[v2] tty/serial: atmel: fix out of range clock divider handling
diff mbox series

Message ID 20191213140301.16490-1-david.engraf@sysgo.com
State Mainlined
Commit cb47b9f8630ae3fa3f5fbd0c7003faba7abdf711
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Series
  • [v2] tty/serial: atmel: fix out of range clock divider handling
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Commit Message

David Engraf Dec. 13, 2019, 2:03 p.m. UTC
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>
---
 drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++---------------
 1 file changed, 22 insertions(+), 21 deletions(-)

Comments

Greg KH Dec. 13, 2019, 4:07 p.m. UTC | #1
On Fri, Dec 13, 2019 at 03:03:01PM +0100, David Engraf wrote:
> 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>
> ---
>  drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++---------------
>  1 file changed, 22 insertions(+), 21 deletions(-)

What changed from v1?

Always put that below the --- line.

v3 please?

thanks,

greg k-h
David Engraf Dec. 16, 2019, 8:34 a.m. UTC | #2
On 13.12.19 at 17:07, Greg KH wrote:
> On Fri, Dec 13, 2019 at 03:03:01PM +0100, David Engraf wrote:
>> 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>
>> ---
>>   drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++---------------
>>   1 file changed, 22 insertions(+), 21 deletions(-)
> 
> What changed from v1?
> 
> Always put that below the --- line.

Oh sorry.

> v3 please?

Sure.

Best regards
- David

> thanks,
> 
> greg k-h
>

Patch
diff mbox series

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index a8dc8af83f39..1ba9bc667e13 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2270,27 +2270,6 @@  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
@@ -2317,6 +2296,28 @@  static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
 		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);
 	atmel_port->tx_stopped = false;