On 25/10/2016 18:22, Alexandre Belloni wrote:
> Hi,
>
> On 25/10/2016 at 18:11:35 +0200, Richard Genoud wrote :
>> commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when
>> hardware handshake is enabled"), despite its title, broke hardware
>> handshake on *every* Atmel platforms.
>>
>> The only one partially working is the SAMA5D2.
>>
>
> [...]
>
>> Changes since v4:
>> - the mctrl_gpio_use_rtscts() is gone since it was atmel_serial
>> specific. (so patch 1 is gone)
>> - patches 2 and 3 have been merged together since it didn't make
>> a lot of sense to correct the GPIO case in one separate patch.
>> - ATMEL_US_USMODE_HWHS is now unset for platform with PDC
>>
>> Changes since v3:
>> - remove superfluous #include <linux/err.h> (thanks to Uwe)
>> - rebase on next-20160930
>>
>> Changes since v2:
>> - remove IS_ERR_OR_NULL() test in patch 1/3 as Uwe suggested.
>> - fix typos in patch 2/3
>> - rebase on next-20160927
>> - simplify the logic in patch 3/3.
>>
>> Changes since v1:
>> - Correct patch 1 with the error found by kbuild.
>> - Add Alexandre's Acked-by on patch 2
>> - Rewrite patch 3 logic in the light of the on-going discussion
>> with Cyrille and Alexandre.
>>
>
> The changelog has to go after the --- marker.
You're right.
thanks !
>> * the list may not be exhaustive
>>
>> Signed-off-by: Richard Genoud <richard.genoud@xxxxxxxxx>
>
> Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
>
>> ---
>> drivers/tty/serial/atmel_serial.c | 25 +++++++++++++++++++++----
>> 1 file changed, 21 insertions(+), 4 deletions(-)
>>
>> I think this should go in the stable tree since it fixes the flow
>> control broken since v4.0.
>> But It won't compile on versions before 4.9rc1 because:
>> function atmel_use_fifo was introduced in 4.4.12 / 4.7
>> variable atmel_port was introduced in 4.9rc1
>>
>> That's why I didn't add the Cc stable in the email body.
>>
>>
>> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
>> index fd8aa1f4ba78..2c7c45904ba7 100644
>> --- a/drivers/tty/serial/atmel_serial.c
>> +++ b/drivers/tty/serial/atmel_serial.c
>> @@ -2132,11 +2132,28 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
>> mode |= ATMEL_US_USMODE_RS485;
>> } else if (termios->c_cflag & CRTSCTS) {
>> /* RS232 with hardware handshake (RTS/CTS) */
>> - if (atmel_use_dma_rx(port) && !atmel_use_fifo(port)) {
>> - dev_info(port->dev, "not enabling hardware flow control because DMA is used");
>> - termios->c_cflag &= ~CRTSCTS;
>> - } else {
>> + if (atmel_use_fifo(port) &&
>> + !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
>> + /*
>> + * with ATMEL_US_USMODE_HWHS set, the controller will
>> + * be able to drive the RTS pin high/low when the RX
>> + * FIFO is above RXFTHRES/below RXFTHRES2.
>> + * It will also disable the transmitter when the CTS
>> + * pin is high.
>> + * This mode is not activated if CTS pin is a GPIO
>> + * because in this case, the transmitter is always
>> + * disabled.
>> + * If the RTS pin is a GPIO, the controller won't be
>> + * able to drive it according to the FIFO thresholds,
>> + * but it will be handled by the driver.
>> + */
>> mode |= ATMEL_US_USMODE_HWHS;
>> + } else {
>> + /*
>> + * For platforms without FIFO, the flow control is
>> + * handled by the driver.
>> + */
>> + mode |= ATMEL_US_USMODE_NORMAL;
>> }
>> } else {
>> /* RS232 without hadware handshake */
>
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