led-class.c 4.6 KB

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  1. /*
  2. * LED Class Core
  3. *
  4. * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
  5. * Copyright (C) 2005-2006 Richard Purdie <rpurdie@openedhand.com>
  6. *
  7. * This program is free software; you can redistribute it and/or modify
  8. * it under the terms of the GNU General Public License version 2 as
  9. * published by the Free Software Foundation.
  10. */
  11. #include <linux/module.h>
  12. #include <linux/kernel.h>
  13. #include <linux/init.h>
  14. #include <linux/list.h>
  15. #include <linux/spinlock.h>
  16. #include <linux/device.h>
  17. #include <linux/sysdev.h>
  18. #include <linux/timer.h>
  19. #include <linux/err.h>
  20. #include <linux/ctype.h>
  21. #include <linux/leds.h>
  22. #include "leds.h"
  23. static struct class *leds_class;
  24. static ssize_t led_brightness_show(struct class_device *dev, char *buf)
  25. {
  26. struct led_classdev *led_cdev = class_get_devdata(dev);
  27. ssize_t ret = 0;
  28. /* no lock needed for this */
  29. sprintf(buf, "%u\n", led_cdev->brightness);
  30. ret = strlen(buf) + 1;
  31. return ret;
  32. }
  33. static ssize_t led_brightness_store(struct class_device *dev,
  34. const char *buf, size_t size)
  35. {
  36. struct led_classdev *led_cdev = class_get_devdata(dev);
  37. ssize_t ret = -EINVAL;
  38. char *after;
  39. unsigned long state = simple_strtoul(buf, &after, 10);
  40. size_t count = after - buf;
  41. if (*after && isspace(*after))
  42. count++;
  43. if (count == size) {
  44. ret = count;
  45. led_set_brightness(led_cdev, state);
  46. }
  47. return ret;
  48. }
  49. static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
  50. led_brightness_store);
  51. #ifdef CONFIG_LEDS_TRIGGERS
  52. static CLASS_DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  53. #endif
  54. /**
  55. * led_classdev_suspend - suspend an led_classdev.
  56. * @led_cdev: the led_classdev to suspend.
  57. */
  58. void led_classdev_suspend(struct led_classdev *led_cdev)
  59. {
  60. led_cdev->flags |= LED_SUSPENDED;
  61. led_cdev->brightness_set(led_cdev, 0);
  62. }
  63. EXPORT_SYMBOL_GPL(led_classdev_suspend);
  64. /**
  65. * led_classdev_resume - resume an led_classdev.
  66. * @led_cdev: the led_classdev to resume.
  67. */
  68. void led_classdev_resume(struct led_classdev *led_cdev)
  69. {
  70. led_cdev->brightness_set(led_cdev, led_cdev->brightness);
  71. led_cdev->flags &= ~LED_SUSPENDED;
  72. }
  73. EXPORT_SYMBOL_GPL(led_classdev_resume);
  74. /**
  75. * led_classdev_register - register a new object of led_classdev class.
  76. * @dev: The device to register.
  77. * @led_cdev: the led_classdev structure for this device.
  78. */
  79. int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
  80. {
  81. int rc;
  82. led_cdev->class_dev = class_device_create(leds_class, NULL, 0,
  83. parent, "%s", led_cdev->name);
  84. if (unlikely(IS_ERR(led_cdev->class_dev)))
  85. return PTR_ERR(led_cdev->class_dev);
  86. class_set_devdata(led_cdev->class_dev, led_cdev);
  87. /* register the attributes */
  88. rc = class_device_create_file(led_cdev->class_dev,
  89. &class_device_attr_brightness);
  90. if (rc)
  91. goto err_out;
  92. /* add to the list of leds */
  93. write_lock(&leds_list_lock);
  94. list_add_tail(&led_cdev->node, &leds_list);
  95. write_unlock(&leds_list_lock);
  96. #ifdef CONFIG_LEDS_TRIGGERS
  97. rwlock_init(&led_cdev->trigger_lock);
  98. rc = class_device_create_file(led_cdev->class_dev,
  99. &class_device_attr_trigger);
  100. if (rc)
  101. goto err_out_led_list;
  102. led_trigger_set_default(led_cdev);
  103. #endif
  104. printk(KERN_INFO "Registered led device: %s\n",
  105. led_cdev->class_dev->class_id);
  106. return 0;
  107. #ifdef CONFIG_LEDS_TRIGGERS
  108. err_out_led_list:
  109. class_device_remove_file(led_cdev->class_dev,
  110. &class_device_attr_brightness);
  111. list_del(&led_cdev->node);
  112. #endif
  113. err_out:
  114. class_device_unregister(led_cdev->class_dev);
  115. return rc;
  116. }
  117. EXPORT_SYMBOL_GPL(led_classdev_register);
  118. /**
  119. * led_classdev_unregister - unregisters a object of led_properties class.
  120. * @led_cdev: the led device to unregister
  121. *
  122. * Unregisters a previously registered via led_classdev_register object.
  123. */
  124. void led_classdev_unregister(struct led_classdev *led_cdev)
  125. {
  126. class_device_remove_file(led_cdev->class_dev,
  127. &class_device_attr_brightness);
  128. #ifdef CONFIG_LEDS_TRIGGERS
  129. class_device_remove_file(led_cdev->class_dev,
  130. &class_device_attr_trigger);
  131. write_lock(&led_cdev->trigger_lock);
  132. if (led_cdev->trigger)
  133. led_trigger_set(led_cdev, NULL);
  134. write_unlock(&led_cdev->trigger_lock);
  135. #endif
  136. class_device_unregister(led_cdev->class_dev);
  137. write_lock(&leds_list_lock);
  138. list_del(&led_cdev->node);
  139. write_unlock(&leds_list_lock);
  140. }
  141. EXPORT_SYMBOL_GPL(led_classdev_unregister);
  142. static int __init leds_init(void)
  143. {
  144. leds_class = class_create(THIS_MODULE, "leds");
  145. if (IS_ERR(leds_class))
  146. return PTR_ERR(leds_class);
  147. return 0;
  148. }
  149. static void __exit leds_exit(void)
  150. {
  151. class_destroy(leds_class);
  152. }
  153. subsys_initcall(leds_init);
  154. module_exit(leds_exit);
  155. MODULE_AUTHOR("John Lenz, Richard Purdie");
  156. MODULE_LICENSE("GPL");
  157. MODULE_DESCRIPTION("LED Class Interface");