From 3bf699f7a8c650372b8d7e8ff4332a54e3a4fffa Mon Sep 17 00:00:00 2001 From: Alain Volmat <alain.volmat@foss.st.com> Date: Mon, 12 Sep 2022 10:42:00 +0200 Subject: [PATCH] i2c: stm32: do not set the STOP condition on error 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/20220815145211.31342-2-jorge@foundries.io/ Reported-by: Jorge Ramirez-Ortiz, Foundries <jorge@foundries.io> Signed-off-by: Jorge Ramirez-Ortiz <jorge@foundries.io> Signed-off-by: Alain Volmat <alain.volmat@foss.st.com> Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> Reviewed-by: Heiko Schocher <hs@denx.de> Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com> Tested-by: Patrick Delaunay <patrick.delaunay@foss.st.com> --- 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 8d680eea9b..80bd3c4caf 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); } -- 2.39.5