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 #include <linux/workqueue.h>
  24
  25 struct gpio_led_data {
  26         struct led_classdev cdev;
  27         struct gpio_desc *gpiod;
  28         struct work_struct work;
  29         u8 new_level;
  30         u8 can_sleep;
  31         u8 blinking;
  32         int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state,
  33                         unsigned long *delay_on, unsigned long *delay_off);
  34 };
  35
  36 static void gpio_led_work(struct work_struct *work)
  37 {
  38         struct gpio_led_data *led_dat =
  39                 container_of(work, struct gpio_led_data, work);
  40
  41         if (led_dat->blinking) {
  42                 led_dat->platform_gpio_blink_set(led_dat->gpiod,
  43                                         led_dat->new_level, NULL, NULL);
  44                 led_dat->blinking = 0;
  45         } else
  46                 gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level);
  47 }
  48
  49 static void gpio_led_set(struct led_classdev *led_cdev,
  50         enum led_brightness value)
  51 {
  52         struct gpio_led_data *led_dat =
  53                 container_of(led_cdev, struct gpio_led_data, cdev);
  54         int level;
  55
  56         if (value == LED_OFF)
  57                 level = 0;
  58         else
  59                 level = 1;
  60
  61         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  62          * seem to have a reliable way to know if we're already in one; so
  63          * let's just assume the worst.
  64          */
  65         if (led_dat->can_sleep) {
  66                 led_dat->new_level = level;
  67                 schedule_work(&led_dat->work);
  68         } else {
  69                 if (led_dat->blinking) {
  70                         led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
  71                                                          NULL, NULL);
  72                         led_dat->blinking = 0;
  73                 } else
  74                         gpiod_set_value(led_dat->gpiod, level);
  75         }
  76 }
  77
  78 static int gpio_blink_set(struct led_classdev *led_cdev,
  79         unsigned long *delay_on, unsigned long *delay_off)
  80 {
  81         struct gpio_led_data *led_dat =
  82                 container_of(led_cdev, struct gpio_led_data, cdev);
  83
  84         led_dat->blinking = 1;
  85         return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK,
  86                                                 delay_on, delay_off);
  87 }
  88
  89 static int create_gpio_led(const struct gpio_led *template,
  90         struct gpio_led_data *led_dat, struct device *parent,
  91         int (*blink_set)(struct gpio_desc *, int, unsigned long *,
  92                          unsigned long *))
  93 {
  94         int ret, state;
  95
  96         led_dat->gpiod = template->gpiod;
  97         if (!led_dat->gpiod) {
  98                 /*
  99                  * This is the legacy code path for platform code that
 100                  * still uses GPIO numbers. Ultimately we would like to get
 101                  * rid of this block completely.
 102                  */
 103                 unsigned long flags = 0;
 104
 105                 /* skip leds that aren't available */
 106                 if (!gpio_is_valid(template->gpio)) {
 107                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 108                                         template->gpio, template->name);
 109                         return 0;
 110                 }
 111
 112                 if (template->active_low)
 113                         flags |= GPIOF_ACTIVE_LOW;
 114
 115                 ret = devm_gpio_request_one(parent, template->gpio, flags,
 116                                             template->name);
 117                 if (ret < 0)
 118                         return ret;
 119
 120                 led_dat->gpiod = gpio_to_desc(template->gpio);
 121                 if (IS_ERR(led_dat->gpiod))
 122                         return PTR_ERR(led_dat->gpiod);
 123         }
 124
 125         led_dat->cdev.name = template->name;
 126         led_dat->cdev.default_trigger = template->default_trigger;
 127         led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);
 128         led_dat->blinking = 0;
 129         if (blink_set) {
 130                 led_dat->platform_gpio_blink_set = blink_set;
 131                 led_dat->cdev.blink_set = gpio_blink_set;
 132         }
 133         led_dat->cdev.brightness_set = gpio_led_set;
 134         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 135                 state = !!gpiod_get_value_cansleep(led_dat->gpiod);
 136         else
 137                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 138         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 139         if (!template->retain_state_suspended)
 140                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 141
 142         ret = gpiod_direction_output(led_dat->gpiod, state);
 143         if (ret < 0)
 144                 return ret;
 145
 146         INIT_WORK(&led_dat->work, gpio_led_work);
 147
 148         return led_classdev_register(parent, &led_dat->cdev);
 149 }
 150
 151 static void delete_gpio_led(struct gpio_led_data *led)
 152 {
 153         led_classdev_unregister(&led->cdev);
 154         cancel_work_sync(&led->work);
 155 }
 156
