some unsent data have already been
> + * written into TXDR. To avoid sending old data in a
> + * further transfer, flush TXDR in case of any error
> + */
> + writel_relaxed(STM32F7_I2C_ISR_TXE,
> + i2c_dev->base + STM32F7_I2C_ISR);
> goto pm_free;
> + }
>
> if (!timeout) {
> dev_dbg(dev, "Access to slave 0x%x timed out\n", f7_msg->addr);
>
--
--
~ Py MORDRET
--
