drivers/leds/leds-gpio.c

   1 /*
   2  * LEDs driver for GPIOs
   3  *
   4  * Copyright (C) 2007 8D Technologies inc.
   5  * Raphael Assenat <raph@8d.com>
   6  * Copyright (C) 2008 Freescale Semiconductor, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13 #include <linux/err.h>
  14 #include <linux/gpio.h>
  15 #include <linux/gpio/consumer.h>
  16 #include <linux/kernel.h>
  17 #include <linux/leds.h>
  18 #include <linux/module.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/property.h>
  22 #include <linux/slab.h>
  23
  24 struct gpio_led_data {
  25         struct led_classdev cdev;
  26         struct gpio_desc *gpiod;
  27         u8 can_sleep;
  28         u8 blinking;
  29         gpio_blink_set_t platform_gpio_blink_set;
  30 };
  31
  32 static inline struct gpio_led_data *
  33                         cdev_to_gpio_led_data(struct led_classdev *led_cdev)
  34 {
  35         return container_of(led_cdev, struct gpio_led_data, cdev);
  36 }
  37
  38 static void gpio_led_set(struct led_classdev *led_cdev,
  39         enum led_brightness value)
  40 {
  41         struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
  42         int level;
  43
  44         if (value == LED_OFF)
  45                 level = 0;
  46         else
  47                 level = 1;
  48
  49         if (led_dat->blinking) {
  50                 led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
  51                                                  NULL, NULL);
  52                 led_dat->blinking = 0;
  53         } else if (led_dat->cdev.flags & SET_GPIO_INPUT) {
  54                 gpiod_direction_input(led_dat->gpiod);
  55                 led_dat->cdev.flags &= ~SET_GPIO_INPUT;
  56         } else if (led_dat->cdev.flags & SET_GPIO_OUTPUT) {
  57                 gpiod_direction_output(led_dat->gpiod, level);
  58                 led_dat->cdev.flags &= ~SET_GPIO_OUTPUT;
  59         } else {
  60                 if (led_dat->can_sleep ||
  61                         (led_dat->cdev.flags & (SET_GPIO_INPUT | SET_GPIO_OUTPUT) ))
  62                         gpiod_set_value_cansleep(led_dat->gpiod, level);
  63                 else
  64                         gpiod_set_value(led_dat->gpiod, level);
  65         }
  66 }
  67
  68 static int gpio_led_set_blocking(struct led_classdev *led_cdev,
  69         enum led_brightness value)
  70 {
  71         gpio_led_set(led_cdev, value);
  72         return 0;
  73 }
  74
  75 static enum led_brightness gpio_led_get(struct led_classdev *led_cdev)
  76 {
  77         struct gpio_led_data *led_dat =
  78                 container_of(led_cdev, struct gpio_led_data, cdev);
  79         return gpiod_get_value_cansleep(led_dat->gpiod) ? LED_FULL : LED_OFF;
  80 }
  81
  82 static int gpio_blink_set(struct led_classdev *led_cdev,
  83         unsigned long *delay_on, unsigned long *delay_off)
  84 {
  85         struct gpio_led_data *led_dat = cdev_to_gpio_led_data(led_cdev);
  86
  87         led_dat->blinking = 1;
  88         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
  89                                                 delay_on, delay_off);
  90 }
  91
  92 static int create_gpio_led(const struct gpio_led *template,
  93         struct gpio_led_data *led_dat, struct device *parent,
  94         struct device_node *np, gpio_blink_set_t blink_set)
  95 {
  96         int ret, state;
  97
  98         led_dat->gpiod = template->gpiod;
  99         if (!led_dat->gpiod) {
 100                 /*
 101                  * This is the legacy code path for platform code that
 102                  * still uses GPIO numbers. Ultimately we would like to get
 103                  * rid of this block completely.
