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-rw-r--r--Documentation/acpi/enumeration.txt26
1 files 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 <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.