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 unsigned long state; 48 ssize_t ret = -EINVAL; 49 50 ret = kstrtoul(buf, 10, &state); 51 if (ret) 52 return ret; 53 54 if (state == LED_OFF) 55 led_trigger_remove(led_cdev); 56 led_set_brightness(led_cdev, state); 57 58 return size; 59 } 60 61 static ssize_t led_max_brightness_show(struct device *dev, 62 struct device_attribute *attr, char *buf) 63 { 64 struct led_classdev *led_cdev = dev_get_drvdata(dev); 65 66 return sprintf(buf, "%u\n", led_cdev->max_brightness); 67 } 68 69 static struct device_attribute led_class_attrs[] = { 70 __ATTR(brightness, 0644, led_brightness_show, led_brightness_store), 71 __ATTR(max_brightness, 0444, led_max_brightness_show, NULL), 72 #ifdef CONFIG_LEDS_TRIGGERS 73 __ATTR(trigger, 0644, led_trigger_show, led_trigger_store), 74 #endif 75 __ATTR_NULL, 76 }; 77 78 static void led_timer_function(unsigned long data) 79 { 80 struct led_classdev *led_cdev = (void *)data; 81 unsigned long brightness; 82 unsigned long delay; 83 84 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 85 led_set_brightness(led_cdev, LED_OFF); 86 return; 87 } 88 89 brightness = led_get_brightness(led_cdev); 90 if (!brightness) { 91 /* Time to switch the LED on. */ 92 brightness = led_cdev->blink_brightness; 93 delay = led_cdev->blink_delay_on; 94 } else { 95 /* Store the current brightness value to be able 96 * to restore it when the delay_off period is over. 97 */ 98 led_cdev->blink_brightness = brightness; 99 brightness = LED_OFF; 100 delay = led_cdev->blink_delay_off; 101 } 102 103 led_set_brightness(led_cdev, brightness); 104 105 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 106 } 107 108 /** 109 * led_classdev_suspend - suspend an led_classdev. 110 * @led_cdev: the led_classdev to suspend. 111 */ 112 void led_classdev_suspend(struct led_classdev *led_cdev) 113 { 114 led_cdev->flags |= LED_SUSPENDED; 115 led_cdev->brightness_set(led_cdev, 0); 116 } 117 EXPORT_SYMBOL_GPL(led_classdev_suspend); 118 119 /** 120 * led_classdev_resume - resume an led_classdev. 121 * @led_cdev: the led_classdev to resume. 122 */ 123 void led_classdev_resume(struct led_classdev *led_cdev) 124 { 125 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 126 led_cdev->flags &= ~LED_SUSPENDED; 127 } 128 EXPORT_SYMBOL_GPL(led_classdev_resume); 129 130 static int led_suspend(struct device *dev, pm_message_t state) 131 { 132 struct led_classdev *led_cdev = dev_get_drvdata(dev); 133 134 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 135 led_classdev_suspend(led_cdev); 136 137 return 0; 138 } 139 140 static int led_resume(struct device *dev) 141 { 142 struct led_classdev *led_cdev = dev_get_drvdata(dev); 143 144 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 145 led_classdev_resume(led_cdev); 146 147 return 0; 148 } 149 150 /** 151 * led_classdev_register - register a new object of led_classdev class. 152 * @parent: The device to register. 153 * @led_cdev: the led_classdev structure for this device. 154 */ 155 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 156 { 157 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 158 "%s", led_cdev->name); 159 if (IS_ERR(led_cdev->dev)) 160 return PTR_ERR(led_cdev->dev); 161 162 #ifdef CONFIG_LEDS_TRIGGERS 163 init_rwsem(&led_cdev->trigger_lock); 164 #endif 165 /* add to the list of leds */ 166 down_write(&leds_list_lock); 167 list_add_tail(&led_cdev->node, &leds_list); 168 up_write(&leds_list_lock); 169 170 if (!led_cdev->max_brightness) 171 led_cdev->max_brightness = LED_FULL; 172 173 led_update_brightness(led_cdev); 174 175 init_timer(&led_cdev->blink_timer); 176 led_cdev->blink_timer.function = led_timer_function; 177 led_cdev->blink_timer.data = (unsigned long)led_cdev; 178 179 #ifdef CONFIG_LEDS_TRIGGERS 180 led_trigger_set_default(led_cdev); 181 #endif 182 183 printk(KERN_DEBUG "Registered led device: %s\n", 184 led_cdev->name); 185 186 return 0; 187 } 188 EXPORT_SYMBOL_GPL(led_classdev_register); 189 190 /** 191 * led_classdev_unregister - unregisters a object of led_properties class. 192 * @led_cdev: the led device to unregister 193 * 194 * Unregisters a previously registered via led_classdev_register object. 195 */ 196 void led_classdev_unregister(struct led_classdev *led_cdev) 197 { 198 #ifdef CONFIG_LEDS_TRIGGERS 199 down_write(&led_cdev->trigger_lock); 200 if (led_cdev->trigger) 201 led_trigger_set(led_cdev, NULL); 202 up_write(&led_cdev->trigger_lock); 203 #endif 204 205 /* Stop blinking */ 206 led_brightness_set(led_cdev, LED_OFF); 207 208 device_unregister(led_cdev->dev); 209 210 down_write(&leds_list_lock); 211 list_del(&led_cdev->node); 212 up_write(&leds_list_lock); 213 } 214 EXPORT_SYMBOL_GPL(led_classdev_unregister); 215 216 static int __init leds_init(void) 217 { 218 leds_class = class_create(THIS_MODULE, "leds"); 219 if (IS_ERR(leds_class)) 220 return PTR_ERR(leds_class); 221 leds_class->suspend = led_suspend; 222 leds_class->resume = led_resume; 223 leds_class->dev_attrs = led_class_attrs; 224 return 0; 225 } 226 227 static void __exit leds_exit(void) 228 { 229 class_destroy(leds_class); 230 } 231 232 subsys_initcall(leds_init); 233 module_exit(leds_exit); 234 235 MODULE_AUTHOR("John Lenz, Richard Purdie"); 236 MODULE_LICENSE("GPL"); 237 MODULE_DESCRIPTION("LED Class Interface"); 238