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

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.
What is the reason to have it in startup() ?
Is it because USART can be started without calling set_termios at all ? Like
to reuse bootloader's last settings ?

Thanks, Martin


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