of_get_gpio说明

/**

• of_get_gpio() - Get a GPIO number to use with GPIO API
• @np: device node to get GPIO from
• @index: index of the GPIO
• Returns GPIO number to use with Linux generic GPIO API, or one of the errno

• value on the error condition.
  /
  static inline int of_get_gpio(const struct device_node np, int index)
  {
  return of_get_gpio_flags(np, index, NULL);
  }

  这个index 表示gpios节点的索引位置，gpios支持多个节点，每个节点由<gpio_chip gpio_num default_level>
  eg:
  gpios = <&ap_gpio 145 0 &ap_gpio 144 0>;