| 1 | /* |
| 2 | * LED Class Core |
| 3 | * |
| 4 | * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu> |
| 5 | * Copyright (C) 2005-2007 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 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/list.h> |
| 16 | #include <linux/spinlock.h> |
| 17 | #include <linux/device.h> |
| 18 | #include <linux/sysdev.h> |
| 19 | #include <linux/timer.h> |
| 20 | #include <linux/err.h> |
| 21 | #include <linux/ctype.h> |
| 22 | #include <linux/leds.h> |
| 23 | #include "leds.h" |
| 24 | |
| 25 | static struct class *leds_class; |
| 26 | |
| 27 | static void led_update_brightness(struct led_classdev *led_cdev) |
| 28 | { |
| 29 | if (led_cdev->brightness_get) |
| 30 | led_cdev->brightness = led_cdev->brightness_get(led_cdev); |
| 31 | } |
| 32 | |
| 33 | static ssize_t led_brightness_show(struct device *dev, |
| 34 | struct device_attribute *attr, char *buf) |
| 35 | { |
| 36 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 37 | |
| 38 | /* no lock needed for this */ |
| 39 | led_update_brightness(led_cdev); |
| 40 | |
| 41 | return sprintf(buf, "%u\n", led_cdev->brightness); |
| 42 | } |
| 43 | |
| 44 | static ssize_t led_brightness_store(struct device *dev, |
| 45 | struct device_attribute *attr, const char *buf, size_t size) |
| 46 | { |
| 47 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 48 | ssize_t ret = -EINVAL; |
| 49 | char *after; |
| 50 | unsigned long state = simple_strtoul(buf, &after, 10); |
| 51 | size_t count = after - buf; |
| 52 | |
| 53 | if (*after && isspace(*after)) |
| 54 | count++; |
| 55 | |
| 56 | if (count == size) { |
| 57 | ret = count; |
| 58 | |
| 59 | if (state == LED_OFF) |
| 60 | led_trigger_remove(led_cdev); |
| 61 | led_set_brightness(led_cdev, state); |
| 62 | } |
| 63 | |
| 64 | return ret; |
| 65 | } |
| 66 | |
| 67 | static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store); |
| 68 | #ifdef CONFIG_LEDS_TRIGGERS |
| 69 | static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); |
| 70 | #endif |
| 71 | |
| 72 | /** |
| 73 | * led_classdev_suspend - suspend an led_classdev. |
| 74 | * @led_cdev: the led_classdev to suspend. |
| 75 | */ |
| 76 | void led_classdev_suspend(struct led_classdev *led_cdev) |
| 77 | { |
| 78 | led_cdev->flags |= LED_SUSPENDED; |
| 79 | led_cdev->brightness_set(led_cdev, 0); |
| 80 | } |
| 81 | EXPORT_SYMBOL_GPL(led_classdev_suspend); |
| 82 | |
| 83 | /** |
| 84 | * led_classdev_resume - resume an led_classdev. |
| 85 | * @led_cdev: the led_classdev to resume. |
| 86 | */ |
| 87 | void led_classdev_resume(struct led_classdev *led_cdev) |
| 88 | { |
| 89 | led_cdev->brightness_set(led_cdev, led_cdev->brightness); |
| 90 | led_cdev->flags &= ~LED_SUSPENDED; |
| 91 | } |
| 92 | EXPORT_SYMBOL_GPL(led_classdev_resume); |
| 93 | |
| 94 | /** |
| 95 | * led_classdev_register - register a new object of led_classdev class. |
| 96 | * @dev: The device to register. |
| 97 | * @led_cdev: the led_classdev structure for this device. |
| 98 | */ |
| 99 | int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) |
| 100 | { |
| 101 | int rc; |
| 102 | |
| 103 | led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, |
| 104 | "%s", led_cdev->name); |
| 105 | if (IS_ERR(led_cdev->dev)) |
| 106 | return PTR_ERR(led_cdev->dev); |
| 107 | |
| 108 | /* register the attributes */ |
| 109 | rc = device_create_file(led_cdev->dev, &dev_attr_brightness); |
| 110 | if (rc) |
| 111 | goto err_out; |
| 112 | |
| 113 | /* add to the list of leds */ |
| 114 | down_write(&leds_list_lock); |
| 115 | list_add_tail(&led_cdev->node, &leds_list); |
| 116 | up_write(&leds_list_lock); |
| 117 | |
| 118 | led_update_brightness(led_cdev); |
| 119 | |
| 120 | #ifdef CONFIG_LEDS_TRIGGERS |
| 121 | init_rwsem(&led_cdev->trigger_lock); |
| 122 | |
| 123 | rc = device_create_file(led_cdev->dev, &dev_attr_trigger); |
| 124 | if (rc) |
| 125 | goto err_out_led_list; |
| 126 | |
| 127 | led_trigger_set_default(led_cdev); |
| 128 | #endif |
| 129 | |
| 130 | printk(KERN_INFO "Registered led device: %s\n", |
| 131 | led_cdev->name); |
| 132 | |
| 133 | return 0; |
| 134 | |
| 135 | #ifdef CONFIG_LEDS_TRIGGERS |
| 136 | err_out_led_list: |
| 137 | device_remove_file(led_cdev->dev, &dev_attr_brightness); |
| 138 | list_del(&led_cdev->node); |
| 139 | #endif |
| 140 | err_out: |
| 141 | device_unregister(led_cdev->dev); |
| 142 | return rc; |
| 143 | } |
| 144 | EXPORT_SYMBOL_GPL(led_classdev_register); |
| 145 | |
| 146 | /** |
| 147 | * led_classdev_unregister - unregisters a object of led_properties class. |
| 148 | * @led_cdev: the led device to unregister |
| 149 | * |
| 150 | * Unregisters a previously registered via led_classdev_register object. |
| 151 | */ |
| 152 | void led_classdev_unregister(struct led_classdev *led_cdev) |
| 153 | { |
| 154 | device_remove_file(led_cdev->dev, &dev_attr_brightness); |
| 155 | #ifdef CONFIG_LEDS_TRIGGERS |
| 156 | device_remove_file(led_cdev->dev, &dev_attr_trigger); |
| 157 | down_write(&led_cdev->trigger_lock); |
| 158 | if (led_cdev->trigger) |
| 159 | led_trigger_set(led_cdev, NULL); |
| 160 | up_write(&led_cdev->trigger_lock); |
| 161 | #endif |
| 162 | |
| 163 | device_unregister(led_cdev->dev); |
| 164 | |
| 165 | down_write(&leds_list_lock); |
| 166 | list_del(&led_cdev->node); |
| 167 | up_write(&leds_list_lock); |
| 168 | } |
| 169 | EXPORT_SYMBOL_GPL(led_classdev_unregister); |
| 170 | |
| 171 | static int __init leds_init(void) |
| 172 | { |
| 173 | leds_class = class_create(THIS_MODULE, "leds"); |
| 174 | if (IS_ERR(leds_class)) |
| 175 | return PTR_ERR(leds_class); |
| 176 | return 0; |
| 177 | } |
| 178 | |
| 179 | static void __exit leds_exit(void) |
| 180 | { |
| 181 | class_destroy(leds_class); |
| 182 | } |
| 183 | |
| 184 | subsys_initcall(leds_init); |
| 185 | module_exit(leds_exit); |
| 186 | |
| 187 | MODULE_AUTHOR("John Lenz, Richard Purdie"); |
| 188 | MODULE_LICENSE("GPL"); |
| 189 | MODULE_DESCRIPTION("LED Class Interface"); |