[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@xxxxxxxxxx>]

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.

Fixes: 6fd03f024828 ("gpiolib: acpi: support bias pull disable")
Reviewed-by: Andy Shevchenko <andy@xxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Cc: Nuno Sá <nuno.sa@xxxxxxxxxx>
---
Changes v2:
- Add {} to else if (quirks & DMI_QUIRK_SD_CD_ENABLE_PULL_UP) branch
---
 drivers/mmc/host/sdhci-acpi.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
index f7d4808413cb..eb8f427f9770 100644
--- a/drivers/mmc/host/sdhci-acpi.c
+++ b/drivers/mmc/host/sdhci-acpi.c
@@ -10,6 +10,7 @@
 #include <linux/export.h>
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/pinctrl/pinconf-generic.h>
 #include <linux/platform_device.h>
 #include <linux/ioport.h>
 #include <linux/io.h>
@@ -81,6 +82,7 @@ enum {
 	DMI_QUIRK_RESET_SD_SIGNAL_VOLT_ON_SUSP			= BIT(0),
 	DMI_QUIRK_SD_NO_WRITE_PROTECT				= BIT(1),
 	DMI_QUIRK_SD_CD_ACTIVE_HIGH				= BIT(2),
+	DMI_QUIRK_SD_CD_ENABLE_PULL_UP				= BIT(3),
 };
 
 static inline void *sdhci_acpi_priv(struct sdhci_acpi_host *c)
@@ -734,6 +736,14 @@ static const struct dmi_system_id sdhci_acpi_quirks[] = {
 		},
 		.driver_data = (void *)DMI_QUIRK_SD_NO_WRITE_PROTECT,
 	},
+	{
+		/* Asus T100TA, needs pull-up for cd but DSDT GpioInt has NoPull set */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "T100TA"),
+		},
+		.driver_data = (void *)DMI_QUIRK_SD_CD_ENABLE_PULL_UP,
+	},
 	{
 		/*
 		 * The Lenovo Miix 320-10ICR has a bug in the _PS0 method of
@@ -908,6 +918,9 @@ static int sdhci_acpi_probe(struct platform_device *pdev)
 				goto err_free;
 			dev_warn(dev, "failed to setup card detect gpio\n");
 			c->use_runtime_pm = false;
+		} else if (quirks & DMI_QUIRK_SD_CD_ENABLE_PULL_UP) {
+			mmc_gpiod_set_cd_config(host->mmc,
+						PIN_CONF_PACKED(PIN_CONFIG_BIAS_PULL_UP, 20000));
 		}
 
 		if (quirks & DMI_QUIRK_RESET_SD_SIGNAL_VOLT_ON_SUSP)
-- 
2.44.0