linux-kernel - Linux 内核中的 gpiod_* 与 gpio_* 方法

Question

Linux 设备驱动程序编程中哪种 GPIO API 更适合以及在什么条件下使用:gpio_set_value() 或 gpiod_set_value()？

一种将 GPIO desc 作为对象，另一种则采用从设备树中解析出的 GPIO。

Answer 1

对于所有新驱动程序，建议使用 gpiod_* API。老gpio_* API 现已被视为已弃用。

来自this提交:

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.

有关新 gpiod API 的详细信息，请参阅下一个链接:

• [LWN article] GPIO in the kernel: future directions

• [Kernel documentation] GPIO Descriptor Consumer Interface

  (以及 this 提交添加的其余 gpiod 内核文档)