[1/2] gpio: acpi: add quirk to override GpioInt polarity
diff mbox series

Message ID 20190830000024.20384-1-peter@typeblog.net
State New
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  • [1/2] gpio: acpi: add quirk to override GpioInt polarity
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Commit Message

Peter Cai Aug. 30, 2019, midnight UTC
On GPD P2 Max, the firmware could not reset the touch panel correctly.
The kernel needs to take on the job instead, but the GpioInt definition
in DSDT specifies ActiveHigh while the GPIO pin should actually be
ActiveLow.

We need to override the polarity defined by DSDT. The GPIO driver
already allows defining polarity in acpi_gpio_params, but the option is
not applied to GpioInt.

This patch adds a new quirk that enables the polarity specified in
acpi_gpio_params to also be applied to GpioInt.

Signed-off-by: Peter Cai <peter@typeblog.net>
---
 drivers/gpio/gpiolib-acpi.c | 10 +++++++++-
 include/linux/acpi.h        |  6 ++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

Comments

Andy Shevchenko Aug. 30, 2019, 11:42 a.m. UTC | #1
On Fri, Aug 30, 2019 at 08:00:23AM +0800, Peter Cai wrote:
> On GPD P2 Max, the firmware could not reset the touch panel correctly.
> The kernel needs to take on the job instead, but the GpioInt definition
> in DSDT specifies ActiveHigh while the GPIO pin should actually be
> ActiveLow.
> 
> We need to override the polarity defined by DSDT. The GPIO driver
> already allows defining polarity in acpi_gpio_params, but the option is
> not applied to GpioInt.
> 
> This patch adds a new quirk that enables the polarity specified in
> acpi_gpio_params to also be applied to GpioInt.

In general if it's really the case, I'm not objecting to have another quirk.
So, I would wait for the comments on the second patch to see how it's going.

>  include/linux/acpi.h        |  6 ++++++

The GPIO part of the header had been moved to the drivers/gpio/gpiolib-acpi.h.
Please, base your series on top of the gpio/for-next.

>  			lookup->info.flags = GPIOD_IN;
> -			lookup->info.polarity = agpio->polarity;

> +			if (lookup->info.quirks &
> +					ACPI_GPIO_QUIRK_OVERRIDE_POLARITY) {

Disregard checkpatch I would leave this on one line.

> +				dev_warn(&lookup->info.adev->dev, FW_BUG "Incorrect polarity specified by GpioInt, overriding.\n");
> +				lookup->info.polarity = lookup->active_low;
> +			} else {
> +				lookup->info.polarity = agpio->polarity;
> +			}
>  			lookup->info.triggering = agpio->triggering;

Since the quirk makes sense only for GpioInt and basically no-op for GpioIo,
I would move the check out of if (gpioint) {} else {} conditional:

	if (gpioint) {
		...
	} else {
		...
	}

	if (quirk) {
		dev_warn();
		polarity = ...;
	}

Patch
diff mbox series

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 39f2f9035c11..1a07c79ca2de 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -583,13 +583,21 @@  static int acpi_populate_gpio_lookup(struct acpi_resource *ares, void *data)
 		/*
 		 * Polarity and triggering are only specified for GpioInt
 		 * resource.
+		 * Polarity specified by GpioInt may be ignored if
+		 * ACPI_GPIO_QUIRK_OVERRIDE_POLARITY is set.
 		 * Note: we expect here:
 		 * - ACPI_ACTIVE_LOW == GPIO_ACTIVE_LOW
 		 * - ACPI_ACTIVE_HIGH == GPIO_ACTIVE_HIGH
 		 */
 		if (lookup->info.gpioint) {
 			lookup->info.flags = GPIOD_IN;
-			lookup->info.polarity = agpio->polarity;
+			if (lookup->info.quirks &
+					ACPI_GPIO_QUIRK_OVERRIDE_POLARITY) {
+				dev_warn(&lookup->info.adev->dev, FW_BUG "Incorrect polarity specified by GpioInt, overriding.\n");
+				lookup->info.polarity = lookup->active_low;
+			} else {
+				lookup->info.polarity = agpio->polarity;
+			}
 			lookup->info.triggering = agpio->triggering;
 		} else {
 			lookup->info.flags = acpi_gpio_to_gpiod_flags(agpio);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 9426b9aaed86..6569773ceffd 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1014,6 +1014,12 @@  struct acpi_gpio_mapping {
  * get GpioIo type explicitly, this quirk may be used.
  */
 #define ACPI_GPIO_QUIRK_ONLY_GPIOIO		BIT(1)
+/*
+ * Use the GPIO polarity (ActiveHigh / ActiveLow) from acpi_gpio_params
+ * for GpioInt as well. The default behavior is to use the one specified
+ * by GpioInt, which can be incorrect on some devices.
+ */
+#define ACPI_GPIO_QUIRK_OVERRIDE_POLARITY	BIT(2)
 
 	unsigned int quirks;
 };