linux-kernel - Re: [PATCH 1/2] Input: atmel_mxt_ts - Get IRQ edge/level flags on DT booting

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Date:	Thu, 07 Aug 2014 03:47:24 +0200
From:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
To:	Tomasz Figa <tomasz.figa@...il.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:	Nick Dyer <nick.dyer@...ev.co.uk>,
	Stephen Warren <swarren@...dia.com>,
	Yufeng Shen <miletus@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Doug Anderson <dianders@...omium.org>,
	Olof Johansson <olof@...om.net>, linux-input@...r.kernel.org,
	devicetree@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] Input: atmel_mxt_ts - Get IRQ edge/level flags on
 DT booting

Hello Tomasz,

Thanks a lot for your feedback.

On 08/07/2014 03:14 AM, Tomasz Figa wrote:
> Hi Javier,
> 
> 
> Have you observed an actual failure due to this? I believe that

Yes, I found this issue since the driver was not taking into account the value
defined in the edge/level type cells from the "interrupts" DT property.

Only doing the change in the following patch was not enough:

[PATCH 1/1] ARM: dts: Add Peach Pit and Pi dts entry for atmel touchpad [0].

> irq_of_parse_and_map() already sets up IRQ trigger type based on DT
> data, by calling irq_create_of_mapping() which in turn calls
> irq_set_irq_type().
>

Right but somehow when the IRQ is actually requested the type is overwritten by
the value passed to request_threaded_irq() and interrupts are not being
generated by the device without this patch.

Do you think that this is a bug in the "interrupt-parent" irqchip driver or the
IRQ core? I'm not that familiar with the IRQ subsystem.

>>  
>> +	if (client->dev.of_node)
>> +		irqflags = irq_get_trigger_type(client->irq);
> 
> It might be a bit cleaner to just assign the flags to pdata->irqflags in
> mxt_parse_dt() instead. That would also account for the fact that pdata,
> if provided, should have priority over DT.
> 

You are totally right, also this will break if CONFIG_OF is not enabled since
dev.of_node will not be defined. While this already is taken into account for
mxt_parse_dt() by defining an empty function.

I'll change it in v2 if getting the flags from the driver is the right approach
instead of fixing the irqchip driver or the IRQ core.

> Best regards,
> Tomasz
> 

Best regards,
Javier

[0]: http://www.spinics.net/lists/kernel/msg1802099.html
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