Commit 25487533 authored Mar 24, 2016 by Dmitry Torokhov Committed by Linus Walleij Apr 08, 2016

gpio / ACPI: ignore GpioInt() GPIOs when requesting GPIO_OUT_*



When firmware does not use _DSD properties that allow properly name GPIO
resources, the kernel falls back on parsing _CRS resources, and will
return entries described as GpioInt() as general purpose GPIOs even
though they are meant to be used simply as interrupt sources for the
device:

Device (ETSA)
{
	Name (_HID, "ELAN0001")
	...

	Method(_CRS, 0x0, NotSerialized)
	{
		Name(BUF0,ResourceTemplate ()
		{
			I2CSerialBus(
				0x10,                     /* SlaveAddress */
				ControllerInitiated,      /* SlaveMode */
				400000,                   /* ConnectionSpeed */
				AddressingMode7Bit,       /* AddressingMode */
				"\\_SB.I2C1",             /* ResourceSource */
			)
			GpioInt (Edge, ActiveLow, ExclusiveAndWake, PullNone,,
				 "\\_SB.GPSW") { BOARD_TOUCH_GPIO_INDEX }
		} )
		Return (BUF0)
	}
...
}

This gives troubles with drivers such as Elan Touchscreen driver
(elants_i2c) that uses devm_gpiod_get to look up "reset" GPIO line and
decide whether the driver is responsible for powering up and resetting
the device, or firmware is. In the above case the lookup succeeds, we
map GPIO as output and later fail to request client->irq interrupt that
is mapped to the same GPIO.

Let's ignore resources described as GpioInt() while parsing _CRS when
requesting output GPIOs (but allow them when requesting GPIOD_ASIS or
GPIOD_IN as some drivers, such as i2c-hid, do request GPIO as input and
then map it to interrupt with gpiod_to_irq).

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

parent 9735a227

drivers/gpio/gpiolib.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -2231,9 +2231,11 @@ static struct gpio_desc of_find_gpio(struct device dev, const char *con_id,
		return desc;
		}

		static struct gpio_desc acpi_find_gpio(struct device dev, const char *con_id,
		static struct gpio_desc acpi_find_gpio(struct device dev,
		const char *con_id,
		unsigned int idx,
		enum gpio_lookup_flags *flags)
		enum gpiod_flags flags,
		enum gpio_lookup_flags *lookupflags)
		{
		struct acpi_device *adev = ACPI_COMPANION(dev);
		struct acpi_gpio_info info;
		@@ -2264,10 +2266,16 @@ static struct gpio_desc acpi_find_gpio(struct device dev, const char *con_id,
		desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info);
		if (IS_ERR(desc))
		return desc;

		if ((flags == GPIOD_OUT_LOW \|\| flags == GPIOD_OUT_HIGH) &&
		info.gpioint) {
		dev_dbg(dev, "refusing GpioInt() entry when doing GPIOD_OUT_* lookup\n");
		return ERR_PTR(-ENOENT);
		}
		}

		if (info.polarity == GPIO_ACTIVE_LOW)
		*flags \|= GPIO_ACTIVE_LOW;
		*lookupflags \|= GPIO_ACTIVE_LOW;

		return desc;
		}
		@@ -2530,7 +2538,7 @@ struct gpio_desc __must_check gpiod_get_index(struct device dev,
		desc = of_find_gpio(dev, con_id, idx, &lookupflags);
		} else if (ACPI_COMPANION(dev)) {
		dev_dbg(dev, "using ACPI for GPIO lookup\n");
		desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
		desc = acpi_find_gpio(dev, con_id, idx, flags, &lookupflags);
		}
		}

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