Re: [PATCH v3 6/6] mmc: sdhci-acpi: Add quirk to enable pull-up on the card-detect GPIO on Asus T100TA

[Hans de Goede <hdegoede@redhat.com>]

Hi Andy,

On 4/10/24 10:06 PM, Andy Shevchenko wrote:
> On Wed, Apr 10, 2024 at 09:16:39PM +0200, Hans de Goede wrote:
>> The card-detect GPIO for the microSD slot on Asus T100TA / T100TAM models
>> stopped working under Linux after commit 6fd03f024828 ("gpiolib: acpi:
>> support bias pull disable").
>>
>> The GPIO in question is connected to a mechanical switch in the slot
>> which shorts the pin to GND when a card is inserted.
>>
>> The GPIO pin correctly gets configured with a 20K pull-up by the BIOS,
>> but there is a bug in the DSDT where the GpioInt for the card-detect is
>> configured with a PullNone setting:
>>
>>     GpioInt (Edge, ActiveBoth, SharedAndWake, PullNone, 0x2710,
>>         "\\_SB.GPO0", 0x00, ResourceConsumer, ,
>>         )
>>         {   // Pin list
>>         0x0026
>>         }
>>
>> Linux now actually honors the PullNone setting and disables the 20K pull-up
>> configured by the BIOS.
>>
>> Add a new DMI_QUIRK_SD_CD_ENABLE_PULL_UP quirk which when set calls
>> mmc_gpiod_set_cd_config() to re-enable the pull-up and set this for
>> the Asus T100TA models to fix this.
> 
> ...
> 
>> +			mmc_gpiod_set_cd_config(host->mmc,
>> +						PIN_CONF_PACKED(PIN_CONFIG_BIAS_PULL_UP, 20000));
> 
> 
> Just noticed, the PIN_CONF_PACKED() is a helper for pinconf-generic.h. It seems
> unusual to use it directly, and AFAIU documentation, it's for static
> initialisations, however it's not explicitly said.

I saw the static vs runtime comment, but I assumed that applies
to the parameters passed to PIN_CONF_PACKED() being determined at
runtime (not the cases here) vs the parameters being static / const.

Regards,

Hans