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/workqueue.h>
  18
  19 #include <asm/gpio.h>
  20
  21 struct gpio_led_data {
  22         struct led_classdev cdev;
  23         unsigned gpio;
  24         struct work_struct work;
  25         u8 new_level;
  26         u8 can_sleep;
  27         u8 active_low;
  28         int (*platform_gpio_blink_set)(unsigned gpio,
  29                         unsigned long *delay_on, unsigned long *delay_off);
  30 };
  31
  32 static void gpio_led_work(struct work_struct *work)
  33 {
  34         struct gpio_led_data    *led_dat =
  35                 container_of(work, struct gpio_led_data, work);
  36
  37         gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  38 }
  39
  40 static void gpio_led_set(struct led_classdev *led_cdev,
  41         enum led_brightness value)
  42 {
  43         struct gpio_led_data *led_dat =
  44                 container_of(led_cdev, struct gpio_led_data, cdev);
  45         int level;
  46
  47         if (value == LED_OFF)
  48                 level = 0;
  49         else
  50                 level = 1;
  51
  52         if (led_dat->active_low)
  53                 level = !level;
  54
  55         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  56          * seem to have a reliable way to know if we're already in one; so
  57          * let's just assume the worst.
  58          */
  59         if (led_dat->can_sleep) {
  60                 led_dat->new_level = level;
  61                 schedule_work(&led_dat->work);
  62         } else
  63                 gpio_set_value(led_dat->gpio, level);
  64 }
  65
  66 static int gpio_blink_set(struct led_classdev *led_cdev,
  67         unsigned long *delay_on, unsigned long *delay_off)
  68 {
  69         struct gpio_led_data *led_dat =
  70                 container_of(led_cdev, struct gpio_led_data, cdev);
  71
  72         return led_dat->platform_gpio_blink_set(led_dat->gpio, delay_on, delay_off);
  73 }
  74
  75 static int __devinit create_gpio_led(const struct gpio_led *template,
  76         struct gpio_led_data *led_dat, struct device *parent,
  77         int (*blink_set)(unsigned, unsigned long *, unsigned long *))
  78 {
  79         int ret, state;
  80
  81         /* skip leds that aren't available */
  82         if (!gpio_is_valid(template->gpio)) {
  83                 printk(KERN_INFO "Skipping unavilable LED gpio %d (%s)\n",
  84                                 template->gpio, template->name);
  85                 return 0;
  86         }
  87
  88         ret = gpio_request(template->gpio, template->name);
  89         if (ret < 0)
  90                 return ret;
  91
  92         led_dat->cdev.name = template->name;
  93         led_dat->cdev.default_trigger = template->default_trigger;
  94         led_dat->gpio = template->gpio;
  95         led_dat->can_sleep = gpio_cansleep(template->gpio);
  96         led_dat->active_low = template->active_low;
  97         if (blink_set) {
  98                 led_dat->platform_gpio_blink_set = blink_set;
  99                 led_dat->cdev.blink_set = gpio_blink_set;
 100         }
 101         led_dat->cdev.brightness_set = gpio_led_set;
 102         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 103                 state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low;
 104         else
 105                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 106         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 107         if (!template->retain_state_suspended)
 108                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 109
 110         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 111         if (ret < 0)
 112                 goto err;
 113
 114         INIT_WORK(&led_dat->work, gpio_led_work);
 115
 116         ret = led_classdev_register(parent, &led_dat->cdev);
 117         if (ret < 0)
 118                 goto err;
 119
 120         return 0;
 121 err:
 122         gpio_free(led_dat->gpio);
 123         return ret;
 124 }
 125
 126 static void delete_gpio_led(struct gpio_led_data *led)
 127 {
 128         if (!gpio_is_valid(led->gpio))
 129                 return;
 130         led_classdev_unregister(&led->cdev);
 131         cancel_work_sync(&led->work);
 132         gpio_free(led->gpio);
 133 }
 134
 135 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 136 static int __devinit gpio_led_probe(struct platform_device *pdev)
 137 {
 138         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 139         struct gpio_led_data *leds_data;
 140         int i, ret = 0;
 141
 142         if (!pdata)
 143                 return -EBUSY;
 144
 145         leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
 146                                 GFP_KERNEL);
 147         if (!leds_data)
 148                 return -ENOMEM;
 149
 150         for (i = 0; i < pdata->num_leds; i++) {
 151                 ret = create_gpio_led(&pdata->leds[i], &leds_data[i],
 152                                       &pdev->dev, pdata->gpio_blink_set);
 153                 if (ret < 0)
 154                         goto err;
 155         }
 156
 157         platform_set_drvdata(pdev, leds_data);
 158
 159         return 0;
 160
 161 err:
 162         for (i = i - 1; i >= 0; i--)
 163                 delete_gpio_led(&leds_data[i]);
 164
 165         kfree(leds_data);
 166
 167         return ret;
 168 }
 169
 170 static int __devexit gpio_led_remove(struct platform_device *pdev)
