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/kernel.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/gpio.h>
  16 #include <linux/leds.h>
  17 #include <linux/of.h>
  18 #include <linux/of_platform.h>
  19 #include <linux/of_gpio.h>
  20 #include <linux/slab.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/module.h>
  23 #include <linux/err.h>
  24
  25 struct gpio_led_data {
  26         struct led_classdev cdev;
  27         unsigned gpio;
  28         struct work_struct work;
  29         u8 new_level;
  30         u8 can_sleep;
  31         u8 active_low;
  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                 led_dat->platform_gpio_blink_set(led_dat->gpio,
  44                                                  led_dat->new_level,
  45                                                  NULL, NULL);
  46                 led_dat->blinking = 0;
  47         } else
  48                 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  49 }
  50
  51 static void gpio_led_set(struct led_classdev *led_cdev,
  52         enum led_brightness value)
  53 {
  54         struct gpio_led_data *led_dat =
  55                 container_of(led_cdev, struct gpio_led_data, cdev);
  56         int level;
  57
  58         if (value == LED_OFF)
  59                 level = 0;
  60         else
  61                 level = 1;
  62
  63         if (led_dat->active_low)
  64                 level = !level;
  65
  66         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  67          * seem to have a reliable way to know if we're already in one; so
  68          * let's just assume the worst.
  69          */
  70         if (led_dat->can_sleep) {
  71                 led_dat->new_level = level;
  72                 schedule_work(&led_dat->work);
  73         } else {
  74                 if (led_dat->blinking) {
  75                         led_dat->platform_gpio_blink_set(led_dat->gpio, level,
  76                                                          NULL, NULL);
  77                         led_dat->blinking = 0;
  78                 } else
  79                         gpio_set_value(led_dat->gpio, level);
  80         }
  81 }
  82
  83 static int gpio_blink_set(struct led_classdev *led_cdev,
  84         unsigned long *delay_on, unsigned long *delay_off)
  85 {
  86         struct gpio_led_data *led_dat =
  87                 container_of(led_cdev, struct gpio_led_data, cdev);
  88
  89         led_dat->blinking = 1;
  90         return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
  91                                                 delay_on, delay_off);
  92 }
  93
  94 static int create_gpio_led(const struct gpio_led *template,
  95         struct gpio_led_data *led_dat, struct device *parent,
  96         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
  97 {
  98         int ret, state;
  99
 100         led_dat->gpio = -1;
 101
 102         /* skip leds that aren't available */
 103         if (!gpio_is_valid(template->gpio)) {
 104                 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 105                                 template->gpio, template->name);
 106                 return 0;
 107         }
 108
 109         ret = devm_gpio_request(parent, template->gpio, template->name);
 110         if (ret < 0)
 111                 return ret;
 112
 113         led_dat->cdev.name = template->name;
 114         led_dat->cdev.default_trigger = template->default_trigger;
 115         led_dat->gpio = template->gpio;
 116         led_dat->can_sleep = gpio_cansleep(template->gpio);
 117         led_dat->active_low = template->active_low;
 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         led_dat->cdev.brightness_set = gpio_led_set;
 124         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 125                 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;
 126         else
 127                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 128         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 129         if (!template->retain_state_suspended)
 130                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 131
 132         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 133         if (ret < 0)
 134                 return ret;
 135
 136         INIT_WORK(&led_dat->work, gpio_led_work);
 137
 138         ret = led_classdev_register(parent, &led_dat->cdev);
 139         if (ret < 0)
 140                 return ret;
 141
 142         return 0;
 143 }
 144
 145 static void delete_gpio_led(struct gpio_led_data *led)
 146 {
 147         if (!gpio_is_valid(led->gpio))
 148                 return;
 149         led_classdev_unregister(&led->cdev);
 150         cancel_work_sync(&led->work);
 151 }
 152
 153 struct gpio_leds_priv {
 154         int num_leds;
 155         struct gpio_led_data leds[];
 156 };
 157
 158 static inline int sizeof_gpio_leds_priv(int num_leds)
 159 {
 160         return sizeof(struct gpio_leds_priv) +
 161                 (sizeof(struct gpio_led_data) * num_leds);
 162 }
 163
 164 /* Code to create from OpenFirmware platform devices */
 165 #ifdef CONFIG_OF_GPIO
 166 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
