linux-kernel - Re: sdhci driver card-detect is broken because gpiolib can't fallback to

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Message-ID: <CAHp75Vdf7NxFtgZx+hqsA1YZY4szD5Ba9jbyo4CeeDHeaU3YAQ@mail.gmail.com>
Date:   Wed, 26 Sep 2018 11:42:21 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:     Rajat Jain <rajatja@...gle.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Dmitry Torokhov <dtor@...gle.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-mmc <linux-mmc@...r.kernel.org>,
        Rajat Jain <rajatxjain@...il.com>
Subject: Re: sdhci driver card-detect is broken because gpiolib can't fallback
 to _CRS?

On Wed, Sep 26, 2018 at 10:49 AM Mika Westerberg
<mika.westerberg@...ux.intel.com> wrote:
>
> Hi,
>
> On Tue, Sep 25, 2018 at 01:54:57PM -0700, Rajat Jain wrote:
> > * Use con_id=NULL if it is dealing with a legacy BIOS (i.e. no _DSD
> > properties in the ACPI).
> > * Use con_id=<actual string> if it is dealing with a modern BIOS (i.e.
> > which provides _DSD for the <string> property)
>
> Or you can use con_id=<actual string> everywhere and supply
> acpi_dev_add_driver_gpios() where needed to cover cases where BIOS does
> not provide _DSD. See also Documentation/acpi/gpio-properties.txt for
> more information.

Thanks, Mika. That is exactly the way how I suggested to fix and
actually fixed a lot of drivers already.

Run `git grep -n -w devm_acpi_dev_add_driver_gpios` to find examples.

> In case of SDHCI I think the correct way is to stick using _CRS lookup
> only because there typically is just one GpioInt() and I have not seen a
> single BIOS yet where they implement _DSD for this besides yours. If
> there is not way to change the BIOS implementation then I guess we just
> need to amend the driver to call acpi_dev_add_driver_gpios().

True.

-- 
With Best Regards,
Andy Shevchenko