Re: [PATCH v3 3/3] i2c: stm32: do not set the STOP condition on error

[Patrice CHOTARD]

Hi Alain

On 9/9/22 18:06, Alain Volmat wrote:
> 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-jo...@foundries.io/
> 
> Reported-by: Jorge Ramirez-Ortiz, Foundries <jo...@foundries.io>
> Signed-off-by: Jorge Ramirez-Ortiz <jo...@foundries.io>
> Signed-off-by: Alain Volmat <alain.vol...@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 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(&regs->cr2, mask);
> +     /* End of transfer, send stop condition if appropriate */
> +     if (!ret && !(status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS)))
> +             setbits_le32(&regs->cr2, STM32_I2C_CR2_STOP);
>  
>       return stm32_i2c_check_end_of_message(i2c_priv);
>  }

Reviewed-by: Patrice Chotard <patrice.chot...@foss.st.com>

Thanks
Patrice