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/of_gpio.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/slab.h>
  24 #include <linux/workqueue.h>
  25
  26 struct gpio_led_data {
  27         struct led_classdev cdev;
  28         struct gpio_desc *gpiod;
  29         struct work_struct work;
  30         u8 new_level;
  31         u8 can_sleep;
  32         u8 blinking;
  33         int (*platform_gpio_blink_set)(unsigned gpio, int state,
  34                         unsigned long *delay_on, unsigned long *delay_off);
  35 };
  36
  37 static void gpio_led_work(struct work_struct *work)
  38 {
  39         struct gpio_led_data *led_dat =
  40                 container_of(work, struct gpio_led_data, work);
  41
  42         if (led_dat->blinking) {
  43                 int gpio = desc_to_gpio(led_dat->gpiod);
  44                 int level = led_dat->new_level;
  45
  46                 if (gpiod_is_active_low(led_dat->gpiod))
  47                         level = !level;
  48
  49                 led_dat->platform_gpio_blink_set(gpio, level, NULL, NULL);
  50                 led_dat->blinking = 0;
  51         } else
  52                 gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level);
  53 }
  54
  55 static void gpio_led_set(struct led_classdev *led_cdev,
  56         enum led_brightness value)
  57 {
  58         struct gpio_led_data *led_dat =
  59                 container_of(led_cdev, struct gpio_led_data, cdev);
  60         int level;
  61
  62         if (value == LED_OFF)
  63                 level = 0;
  64         else
  65                 level = 1;
  66
  67         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  68          * seem to have a reliable way to know if we're already in one; so
  69          * let's just assume the worst.
  70          */
  71         if (led_dat->can_sleep) {
  72                 led_dat->new_level = level;
  73                 schedule_work(&led_dat->work);
  74         } else {
  75                 if (led_dat->blinking) {
  76                         int gpio = desc_to_gpio(led_dat->gpiod);
  77
  78                         if (gpiod_is_active_low(led_dat->gpiod))
  79                                 level = !level;
  80
  81                         led_dat->platform_gpio_blink_set(gpio, level, NULL,
  82                                                          NULL);
  83                         led_dat->blinking = 0;
  84                 } else
  85                         gpiod_set_value(led_dat->gpiod, level);
  86         }
  87 }
  88
  89 static int gpio_blink_set(struct led_classdev *led_cdev,
  90         unsigned long *delay_on, unsigned long *delay_off)
  91 {
  92         struct gpio_led_data *led_dat =
  93                 container_of(led_cdev, struct gpio_led_data, cdev);
  94         int gpio = desc_to_gpio(led_dat->gpiod);
  95
  96         led_dat->blinking = 1;
  97         return led_dat->platform_gpio_blink_set(gpio, GPIO_LED_BLINK,
  98                                                 delay_on, delay_off);
  99 }
 100
 101 static int create_gpio_led(const struct gpio_led *template,
 102         struct gpio_led_data *led_dat, struct device *parent,
 103         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
 104 {
 105         int ret, state;
 106
 107         if (!template->gpiod) {
 108                 unsigned long flags = 0;
 109
 110                 /* skip leds that aren't available */
 111                 if (!gpio_is_valid(template->gpio)) {
 112                         dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 113                                         template->gpio, template->name);
 114                         return 0;
 115                 }
 116
 117                 if (template->active_low)
 118                         flags |= GPIOF_ACTIVE_LOW;
 119
 120                 ret = devm_gpio_request_one(parent, template->gpio, flags,
 121                                             template->name);
 122                 if (ret < 0)
 123                         return ret;
 124
 125                 led_dat->gpiod = gpio_to_desc(template->gpio);
 126                 if (IS_ERR(led_dat->gpiod))
 127                         return PTR_ERR(led_dat->gpiod);
 128         }
 129
 130         led_dat->cdev.name = template->name;
 131         led_dat->cdev.default_trigger = template->default_trigger;
 132         led_dat->gpiod = template->gpiod;
 133         led_dat->can_sleep = gpiod_cansleep(template->gpiod);
 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_set = gpio_led_set;
 140         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 141                 state = !!gpiod_get_value_cansleep(led_dat->gpiod);
 142         else
 143                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 144         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 145         if (!template->retain_state_suspended)
 146                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 147
 148         ret = gpiod_direction_output(led_dat->gpiod, state);
 149         if (ret < 0)
 150                 return ret;
 151
 152         INIT_WORK(&led_dat->work, gpio_led_work);
 153
 154         return led_classdev_register(parent, &led_dat->cdev);
 155 }
 156
 157 static void delete_gpio_led(struct gpio_led_data *led)
 158 {
 159         led_classdev_unregister(&led->cdev);
 160         cancel_work_sync(&led->work);
 161 }
 162
 163 struct gpio_leds_priv {
 164         int num_leds;
 165         struct gpio_led_data leds[];
 166 };
 167
