lkml.org 
[lkml]   [2020]   [Jan]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.14 72/91] tty/serial: atmel: fix out of range clock divider handling
Date
From: David Engraf <david.engraf@sysgo.com>

[ Upstream commit cb47b9f8630ae3fa3f5fbd0c7003faba7abdf711 ]

Use MCK_DIV8 when the clock divider is > 65535. Unfortunately the mode
register was already written thus the clock selection is ignored.

Fix by doing the baud rate calulation before setting the mode.

Fixes: 5bf5635ac170 ("tty/serial: atmel: add fractional baud rate support")
Signed-off-by: David Engraf <david.engraf@sysgo.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191216085403.17050-1-david.engraf@sysgo.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++---------------
1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 9ee41ba0e55b..367ce812743e 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2183,27 +2183,6 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
mode |= ATMEL_US_USMODE_NORMAL;
}

- /* 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
- */
- if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
- unsigned int rts_state;
-
- if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
- /* let the hardware control the RTS line */
- rts_state = ATMEL_US_RTSDIS;
- } else {
- /* force RTS line to low level */
- rts_state = ATMEL_US_RTSEN;
- }
-
- atmel_uart_writel(port, ATMEL_US_CR, rts_state);
- }
-
/*
* Set the baud rate:
* Fractional baudrate allows to setup output frequency more
@@ -2229,6 +2208,28 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
quot = cd | fp << ATMEL_US_FP_OFFSET;

atmel_uart_writel(port, ATMEL_US_BRGR, quot);
+
+ /* 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
+ */
+ if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
+ unsigned int rts_state;
+
+ if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
+ /* let the hardware control the RTS line */
+ rts_state = ATMEL_US_RTSDIS;
+ } else {
+ /* force RTS line to low level */
+ rts_state = ATMEL_US_RTSEN;
+ }
+
+ atmel_uart_writel(port, ATMEL_US_CR, rts_state);
+ }
+
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);

--
2.20.1


\
 
 \ /
  Last update: 2020-01-02 23:51    [W:0.349 / U:3.596 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site