On 3/1/21 11:40 PM, Martin DEVERA wrote:

On 3/1/21 11:28 AM, Fabrice Gasnier wrote:

quoted

On 2/27/21 5:41 PM, Martin Devera wrote:

quoted

STM32 F7/H7 usarts supports RX & TX pin swapping.
Add option to turn it on.
Tested on STM32MP157.

Signed-off-by: Martin Devera <redacted>
---
  drivers/tty/serial/stm32-usart.c | 3 ++-
  drivers/tty/serial/stm32-usart.h | 1 +
  2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/stm32-usart.c

b/drivers/tty/serial/stm32-usart.c
index b3675cf25a69..3650c8798061 100644

--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c

@@ -758,7 +758,7 @@ static void stm32_usart_set_termios(struct

uart_port *port,
      cr1 = USART_CR1_TE | USART_CR1_RE;
      if (stm32_port->fifoen)
          cr1 |= USART_CR1_FIFOEN;
-    cr2 = 0;
+    cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;

Hi Martin,

Same could be done in the startup routine, that enables the port for
reception (as described in Documentation/driver-api/serial/driver.rst)

Hello Fabrice,

I already incorporated all your comments but I'm struggling with the one
above.
The code must be in stm32_usart_set_termios too, because CR2 is modified.

Hi Martin,

Yes, sure,

What is the reason to have it in startup() ?

RX is enabled at both places. So the swap setting should be there too.

Is it because USART can be started without calling set_termios at all ?

Yes, that's what the driver API expects: "startup(port)" ... "Enable the
port for reception."

Best Regards,
Fabrice

Like
to reuse bootloader's last settings ?

Thanks, Martin