diff mbox series

serial: stm32: Clear prev values before setting RTS delays

Message ID 20220627150753.34510-1-ilpo.jarvinen@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series serial: stm32: Clear prev values before setting RTS delays | expand

Commit Message

Ilpo Järvinen June 27, 2022, 3:07 p.m. UTC
The code lacks clearing of previous DEAT/DEDT values. Thus, changing
values on the fly results in garbage delays tending towards the maximum
value as more and more bits are ORed together. (Leaving RS485 mode
would have cleared the old values though).

Fixes: 1bcda09d2910 ("serial: stm32: add support for RS485 hardware control mode")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

---
 drivers/tty/serial/stm32-usart.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index db3dd9731ee1..0cfe183f4076 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -72,6 +72,8 @@  static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
 	*cr3 |= USART_CR3_DEM;
 	over8 = *cr1 & USART_CR1_OVER8;
 
+	*cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
+
 	if (over8)
 		rs485_deat_dedt = delay_ADE * baud * 8;
 	else