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/ctype.h> 13 #include <linux/device.h> 14 #include <linux/err.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/leds.h> 18 #include <linux/list.h> 19 #include <linux/module.h> 20 #include <linux/slab.h> 21 #include <linux/spinlock.h> 22 #include <linux/timer.h> 23 #include "leds.h" 24 25 static struct class *leds_class; 26 27 static ssize_t brightness_show(struct device *dev, 28 struct device_attribute *attr, char *buf) 29 { 30 struct led_classdev *led_cdev = dev_get_drvdata(dev); 31 32 /* no lock needed for this */ 33 led_update_brightness(led_cdev); 34 35 return sprintf(buf, "%u\n", led_cdev->brightness); 36 } 37 38 static ssize_t brightness_store(struct device *dev, 39 struct device_attribute *attr, const char *buf, size_t size) 40 { 41 struct led_classdev *led_cdev = dev_get_drvdata(dev); 42 unsigned long state; 43 ssize_t ret = -EINVAL; 44 45 ret = kstrtoul(buf, 10, &state); 46 if (ret) 47 return ret; 48 49 if (state == LED_OFF) 50 led_trigger_remove(led_cdev); 51 __led_set_brightness(led_cdev, state); 52 53 return size; 54 } 55 static DEVICE_ATTR_RW(brightness); 56 57 static ssize_t max_brightness_show(struct device *dev, 58 struct device_attribute *attr, char *buf) 59 { 60 struct led_classdev *led_cdev = dev_get_drvdata(dev); 61 62 return sprintf(buf, "%u\n", led_cdev->max_brightness); 63 } 64 static DEVICE_ATTR_RO(max_brightness); 65 66 #ifdef CONFIG_LEDS_TRIGGERS 67 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); 68 static struct attribute *led_trigger_attrs[] = { 69 &dev_attr_trigger.attr, 70 NULL, 71 }; 72 static const struct attribute_group led_trigger_group = { 73 .attrs = led_trigger_attrs, 74 }; 75 #endif 76 77 static struct attribute *led_class_attrs[] = { 78 &dev_attr_brightness.attr, 79 &dev_attr_max_brightness.attr, 80 NULL, 81 }; 82 83 static const struct attribute_group led_group = { 84 .attrs = led_class_attrs, 85 }; 86 87 static const struct attribute_group *led_groups[] = { 88 &led_group, 89 #ifdef CONFIG_LEDS_TRIGGERS 90 &led_trigger_group, 91 #endif 92 NULL, 93 }; 94 95 static void led_timer_function(unsigned long data) 96 { 97 struct led_classdev *led_cdev = (void *)data; 98 unsigned long brightness; 99 unsigned long delay; 100 101 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 102 __led_set_brightness(led_cdev, LED_OFF); 103 return; 104 } 105 106 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) { 107 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 108 return; 109 } 110 111 brightness = led_get_brightness(led_cdev); 112 if (!brightness) { 113 /* Time to switch the LED on. */ 114 brightness = led_cdev->blink_brightness; 115 delay = led_cdev->blink_delay_on; 116 } else { 117 /* Store the current brightness value to be able 118 * to restore it when the delay_off period is over. 119 */ 120 led_cdev->blink_brightness = brightness; 121 brightness = LED_OFF; 122 delay = led_cdev->blink_delay_off; 123 } 124 125 __led_set_brightness(led_cdev, brightness); 126 127 /* Return in next iteration if led is in one-shot mode and we are in 128 * the final blink state so that the led is toggled each delay_on + 129 * delay_off milliseconds in worst case. 130 */ 131 if (led_cdev->flags & LED_BLINK_ONESHOT) { 132 if (led_cdev->flags & LED_BLINK_INVERT) { 133 if (brightness) 134 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 135 } else { 136 if (!brightness) 137 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 138 } 139 } 140 141 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 142 } 143 144 static void set_brightness_delayed(struct work_struct *ws) 145 { 146 struct led_classdev *led_cdev = 147 container_of(ws, struct led_classdev, set_brightness_work); 148 149 led_stop_software_blink(led_cdev); 150 151 __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 152 } 153 154 /** 155 * led_classdev_suspend - suspend an led_classdev. 