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Commit c884fbd4 authored by Mika Westerberg's avatar Mika Westerberg Committed by Linus Walleij
Browse files

gpio / ACPI: Add support for retrieving GpioInt resources from a device 



ACPI specification knows two types of GPIOs: GpioIo and GpioInt. The latter
is used to describe that a given device interrupt line is connected to a
specific GPIO pin. Typical ACPI _CRS entry for such device looks like
below:

    Name (_CRS, ResourceTemplate ()
    {
        I2cSerialBus (0x004A, ControllerInitiated, 0x00061A80,
                      AddressingMode7Bit, "\\_SB.PCI0.I2C6",
                      0x00, ResourceConsumer)
        GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
                IoRestrictionOutputOnly, "\\_SB.GPO0",
                0x00, ResourceConsumer)
        {
            0x004B
        }
        GpioInt (Level, ActiveLow, Shared, PullDefault, 0x0000,
                 "\\_SB.GPO0", 0x00, ResourceConsumer)
        {
            0x004C
        }
    })

Currently drivers need to request a GPIO corresponding to the right GpioInt
and then translate that to Linux IRQ number. This adds unnecessary lines of
boiler-plate code.

We can ease this a bit by introducing acpi_dev_gpio_irq_get() analogous to
of_irq_get(). This function translates given GpioInt resource under the
device in question to the suitable Linux IRQ number.

Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 442b2494

drivers/gpio/gpiolib-acpi.c

+29 −0
Original line number Diff line number Diff line
@@ -514,6 +514,35 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev, 
	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);

}



/**

 * acpi_dev_gpio_irq_get() - Find GpioInt and translate it to Linux IRQ number

 * @adev: pointer to a ACPI device to get IRQ from

 * @index: index of GpioInt resource (starting from %0)

 *

 * If the device has one or more GpioInt resources, this function can be

 * used to translate from the GPIO offset in the resource to the Linux IRQ

 * number.

 *

 * Return: Linux IRQ number (>%0) on success, negative errno on failure.

 */

int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)

{

	int idx, i;



	for (i = 0, idx = 0; idx <= index; i++) {

		struct acpi_gpio_info info;

		struct gpio_desc *desc;



		desc = acpi_get_gpiod_by_index(adev, NULL, i, &info);

		if (IS_ERR(desc))

			break;

		if (info.gpioint && idx++ == index)

			return gpiod_to_irq(desc);

	}

	return -ENOENT;

}

EXPORT_SYMBOL_GPL(acpi_dev_gpio_irq_get);



static acpi_status

acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,

			    u32 bits, u64 *value, void *handler_context,

include/linux/acpi.h

+7 −0
Original line number Diff line number Diff line
@@ -721,6 +721,8 @@ static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev) 
	if (adev)

		adev->driver_gpios = NULL;

}



int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index);

#else

static inline int acpi_dev_add_driver_gpios(struct acpi_device *adev,

			      const struct acpi_gpio_mapping *gpios)
@@ -728,6 +730,11 @@ static inline int acpi_dev_add_driver_gpios(struct acpi_device *adev, 
	return -ENXIO;

}

static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev) {}



static inline int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)

{

	return -ENXIO;

}

#endif



/* Device properties */