Re: [PATCH v3] input: Add support for ChipOne icn8318 based touchscreens

[Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

Hi,

On 03/22/2015 11:42 PM, Dmitry Torokhov wrote:
> On Sun, Mar 22, 2015 at 12:00:55PM +0100, Hans de Goede wrote:
>> Hi,
>>
>> On 22-03-15 05:03, Dmitry Torokhov wrote:
>>> Hi Hans,
>>>
>>> On Tue, Mar 10, 2015 at 06:05:33PM +0100, Hans de Goede wrote:
>>>> +	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
>>>> +					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>>>
>>> Shouldn't we let DT data tell us what trigger to use? I.e. just leave
>>> IRQF_ONESHOT here?
>>
>> That is an interesting question, that new data is available is signalled by
>> the irq pin of the chip going low is a property of the chip, not the board
>> layout, so I believe it is best to leave this as is.
>
> My concern is that even if pin behavior is property of chip maybe on
> some boards we want to use level-triggered interrupts instead of edge?
> And if we indeed want to hard-code the trigger then shouldn't the
> binding document use onecell mapping (so that users do not attempt to
> configure triggers from DT)?

The number of irq cells is specified by the interrupt controller driver
rather then by the device binding.

>
>>
>> Also note that if we want to get this from devicetree, that simply leaving out the
>> flag is not enough, we must specifically get the data from devicetree and pass
>> it into request_irq AFAICT. So the above would change to:
>>
>> 	irqflags = irqd_get_trigger_type(irq_get_irq_data(client->irq)) | IRQF_ONESHOT,
>> 	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq, irqflags,
>
> No, of_irq_get() that i2c core calls before probing driver should
> already set the trigger type for us. There is no need for the individual
> drivers to do that.

Ah I see, ok I've just tested removing the IRQF_TRIGGER_FALLING flag and indeed
things still work fine, so feel free to merge this patch with that flagged dropped.

Regards,

Hans