From: Grant Likely <grant.likely@secretlab.ca>
To: Viresh Kumar <viresh.kumar@linaro.org>, lee.jones@linaro.org
Cc: 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: Mon, 26 Nov 2012 18:40:15 +0000 [thread overview]
Message-ID: <20121126184015.784993E091F@localhost> (raw)
In-Reply-To: <CAKohpomAM2pw9kgB6khtHzQ2WCXKZ9_pi1_sOH2dQToVS8ep4w@mail.gmail.com>
On Fri, 23 Nov 2012 23:03:47 +0530, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 23 November 2012 15:11, Grant Likely <grant.likely@secretlab.ca> wrote:
> > On Fri, 23 Nov 2012 00:26:20 +0530, Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> >> + - irq-trigger : IRQ trigger to use for the interrupt to the host
> >> + - irq-invert-polarity : bool, IRQ line is connected with reversed polarity
> >
> > This looks odd. Normally the interrupt polarity should be encoded in the irq
> > specifier flags field.
>
> Hi Grant and Lee Jones,
>
> This looks odd because stmpe is odd, i am taking the discussion held
> with Lee jones to this thread.
>
> So, how interrupt stuff works currently in DT..
> We have a interrupt controller IC:
>
> ic: interrupt-controller@40008000 {
> compatible = "foo";
> interrupt-controller;
> #interrupt-cells = <2>;
> ...
> };
>
> And we have a user of this IC:
>
> foo-peripheral@40048000 {
> compatible = "foo-peripheral";
> interrupt-parent = <&ic>;
> interrupts = <39 4>;
> };
>
> Here first field of "interrupts" gives interrupt line number and the second one
> gives polarity, interrupt type etc..
>
> All is good till now. Now, every interrupt controller supports the first
> field, but the second one depends on its capabilities. An interrupt controller
> might not have registers to configure interrupt polarity, type, etc of
> the interrupt
> it will service and so the second field wouldn't be available for them.
>
> For now just think stmpe is not a MFD and not a interrupt controller
> either. It is
> just a simple device, dev-foo.
>
> It will declare values of its interrupts field based on the type of
> interrupt controller
> that will service its interrupt and that can be anything like VIC/GIC/GPIO
> controller.
Ah, so it is configuring the way the device emits interrupts; not how
the interrupt controller processes them. Fair enough.
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?
g.
next prev parent reply other threads:[~2012-11-26 21:33 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-22 18:56 [PATCH V1 1/3] mfd: stmpe: Arrange #include <header files> in alphabetical order Viresh Kumar
2012-11-22 18:56 ` [PATCH V1 2/3] mfd: stmpe-i2c: Move .driver structure fields inside {} in stmpe_i2c_driver Viresh Kumar
2012-11-26 11:15 ` Samuel Ortiz
2012-11-22 18:56 ` [PATCH V3 3/3] mfd: stmpe: Update DT support in stmpe driver Viresh Kumar
2012-11-23 9:41 ` Grant Likely
2012-11-23 17:33 ` Viresh Kumar
2012-11-26 11:18 ` Lee Jones
2012-11-26 18:40 ` Grant Likely [this message]
2012-11-27 2:40 ` Viresh Kumar
2012-11-27 3:28 ` Viresh Kumar
2012-11-27 8:40 ` Lee Jones
2012-11-27 8:46 ` Viresh Kumar
2012-11-27 19:55 ` Rabin Vincent
2012-11-28 2:13 ` Viresh Kumar
2012-11-28 9:00 ` Lee Jones
2012-11-23 10:03 ` Lee Jones
2012-11-26 11:16 ` [PATCH V1 1/3] mfd: stmpe: Arrange #include <header files> in alphabetical order Samuel Ortiz
2012-11-26 11:22 ` Viresh Kumar
2012-11-26 13:25 ` Lee Jones
2012-11-26 14:55 ` Viresh Kumar
2012-11-26 15:31 ` Lee Jones
2012-11-26 16:05 ` Samuel Ortiz
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