[PATCH 1/2] gpio / ACPI: Add support for retrieving GpioInt resources from a device

From: Mika Westerberg
Date: Tue Apr 28 2015 - 11:05:51 EST


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: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib-acpi.c | 29 +++++++++++++++++++++++++++++
include/linux/acpi.h | 7 +++++++
2 files changed, 36 insertions(+)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index d2303d50f561..bff29bb0a3fe 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -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,
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index e4da5e35e29c..f57c440642cd 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -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 */
--
2.1.4

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