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         int (*platform_gpio_blink_set)(unsigned gpio,
  30                         unsigned long *delay_on, unsigned long *delay_off);
  31 };
  32
  33 static void gpio_led_work(struct work_struct *work)
  34 {
  35         struct gpio_led_data    *led_dat =
  36                 container_of(work, struct gpio_led_data, work);
  37
  38         gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  39 }
  40
  41 static void gpio_led_set(struct led_classdev *led_cdev,
  42         enum led_brightness value)
  43 {
  44         struct gpio_led_data *led_dat =
  45                 container_of(led_cdev, struct gpio_led_data, cdev);
  46         int level;
  47
  48         if (value == LED_OFF)
  49                 level = 0;
  50         else
  51                 level = 1;
  52
  53         if (led_dat->active_low)
  54                 level = !level;
  55
  56         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  57          * seem to have a reliable way to know if we're already in one; so
  58          * let's just assume the worst.
  59          */
  60         if (led_dat->can_sleep) {
  61                 led_dat->new_level = level;
  62                 schedule_work(&led_dat->work);
  63         } else
  64                 gpio_set_value(led_dat->gpio, level);
  65 }
  66
  67 static int gpio_blink_set(struct led_classdev *led_cdev,
  68         unsigned long *delay_on, unsigned long *delay_off)
  69 {
  70         struct gpio_led_data *led_dat =
  71                 container_of(led_cdev, struct gpio_led_data, cdev);
  72
  73         return led_dat->platform_gpio_blink_set(led_dat->gpio, delay_on, delay_off);
  74 }
  75
  76 static int __devinit create_gpio_led(const struct gpio_led *template,
  77         struct gpio_led_data *led_dat, struct device *parent,
  78         int (*blink_set)(unsigned, unsigned long *, unsigned long *))
  79 {
  80         int ret, state;
  81
  82         led_dat->gpio = -1;
  83
  84         /* skip leds that aren't available */
  85         if (!gpio_is_valid(template->gpio)) {
  86                 printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)\n",
  87                                 template->gpio, template->name);
  88                 return 0;
  89         }
  90
  91         ret = gpio_request(template->gpio, template->name);
  92         if (ret < 0)
  93                 return ret;
  94
  95         led_dat->cdev.name = template->name;
  96         led_dat->cdev.default_trigger = template->default_trigger;
  97         led_dat->gpio = template->gpio;
  98         led_dat->can_sleep = gpio_cansleep(template->gpio);
  99         led_dat->active_low = template->active_low;
 100         if (blink_set) {
 101                 led_dat->platform_gpio_blink_set = blink_set;
 102                 led_dat->cdev.blink_set = gpio_blink_set;
 103         }
 104         led_dat->cdev.brightness_set = gpio_led_set;
 105         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 106                 state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low;
 107         else
 108                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 109         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 110         if (!template->retain_state_suspended)
 111                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 112
 113         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 114         if (ret < 0)
 115                 goto err;
 116
 117         INIT_WORK(&led_dat->work, gpio_led_work);
 118
 119         ret = led_classdev_register(parent, &led_dat->cdev);
 120         if (ret < 0)
 121                 goto err;
 122
 123         return 0;
 124 err:
 125         gpio_free(led_dat->gpio);
 126         return ret;
 127 }
 128
 129 static void delete_gpio_led(struct gpio_led_data *led)
 130 {
 131         if (!gpio_is_valid(led->gpio))
 132                 return;
 133         led_classdev_unregister(&led->cdev);
 134         cancel_work_sync(&led->work);
 135         gpio_free(led->gpio);
 136 }
 137
 138 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 139 static int __devinit gpio_led_probe(struct platform_device *pdev)
 140 {
 141         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 142         struct gpio_led_data *leds_data;
 143         int i, ret = 0;
 144
 145         if (!pdata)
 146                 return -EBUSY;
 147
 148         leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
 149                                 GFP_KERNEL);
 150         if (!leds_data)
 151                 return -ENOMEM;
 152
 153         for (i = 0; i < pdata->num_leds; i++) {
 154                 ret = create_gpio_led(&pdata->leds[i], &leds_data[i],
 155                                       &pdev->dev, pdata->gpio_blink_set);
 156                 if (ret < 0)
 157                         goto err;
 158         }
 159
 160         platform_set_drvdata(pdev, leds_data);
 161
 162         return 0;
 163
 164 err:
 165         for (i = i - 1; i >= 0; i--)
 166                 delete_gpio_led(&leds_data[i]);
 167
 168         kfree(leds_data);
 169
 170         return ret;
 171 }
 172
 173 static int __devexit gpio_led_remove(struct platform_device *pdev)
 174 {
 175         int i;
 176         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 177         struct gpio_led_data *leds_data;
