linux-kernel - Re: [PATCH v3 3/5] mfd: arizona: Add support for ACPI enumeration of WM5102 connected over SPI

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Date:   Wed, 20 Jan 2021 21:59:13 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Mark Brown <broonie@...nel.org>, Lee Jones <lee.jones@...aro.org>,
        Cezary Rojewski <cezary.rojewski@...el.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Liam Girdwood <liam.r.girdwood@...ux.intel.com>,
        Jie Yang <yang.jie@...ux.intel.com>,
        patches@...nsource.cirrus.com,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        ALSA Development Mailing List <alsa-devel@...a-project.org>,
        Christian Hartmann <cornogle@...glemail.com>
Subject: Re: [PATCH v3 3/5] mfd: arizona: Add support for ACPI enumeration of
 WM5102 connected over SPI

On Wed, Jan 20, 2021 at 9:18 PM Hans de Goede <hdegoede@...hat.com> wrote:
> On 1/18/21 2:34 PM, Mark Brown wrote:
> > On Mon, Jan 18, 2021 at 02:13:50PM +0100, Hans de Goede wrote:
> >
> >> More in general I'm not aware of any (recent-ish) x86 GPIO controllers
> >> not being able to do active low interrupts. In theory we could hit this
> >> code path on ARM devices using ACPI enumeration, but I don't think it
> >> is likely we will see a combination of ARM + ACPI enumeration +
> >> WM5102 + GPIO controller not capable of active-low interrupts.
> >
> > I've not seen this issue on any ARM based systems.
> >
> >> This overriding of the flags definitely is necessary on the Lenovo
> >> devices in question. I could add a
> >> "if (dmi_name_in_vendors("LENOVO"))" guard around it, but that
> >> seems unnecessary.
> >
> > Possibly just an update to the comment to make it clear that some
> > firmwares might legitimately set the flag?
>
> Ok, I've extended the comment above the override of the irq-flags with
> the following paragraph for v4 of this patch-set:
>
>          * Note theoretically it is possible that some boards are not capable
>          * of handling active low level interrupts. In that case setting the
>          * flag to IRQF_TRIGGER_FALLING would not be a bug (and we would need
>          * to work around this) but sofar all known usages of IRQF_TRIGGER_FALLING

so far

>          * are a bug in the boards DSDT.

board's

-- 
With Best Regards,
Andy Shevchenko