 168 static inline int sizeof_gpio_leds_priv(int num_leds)
 169 {
 170         return sizeof(struct gpio_leds_priv) +
 171                 (sizeof(struct gpio_led_data) * num_leds);
 172 }
 173
 174 /* Code to create from OpenFirmware platform devices */
 175 #ifdef CONFIG_OF_GPIO
 176 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
 177 {
 178         struct device_node *np = pdev->dev.of_node, *child;
 179         struct gpio_leds_priv *priv;
 180         int count, ret;
 181
 182         /* count LEDs in this device, so we know how much to allocate */
 183         count = of_get_available_child_count(np);
 184         if (!count)
 185                 return ERR_PTR(-ENODEV);
 186
 187         for_each_available_child_of_node(np, child)
 188                 if (of_get_gpio(child, 0) == -EPROBE_DEFER)
 189                         return ERR_PTR(-EPROBE_DEFER);
 190
 191         priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
 192                         GFP_KERNEL);
 193         if (!priv)
 194                 return ERR_PTR(-ENOMEM);
 195
 196         for_each_available_child_of_node(np, child) {
 197                 struct gpio_led led = {};
 198                 enum of_gpio_flags flags;
 199                 const char *state;
 200
 201                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 202                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 203                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 204                 led.default_trigger =
 205                         of_get_property(child, "linux,default-trigger", NULL);
 206                 state = of_get_property(child, "default-state", NULL);
 207                 if (state) {
 208                         if (!strcmp(state, "keep"))
 209                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 210                         else if (!strcmp(state, "on"))
 211                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 212                         else
 213                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 214                 }
 215
 216                 if (of_get_property(child, "retain-state-suspended", NULL))
 217                         led.retain_state_suspended = 1;
 218
 219                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
 220                                       &pdev->dev, NULL);
 221                 if (ret < 0) {
 222                         of_node_put(child);
 223                         goto err;
 224                 }
 225         }
 226
 227         return priv;
 228
 229 err:
 230         for (count = priv->num_leds - 2; count >= 0; count--)
 231                 delete_gpio_led(&priv->leds[count]);
 232         return ERR_PTR(-ENODEV);
 233 }
 234
 235 static const struct of_device_id of_gpio_leds_match[] = {
 236         { .compatible = "gpio-leds", },
 237         {},
 238 };
 239
 240 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 241 #else /* CONFIG_OF_GPIO */
 242 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
 243 {
 244         return ERR_PTR(-ENODEV);
 245 }
 246 #endif /* CONFIG_OF_GPIO */
 247
 248 static int gpio_led_probe(struct platform_device *pdev)
 249 {
 250         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 251         struct gpio_leds_priv *priv;
 252         int i, ret = 0;
 253
 254         if (pdata && pdata->num_leds) {
 255                 priv = devm_kzalloc(&pdev->dev,
 256                                 sizeof_gpio_leds_priv(pdata->num_leds),
 257                                         GFP_KERNEL);
 258                 if (!priv)
 259                         return -ENOMEM;
 260
 261                 priv->num_leds = pdata->num_leds;
 262                 for (i = 0; i < priv->num_leds; i++) {
 263                         ret = create_gpio_led(&pdata->leds[i],
 264                                               &priv->leds[i],
 265                                               &pdev->dev, pdata->gpio_blink_set);
 266                         if (ret < 0) {
 267                                 /* On failure: unwind the led creations */
 268                                 for (i = i - 1; i >= 0; i--)
 269                                         delete_gpio_led(&priv->leds[i]);
 270                                 return ret;
 271                         }
 272                 }
 273         } else {
 274                 priv = gpio_leds_create_of(pdev);
 275                 if (IS_ERR(priv))
 276                         return PTR_ERR(priv);
 277         }
 278
 279         platform_set_drvdata(pdev, priv);
 280
 281         return 0;
 282 }
 283
 284 static int gpio_led_remove(struct platform_device *pdev)
 285 {
 286         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 287         int i;
 288
 289         for (i = 0; i < priv->num_leds; i++)
 290                 delete_gpio_led(&priv->leds[i]);
 291
 292         return 0;
 293 }
 294
 295 static struct platform_driver gpio_led_driver = {
 296         .probe          = gpio_led_probe,
 297         .remove         = gpio_led_remove,
 298         .driver         = {
 299                 .name   = "leds-gpio",
 300                 .owner  = THIS_MODULE,
 301                 .of_match_table = of_match_ptr(of_gpio_leds_match),
 302         },
 303 };
 304
 305 module_platform_driver(gpio_led_driver);
 306
 307 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 308 MODULE_DESCRIPTION("GPIO LED driver");
 309 MODULE_LICENSE("GPL");
 310 MODULE_ALIAS("platform:leds-gpio");