156 * @led_cdev: the led_classdev to suspend. 157 */ 158 void led_classdev_suspend(struct led_classdev *led_cdev) 159 { 160 led_cdev->flags |= LED_SUSPENDED; 161 led_cdev->brightness_set(led_cdev, 0); 162 } 163 EXPORT_SYMBOL_GPL(led_classdev_suspend); 164 165 /** 166 * led_classdev_resume - resume an led_classdev. 167 * @led_cdev: the led_classdev to resume. 168 */ 169 void led_classdev_resume(struct led_classdev *led_cdev) 170 { 171 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 172 led_cdev->flags &= ~LED_SUSPENDED; 173 } 174 EXPORT_SYMBOL_GPL(led_classdev_resume); 175 176 static int led_suspend(struct device *dev) 177 { 178 struct led_classdev *led_cdev = dev_get_drvdata(dev); 179 180 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 181 led_classdev_suspend(led_cdev); 182 183 return 0; 184 } 185 186 static int led_resume(struct device *dev) 187 { 188 struct led_classdev *led_cdev = dev_get_drvdata(dev); 189 190 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 191 led_classdev_resume(led_cdev); 192 193 return 0; 194 } 195 196 static const struct dev_pm_ops leds_class_dev_pm_ops = { 197 .suspend = led_suspend, 198 .resume = led_resume, 199 }; 200 201 /** 202 * led_classdev_register - register a new object of led_classdev class. 203 * @parent: The device to register. 204 * @led_cdev: the led_classdev structure for this device. 205 */ 206 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 207 { 208 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 209 led_cdev, led_cdev->groups, 210 "%s", led_cdev->name); 211 if (IS_ERR(led_cdev->dev)) 212 return PTR_ERR(led_cdev->dev); 213 214 #ifdef CONFIG_LEDS_TRIGGERS 215 init_rwsem(&led_cdev->trigger_lock); 216 #endif 217 /* add to the list of leds */ 218 down_write(&leds_list_lock); 219 list_add_tail(&led_cdev->node, &leds_list); 220 up_write(&leds_list_lock); 221 222 if (!led_cdev->max_brightness) 223 led_cdev->max_brightness = LED_FULL; 224 225 led_update_brightness(led_cdev); 226 227 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 228 229 init_timer(&led_cdev->blink_timer); 230 led_cdev->blink_timer.function = led_timer_function; 231 led_cdev->blink_timer.data = (unsigned long)led_cdev; 232 233 #ifdef CONFIG_LEDS_TRIGGERS 234 led_trigger_set_default(led_cdev); 235 #endif 236 237 dev_dbg(parent, "Registered led device: %s\n", 238 led_cdev->name); 239 240 return 0; 241 } 242 EXPORT_SYMBOL_GPL(led_classdev_register); 243 244 /** 245 * led_classdev_unregister - unregisters a object of led_properties class. 246 * @led_cdev: the led device to unregister 247 * 248 * Unregisters a previously registered via led_classdev_register object. 249 */ 250 void led_classdev_unregister(struct led_classdev *led_cdev) 251 { 252 #ifdef CONFIG_LEDS_TRIGGERS 253 down_write(&led_cdev->trigger_lock); 254 if (led_cdev->trigger) 255 led_trigger_set(led_cdev, NULL); 256 up_write(&led_cdev->trigger_lock); 257 #endif 258 259 cancel_work_sync(&led_cdev->set_brightness_work); 260 261 /* Stop blinking */ 262 led_stop_software_blink(led_cdev); 263 led_set_brightness(led_cdev, LED_OFF); 264 265 device_unregister(led_cdev->dev); 266 267 down_write(&leds_list_lock); 268 list_del(&led_cdev->node); 269 up_write(&leds_list_lock); 270 } 271 EXPORT_SYMBOL_GPL(led_classdev_unregister); 272 273 static int __init leds_init(void) 274 { 275 leds_class = class_create(THIS_MODULE, "leds"); 276 if (IS_ERR(leds_class)) 277 return PTR_ERR(leds_class); 278 leds_class->pm = &leds_class_dev_pm_ops; 279 leds_class->dev_groups = led_groups; 280 return 0; 281 } 282 283 static void __exit leds_exit(void) 284 { 285 class_destroy(leds_class); 286 } 287 288 subsys_initcall(leds_init); 289 module_exit(leds_exit); 290 291 MODULE_AUTHOR("John Lenz, Richard Purdie"); 292 MODULE_LICENSE("GPL"); 293 MODULE_DESCRIPTION("LED Class Interface"); 294