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/timer.h> 19 #include <linux/err.h> 20 #include <linux/ctype.h> 21 #include <linux/leds.h> 22 #include "leds.h" 23 24 static struct class *leds_class; 25 26 static void led_update_brightness(struct led_classdev *led_cdev) 27 { 28 if (led_cdev->brightness_get) 29 led_cdev->brightness = led_cdev->brightness_get(led_cdev); 30 } 31 32 static ssize_t led_brightness_show(struct device *dev, 33 struct device_attribute *attr, char *buf) 34 { 35 struct led_classdev *led_cdev = dev_get_drvdata(dev); 36 37 /* no lock needed for this */ 38 led_update_brightness(led_cdev); 39 40 return sprintf(buf, "%u\n", led_cdev->brightness); 41 } 42 43 static ssize_t led_brightness_store(struct device *dev, 44 struct device_attribute *attr, const char *buf, size_t size) 45 { 46 struct led_classdev *led_cdev = dev_get_drvdata(dev); 47 ssize_t ret = -EINVAL; 48 char *after; 49 unsigned long state = simple_strtoul(buf, &after, 10); 50 size_t count = after - buf; 51 52 if (isspace(*after)) 53 count++; 54 55 if (count == size) { 56 ret = count; 57 58 if (state == LED_OFF) 59 led_trigger_remove(led_cdev); 60 led_set_brightness(led_cdev, state); 61 } 62 63 return ret; 64 } 65 66 static ssize_t led_max_brightness_show(struct device *dev, 67 struct device_attribute *attr, char *buf) 68 { 69 struct led_classdev *led_cdev = dev_get_drvdata(dev); 70 71 return sprintf(buf, "%u\n", led_cdev->max_brightness); 72 } 73 74 static struct device_attribute led_class_attrs[] = { 75 __ATTR(brightness, 0644, led_brightness_show, led_brightness_store), 76 __ATTR(max_brightness, 0444, led_max_brightness_show, NULL), 77 #ifdef CONFIG_LEDS_TRIGGERS 78 __ATTR(trigger, 0644, led_trigger_show, led_trigger_store), 79 #endif 80 __ATTR_NULL, 81 }; 82 83 static void led_timer_function(unsigned long data) 84 { 85 struct led_classdev *led_cdev = (void *)data; 86 unsigned long brightness; 87 unsigned long delay; 88 89 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 90 led_set_brightness(led_cdev, LED_OFF); 91 return; 92 } 93 94 brightness = led_get_brightness(led_cdev); 95 if (!brightness) { 96 /* Time to switch the LED on. */ 97 brightness = led_cdev->blink_brightness; 98 delay = led_cdev->blink_delay_on; 99 } else { 100 /* Store the current brightness value to be able 101 * to restore it when the delay_off period is over. 102 */ 103 led_cdev->blink_brightness = brightness; 104 brightness = LED_OFF; 105 delay = led_cdev->blink_delay_off; 106 } 107 108 led_set_brightness(led_cdev, brightness); 109 110 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 111 } 112 113 /** 114 * led_classdev_suspend - suspend an led_classdev. 115 * @led_cdev: the led_classdev to suspend. 116 */ 117 void led_classdev_suspend(struct led_classdev *led_cdev) 118 { 119 led_cdev->flags |= LED_SUSPENDED; 120 led_cdev->brightness_set(led_cdev, 0); 121 } 122 EXPORT_SYMBOL_GPL(led_classdev_suspend); 123 124 /** 125 * led_classdev_resume - resume an led_classdev. 126 * @led_cdev: the led_classdev to resume. 127 */ 128 void led_classdev_resume(struct led_classdev *led_cdev) 129 { 130 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 131 led_cdev->flags &= ~LED_SUSPENDED; 132 } 133 EXPORT_SYMBOL_GPL(led_classdev_resume); 134 135 static int led_suspend(struct device *dev, pm_message_t state) 136 { 137 struct led_classdev *led_cdev = dev_get_drvdata(dev); 138 139 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 140 led_classdev_suspend(led_cdev); 141 142 return 0; 143 } 144 145 static int led_resume(struct device *dev) 146 { 147 struct led_classdev *led_cdev = dev_get_drvdata(dev); 148 149 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 150 led_classdev_resume(led_cdev); 151 152 return 0; 153 } 154 155 /** 156 * led_classdev_register - register a new object of led_classdev class. 157 * @parent: The device to register. 158 * @led_cdev: the led_classdev structure for this device. 159 */ 160 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 161 { 162 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 163 "%s", led_cdev->name); 164 if (IS_ERR(led_cdev->dev)) 165 return PTR_ERR(led_cdev->dev); 166 167 #ifdef CONFIG_LEDS_TRIGGERS 168 init_rwsem(&led_cdev->trigger_lock); 169 #endif 170 /* add to the list of leds */ 171 down_write(&leds_list_lock); 172 list_add_tail(&led_cdev->node, &leds_list); 173 up_write(&leds_list_lock); 174 175 if (!led_cdev->max_brightness) 176 led_cdev->max_brightness = LED_FULL; 177 178 led_update_brightness(led_cdev); 179 180 init_timer(&led_cdev->blink_timer); 181 led_cdev->blink_timer.function = led_timer_function; 182 led_cdev->blink_timer.data = (unsigned long)led_cdev; 183 184 #ifdef CONFIG_LEDS_TRIGGERS 185 led_trigger_set_default(led_cdev); 186 #endif 187 188 printk(KERN_DEBUG "Registered led device: %s\n", 189 led_cdev->name); 190 191 return 0; 192 } 193 EXPORT_SYMBOL_GPL(led_classdev_register); 194 195 /** 196 * led_classdev_unregister - unregisters a object of led_properties class. 197 * @led_cdev: the led device to unregister 198 * 199 * Unregisters a previously registered via led_classdev_register object. 200 */ 201 void led_classdev_unregister(struct led_classdev *led_cdev) 202 { 203 #ifdef CONFIG_LEDS_TRIGGERS 204 down_write(&led_cdev->trigger_lock); 205 if (led_cdev->trigger) 206 led_trigger_set(led_cdev, NULL); 207 up_write(&led_cdev->trigger_lock); 208 #endif 209 210 /* Stop blinking */ 211 led_brightness_set(led_cdev, LED_OFF); 212 213 device_unregister(led_cdev->dev); 214 215 down_write(&leds_list_lock); 216 list_del(&led_cdev->node); 217 up_write(&leds_list_lock); 218 } 219 EXPORT_SYMBOL_GPL(led_classdev_unregister); 220 221 static int __init leds_init(void) 222 { 223 leds_class = class_create(THIS_MODULE, "leds"); 224 if (IS_ERR(leds_class)) 225 return PTR_ERR(leds_class); 226 leds_class->suspend = led_suspend; 227 leds_class->resume = led_resume; 228 leds_class->dev_attrs = led_class_attrs; 229 return 0; 230 } 231 232 static void __exit leds_exit(void) 233 { 234 class_destroy(leds_class); 235 } 236 237 subsys_initcall(leds_init); 238 module_exit(leds_exit); 239 240 MODULE_AUTHOR("John Lenz, Richard Purdie"); 241 MODULE_LICENSE("GPL"); 242 MODULE_DESCRIPTION("LED Class Interface"); 243