 178
 179         leds_data = platform_get_drvdata(pdev);
 180
 181         for (i = 0; i < pdata->num_leds; i++)
 182                 delete_gpio_led(&leds_data[i]);
 183
 184         kfree(leds_data);
 185
 186         return 0;
 187 }
 188
 189 static struct platform_driver gpio_led_driver = {
 190         .probe          = gpio_led_probe,
 191         .remove         = __devexit_p(gpio_led_remove),
 192         .driver         = {
 193                 .name   = "leds-gpio",
 194                 .owner  = THIS_MODULE,
 195         },
 196 };
 197
 198 MODULE_ALIAS("platform:leds-gpio");
 199 #endif /* CONFIG_LEDS_GPIO_PLATFORM */
 200
 201 /* Code to create from OpenFirmware platform devices */
 202 #ifdef CONFIG_LEDS_GPIO_OF
 203 #include <linux/of_platform.h>
 204 #include <linux/of_gpio.h>
 205
 206 struct gpio_led_of_platform_data {
 207         int num_leds;
 208         struct gpio_led_data led_data[];
 209 };
 210
 211 static int __devinit of_gpio_leds_probe(struct of_device *ofdev,
 212                                         const struct of_device_id *match)
 213 {
 214         struct device_node *np = ofdev->node, *child;
 215         struct gpio_led_of_platform_data *pdata;
 216         int count = 0, ret;
 217
 218         /* count LEDs defined by this device, so we know how much to allocate */
 219         for_each_child_of_node(np, child)
 220                 count++;
 221         if (!count)
 222                 return 0; /* or ENODEV? */
 223
 224         pdata = kzalloc(sizeof(*pdata) + sizeof(struct gpio_led_data) * count,
 225                         GFP_KERNEL);
 226         if (!pdata)
 227                 return -ENOMEM;
 228
 229         for_each_child_of_node(np, child) {
 230                 struct gpio_led led = {};
 231                 enum of_gpio_flags flags;
 232                 const char *state;
 233
 234                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 235                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 236                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 237                 led.default_trigger =
 238                         of_get_property(child, "linux,default-trigger", NULL);
 239                 state = of_get_property(child, "default-state", NULL);
 240                 if (state) {
 241                         if (!strcmp(state, "keep"))
 242                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 243                         else if(!strcmp(state, "on"))
 244                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 245                         else
 246                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 247                 }
 248
 249                 ret = create_gpio_led(&led, &pdata->led_data[pdata->num_leds++],
 250                                       &ofdev->dev, NULL);
 251                 if (ret < 0) {
 252                         of_node_put(child);
 253                         goto err;
 254                 }
 255         }
 256
 257         dev_set_drvdata(&ofdev->dev, pdata);
 258
 259         return 0;
 260
 261 err:
 262         for (count = pdata->num_leds - 2; count >= 0; count--)
 263                 delete_gpio_led(&pdata->led_data[count]);
 264
 265         kfree(pdata);
 266
 267         return ret;
 268 }
 269
 270 static int __devexit of_gpio_leds_remove(struct of_device *ofdev)
 271 {
 272         struct gpio_led_of_platform_data *pdata = dev_get_drvdata(&ofdev->dev);
 273         int i;
 274
 275         for (i = 0; i < pdata->num_leds; i++)
 276                 delete_gpio_led(&pdata->led_data[i]);
 277
 278         kfree(pdata);
 279
 280         dev_set_drvdata(&ofdev->dev, NULL);
 281
 282         return 0;
 283 }
 284
 285 static const struct of_device_id of_gpio_leds_match[] = {
 286         { .compatible = "gpio-leds", },
 287         {},
 288 };
 289
 290 static struct of_platform_driver of_gpio_leds_driver = {
 291         .driver = {
 292                 .name = "of_gpio_leds",
 293                 .owner = THIS_MODULE,
 294         },
 295         .match_table = of_gpio_leds_match,
 296         .probe = of_gpio_leds_probe,
 297         .remove = __devexit_p(of_gpio_leds_remove),
 298 };
 299 #endif
 300
 301 static int __init gpio_led_init(void)
 302 {
 303         int ret;
 304
 305 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 306         ret = platform_driver_register(&gpio_led_driver);
 307         if (ret)
 308                 return ret;
 309 #endif
 310 #ifdef CONFIG_LEDS_GPIO_OF
 311         ret = of_register_platform_driver(&of_gpio_leds_driver);
 312 #endif
 313 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 314         if (ret)
 315                 platform_driver_unregister(&gpio_led_driver);
 316 #endif
 317
 318         return ret;
 319 }
 320
 321 static void __exit gpio_led_exit(void)
 322 {
 323 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 324         platform_driver_unregister(&gpio_led_driver);
 325 #endif
 326 #ifdef CONFIG_LEDS_GPIO_OF
 327         of_unregister_platform_driver(&of_gpio_leds_driver);
 328 #endif
 329 }
 330
 331 module_init(gpio_led_init);
 332 module_exit(gpio_led_exit);
 333
 334 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 335 MODULE_DESCRIPTION("GPIO LED driver");
 336 MODULE_LICENSE("GPL");