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/leds.h>
  17 #include <linux/slab.h>
  18 #include <linux/workqueue.h>
  19
  20 #include <asm/gpio.h>
  21
  22 struct gpio_led_data {
  23         struct led_classdev cdev;
  24         unsigned gpio;
  25         struct work_struct work;
  26         u8 new_level;
  27         u8 can_sleep;
  28         u8 active_low;
  29         u8 blinking;
  30         int (*platform_gpio_blink_set)(unsigned gpio, int state,
  31                         unsigned long *delay_on, unsigned long *delay_off);
  32 };
  33
  34 static void gpio_led_work(struct work_struct *work)
  35 {
  36         struct gpio_led_data    *led_dat =
  37                 container_of(work, struct gpio_led_data, work);
  38
  39         if (led_dat->blinking) {
  40                 led_dat->platform_gpio_blink_set(led_dat->gpio,
  41                                                  led_dat->new_level,
  42                                                  NULL, NULL);
  43                 led_dat->blinking = 0;
  44         } else
  45                 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  46 }
  47
  48 static void gpio_led_set(struct led_classdev *led_cdev,
  49         enum led_brightness value)
  50 {
  51         struct gpio_led_data *led_dat =
  52                 container_of(led_cdev, struct gpio_led_data, cdev);
  53         int level;
  54
  55         if (value == LED_OFF)
  56                 level = 0;
  57         else
  58                 level = 1;
  59
  60         if (led_dat->active_low)
  61                 level = !level;
  62
  63         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  64          * seem to have a reliable way to know if we're already in one; so
  65          * let's just assume the worst.
  66          */
  67         if (led_dat->can_sleep) {
  68                 led_dat->new_level = level;
  69                 schedule_work(&led_dat->work);
  70         } else {
  71                 if (led_dat->blinking) {
  72                         led_dat->platform_gpio_blink_set(led_dat->gpio, level,
  73                                                          NULL, NULL);
  74                         led_dat->blinking = 0;
  75                 } else
  76                         gpio_set_value(led_dat->gpio, level);
  77         }
  78 }
  79
  80 static int gpio_blink_set(struct led_classdev *led_cdev,
  81         unsigned long *delay_on, unsigned long *delay_off)
  82 {
  83         struct gpio_led_data *led_dat =
  84                 container_of(led_cdev, struct gpio_led_data, cdev);
  85
  86         led_dat->blinking = 1;
  87         return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
  88                                                 delay_on, delay_off);
  89 }
  90
  91 static int __devinit create_gpio_led(const struct gpio_led *template,
  92         struct gpio_led_data *led_dat, struct device *parent,
  93         int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))
  94 {
  95         int ret, state;
  96
  97         led_dat->gpio = -1;
  98
  99         /* skip leds that aren't available */
 100         if (!gpio_is_valid(template->gpio)) {
 101                 printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)\n",
 102                                 template->gpio, template->name);
 103                 return 0;
 104         }
 105
 106         ret = gpio_request(template->gpio, template->name);
 107         if (ret < 0)
 108                 return ret;
 109
 110         led_dat->cdev.name = template->name;
 111         led_dat->cdev.default_trigger = template->default_trigger;
 112         led_dat->gpio = template->gpio;
 113         led_dat->can_sleep = gpio_cansleep(template->gpio);
 114         led_dat->active_low = template->active_low;
 115         led_dat->blinking = 0;
 116         if (blink_set) {
 117                 led_dat->platform_gpio_blink_set = blink_set;
 118                 led_dat->cdev.blink_set = gpio_blink_set;
 119         }
 120         led_dat->cdev.brightness_set = gpio_led_set;
 121         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 122                 state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low;
 123         else
 124                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 125         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 126         if (!template->retain_state_suspended)
 127                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 128
 129         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 130         if (ret < 0)
 131                 goto err;
 132
 133         INIT_WORK(&led_dat->work, gpio_led_work);
 134
 135         ret = led_classdev_register(parent, &led_dat->cdev);
 136         if (ret < 0)
 137                 goto err;
 138
 139         return 0;
 140 err:
 141         gpio_free(led_dat->gpio);
 142         return ret;
 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         gpio_free(led->gpio);
 152 }
 153
 154 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 155 static int __devinit gpio_led_probe(struct platform_device *pdev)
 156 {
 157         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 158         struct gpio_led_data *leds_data;
 159         int i, ret = 0;
 160
 161         if (!pdata)
 162                 return -EBUSY;
 163
 164         leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
 165                                 GFP_KERNEL);
 166         if (!leds_data)
 167                 return -ENOMEM;
 168
 169         for (i = 0; i < pdata->num_leds; i++) {
 170                 ret = create_gpio_led(&pdata->leds[i], &leds_data[i],
 171                                       &pdev->dev, pdata->gpio_blink_set);
 172                 if (ret < 0)
 173                         goto err;
