From: Alain Volmat Date: Mon, 20 Sep 2021 15:21:29 +0000 (+0200) Subject: i2c: stm32f7: flush TX FIFO upon transfer errors X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a153d4253530ef2b9a258cd0ed4771f0dd5774c7;p=linux.git 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: aeb068c57214 ("i2c: i2c-stm32f7: add driver") Signed-off-by: Alain Volmat Reviewed-by: Pierre-Yves MORDRET Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c index b9b19a2a2ffa0..ed977b6f7ab67 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);