From 45f394391f93596782c6a5ec14f0a5428f60f9b3 Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Thu, 10 Oct 2013 11:01:11 +0300 Subject: [PATCH] gpiolib / ACPI: document the GPIO descriptor based interface 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 Acked-by: Rafael J. Wysocki Reviewed-by: Alexandre Courbot Signed-off-by: Linus Walleij --- 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 aca4e69121b7..b994bcb32b92 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 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 + ... + + 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. -- 2.20.1