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 #ifdef CONFIG_LEDS_TRIGGERS 114 init_rwsem(&led_cdev->trigger_lock); 115 #endif 116 /* add to the list of leds */ 117 down_write(&leds_list_lock); 118 list_add_tail(&led_cdev->node, &leds_list); 119 up_write(&leds_list_lock); 120 121 led_update_brightness(led_cdev); 122 123 #ifdef CONFIG_LEDS_TRIGGERS 124 rc = device_create_file(led_cdev->dev, &dev_attr_trigger); 125 if (rc) 126 goto err_out_led_list; 127 128 led_trigger_set_default(led_cdev); 129 #endif 130 131 printk(KERN_INFO "Registered led device: %s\n", 132 led_cdev->name); 133 134 return 0; 135 136 #ifdef CONFIG_LEDS_TRIGGERS 137 err_out_led_list: 138 device_remove_file(led_cdev->dev, &dev_attr_brightness); 139 list_del(&led_cdev->node); 140 #endif 141 err_out: 142 device_unregister(led_cdev->dev); 143 return rc; 144 } 145 EXPORT_SYMBOL_GPL(led_classdev_register); 146 147 /** 148 * led_classdev_unregister - unregisters a object of led_properties class. 149 * @led_cdev: the led device to unregister 150 * 151 * Unregisters a previously registered via led_classdev_register object. 152 */ 153 void led_classdev_unregister(struct led_classdev *led_cdev) 154 { 155 device_remove_file(led_cdev->dev, &dev_attr_brightness); 156 #ifdef CONFIG_LEDS_TRIGGERS 157 device_remove_file(led_cdev->dev, &dev_attr_trigger); 158 down_write(&led_cdev->trigger_lock); 159 if (led_cdev->trigger) 160 led_trigger_set(led_cdev, NULL); 161 up_write(&led_cdev->trigger_lock); 162 #endif 163 164 device_unregister(led_cdev->dev); 165 166 down_write(&leds_list_lock); 167 list_del(&led_cdev->node); 168 up_write(&leds_list_lock); 169 } 170 EXPORT_SYMBOL_GPL(led_classdev_unregister); 171 172 static int __init leds_init(void) 173 { 174 leds_class = class_create(THIS_MODULE, "leds"); 175 if (IS_ERR(leds_class)) 176 return PTR_ERR(leds_class); 177 return 0; 178 } 179 180 static void __exit leds_exit(void) 181 { 182 class_destroy(leds_class); 183 } 184 185 subsys_initcall(leds_init); 186 module_exit(leds_exit); 187 188 MODULE_AUTHOR("John Lenz, Richard Purdie"); 189 MODULE_LICENSE("GPL"); 190 MODULE_DESCRIPTION("LED Class Interface"); 191