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         int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state,
  30                         unsigned long *delay_on, unsigned long *delay_off);
  31 };
  32
  33 static void gpio_led_set(struct led_classdev *led_cdev,
  34         enum led_brightness value)
  35 {
  36         struct gpio_led_data *led_dat =
  37                 container_of(led_cdev, struct gpio_led_data, cdev);
  38         int level;
  39
  40         if (value == LED_OFF)
  41                 level = 0;
  42         else
  43                 level = 1;
  44
  45         if (led_dat->blinking) {
  46                 led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
  47                                                  NULL, NULL);
  48                 led_dat->blinking = 0;
  49         } else {
  50                 if (led_dat->can_sleep)
  51                         gpiod_set_value_cansleep(led_dat->gpiod, level);
  52                 else
  53                         gpiod_set_value(led_dat->gpiod, level);
  54         }
  55 }
  56
  57 static int gpio_led_set_blocking(struct led_classdev *led_cdev,
  58         enum led_brightness value)
  59 {
  60         gpio_led_set(led_cdev, value);
  61         return 0;
  62 }
  63
  64 static int gpio_blink_set(struct led_classdev *led_cdev,
  65         unsigned long *delay_on, unsigned long *delay_off)
  66 {
  67         struct gpio_led_data *led_dat =
  68                 container_of(led_cdev, struct gpio_led_data, cdev);
  69
  70         led_dat->blinking = 1;
  71         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
  72                                                 delay_on, delay_off);
  73 }
  74
  75 static int create_gpio_led(const struct gpio_led *template,
  76         struct gpio_led_data *led_dat, struct device *parent,
  77         int (*blink_set)(struct gpio_desc *, int, unsigned long *,
  78                          unsigned long *))
  79 {
  80         int ret, state;
  81
  82         led_dat->gpiod = template->gpiod;
  83         if (!led_dat->gpiod) {
  84                 /*
  85                  * This is the legacy code path for platform code that
  86                  * still uses GPIO numbers. Ultimately we would like to get
  87                  * rid of this block completely.
  88                  */
  89                 unsigned long flags = GPIOF_OUT_INIT_LOW;
  90
  91                 /* skip leds that aren't available */
  92                 if (!gpio_is_valid(template->gpio)) {
  93                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
  94                                         template->gpio, template->name);
  95                         return 0;
  96                 }
  97
  98                 if (template->active_low)
  99                         flags |= GPIOF_ACTIVE_LOW;
 100
 101                 ret = devm_gpio_request_one(parent, template->gpio, flags,
 102                                             template->name);
 103                 if (ret < 0)
 104                         return ret;
 105
 106                 led_dat->gpiod = gpio_to_desc(template->gpio);
 107                 if (!led_dat->gpiod)
 108                         return -EINVAL;
 109         }
 110
 111         led_dat->cdev.name = template->name;
 112         led_dat->cdev.default_trigger = template->default_trigger;
 113         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
 114         if (!led_dat->can_sleep)
 115                 led_dat->cdev.brightness_set = gpio_led_set;
 116         else
 117                 led_dat->cdev.brightness_set_blocking = gpio_led_set_blocking;
 118         led_dat->blinking = 0;
 119         if (blink_set) {
 120                 led_dat->platform_gpio_blink_set = blink_set;
 121                 led_dat->cdev.blink_set = gpio_blink_set;
 122         }
 123         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 124                 state = !!gpiod_get_value_cansleep(led_dat->gpiod);
 125         else
 126                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 127         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 128         if (!template->retain_state_suspended)
 129                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 130         if (template->panic_indicator)
 131                 led_dat->cdev.flags |= LED_PANIC_INDICATOR;
 132
 133         ret = gpiod_direction_output(led_dat->gpiod, state);
 134         if (ret < 0)
 135                 return ret;
 136
 137         return led_classdev_register(parent, &led_dat->cdev);
 138 }
 139
 140 struct gpio_leds_priv {
 141         int num_leds;
 142         struct gpio_led_data leds[];
 143 };
 144
 145 static inline int sizeof_gpio_leds_priv(int num_leds)
 146 {
 147         return sizeof(struct gpio_leds_priv) +
 148                 (sizeof(struct gpio_led_data) * num_leds);
 149 }
 150
 151 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
 152 {
 153         struct device *dev = &pdev->dev;
 154         struct fwnode_handle *child;
 155         struct gpio_leds_priv *priv;
 156         int count, ret;
 157         struct device_node *np;
 158
 159         count = device_get_child_node_count(dev);
 160         if (!count)
 161                 return ERR_PTR(-ENODEV);
 162
 163         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
 164         if (!priv)
 165                 return ERR_PTR(-ENOMEM);
 166
 167         device_for_each_child_node(dev, child) {
 168                 struct gpio_led_data *led_dat = &priv->leds[priv->num_leds];
