1 /* 2 * LED Triggers Core 3 * 4 * Copyright 2005-2007 Openedhand Ltd. 5 * 6 * Author: Richard Purdie <rpurdie@openedhand.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/list.h> 18 #include <linux/spinlock.h> 19 #include <linux/device.h> 20 #include <linux/sysdev.h> 21 #include <linux/timer.h> 22 #include <linux/rwsem.h> 23 #include <linux/leds.h> 24 #include "leds.h" 25 26 /* 27 * Nests outside led_cdev->trigger_lock 28 */ 29 static DECLARE_RWSEM(triggers_list_lock); 30 static LIST_HEAD(trigger_list); 31 32 /* Used by LED Class */ 33 34 ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, 35 const char *buf, size_t count) 36 { 37 struct led_classdev *led_cdev = dev_get_drvdata(dev); 38 char trigger_name[TRIG_NAME_MAX]; 39 struct led_trigger *trig; 40 size_t len; 41 42 trigger_name[sizeof(trigger_name) - 1] = '\0'; 43 strncpy(trigger_name, buf, sizeof(trigger_name) - 1); 44 len = strlen(trigger_name); 45 46 if (len && trigger_name[len - 1] == '\n') 47 trigger_name[len - 1] = '\0'; 48 49 if (!strcmp(trigger_name, "none")) { 50 led_trigger_remove(led_cdev); 51 return count; 52 } 53 54 down_read(&triggers_list_lock); 55 list_for_each_entry(trig, &trigger_list, next_trig) { 56 if (!strcmp(trigger_name, trig->name)) { 57 down_write(&led_cdev->trigger_lock); 58 led_trigger_set(led_cdev, trig); 59 up_write(&led_cdev->trigger_lock); 60 61 up_read(&triggers_list_lock); 62 return count; 63 } 64 } 65 up_read(&triggers_list_lock); 66 67 return -EINVAL; 68 } 69 EXPORT_SYMBOL_GPL(led_trigger_store); 70 71 ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, 72 char *buf) 73 { 74 struct led_classdev *led_cdev = dev_get_drvdata(dev); 75 struct led_trigger *trig; 76 int len = 0; 77 78 down_read(&triggers_list_lock); 79 down_read(&led_cdev->trigger_lock); 80 81 if (!led_cdev->trigger) 82 len += sprintf(buf+len, "[none] "); 83 else 84 len += sprintf(buf+len, "none "); 85 86 list_for_each_entry(trig, &trigger_list, next_trig) { 87 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name, 88 trig->name)) 89 len += sprintf(buf+len, "[%s] ", trig->name); 90 else 91 len += sprintf(buf+len, "%s ", trig->name); 92 } 93 up_read(&led_cdev->trigger_lock); 94 up_read(&triggers_list_lock); 95 96 len += sprintf(len+buf, "\n"); 97 return len; 98 } 99 EXPORT_SYMBOL_GPL(led_trigger_show); 100 101 /* Caller must ensure led_cdev->trigger_lock held */ 102 void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger) 103 { 104 unsigned long flags; 105 106 /* Remove any existing trigger */ 107 if (led_cdev->trigger) { 108 write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags); 109 list_del(&led_cdev->trig_list); 110 write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, 111 flags); 112 if (led_cdev->trigger->deactivate) 113 led_cdev->trigger->deactivate(led_cdev); 114 led_set_brightness(led_cdev, LED_OFF); 115 } 116 if (trigger) { 117 write_lock_irqsave(&trigger->leddev_list_lock, flags); 118 list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs); 119 write_unlock_irqrestore(&trigger->leddev_list_lock, flags); 120 if (trigger->activate) 121 trigger->activate(led_cdev); 122 } 123 led_cdev->trigger = trigger; 124 } 125 EXPORT_SYMBOL_GPL(led_trigger_set); 126 127 void led_trigger_remove(struct led_classdev *led_cdev) 128 { 129 down_write(&led_cdev->trigger_lock); 130 led_trigger_set(led_cdev, NULL); 131 up_write(&led_cdev->trigger_lock); 132 } 133 EXPORT_SYMBOL_GPL(led_trigger_remove); 134 135 void led_trigger_set_default(struct led_classdev *led_cdev) 136 { 137 struct led_trigger *trig; 138 139 if (!led_cdev->default_trigger) 140 return; 141 142 down_read(&triggers_list_lock); 143 down_write(&led_cdev->trigger_lock); 144 list_for_each_entry(trig, &trigger_list, next_trig) { 145 if (!strcmp(led_cdev->default_trigger, trig->name)) 146 led_trigger_set(led_cdev, trig); 147 } 148 up_write(&led_cdev->trigger_lock); 149 up_read(&triggers_list_lock); 150 } 151 EXPORT_SYMBOL_GPL(led_trigger_set_default); 152 153 /* LED Trigger Interface */ 154 155 int led_trigger_register(struct led_trigger *trigger) 156 { 157 struct led_classdev *led_cdev; 158 159 rwlock_init(&trigger->leddev_list_lock); 160 INIT_LIST_HEAD(&trigger->led_cdevs); 161 162 /* Add to the list of led triggers */ 163 down_write(&triggers_list_lock); 164 list_add_tail(&trigger->next_trig, &trigger_list); 165 up_write(&triggers_list_lock); 166 167 /* Register with any LEDs that have this as a default trigger */ 168 down_read(&leds_list_lock); 169 list_for_each_entry(led_cdev, &leds_list, node) { 170 down_write(&led_cdev->trigger_lock); 171 if (!led_cdev->trigger && led_cdev->default_trigger && 172 !strcmp(led_cdev->default_trigger, trigger->name)) 173 led_trigger_set(led_cdev, trigger); 174 up_write(&led_cdev->trigger_lock); 175 } 176 up_read(&leds_list_lock); 177 178 return 0; 179 } 180 EXPORT_SYMBOL_GPL(led_trigger_register); 181 182 void led_trigger_unregister(struct led_trigger *trigger) 183 { 184 struct led_classdev *led_cdev; 185 186 /* Remove from the list of led triggers */ 187 down_write(&triggers_list_lock); 188 list_del(&trigger->next_trig); 189 up_write(&triggers_list_lock); 190 191 /* Remove anyone actively using this trigger */ 192 down_read(&leds_list_lock); 193 list_for_each_entry(led_cdev, &leds_list, node) { 194 down_write(&led_cdev->trigger_lock); 195 if (led_cdev->trigger == trigger) 196 led_trigger_set(led_cdev, NULL); 197 up_write(&led_cdev->trigger_lock); 198 } 199 up_read(&leds_list_lock); 200 } 201 EXPORT_SYMBOL_GPL(led_trigger_unregister); 202 203 /* