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 ssize_t ret = 0; 38 39 /* no lock needed for this */ 40 led_update_brightness(led_cdev); 41 sprintf(buf, "%u\n", led_cdev->brightness); 42 ret = strlen(buf) + 1; 43 44 return ret; 45 } 46 47 static ssize_t led_brightness_store(struct device *dev, 48 struct device_attribute *attr, const char *buf, size_t size) 49 { 50 struct led_classdev *led_cdev = dev_get_drvdata(dev); 51 ssize_t ret = -EINVAL; 52 char *after; 53 unsigned long state = simple_strtoul(buf, &after, 10); 54 size_t count = after - buf; 55 56 if (*after && isspace(*after)) 57 count++; 58 59 if (count == size) { 60 ret = count; 61 62 if (state == LED_OFF) 63 led_trigger_remove(led_cdev); 64 led_set_brightness(led_cdev, state); 65 } 66 67 return ret; 68 } 69 70 static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store); 71 #ifdef CONFIG_LEDS_TRIGGERS 72 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); 73 #endif 74 75 /** 76 * led_classdev_suspend - suspend an led_classdev. 77 * @led_cdev: the led_classdev to suspend. 78 */ 79 void led_classdev_suspend(struct led_classdev *led_cdev) 80 { 81 led_cdev->flags |= LED_SUSPENDED; 82 led_cdev->brightness_set(led_cdev, 0); 83 } 84 EXPORT_SYMBOL_GPL(led_classdev_suspend); 85 86 /** 87 * led_classdev_resume - resume an led_classdev. 88 * @led_cdev: the led_classdev to resume. 89 */ 90 void led_classdev_resume(struct led_classdev *led_cdev) 91 { 92 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 93 led_cdev->flags &= ~LED_SUSPENDED; 94 } 95 EXPORT_SYMBOL_GPL(led_classdev_resume); 96 97 /** 98 * led_classdev_register - register a new object of led_classdev class. 99 * @dev: The device to register. 100 * @led_cdev: the led_classdev structure for this device. 101 */ 102 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 103 { 104 int rc; 105 106 led_cdev->dev = device_create(leds_class, parent, 0, "%s", 107 led_cdev->name); 108 if (IS_ERR(led_cdev->dev)) 109 return PTR_ERR(led_cdev->dev); 110 111 dev_set_drvdata(led_cdev->dev, led_cdev); 112 113 /* register the attributes */ 114 rc = device_create_file(led_cdev->dev, &dev_attr_brightness); 115 if (rc) 116 goto err_out; 117 118 /* add to the list of leds */ 119 down_write(&leds_list_lock); 120 list_add_tail(&led_cdev->node, &leds_list); 121 up_write(&leds_list_lock); 122 123 led_update_brightness(led_cdev); 124 125 #ifdef CONFIG_LEDS_TRIGGERS 126 init_rwsem(&led_cdev->trigger_lock); 127 128 rc = device_create_file(led_cdev->dev, &dev_attr_trigger); 129 if (rc) 130 goto err_out_led_list; 131 132 led_trigger_set_default(led_cdev); 133 #endif 134 135 printk(KERN_INFO "Registered led device: %s\n", 136 led_cdev->name); 137 138 return 0; 139 140 #ifdef CONFIG_LEDS_TRIGGERS 141 err_out_led_list: 142 device_remove_file(led_cdev->dev, &dev_attr_brightness); 143 list_del(&led_cdev->node); 144 #endif 145 err_out: 146 device_unregister(led_cdev->dev); 147 return rc; 148 } 149 EXPORT_SYMBOL_GPL(led_classdev_register); 150 151 /** 152 * __led_classdev_unregister - unregisters a object of led_properties class. 153 * @led_cdev: the led device to unregister 154 * 155 * Unregisters a previously registered via led_classdev_register object. 156 */ 157 void led_classdev_unregister(struct led_classdev *led_cdev) 158 { 159 device_remove_file(led_cdev->dev, &dev_attr_brightness); 160 #ifdef CONFIG_LEDS_TRIGGERS 161 device_remove_file(led_cdev->dev, &dev_attr_trigger); 162 down_write(&led_cdev->trigger_lock); 163 if (led_cdev->trigger) 164 led_trigger_set(led_cdev, NULL); 165 up_write(&led_cdev->trigger_lock); 166 #endif 167 168 device_unregister(led_cdev->dev); 169 170 down_write(&leds_list_lock); 171 list_del(&led_cdev->node); 172 up_write(&leds_list_lock); 173 } 174 EXPORT_SYMBOL_GPL(led_classdev_unregister); 175 176 static int __init leds_init(void) 177 { 178 leds_class = class_create(THIS_MODULE, "leds"); 179 if (IS_ERR(leds_class)) 180 return PTR_ERR(leds_class); 181 return 0; 182 } 183 184 static void __exit leds_exit(void) 185 { 186 class_destroy(leds_class); 187 } 188 189 subsys_initcall(leds_init); 190 module_exit(leds_exit); 191 192 MODULE_AUTHOR("John Lenz, Richard Purdie"); 193 MODULE_LICENSE("GPL"); 194 MODULE_DESCRIPTION("LED Class Interface"); 195