linux-kernel - Re: [PATCH 1/8] Input: elan_i2c - Use PM subsystem to manage wake irq

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Date:   Thu, 1 Sep 2022 09:57:55 +0300
From:   Tony Lindgren <tony@...mide.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Raul Rangel <rrangel@...omium.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        linux-input <linux-input@...r.kernel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Mario Limonciello <mario.limonciello@....com>,
        Tim Van Patten <timvp@...gle.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        "jingle.wu" <jingle.wu@....com.tw>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/8] Input: elan_i2c - Use PM subsystem to manage wake irq

* Rafael J. Wysocki <rafael@...nel.org> [220831 18:35]:
> On Wed, Aug 31, 2022 at 8:14 PM Raul Rangel <rrangel@...omium.org> wrote:
> >
> > On Wed, Aug 31, 2022 at 12:01 PM Rafael J. Wysocki <rafael@...nel.org> wrote:
> > >
> > > On Wed, Aug 31, 2022 at 1:16 AM Raul E Rangel <rrangel@...omium.org> wrote:
> > > >
> > > > The Elan I2C touchpad driver is currently manually managing the wake
> > > > IRQ. This change removes the explicit enable_irq_wake/disable_irq_wake
> > > > and instead relies on the PM subsystem. This is done by calling
> > > > dev_pm_set_wake_irq.
> > > >
> > > > i2c_device_probe already calls dev_pm_set_wake_irq when using device
> > > > tree, so it's only required when using ACPI. The net result is that this
> > > > change should be a no-op. i2c_device_remove also already calls
> > > > dev_pm_clear_wake_irq, so we don't need to do that in this driver.
> > > >
> > > > I tested this on an ACPI system where the touchpad doesn't have _PRW
> > > > defined. I verified I can still wake the system and that the wake source
> > > > was the touchpad IRQ GPIO.
> > > >
> > > > Signed-off-by: Raul E Rangel <rrangel@...omium.org>
> > >
> >
> >
> > > I like this a lot, but the assumption in the wakeirq code is that the
> > > IRQ in question will be dedicated for signaling wakeup.  Does it hold
> > > here?
> >
> > The wakeirq code defines two methods: `dev_pm_set_wake_irq` and
> > `dev_pm_set_dedicated_wake_irq`.
> > The latter is used when you have a dedicated wakeup signal. In this
> > driver it's currently assumed
> > that the IRQ and the wake IRQ are the same, so I used `dev_pm_set_wake_irq`.
> >
> > This change in theory also fixes a bug where you define a dedicated
> > wake irq in DT, but
> > then the driver enables the `client->irq` as a wake source. In
> > practice this doesn't happen
> > since the elan touchpads only have a single IRQ line.
> 
> OK, thanks!
> 
> Please feel free to add
> 
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> to the patch.

Looks good to me too:

Reviewed-by: Tony Lindgren <tony@...mide.com>