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gpiod_* vs gpio_* methods in the Linux Kernel

Which of the GPIO APIs in Linux device driver programming is preferable and in what conditions: gpio_set_value() or gpiod_set_value()?

One takes the GPIO desc as the object while other takes the GPIO parsed from the device tree.

Solution

  • For all new drivers it's recommended to use gpiod_* API. Old gpio_* API is considered deprecated now.

    From this commit:

    gpiolib: export descriptor-based GPIO interface

    This patch exports the gpiod_* family of API functions, a safer alternative to the legacy GPIO interface. Differences between the gpiod and legacy gpio APIs are:

    • gpio works with integers, whereas gpiod operates on opaque handlers which cannot be forged or used before proper acquisition
    • gpiod get/set functions are aware of the active low state of a GPIO
    • gpio consumers should now include <linux/gpio/consumer.h> to access the new interface, whereas chips drivers will use <linux/gpio/driver.h>

    The legacy gpio API is now built as inline functions on top of gpiod.

    See next links for details on new gpiod API: