Re: [PATCH 20/51] Input: atmel_mxt_ts - Set default irqflags when there is no pdata

From: Yufeng Shen
Date: Mon May 26 2014 - 14:18:35 EST


On Sat, May 24, 2014 at 8:41 AM, Nick Dyer <nick.dyer@xxxxxxxxxxx> wrote:
> Yufeng Shen wrote:
>> On Thu, May 22, 2014 at 10:29 AM, Nick Dyer <nick.dyer@xxxxxxxxxxx> wrote:
>>> Dmitry Torokhov wrote:
>>>>>> Make the irqflags default to be IRQF_TRIGGER_FALLING if no platform data is
>>>>>> provided.
>>>>
>>>> I think if there is no platform data we should use 0 as IRQ falgs and
>>>> assume that IRQ line is properly configured by the board code or via
>>>> device tree.
>>>
>>> Benson/Yufeng - do you still have a requirement to probe without platform
>>> data or device tree? I'm just merging in some changes to add device tree
>>> support, and it would simplify things a bit if I can drop this patch.
>>
>> It has been working for quite a while for boards/devices that don't
>> provide platform data. If we drop the default IRQ flags, sure we can add
>> code for each board to configure the IRQ separately, but that's just
>> adding extra work. Is there strong reason why we should not do the
>> default setting in the driver if it is not already configured in
>> platform data?
>
> OK, I will keep it in my tree for the moment, since you are using it.
>
> The reason I checked is that in general, I would like to be conservative
> about what is pushed upstream, because it will need maintaining for a long
> time.
>
> The other reason is that in fact Atmel recommend IRQF_TRIGGER_LOW for these
> chips, not IRQF_TRIGGER_FALLING, so there is a bit of an inconsistency here.

I think I chose IRQF_TRIGGER_FALLING is because when I do a search in
the upstream
code where platform is configured, the irq is always set to be
IRQF_TRIGGER_FALLING
so I was assuming IRQF_TRIGGER_FALLING is a safe bet.

But you would definitely know better than me on this since the atmel
chips that I have
access to are quite limited.
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