[PATCH 5/8] tty/serial: at91: add dtr control via gpio

[Richard Genoud]

2014-02-07 16:21 GMT+01:00 Alexander Shiyan <shc_work at mail.ru>:
> Hello.
>
> Пятница,  7 февраля 2014, 15:59 +01:00 от Richard Genoud <richard.genoud at gmail.com>:
>> On sam9x5, the USART controller doesn't handle DTR/DSR/DCD/RI signals,
>> so we have to control them via GPIO.
>>
>> This patch permits to use a GPIO to control the DTR signal.
>>
>> Signed-off-by: Richard Genoud <richard.genoud at gmail.com>
>> ---
> ...
>> +     if (gpio_is_valid(atmel_port->gpio.dtr)) {
>> +             if (mctrl & TIOCM_DTR)
>> +                     gpio_set_value(atmel_port->gpio.dtr, 0);
>> +             else
>> +                     gpio_set_value(atmel_port->gpio.dtr, 1);
>> +     }
>
> So, if you use GPIO for such purpose (here and in the other patches),
> you should take and use GPIO active level from bindings.
> It will make use of GPIO more flexible and deliver us from further special
> possible bindings to declare the active level.
Yes, I could do that. I'll have to change the alreday merged RTS
binding so that it gets it's active level from DTS, but I don't think
it's a problem, since it's not already in mainline.
Linus, Nicolas, what do you think ?

> Actually, it would be good to have a separate unit for mctrl GPIOs,
> which could be used for other drivers.
good idea, I can add them in serial_core.c

Thanks!

Richard.