linux-kernel - Re: [PATCH 2/2] gpio: sch: Add interrupt support

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Message-ID: <20190424100130.GB2654@lahna.fi.intel.com>
Date:   Wed, 24 Apr 2019 13:01:30 +0300
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     Jan Kiszka <jan.kiszka@...mens.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-gpio@...r.kernel.org, linux-acpi@...r.kernel.org,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH 2/2] gpio: sch: Add interrupt support

On Wed, Apr 24, 2019 at 11:48:09AM +0200, Jan Kiszka wrote:
> On 24.04.19 11:45, Mika Westerberg wrote:
> > On Wed, Apr 24, 2019 at 11:36:58AM +0200, Jan Kiszka wrote:
> > > OK, there is that table, but what is it supposed to tell me about the
> > > event and where to hook into it better?
> > ...
> > > [02Eh 0046   2]                SCI Interrupt : 0009
> > 
> > This is the SCI interrupt GSI number. IIRC it maps 1:1 to Linux
> > interrupt number so you should see it in /proc/interrupts. When a GPE
> > event is triggered it should be handled in the ACPI core.
> > 
> 
> Yes, clear, all this happens already. But I need to link the core with the
> sch gpio handler so that the gpio event is filtered out and the right
> virtual gpio interrupt is triggered. So, other than
> acpi_install_sci_handler, how should I establish that link?

I think what you want is "GPIO signaled ACPI event". It works so that
you declare _AEI method below the GPIO controller listing the GPIOs you
want to trigger events for and then either _Lxx, _Exx or _EVT method for
each of them under the same controller. GPIO core then handles it
automatically when you register the GPIO chip. See also
acpi_gpiochip_request_interrupts().