Hi,
On 13.12.19 at 10:57, Richard Genoud wrote:
Hi,
Le 11/12/2019 à 17:29, David Engraf a écrit :
Use MCK_DIV8 when the clock divider is > 65535. Unfortunately the mode
register was already written thus the clock selection is ignored.
Fix by writing the mode register after calculating the baudrate.
Signed-off-by: David Engraf <david.engraf@xxxxxxxxx>
It seems that this bug was introduced by:
commit 5bf5635ac170 ("tty/serial: atmel: add fractional baud rate support")
Could you add the "Fixes:" header ?
Sure.
Ludovic, could you check if this was your intent at the time ?
---
drivers/tty/serial/atmel_serial.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index a8dc8af83f39..9983e2fabbac 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2270,9 +2270,6 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
mode |= ATMEL_US_USMODE_NORMAL;
}
I think it's better to mo move the "Set baud rate" block here (cf bellow)
- /* set the mode, clock divisor, parity, stop bits and data size */
- atmel_uart_writel(port, ATMEL_US_MR, mode);
-
/*
* when switching the mode, set the RTS line state according to the
* new mode, otherwise keep the former state
@@ -2315,6 +2312,9 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
}
quot = cd | fp << ATMEL_US_FP_OFFSET;
+ /* set the mode, clock divisor, parity, stop bits and data size */
+ atmel_uart_writel(port, ATMEL_US_MR, mode);
+
I think your patch is good, but I'll be happier if instead of moving
those 2 lines here, the whole "Set the baud rate" block was moved before
"atmel_uart_writel(port, ATMEL_US_MR, mode);"
That's because at line 2291 the ATMEL_US_CR register is set with
ATMEL_US_RTSDIS or ATMEL_US_RTSEN.
And those 2 values have a different effect depending on US_MR.USART_MODE
Quoting from the relase manual:
RTSEN:
1: Drives RTS pin to 1 if US_MR.USART_MODE field = 2, else drives RTS
pin to 0 if US_MR.USART_MODE field = 0.
RTSDIS:
1: Drives RTS pin to 0 if US_MR.USART_MODE field = 2, else drives RTS
pin to 1 if US_MR.USART_MODE field = 0.
So, I think it's better to set the mode register before setting the
control register.
I fully agree, the RTS pin configuration depends on USART_MODE. I will
make a new version of the patch.
Thanks
- David
if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
atmel_uart_writel(port, ATMEL_US_BRGR, quot);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
Thanks !
