Re: [PATCH V3 3/3] mfd: stmpe: Update DT support in stmpe driver

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: lee.jones@linaro.org, sameo@linux.intel.com,
	devicetree-discuss@lists.ozlabs.org, spear-devel@list.st.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3 3/3] mfd: stmpe: Update DT support in stmpe driver
Date: Tue, 27 Nov 2012 08:58:44 +0530	[thread overview]
Message-ID: <CAKohpomOxfLhpZqpk3aymdNa7UAGRcex7d+N5srkFDnrhtULTw@mail.gmail.com> (raw)
In-Reply-To: <CAKohpo=dHz-fJRdwovOWesAZJwibgrNk-+2t--JK+T_sBsu9Tw@mail.gmail.com>

On 27 November 2012 08:10, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 27 November 2012 00:10, Grant Likely <grant.likely@secretlab.ca> wrote:
>> It would actually be good to ask the interrupt controller driver what
>> kind of interrupt signal it expects for a given interrupt line. That
>> should also solve the problem and I think it would be more useful to
>> other devices. Can you investigate whether or not
>> irqd_get_trigger_type() returns the information you need?
>
> That's a pretty cool function to use. :)
>
> Will check it out :)

I was thinking about this logic in my earlier mail, don't know what stopped me
from thinking it is wrong. :(

Problem is with invert polarity, which the interrupt controller is not aware of.
For example, suppose interrupt controller needs Rising edge interrupt, but
the board has inverted the line between stmpe and IC. So, we will get
Rising high from the routine you mentioned, but we need to generate
opposite of that to make it rising high.

And so interrupt polarity field is still required.

--
viresh