drivers/led/led_gpio.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2015 Google, Inc
   4  * Written by Simon Glass <sjg@chromium.org>
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <errno.h>
  10 #include <led.h>
  11 #include <asm/gpio.h>
  12 #include <dm/lists.h>
  13 #include <dm/uclass-internal.h>
  14
  15 struct led_gpio_priv {
  16         struct gpio_desc gpio;
  17 };
  18
  19 static int gpio_led_set_state(struct udevice *dev, enum led_state_t state)
  20 {
  21         struct led_gpio_priv *priv = dev_get_priv(dev);
  22         int ret;
  23
  24         if (!dm_gpio_is_valid(&priv->gpio))
  25                 return -EREMOTEIO;
  26         switch (state) {
  27         case LEDST_OFF:
  28         case LEDST_ON:
  29                 break;
  30         case LEDST_TOGGLE:
  31                 ret = dm_gpio_get_value(&priv->gpio);
  32                 if (ret < 0)
  33                         return ret;
  34                 state = !ret;
  35                 break;
  36         default:
  37                 return -ENOSYS;
  38         }
  39
  40         return dm_gpio_set_value(&priv->gpio, state);
  41 }
  42
  43 static enum led_state_t gpio_led_get_state(struct udevice *dev)
  44 {
  45         struct led_gpio_priv *priv = dev_get_priv(dev);
  46         int ret;
  47
  48         if (!dm_gpio_is_valid(&priv->gpio))
  49                 return -EREMOTEIO;
  50         ret = dm_gpio_get_value(&priv->gpio);
  51         if (ret < 0)
  52                 return ret;
  53
  54         return ret ? LEDST_ON : LEDST_OFF;
  55 }
  56
  57 static int led_gpio_probe(struct udevice *dev)
  58 {
  59         struct led_uc_plat *uc_plat = dev_get_uclass_platdata(dev);
  60         struct led_gpio_priv *priv = dev_get_priv(dev);
  61         const char *default_state;
  62         int ret;
  63
  64         /* Ignore the top-level LED node */
  65         if (!uc_plat->label)
  66                 return 0;
  67
  68         ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, GPIOD_IS_OUT);
  69         if (ret)
  70                 return ret;
  71
  72         default_state = dev_read_string(dev, "default-state");
  73         if (default_state) {
  74                 if (!strncmp(default_state, "on", 2))
  75                         gpio_led_set_state(dev, LEDST_ON);
  76                 else if (!strncmp(default_state, "off", 3))
  77                         gpio_led_set_state(dev, LEDST_OFF);
  78         }
  79         return 0;
  80 }
  81
  82 static int led_gpio_remove(struct udevice *dev)
  83 {
  84         /*
  85          * The GPIO driver may have already been removed. We will need to
  86          * address this more generally.
  87          */
  88 #ifndef CONFIG_SANDBOX
  89         struct led_gpio_priv *priv = dev_get_priv(dev);
  90
  91         if (dm_gpio_is_valid(&priv->gpio))
  92                 dm_gpio_free(dev, &priv->gpio);
  93 #endif
  94
  95         return 0;
  96 }
  97
  98 static int led_gpio_bind(struct udevice *parent)
  99 {
 100         struct udevice *dev;
 101         ofnode node;
 102         int ret;
 103
 104         dev_for_each_subnode(node, parent) {
 105                 struct led_uc_plat *uc_plat;
 106                 const char *label;
 107
 108                 label = ofnode_read_string(node, "label");
 109                 if (!label) {
 110                         debug("%s: node %s has no label\n", __func__,
 111                               ofnode_get_name(node));
 112                         return -EINVAL;
 113                 }
 114                 ret = device_bind_driver_to_node(parent, "gpio_led",
 115                                                  ofnode_get_name(node),
 116                                                  node, &dev);
 117                 if (ret)
 118                         return ret;
 119                 uc_plat = dev_get_uclass_platdata(dev);
 120                 uc_plat->label = label;
 121
 122                 if (ofnode_read_bool(node, "default-state")) {
 123                         struct udevice *devp;
 124
 125                         ret = uclass_get_device_tail(dev, 0, &devp);
 126                         if (ret)
 127                                 return ret;
 128                 }
 129         }
 130
 131         return 0;
 132 }
 133
 134 static const struct led_ops gpio_led_ops = {
 135         .set_state      = gpio_led_set_state,
 136         .get_state      = gpio_led_get_state,
 137 };
 138
 139 static const struct udevice_id led_gpio_ids[] = {
 140         { .compatible = "gpio-leds" },
 141         { }
 142 };
 143
 144 U_BOOT_DRIVER(led_gpio) = {
 145         .name   = "gpio_led",
 146         .id     = UCLASS_LED,
 147         .of_match = led_gpio_ids,
 148         .ops    = &gpio_led_ops,
 149         .priv_auto_alloc_size = sizeof(struct led_gpio_priv),
 150         .bind   = led_gpio_bind,
 151         .probe  = led_gpio_probe,
 152         .remove = led_gpio_remove,
 153 };