[PATCH 5/5] Documentation / ACPI: update to GPIO descriptor API

Mika Westerberg
2013-11-21T14:46:19Z

Update the documentation also to reflect the fact that there are no ACPI
specific GPIO interfaces anymore but drivers should instead use the
descriptor based GPIO APIs.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
Documentation/acpi/enumeration.txt | 36 +++++++-----------------------------
1 file changed, 7 insertions(+), 29 deletions(-)

diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index b994bcb32b92..2a1519b87177 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -293,36 +293,13 @@ the device to the driver. For example:

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.
+we need to translate them to the corresponding Linux GPIO descriptors.

-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
-device resources list. For example:
+There is a standard GPIO API for that and is documented in
+Documentation/gpio.txt.

- int gpio_irq, gpio_power;
- int ret;
-
- gpio_irq = acpi_get_gpio_by_index(dev, 1, NULL);
- if (gpio_irq < 0)
- /* handle error */
-
- gpio_power = acpi_get_gpio_by_index(dev, 0, NULL);
- if (gpio_power < 0)
- /* handle error */
-
- /* Now we can use the GPIO numbers */
-
-Other GpioIo parameters must be converted first by the driver to be
-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:
+In the above example we can get the corresponding two GPIO descriptors with
+a code like this:

#include <linux/gpio/consumer.h>
...
@@ -339,4 +316,5 @@ when converted to the GPIO desc:

/* Now we can use the GPIO descriptors */

-See also Documentation/gpio.txt.
+There are also devm_* versions of these functions which release the
+descriptors once the device is released.
--
1.8.4.3