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Commit bc0215cb authored by Alain Volmat's avatar Alain Volmat Committed by Greg Kroah-Hartman
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i2c: stm32f7: flush TX FIFO upon transfer errors 



commit 0c21d02ca469574d2082379db52d1a27b99eed0c 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: aeb068c5 ("i2c: i2c-stm32f7: add driver")
Signed-off-by: default avatarAlain Volmat <alain.volmat@foss.st.com>
Reviewed-by: default avatarPierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 742a5ae1

drivers/i2c/busses/i2c-stm32f7.c

+19 −1
Original line number Diff line number Diff line
@@ -1586,6 +1586,16 @@ 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",
@@ -1634,8 +1644,16 @@ 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);