 157 struct gpio_leds_priv {
 158         int num_leds;
 159         struct gpio_led_data leds[];
 160 };
 161
 162 static inline int sizeof_gpio_leds_priv(int num_leds)
 163 {
 164         return sizeof(struct gpio_leds_priv) +
 165                 (sizeof(struct gpio_led_data) * num_leds);
 166 }
 167
 168 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)
 169 {
 170         struct device *dev = &pdev->dev;
 171         struct fwnode_handle *child;
 172         struct gpio_leds_priv *priv;
 173         int count, ret;
 174         struct device_node *np;
 175
 176         count = device_get_child_node_count(dev);
 177         if (!count)
 178                 return ERR_PTR(-ENODEV);
 179
 180         priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);
 181         if (!priv)
 182                 return ERR_PTR(-ENOMEM);
 183
 184         device_for_each_child_node(dev, child) {
 185                 struct gpio_led led = {};
 186                 const char *state = NULL;
 187
 188                 led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
 189                 if (IS_ERR(led.gpiod)) {
 190                         fwnode_handle_put(child);
 191                         ret = PTR_ERR(led.gpiod);
 192                         goto err;
 193                 }
 194
 195                 np = to_of_node(child);
 196
 197                 if (fwnode_property_present(child, "label")) {
 198                         fwnode_property_read_string(child, "label", &led.name);
 199                 } else {
 200                         if (IS_ENABLED(CONFIG_OF) && !led.name && np)
 201                                 led.name = np->name;
 202                         if (!led.name) {
 203                                 ret = -EINVAL;
 204                                 goto err;
 205                         }
 206                 }
 207                 fwnode_property_read_string(child, "linux,default-trigger",
 208                                             &led.default_trigger);
 209
 210                 if (!fwnode_property_read_string(child, "default-state",
 211                                                  &state)) {
 212                         if (!strcmp(state, "keep"))
 213                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 214                         else if (!strcmp(state, "on"))
 215                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 216                         else
 217                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 218                 }
 219
 220                 if (fwnode_property_present(child, "retain-state-suspended"))
 221                         led.retain_state_suspended = 1;
 222
 223                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds],
 224                                       dev, NULL);
 225                 if (ret < 0) {
 226                         fwnode_handle_put(child);
 227                         goto err;
 228                 }
 229                 priv->num_leds++;
 230         }
 231
 232         return priv;
 233
 234 err:
 235         for (count = priv->num_leds - 1; count >= 0; count--)
 236                 delete_gpio_led(&priv->leds[count]);
 237         return ERR_PTR(ret);
 238 }
 239
 240 static const struct of_device_id of_gpio_leds_match[] = {
 241         { .compatible = "gpio-leds", },
 242         {},
 243 };
 244
 245 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 246
 247 static int gpio_led_probe(struct platform_device *pdev)
 248 {
 249         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 250         struct gpio_leds_priv *priv;
 251         int i, ret = 0;
 252
 253         if (pdata && pdata->num_leds) {
 254                 priv = devm_kzalloc(&pdev->dev,
 255                                 sizeof_gpio_leds_priv(pdata->num_leds),
 256                                         GFP_KERNEL);
 257                 if (!priv)
 258                         return -ENOMEM;
 259
 260                 priv->num_leds = pdata->num_leds;
 261                 for (i = 0; i < priv->num_leds; i++) {
 262                         ret = create_gpio_led(&pdata->leds[i],
 263                                               &priv->leds[i],
 264                                               &pdev->dev, pdata->gpio_blink_set);
 265                         if (ret < 0) {
 266                                 /* On failure: unwind the led creations */
 267                                 for (i = i - 1; i >= 0; i--)
 268                                         delete_gpio_led(&priv->leds[i]);
 269                                 return ret;
 270                         }
 271                 }
 272         } else {
 273                 priv = gpio_leds_create(pdev);
 274                 if (IS_ERR(priv))
 275                         return PTR_ERR(priv);
 276         }
 277
 278         platform_set_drvdata(pdev, priv);
 279
 280         return 0;
 281 }
 282
 283 static int gpio_led_remove(struct platform_device *pdev)
 284 {
 285         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 286         int i;
 287
 288         for (i = 0; i < priv->num_leds; i++)
 289                 delete_gpio_led(&priv->leds[i]);
 290
 291         return 0;
 292 }
 293
 294 static struct platform_driver gpio_led_driver = {
 295         .probe          = gpio_led_probe,
 296         .remove         = gpio_led_remove,
 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");