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To:     linux-kernel@vger.kernel.org
From:   Grant Edwards <grant.b.edwards@gmail.com>
Subject: Re: serial: custom baud rate
Date:   Mon, 14 May 2018 15:36:56 +0000 (UTC)
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On 2018-05-13, Alan Cox <gnomes@lxorguk.ukuu.org.uk> wrote:
> On Thu, 3 May 2018 18:27:14 +0000 (UTC)
> Grant Edwards <grant.b.edwards@gmail.com> wrote:
>
>> On 2018-05-03, Muni Sekhar <munisekharrms@gmail.com> wrote:
>> 
>> > If I need to set a custom baud rates(e.g. 14400, 128000, 256000), does
>> > Linux serial framework has any supporting method?  
>> 
>> Sure, use the termios2 structure instead of the termios structure:
>> 
>>   #include <linux/termios.h>
>> 
>>   struct termios2 t;
>> 
>>   ioctl(fd, TCGETS2, &t)
>> 
>>   t.c_cflag &= ~CBAUD;
>>   t.c_cflag |= BOTHER;
>>   t.c_ispeed = baud;
>>   t.c_ospeed = baud;
>> 
>>   ioctl(fd, TCSETS2, &t)
>> 
>> [Not all devices/drivers support termios2]
>
> That shouldn't be true - all devices get passed ispeed/ospeed and
> everything in tree was using the correct fields as far as I could
> tell last time I checked this

Yep, my mistake.  It looks like the driver where I last ran into this
was an old out-of-tree driver.

-- 
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