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 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) { 90 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 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 /* Return in next iteration if led is in one-shot mode and we are in 111 * the final blink state so that the led is toggled each delay_on + 112 * delay_off milliseconds in worst case. 113 */ 114 if (led_cdev->flags & LED_BLINK_ONESHOT) { 115 if (led_cdev->flags & LED_BLINK_INVERT) { 116 if (brightness) 117 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 118 } else { 119 if (!brightness) 120 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 121 } 122 } 123 124 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 125 } 126 127 static void set_brightness_delayed(struct work_struct *ws) 128 { 129 struct led_classdev *led_cdev = 130 container_of(ws, struct led_classdev, set_brightness_work); 131 132 led_stop_software_blink(led_cdev); 133 134 __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 135 } 136 137 /** 138 * led_classdev_suspend - suspend an led_classdev. 139 * @led_cdev: the led_classdev to suspend. 140 */ 141 void led_classdev_suspend(struct led_classdev *led_cdev) 142 { 143 led_cdev->flags |= LED_SUSPENDED; 144 led_cdev->brightness_set(led_cdev, 0); 145 } 146 EXPORT_SYMBOL_GPL(led_classdev_suspend); 147 148 /** 149 * led_classdev_resume - resume an led_classdev. 150 * @led_cdev: the led_classdev to resume. 151 */ 152 void led_classdev_resume(struct led_classdev *led_cdev) 153 { 154 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 155 led_cdev->flags &= ~LED_SUSPENDED; 156 } 157 EXPORT_SYMBOL_GPL(led_classdev_resume); 158 159 static int led_suspend(struct device *dev) 160 { 161 struct led_classdev *led_cdev = dev_get_drvdata(dev); 162 163 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 164 led_classdev_suspend(led_cdev); 165 166 return 0; 167 } 168 169 static int led_resume(struct device *dev) 170 { 171 struct led_classdev *led_cdev = dev_get_drvdata(dev); 172 173 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 174 led_classdev_resume(led_cdev); 175 176 return 0; 177 } 178 179 static const struct dev_pm_ops leds_class_dev_pm_ops = { 180 .suspend = led_suspend, 181 .resume = led_resume, 182 }; 183 184 /** 185 * led_classdev_register - register a new object of led_classdev class. 186 * @parent: The device to register. 187 * @led_cdev: the led_classdev structure for this device. 188 */ 189 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 190 { 191 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 192 "%s", led_cdev->name); 193 if (IS_ERR(led_cdev->dev)) 194 return PTR_ERR(led_cdev->dev); 195 196 #ifdef CONFIG_LEDS_TRIGGERS 197 init_rwsem(&led_cdev->trigger_lock); 198 #endif 199 /* add to the list of leds */ 200 down_write(&leds_list_lock); 201 list_add_tail(&led_cdev->node, &leds_list); 202 up_write(&leds_list_lock); 203 204 if (!led_cdev->max_brightness) 205 led_cdev->max_brightness = LED_FULL; 206 207 led_update_brightness(led_cdev); 208 209 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 210 211 init_timer(&led_cdev->blink_timer); 212 led_cdev->blink_timer.function = led_timer_function; 213 led_cdev->blink_timer.data = (unsigned long)led_cdev; 214 215 #ifdef CONFIG_LEDS_TRIGGERS 216 led_trigger_set_default(led_cdev); 217 #endif 218 219 dev_dbg(parent, "Registered led device: %s\n", 220 led_cdev->name); 221 222 return 0; 223 } 224 EXPORT_SYMBOL_GPL(led_classdev_register); 225 226 /** 227 * led_classdev_unregister - unregisters a object of led_properties class. 228 * @led_cdev: the led device to unregister 229 * 230 * Unregisters a previously registered via led_classdev_register object. 231 */ 232 void led_classdev_unregister(struct led_classdev *led_cdev) 233 { 234 #ifdef CONFIG_LEDS_TRIGGERS 235 down_write(&led_cdev->trigger_lock); 236 if (led_cdev->trigger) 237 led_trigger_set(led_cdev, NULL); 238 up_write(&led_cdev->trigger_lock); 239 #endif 240 241 cancel_work_sync(&led_cdev->set_brightness_work); 242 243 /* Stop blinking */ 244 led_stop_software_blink(led_cdev); 245 led_set_brightness(led_cdev, LED_OFF); 246 247 device_unregister(led_cdev->dev); 248 249 down_write(&leds_list_lock); 250 list_del(&led_cdev->node); 251 up_write(&leds_list_lock); 252 } 253 EXPORT_SYMBOL_GPL(led_classdev_unregister); 254 255 static int __init leds_init(void) 256 { 257 leds_class = class_create(THIS_MODULE, "leds"); 258 if (IS_ERR(leds_class)) 259 return PTR_ERR(leds_class); 260 leds_class->pm = &leds_class_dev_pm_ops; 261 leds_class->dev_attrs = led_class_attrs; 262 return 0; 263 } 264 265 static void __exit leds_exit(void) 266 { 267 class_destroy(leds_class); 268 } 269 270 subsys_initcall(leds_init); 271 module_exit(leds_exit); 272 273 MODULE_AUTHOR("John Lenz, Richard Purdie"); 274 MODULE_LICENSE("GPL"); 275 MODULE_DESCRIPTION("LED Class Interface"); 276