 169                 struct gpio_led led = {};
 170                 const char *state = NULL;
 171
 172                 led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
 173                 if (IS_ERR(led.gpiod)) {
 174                         fwnode_handle_put(child);
 175                         ret = PTR_ERR(led.gpiod);
 176                         goto err;
 177                 }
 178
 179                 np = to_of_node(child);
 180
 181                 if (fwnode_property_present(child, "label")) {
 182                         fwnode_property_read_string(child, "label", &led.name);
 183                 } else {
 184                         if (IS_ENABLED(CONFIG_OF) && !led.name && np)
 185                                 led.name = np->name;
 186                         if (!led.name) {
 187                                 ret = -EINVAL;
 188                                 goto err;
 189                         }
 190                 }
 191                 fwnode_property_read_string(child, "linux,default-trigger",
 192                                             &led.default_trigger);
 193
 194                 if (!fwnode_property_read_string(child, "default-state",
 195                                                  &state)) {
 196                         if (!strcmp(state, "keep"))
 197                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 198                         else if (!strcmp(state, "on"))
 199                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 200                         else
 201                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 202                 }
 203
 204                 if (fwnode_property_present(child, "retain-state-suspended"))
 205                         led.retain_state_suspended = 1;
 206                 if (fwnode_property_present(child, "panic-indicator"))
 207                         led.panic_indicator = 1;
 208
 209                 ret = create_gpio_led(&led, led_dat, dev, NULL);
 210                 if (ret < 0) {
 211                         fwnode_handle_put(child);
 212                         goto err;
 213                 }
 214                 led_dat->cdev.dev->of_node = np;
 215                 priv->num_leds++;
 216         }
 217
 218         return priv;
 219
 220 err:
 221         for (count = priv->num_leds - 1; count >= 0; count--)
 222                 led_classdev_unregister(&priv->leds[count].cdev);
 223         return ERR_PTR(ret);
 224 }
 225
 226 static const struct of_device_id of_gpio_leds_match[] = {
 227         { .compatible = "gpio-leds", },
 228         {},
 229 };
 230
 231 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 232
 233 static int gpio_led_probe(struct platform_device *pdev)
 234 {
 235         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 236         struct gpio_leds_priv *priv;
 237         int i, ret = 0;
 238
 239         if (pdata && pdata->num_leds) {
 240                 priv = devm_kzalloc(&pdev->dev,
 241                                 sizeof_gpio_leds_priv(pdata->num_leds),
 242                                         GFP_KERNEL);
 243                 if (!priv)
 244                         return -ENOMEM;
 245
 246                 priv->num_leds = pdata->num_leds;
 247                 for (i = 0; i < priv->num_leds; i++) {
 248                         ret = create_gpio_led(&pdata->leds[i],
 249                                               &priv->leds[i],
 250                                               &pdev->dev, pdata->gpio_blink_set);
 251                         if (ret < 0) {
 252                                 /* On failure: unwind the led creations */
 253                                 for (i = i - 1; i >= 0; i--)
 254                                         led_classdev_unregister(
 255                                                         &priv->leds[i].cdev);
 256                                 return ret;
 257                         }
 258                 }
 259         } else {
 260                 priv = gpio_leds_create(pdev);
 261                 if (IS_ERR(priv))
 262                         return PTR_ERR(priv);
 263         }
 264
 265         platform_set_drvdata(pdev, priv);
 266
 267         return 0;
 268 }
 269
 270 static int gpio_led_remove(struct platform_device *pdev)
 271 {
 272         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 273         int i;
 274
 275         for (i = 0; i < priv->num_leds; i++)
 276                 led_classdev_unregister(&priv->leds[i].cdev);
 277
 278         return 0;
 279 }
 280
 281 static void gpio_led_shutdown(struct platform_device *pdev)
 282 {
 283         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 284         int i;
 285
 286         for (i = 0; i < priv->num_leds; i++) {
 287                 struct gpio_led_data *led = &priv->leds[i];
 288
 289                 gpio_led_set(&led->cdev, LED_OFF);
 290         }
 291 }
 292
 293 static struct platform_driver gpio_led_driver = {
 294         .probe          = gpio_led_probe,
 295         .remove         = gpio_led_remove,
 296         .shutdown       = gpio_led_shutdown,
 297         .driver         = {
 298                 .name   = "leds-gpio",
 299                 .of_match_table = of_gpio_leds_match,
 300         },
 301 };
 302
 303 module_platform_driver(gpio_led_driver);
 304
 305 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 306 MODULE_DESCRIPTION("GPIO LED driver");
 307 MODULE_LICENSE("GPL");
 308 MODULE_ALIAS("platform:leds-gpio");