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 <[email protected]>
---
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;
}
- /* 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);
+
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);
--
2.17.1
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 <[email protected]>
It seems that this bug was introduced by:
commit 5bf5635ac170 ("tty/serial: atmel: add fractional baud rate support")
Could you add the "Fixes:" header ?
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.
> 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 !
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 <[email protected]>
>
> 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 !
>
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 <[email protected]>
---
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 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;
--
2.17.1
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 <[email protected]>
> ---
> 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