doc/README.gpio

   1
   2 GPIO hog (CONFIG_GPIO_HOG)
   3 --------
   4
   5 All the GPIO hog are initialized in gpio_hog_probe_all() function called in
   6 board_r.c just before board_late_init() but you can also acces directly to
   7 the gpio with gpio_hog_lookup_name().
   8
   9
  10 Example, for the device tree:
  11
  12         tca6416@20 {
  13                 compatible = "ti,tca6416";
  14                 reg = <0x20>;
  15                 #gpio-cells = <2>;
  16                 gpio-controller;
  17
  18                 env_reset {
  19                         gpio-hog;
  20                         input;
  21                         gpios = <6 GPIO_ACTIVE_LOW>;
  22                 };
  23                 boot_rescue {
  24                         gpio-hog;
  25                         input;
  26                         line-name = "foo-bar-gpio";
  27                         gpios = <7 GPIO_ACTIVE_LOW>;
  28                 };
  29         };
  30
  31 You can than access the gpio in your board code with:
  32
  33         struct gpio_desc *desc;
  34         int ret;
  35
  36         ret = gpio_hog_lookup_name("boot_rescue", &desc);
  37         if (ret)
  38                 return;
  39         if (dm_gpio_get_value(desc) == 1)
  40                 printf("\nBooting into Rescue System\n");
  41         else if (dm_gpio_get_value(desc) == 0)
  42                 printf("\nBoot normal\n");