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i2c: stm32f7: flush TX FIFO upon transfer errors

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commit 0c21d02ca4 upstream.

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: aeb068c572 ("i2c: i2c-stm32f7: add driver")
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alain Volmat
2021-09-20 17:21:29 +02:00
committed by Greg Kroah-Hartman
parent 1c75779dd9
commit 8de6ea757c
1 changed files with 19 additions and 1 deletions
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20
drivers/i2c/busses/i2c-stm32f7.c
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@@ -1665,6 +1665,16 @@ 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",
@@ -1713,8 +1723,16 @@ 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);