 167 {
 168         struct device_node *np = pdev->dev.of_node, *child;
 169         struct gpio_leds_priv *priv;
 170         int count, ret;
 171
 172         /* count LEDs in this device, so we know how much to allocate */
 173         count = of_get_available_child_count(np);
 174         if (!count)
 175                 return ERR_PTR(-ENODEV);
 176
 177         for_each_available_child_of_node(np, child)
 178                 if (of_get_gpio(child, 0) == -EPROBE_DEFER)
 179                         return ERR_PTR(-EPROBE_DEFER);
 180
 181         priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
 182                         GFP_KERNEL);
 183         if (!priv)
 184                 return ERR_PTR(-ENOMEM);
 185
 186         for_each_available_child_of_node(np, child) {
 187                 struct gpio_led led = {};
 188                 enum of_gpio_flags flags;
 189                 const char *state;
 190
 191                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 192                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 193                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 194                 led.default_trigger =
 195                         of_get_property(child, "linux,default-trigger", NULL);
 196                 state = of_get_property(child, "default-state", NULL);
 197                 if (state) {
 198                         if (!strcmp(state, "keep"))
 199                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 200                         else if (!strcmp(state, "on"))
 201                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 202                         else
 203                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 204                 }
 205
 206                 if (of_get_property(child, "retain-state-suspended", NULL))
 207                         led.retain_state_suspended = 1;
 208
 209                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
 210                                       &pdev->dev, NULL);
 211                 if (ret < 0) {
 212                         of_node_put(child);
 213                         goto err;
 214                 }
 215         }
 216
 217         return priv;
 218
 219 err:
 220         for (count = priv->num_leds - 2; count >= 0; count--)
 221                 delete_gpio_led(&priv->leds[count]);
 222         return ERR_PTR(-ENODEV);
 223 }
 224
 225 static const struct of_device_id of_gpio_leds_match[] = {
 226         { .compatible = "gpio-leds", },
 227         {},
 228 };
 229
 230 MODULE_DEVICE_TABLE(of, of_gpio_leds_match);
 231 #else /* CONFIG_OF_GPIO */
 232 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
 233 {
 234         return ERR_PTR(-ENODEV);
 235 }
 236 #endif /* CONFIG_OF_GPIO */
 237
 238
 239 static int gpio_led_probe(struct platform_device *pdev)
 240 {
 241         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 242         struct gpio_leds_priv *priv;
 243         int i, ret = 0;
 244
 245
 246         if (pdata && pdata->num_leds) {
 247                 priv = devm_kzalloc(&pdev->dev,
 248                                 sizeof_gpio_leds_priv(pdata->num_leds),
 249                                         GFP_KERNEL);
 250                 if (!priv)
 251                         return -ENOMEM;
 252
 253                 priv->num_leds = pdata->num_leds;
 254                 for (i = 0; i < priv->num_leds; i++) {
 255                         ret = create_gpio_led(&pdata->leds[i],
 256                                               &priv->leds[i],
 257                                               &pdev->dev, pdata->gpio_blink_set);
 258                         if (ret < 0) {
 259                                 /* On failure: unwind the led creations */
 260                                 for (i = i - 1; i >= 0; i--)
 261                                         delete_gpio_led(&priv->leds[i]);
 262                                 return ret;
 263                         }
 264                 }
 265         } else {
 266                 priv = gpio_leds_create_of(pdev);
 267                 if (IS_ERR(priv))
 268                         return PTR_ERR(priv);
 269         }
 270
 271         platform_set_drvdata(pdev, priv);
 272
 273         return 0;
 274 }
 275
 276 static int gpio_led_remove(struct platform_device *pdev)
 277 {
 278         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 279         int i;
 280
 281         for (i = 0; i < priv->num_leds; i++)
 282                 delete_gpio_led(&priv->leds[i]);
 283
 284         return 0;
 285 }
 286
 287 static struct platform_driver gpio_led_driver = {
 288         .probe          = gpio_led_probe,
 289         .remove         = gpio_led_remove,
 290         .driver         = {
 291                 .name   = "leds-gpio",
 292                 .owner  = THIS_MODULE,
 293                 .of_match_table = of_match_ptr(of_gpio_leds_match),
 294         },
 295 };
 296
 297 module_platform_driver(gpio_led_driver);
 298
 299 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 300 MODULE_DESCRIPTION("GPIO LED driver");
 301 MODULE_LICENSE("GPL");
 302 MODULE_ALIAS("platform:leds-gpio");