 174         }
 175
 176         platform_set_drvdata(pdev, leds_data);
 177
 178         return 0;
 179
 180 err:
 181         for (i = i - 1; i >= 0; i--)
 182                 delete_gpio_led(&leds_data[i]);
 183
 184         kfree(leds_data);
 185
 186         return ret;
 187 }
 188
 189 static int __devexit gpio_led_remove(struct platform_device *pdev)
 190 {
 191         int i;
 192         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 193         struct gpio_led_data *leds_data;
 194
 195         leds_data = platform_get_drvdata(pdev);
 196
 197         for (i = 0; i < pdata->num_leds; i++)
 198                 delete_gpio_led(&leds_data[i]);
 199
 200         kfree(leds_data);
 201
 202         return 0;
 203 }
 204
 205 static struct platform_driver gpio_led_driver = {
 206         .probe          = gpio_led_probe,
 207         .remove         = __devexit_p(gpio_led_remove),
 208         .driver         = {
 209                 .name   = "leds-gpio",
 210                 .owner  = THIS_MODULE,
 211         },
 212 };
 213
 214 MODULE_ALIAS("platform:leds-gpio");
 215 #endif /* CONFIG_LEDS_GPIO_PLATFORM */
 216
 217 /* Code to create from OpenFirmware platform devices */
 218 #ifdef CONFIG_LEDS_GPIO_OF
 219 #include <linux/of_platform.h>
 220 #include <linux/of_gpio.h>
 221
 222 struct gpio_led_of_platform_data {
 223         int num_leds;
 224         struct gpio_led_data led_data[];
 225 };
 226
 227 static int __devinit of_gpio_leds_probe(struct platform_device *ofdev,
 228                                         const struct of_device_id *match)
 229 {
 230         struct device_node *np = ofdev->dev.of_node, *child;
 231         struct gpio_led_of_platform_data *pdata;
 232         int count = 0, ret;
 233
 234         /* count LEDs defined by this device, so we know how much to allocate */
 235         for_each_child_of_node(np, child)
 236                 count++;
 237         if (!count)
 238                 return 0; /* or ENODEV? */
 239
 240         pdata = kzalloc(sizeof(*pdata) + sizeof(struct gpio_led_data) * count,
 241                         GFP_KERNEL);
 242         if (!pdata)
 243                 return -ENOMEM;
 244
 245         for_each_child_of_node(np, child) {
 246                 struct gpio_led led = {};
 247                 enum of_gpio_flags flags;
 248                 const char *state;
 249
 250                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 251                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 252                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 253                 led.default_trigger =
 254                         of_get_property(child, "linux,default-trigger", NULL);
 255                 state = of_get_property(child, "default-state", NULL);
 256                 if (state) {
 257                         if (!strcmp(state, "keep"))
 258                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 259                         else if(!strcmp(state, "on"))
 260                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 261                         else
 262                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 263                 }
 264
 265                 ret = create_gpio_led(&led, &pdata->led_data[pdata->num_leds++],
 266                                       &ofdev->dev, NULL);
 267                 if (ret < 0) {
 268                         of_node_put(child);
 269                         goto err;
 270                 }
 271         }
 272
 273         dev_set_drvdata(&ofdev->dev, pdata);
 274
 275         return 0;
 276
 277 err:
 278         for (count = pdata->num_leds - 2; count >= 0; count--)
 279                 delete_gpio_led(&pdata->led_data[count]);
 280
 281         kfree(pdata);
 282
 283         return ret;
 284 }
 285
 286 static int __devexit of_gpio_leds_remove(struct platform_device *ofdev)
 287 {
 288         struct gpio_led_of_platform_data *pdata = dev_get_drvdata(&ofdev->dev);
 289         int i;
 290
 291         for (i = 0; i < pdata->num_leds; i++)
 292                 delete_gpio_led(&pdata->led_data[i]);
 293
 294         kfree(pdata);
 295
 296         dev_set_drvdata(&ofdev->dev, NULL);
 297
 298         return 0;
 299 }
 300
 301 static const struct of_device_id of_gpio_leds_match[] = {
 302         { .compatible = "gpio-leds", },
 303         {},
 304 };
 305
 306 static struct of_platform_driver of_gpio_leds_driver = {
 307         .driver = {
 308                 .name = "of_gpio_leds",
 309                 .owner = THIS_MODULE,
 310                 .of_match_table = of_gpio_leds_match,
 311         },
 312         .probe = of_gpio_leds_probe,
 313         .remove = __devexit_p(of_gpio_leds_remove),
 314 };
 315 #endif
 316
 317 static int __init gpio_led_init(void)
 318 {
 319         int ret = 0;
 320
 321 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 322         ret = platform_driver_register(&gpio_led_driver);
 323         if (ret)
 324                 return ret;
 325 #endif
 326 #ifdef CONFIG_LEDS_GPIO_OF
 327         ret = of_register_platform_driver(&of_gpio_leds_driver);
 328 #endif
 329 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 330         if (ret)
 331                 platform_driver_unregister(&gpio_led_driver);
 332 #endif
 333
 334         return ret;
 335 }
 336
 337 static void __exit gpio_led_exit(void)
 338 {
 339 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 340         platform_driver_unregister(&gpio_led_driver);
 341 #endif
 342 #ifdef CONFIG_LEDS_GPIO_OF
 343         of_unregister_platform_driver(&of_gpio_leds_driver);
 344 #endif
 345 }
 346
 347 module_init(gpio_led_init);
 348 module_exit(gpio_led_exit);
 349
 350 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 351 MODULE_DESCRIPTION("GPIO LED driver");
 352 MODULE_LICENSE("GPL");