Re: [PATCH v4 3/4] i2c: stm32: do not set the STOP condition on error

[Patrick DELAUNAY]

Hi Alain

On 9/12/22 10:42, 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);

  }

Applied to u-boot-stm/master, thanks!


I also add the missing Reviewed-by when I get the patch from patchwork

http://patchwork.ozlabs.org/project/uboot/patch/20220912084201.1826979-4-alain.vol...@foss.st.com/

+    Reviewed-by: Patrice Chotard <patrice.chot...@foss.st.com>
+    Reviewed-by: Heiko Schocher <h...@denx.de>
+    Reviewed-by: Patrick Delaunay <patrick.delau...@foss.st.com>
+    Tested-by: Patrick Delaunay <patrick.delau...@foss.st.com>

Regards
Patrick