Re: [PATCH v2] serial: 8250_dw: support high baudrates if possible

From: Alex Elder
Date: Thu Jul 10 2014 - 23:12:11 EST


On 07/10/2014 06:13 PM, Greg KH wrote:
> On Tue, Jul 01, 2014 at 10:15:34AM -0500, Alex Elder wrote:
>> Currently the Synopsys DesignWare 8250 driver assumes its UART clock
>> runs at a fixed rate. If a "real" clock was set up using the common
>> clock framework, and that clock's rate is adjustable, it may be
>> possible to support a wider range of baud rates by changing the
>> UART clock rate.
>>
>> This is done by setting up a uart_port->set_termios method that
>> requests a clock rate change if a different rate might make it
>> more likely to achieve a specified baud. A new function
>> dw8250_adjustable_clk() determines whether such clock rate
>> adjustment is an option.
>>
>> Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
>> ---
>> v2: Limit clock changing to specific compatible devices.
>>
>> drivers/tty/serial/8250/8250_dw.c | 57 +++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 57 insertions(+)
>
> This no longer applies due to other changes in this driver. Can you
> please refresh it against my tty-next branch of the tty.git tree and
> resend?

Interesting. Heikki seems to have generalized
byt_set_termios() into dw8250_set_termios(), such
that it's almost the same as what I did.

I think I can just reuse it and simplify my patch
considerably. But I'll do that in the morning...

-Alex


> thanks,
>
> greg k-h
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/