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/init.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/gpio.h>
  17 #include <linux/leds.h>
  18 #include <linux/of.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/of_gpio.h>
  21 #include <linux/slab.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/module.h>
  24 #include <linux/err.h>
  25
  26 struct gpio_led_data {
  27         struct led_classdev cdev;
  28         unsigned gpio;
  29         struct work_struct work;
  30         u8 new_level;
  31         u8 can_sleep;
  32         u8 active_low;
  33         u8 blinking;
  34         int (*platform_gpio_blink_set)(unsigned gpio, int state,
  35                         unsigned long *delay_on, unsigned long *delay_off);
  36 };
  37
  38 static void gpio_led_work(struct work_struct *work)
  39 {
  40         struct gpio_led_data    *led_dat =
  41                 container_of(work, struct gpio_led_data, work);
  42
  43         if (led_dat->blinking) {
  44                 led_dat->platform_gpio_blink_set(led_dat->gpio,
  45                                                  led_dat->new_level,
  46                                                  NULL, NULL);
  47                 led_dat->blinking = 0;
  48         } else
  49                 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  50 }
  51
  52 static void gpio_led_set(struct led_classdev *led_cdev,
  53         enum led_brightness value)
  54 {
  55         struct gpio_led_data *led_dat =
  56                 container_of(led_cdev, struct gpio_led_data, cdev);
  57         int level;
  58
  59         if (value == LED_OFF)
  60                 level = 0;
  61         else
  62                 level = 1;
  63
  64         if (led_dat->active_low)
  65                 level = !level;
  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                         led_dat->platform_gpio_blink_set(led_dat->gpio, level,
  77                                                          NULL, NULL);
  78                         led_dat->blinking = 0;
  79                 } else
  80                         gpio_set_value(led_dat->gpio, level);
  81         }
  82 }
  83
  84 static int gpio_blink_set(struct led_classdev *led_cdev,
  85         unsigned long *delay_on, unsigned long *delay_off)
  86 {
  87         struct gpio_led_data *led_dat =
  88                 container_of(led_cdev, struct gpio_led_data, cdev);
  89
  90         led_dat->blinking = 1;
  91         return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
  92                                                 delay_on, delay_off);
  93 }
  94
  95 static int create_gpio_led(const struct gpio_led *template,
  96         struct gpio_led_data *led_dat, struct device *parent,
  97         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
  98 {
  99         int ret, state;
 100
 101         led_dat->gpio = -1;
 102
 103         /* skip leds that aren't available */
 104         if (!gpio_is_valid(template->gpio)) {
 105                 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n",
 106                                 template->gpio, template->name);
 107                 return 0;
 108         }
 109
 110         ret = devm_gpio_request(parent, template->gpio, template->name);
 111         if (ret < 0)
 112                 return ret;
 113
 114         led_dat->cdev.name = template->name;
 115         led_dat->cdev.default_trigger = template->default_trigger;
 116         led_dat->gpio = template->gpio;
 117         led_dat->can_sleep = gpio_cansleep(template->gpio);
 118         led_dat->active_low = template->active_low;
 119         led_dat->blinking = 0;
 120         if (blink_set) {
 121                 led_dat->platform_gpio_blink_set = blink_set;
 122                 led_dat->cdev.blink_set = gpio_blink_set;
 123         }
 124         led_dat->cdev.brightness_set = gpio_led_set;
 125         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 126                 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;
 127         else
 128                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 129         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 130         if (!template->retain_state_suspended)
 131                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 132
 133         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 134         if (ret < 0)
 135                 return ret;
 136
 137         INIT_WORK(&led_dat->work, gpio_led_work);
 138
 139         ret = led_classdev_register(parent, &led_dat->cdev);
 140         if (ret < 0)
 141                 return ret;
 142
 143         return 0;
 144 }
 145
 146 static void delete_gpio_led(struct gpio_led_data *led)
 147 {
 148         if (!gpio_is_valid(led->gpio))
 149                 return;
 150         led_classdev_unregister(&led->cdev);
 151         cancel_work_sync(&led->work);
 152 }
 153
 154 struct gpio_leds_priv {
 155         int num_leds;
 156         struct gpio_led_data leds[];
 157 };
 158
 159 static inline int sizeof_gpio_leds_priv(int num_leds)
 160 {
 161         return sizeof(struct gpio_leds_priv) +
 162                 (sizeof(struct gpio_led_data) * num_leds);