 104                  */
 105                 unsigned long flags = GPIOF_OUT_INIT_LOW;
 106
 107                 /* skip leds that aren't available */
 108                 if (!gpio_is_valid(template->gpio)) {
 109                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 110                                         template->gpio, template->name);
 111                         return 0;
 112                 }
 113
 114                 if (template->active_low)
 115                         flags |= GPIOF_ACTIVE_LOW;
 116
 117                 ret = devm_gpio_request_one(parent, template->gpio, flags,
 118                                             template->name);
 119                 if (ret < 0)
 120                         return ret;
 121
 122                 led_dat->gpiod = gpio_to_desc(template->gpio);
 123                 if (!led_dat->gpiod)
 124                         return -EINVAL;
 125         }
 126
 127         led_dat->cdev.name = template->name;
 128         led_dat->cdev.default_trigger = template->default_trigger;
 129         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
 130         if (!led_dat->can_sleep)
 131                 led_dat->cdev.brightness_set = gpio_led_set;
 132         else
 133                 led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
 134         led_dat->blinking = 0;
 135         if (blink_set) {
 136                 led_dat->platform_gpio_blink_set = blink_set;
 137                 led_dat->cdev.blink_set = gpio_blink_set;
 138         }
 139         led_dat->cdev.brightness_get = gpio_led_get;
 140         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
 141                 state = gpiod_get_value_cansleep(led_dat->gpiod);
 142                 if (state < 0)
 143                         return state;
 144         } else {
 145                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 146         }
 147         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 148         if (!template->retain_state_suspended)
 149                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 150         if (template->panic_indicator)
 151                 led_dat->cdev.flags |= LED_PANIC_INDICATOR;
 152
 153         ret = gpiod_direction_output(led_dat->gpiod, state);
 154         if (ret < 0)
 155                 return ret;
 156
 157         return devm_of_led_classdev_register(parent, np, &led_dat->cdev);
 158 }
 159
 160 struct gpio_leds_priv {
 161         int num_leds;
 162         struct gpio_led_data leds[];
 163 };
 164
 165 static inline int sizeof_gpio_leds_priv(int num_leds)
 166 {
 167         return sizeof(struct gpio_leds_priv) +
 168                 (sizeof(struct gpio_led_data) * num_leds);
 169 }
 170
 171 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
 172 {
 173         struct device *dev = &pdev->dev;
 174         struct fwnode_handle *child;
 175         struct gpio_leds_priv *priv;
 176         int count, ret;
 177
 178         count = device_get_child_node_count(dev);
 179         if (!count)
 180                 return ERR_PTR(-ENODEV);
 181
 182         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
 183         if (!priv)
 184                 return ERR_PTR(-ENOMEM);
 185
 186         device_for_each_child_node(dev, child) {
 187                 struct gpio_led_data *led_dat = &priv->leds[priv->num_leds];
 188                 struct gpio_led led = {};
 189                 const char *state = NULL;
 190                 struct device_node *np = to_of_node(child);
 191
 192                 ret = fwnode_property_read_string(child, "label", &led.name);
 193                 if (ret && IS_ENABLED(CONFIG_OF) && np)
 194                         led.name = np->name;
 195                 if (!led.name) {
 196                         fwnode_handle_put(child);
 197                         return ERR_PTR(-EINVAL);
 198                 }
 199
 200                 led.gpiod = devm_fwnode_get_gpiod_from_child(dev, NULL, child,
 201                                                              GPIOD_ASIS,
 202                                                              led.name);
 203                 if (IS_ERR(led.gpiod)) {
 204                         fwnode_handle_put(child);
 205                         return ERR_CAST(led.gpiod);
 206                 }
 207
 208                 fwnode_property_read_string(child, "linux,default-trigger",
 209                                             &led.default_trigger);
 210
 211                 if (!fwnode_property_read_string(child, "default-state",
 212                                                  &state)) {
 213                         if (!strcmp(state, "keep"))
 214                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 215                         else if (!strcmp(state, "on"))
 216                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 217                         else
 218                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 219                 }
 220
 221                 if (fwnode_property_present(child, "retain-state-suspended"))
 222                         led.retain_state_suspended = 1;
 223                 if (fwnode_property_present(child, "panic-indicator"))
 224                         led.panic_indicator = 1;
 225
 226                 ret = create_gpio_led(&led, led_dat, dev, np, NULL);
 227                 if (ret < 0) {
 228                         fwnode_handle_put(child);
 229                         return ERR_PTR(ret);
 230                 }
 231                 led_dat->cdev.dev->of_node = np;
 232                 priv->num_leds++;
 233         }
 234
 235         return priv;
 236 }
 237
 238 static const struct of_device_id of_gpio_leds_match[] = {
 239         { .compatible = "gpio-leds", },
 240         {},
 241 };
 242
 243 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 244
 245 static int gpio_led_probe(struct platform_device *pdev)
 246 {
 247         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 248         struct gpio_leds_priv *priv;
 249         int i, ret = 0;
 250
 251         if (pdata && pdata->num_leds) {
 252                 priv = devm_kzalloc(&pdev->dev,
 253                                 sizeof_gpio_leds_priv(pdata->num_leds),
 254                                         GFP_KERNEL);
 255                 if (!priv)
 256                         return -ENOMEM;
 257
 258                 priv->num_leds = pdata->num_leds;
 259                 for (i = 0; i < priv->num_leds; i++) {
 260                         ret = create_gpio_led(&pdata->leds[i], &priv->leds[i],
 261                                               &pdev->dev, NULL,
 262                                               pdata->gpio_blink_set);
 263                         if (ret < 0)
 264                                 return ret;
 265                 }
 266         } else {
 267                 priv = gpio_leds_create(pdev);
 268                 if (IS_ERR(priv))
 269                         return PTR_ERR(priv);
 270         }
 271
 272         platform_set_drvdata(pdev, priv);
 273
 274         return 0;
 275 }
 276
 277 static void gpio_led_shutdown(struct platform_device *pdev)
 278 {
 279         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 280         int i;
 281
 282         for (i = 0; i < priv->num_leds; i++) {
 283                 struct gpio_led_data *led = &priv->leds[i];
 284
 285                 gpio_led_set(&led->cdev, LED_OFF);
 286         }
 287 }
 288
 289 static struct platform_driver gpio_led_driver = {
 290         .probe          = gpio_led_probe,
 291         .shutdown       = gpio_led_shutdown,
 292         .driver         = {
 293                 .name   = "leds-gpio",
 294                 .of_match_table = of_gpio_leds_match,
 295         },
 296 };
 297
 298 module_platform_driver(gpio_led_driver);
 299
 300 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 301 MODULE_DESCRIPTION("GPIO LED driver");
 302 MODULE_LICENSE("GPL");
 303 MODULE_ALIAS("platform:leds-gpio");