Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs
From: Richard Genoud
Date: Fri Sep 30 2016 - 08:27:37 EST
2016-09-30 13:54 GMT+02:00 Alexandre Belloni
> On 30/09/2016 at 13:45:47 +0200, Richard Genoud wrote :
>> 2016-09-30 13:16 GMT+02:00 Alexandre Belloni
>> > On 30/09/2016 at 13:04:28 +0200, Richard Genoud wrote :
>> >> Anyway, the problematics setups are all the setups with USMODE_HWHS
>> >> enabled on platform without Fifos or PDC,
>> >> i.e. all platforms but sama5d2 (Cyrille, correct me if I'm wrong).
>> > This is a wrong assumption, at91rm9200 to at91sam9g45 all have a pdc.
>> > Please, don't break those platforms.
>> > The only affected platforms are sam9x5, sama5d3 and sama5d4.
>> Have you tested them ?
>> And why are you saying that rm9200 and g45 will be broken with this patch ?
>> If they have a pdc, they will fall in the case:
>> (atmel_use_pdc_rx(port) || atmel_use_fifo(port))
>> and thus use:
>> mode |= ATMEL_US_USMODE_HWHS;
>> won't they ?
> Well, this patch wouldn't have my ack if it was breaking them.
Read the code.
>However, I'm still not sure about 3/3.
As I said 2 weeks from now ( https://lkml.org/lkml/2016/9/14/263 ) the
only case where
we would want to drop the CRTSCTS flag is when there's no pin muxed
for CTS/RTS nor GPIOs.
Fell free to give a patch for that.
To be clear : this patch (2/3) unbreaks ALL platforms with GPIOs as CTS/RTS
and 3/3 unbreaks sam9x5 / sama5d3 / sama5d4 platform with CTS/RTS as !GPIOs.