 163 }
 164
 165 /* Code to create from OpenFirmware platform devices */
 166 #ifdef CONFIG_OF_GPIO
 167 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
 168 {
 169         struct device_node *np = pdev->dev.of_node, *child;
 170         struct gpio_leds_priv *priv;
 171         int count, ret;
 172
 173         /* count LEDs in this device, so we know how much to allocate */
 174         count = of_get_available_child_count(np);
 175         if (!count)
 176                 return ERR_PTR(-ENODEV);
 177
 178         for_each_available_child_of_node(np, child)
 179                 if (of_get_gpio(child, 0) == -EPROBE_DEFER)
 180                         return ERR_PTR(-EPROBE_DEFER);
 181
 182         priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
 183                         GFP_KERNEL);
 184         if (!priv)
 185                 return ERR_PTR(-ENOMEM);
 186
 187         for_each_available_child_of_node(np, child) {
 188                 struct gpio_led led = {};
 189                 enum of_gpio_flags flags;
 190                 const char *state;
 191
 192                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 193                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 194                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 195                 led.default_trigger =
 196                         of_get_property(child, "linux,default-trigger", NULL);
 197                 state = of_get_property(child, "default-state", NULL);
 198                 if (state) {
 199                         if (!strcmp(state, "keep"))
 200                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 201                         else if (!strcmp(state, "on"))
 202                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 203                         else
 204                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 205                 }
 206
 207                 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
 208                                       &pdev->dev, NULL);
 209                 if (ret < 0) {
 210                         of_node_put(child);
 211                         goto err;
 212                 }
 213         }
 214
 215         return priv;
 216
 217 err:
 218         for (count = priv->num_leds - 2; count >= 0; count--)
 219                 delete_gpio_led(&priv->leds[count]);
 220         return ERR_PTR(-ENODEV);
 221 }
 222
 223 static const struct of_device_id of_gpio_leds_match[] = {
 224         { .compatible = "gpio-leds", },
 225         {},
 226 };
 227 #else /* CONFIG_OF_GPIO */
 228 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev)
 229 {
 230         return ERR_PTR(-ENODEV);
 231 }
 232 #endif /* CONFIG_OF_GPIO */
 233
 234
 235 static int gpio_led_probe(struct platform_device *pdev)
 236 {
 237         struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
 238         struct gpio_leds_priv *priv;
 239         int i, ret = 0;
 240
 241
 242         if (pdata && pdata->num_leds) {
 243                 priv = devm_kzalloc(&pdev->dev,
 244                                 sizeof_gpio_leds_priv(pdata->num_leds),
 245                                         GFP_KERNEL);
 246                 if (!priv)
 247                         return -ENOMEM;
 248
 249                 priv->num_leds = pdata->num_leds;
 250                 for (i = 0; i < priv->num_leds; i++) {
 251                         ret = create_gpio_led(&pdata->leds[i],
 252                                               &priv->leds[i],
 253                                               &pdev->dev, pdata->gpio_blink_set);
 254                         if (ret < 0) {
 255                                 /* On failure: unwind the led creations */
 256                                 for (i = i - 1; i >= 0; i--)
 257                                         delete_gpio_led(&priv->leds[i]);
 258                                 return ret;
 259                         }
 260                 }
 261         } else {
 262                 priv = gpio_leds_create_of(pdev);
 263                 if (IS_ERR(priv))
 264                         return PTR_ERR(priv);
 265         }
 266
 267         platform_set_drvdata(pdev, priv);
 268
 269         return 0;
 270 }
 271
 272 static int gpio_led_remove(struct platform_device *pdev)
 273 {
 274         struct gpio_leds_priv *priv = platform_get_drvdata(pdev);
 275         int i;
 276
 277         for (i = 0; i < priv->num_leds; i++)
 278                 delete_gpio_led(&priv->leds[i]);
 279
 280         return 0;
 281 }
 282
 283 static struct platform_driver gpio_led_driver = {
 284         .probe          = gpio_led_probe,
 285         .remove         = gpio_led_remove,
 286         .driver         = {
 287                 .name   = "leds-gpio",
 288                 .owner  = THIS_MODULE,
 289                 .of_match_table = of_match_ptr(of_gpio_leds_match),
 290         },
 291 };
 292
 293 module_platform_driver(gpio_led_driver);
 294
 295 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 296 MODULE_DESCRIPTION("GPIO LED driver");
 297 MODULE_LICENSE("GPL");
 298 MODULE_ALIAS("platform:leds-gpio");