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Subject[PATCH v2 5/5] gpiolib / ACPI: document the GPIO descriptor based interface
Date
In addition to the existing ACPI specific GPIO interface, document the new
descriptor based GPIO interface in Documentation/acpi/enumeration.txt, so
it is clear that this new interface is preferred over the ACPI specific
version.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
---
Documentation/acpi/enumeration.txt | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index aca4e69..b994bcb 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -295,10 +295,6 @@ These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0"
specifies the path to the controller. In order to use these GPIOs in Linux
we need to translate them to the Linux GPIO numbers.

-The driver can do this by including <linux/acpi_gpio.h> and then calling
-acpi_get_gpio(path, gpio). This will return the Linux GPIO number or
-negative errno if there was no translation found.
-
In a simple case of just getting the Linux GPIO number from device
resources one can use acpi_get_gpio_by_index() helper function. It takes
pointer to the device and index of the GpioIo/GpioInt descriptor in the
@@ -322,3 +318,25 @@ suitable to the gpiolib before passing them.

In case of GpioInt resource an additional call to gpio_to_irq() must be
done before calling request_irq().
+
+Note that the above API is ACPI specific and not recommended for drivers
+that need to support non-ACPI systems. The recommended way is to use
+the descriptor based GPIO interfaces. The above example looks like this
+when converted to the GPIO desc:
+
+ #include <linux/gpio/consumer.h>
+ ...
+
+ struct gpio_desc *irq_desc, *power_desc;
+
+ irq_desc = gpiod_get_index(dev, NULL, 1);
+ if (IS_ERR(irq_desc))
+ /* handle error */
+
+ power_desc = gpiod_get_index(dev, NULL, 0);
+ if (IS_ERR(power_desc))
+ /* handle error */
+
+ /* Now we can use the GPIO descriptors */
+
+See also Documentation/gpio.txt.
--
1.8.4.rc3


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