Current function stm32_i2c_message_xfer is sending a STOP whatever the result of the transaction is. This can cause issues such as making the bus busy since the controller itself is already sending automatically a STOP when a NACK is generated.
Thanks to Jorge Ramirez-Ortiz for diagnosing and proposing a first fix for this. [1] [1] https://lore.kernel.org/u-boot/[email protected]/ Reported-by: Jorge Ramirez-Ortiz, Foundries <[email protected]> Signed-off-by: Jorge Ramirez-Ortiz <[email protected]> Signed-off-by: Alain Volmat <[email protected]> --- drivers/i2c/stm32f7_i2c.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c index 0ec67b5c12..2db7f44d44 100644 --- a/drivers/i2c/stm32f7_i2c.c +++ b/drivers/i2c/stm32f7_i2c.c @@ -483,9 +483,9 @@ static int stm32_i2c_message_xfer(struct stm32_i2c_priv *i2c_priv, } } - /* End of transfer, send stop condition */ - mask = STM32_I2C_CR2_STOP; - setbits_le32(®s->cr2, mask); + /* End of transfer, send stop condition if appropriate */ + if (!ret && !(status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS))) + setbits_le32(®s->cr2, STM32_I2C_CR2_STOP); return stm32_i2c_check_end_of_message(i2c_priv); } -- 2.25.1