 171 {
 172         int i;
 173         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 174         struct gpio_led_data *leds_data;
 175
 176         leds_data = platform_get_drvdata(pdev);
 177
 178         for (i = 0; i < pdata->num_leds; i++)
 179                 delete_gpio_led(&leds_data[i]);
 180
 181         kfree(leds_data);
 182
 183         return 0;
 184 }
 185
 186 static struct platform_driver gpio_led_driver = {
 187         .probe          = gpio_led_probe,
 188         .remove         = __devexit_p(gpio_led_remove),
 189         .driver         = {
 190                 .name   = "leds-gpio",
 191                 .owner  = THIS_MODULE,
 192         },
 193 };
 194
 195 MODULE_ALIAS("platform:leds-gpio");
 196 #endif /* CONFIG_LEDS_GPIO_PLATFORM */
 197
 198 /* Code to create from OpenFirmware platform devices */
 199 #ifdef CONFIG_LEDS_GPIO_OF
 200 #include <linux/of_platform.h>
 201 #include <linux/of_gpio.h>
 202
 203 struct gpio_led_of_platform_data {
 204         int num_leds;
 205         struct gpio_led_data led_data[];
 206 };
 207
 208 static int __devinit of_gpio_leds_probe(struct of_device *ofdev,
 209                                         const struct of_device_id *match)
 210 {
 211         struct device_node *np = ofdev->node, *child;
 212         struct gpio_led led;
 213         struct gpio_led_of_platform_data *pdata;
 214         int count = 0, ret;
 215
 216         /* count LEDs defined by this device, so we know how much to allocate */
 217         for_each_child_of_node(np, child)
 218                 count++;
 219         if (!count)
 220                 return 0; /* or ENODEV? */
 221
 222         pdata = kzalloc(sizeof(*pdata) + sizeof(struct gpio_led_data) * count,
 223                         GFP_KERNEL);
 224         if (!pdata)
 225                 return -ENOMEM;
 226
 227         memset(&led, 0, sizeof(led));
 228         for_each_child_of_node(np, child) {
 229                 enum of_gpio_flags flags;
 230                 const char *state;
 231
 232                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 233                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 234                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 235                 led.default_trigger =
 236                         of_get_property(child, "linux,default-trigger", NULL);
 237                 state = of_get_property(child, "default-state", NULL);
 238                 if (state) {
 239                         if (!strcmp(state, "keep"))
 240                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 241                         else if(!strcmp(state, "on"))
 242                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 243                         else
 244                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 245                 }
 246
 247                 ret = create_gpio_led(&led, &pdata->led_data[pdata->num_leds++],
 248                                       &ofdev->dev, NULL);
 249                 if (ret < 0) {
 250                         of_node_put(child);
 251                         goto err;
 252                 }
 253         }
 254
 255         dev_set_drvdata(&ofdev->dev, pdata);
 256
 257         return 0;
 258
 259 err:
 260         for (count = pdata->num_leds - 2; count >= 0; count--)
 261                 delete_gpio_led(&pdata->led_data[count]);
 262
 263         kfree(pdata);
 264
 265         return ret;
 266 }
 267
 268 static int __devexit of_gpio_leds_remove(struct of_device *ofdev)
 269 {
 270         struct gpio_led_of_platform_data *pdata = dev_get_drvdata(&ofdev->dev);
 271         int i;
 272
 273         for (i = 0; i < pdata->num_leds; i++)
 274                 delete_gpio_led(&pdata->led_data[i]);
 275
 276         kfree(pdata);
 277
 278         dev_set_drvdata(&ofdev->dev, NULL);
 279
 280         return 0;
 281 }
 282
 283 static const struct of_device_id of_gpio_leds_match[] = {
 284         { .compatible = "gpio-leds", },
 285         {},
 286 };
 287
 288 static struct of_platform_driver of_gpio_leds_driver = {
 289         .driver = {
 290                 .name = "of_gpio_leds",
 291                 .owner = THIS_MODULE,
 292         },
 293         .match_table = of_gpio_leds_match,
 294         .probe = of_gpio_leds_probe,
 295         .remove = __devexit_p(of_gpio_leds_remove),
 296 };
 297 #endif
 298
 299 static int __init gpio_led_init(void)
 300 {
 301         int ret;
 302
 303 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 304         ret = platform_driver_register(&gpio_led_driver);
 305         if (ret)
 306                 return ret;
 307 #endif
 308 #ifdef CONFIG_LEDS_GPIO_OF
 309         ret = of_register_platform_driver(&of_gpio_leds_driver);
 310 #endif
 311 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 312         if (ret)
 313                 platform_driver_unregister(&gpio_led_driver);
 314 #endif
 315
 316         return ret;
 317 }
 318
 319 static void __exit gpio_led_exit(void)
 320 {
 321 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 322         platform_driver_unregister(&gpio_led_driver);
 323 #endif
 324 #ifdef CONFIG_LEDS_GPIO_OF
 325         of_unregister_platform_driver(&of_gpio_leds_driver);
 326 #endif
 327 }
 328
 329 module_init(gpio_led_init);
 330 module_exit(gpio_led_exit);
 331
 332 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 333 MODULE_DESCRIPTION("GPIO LED driver");
 334 MODULE_LICENSE("GPL");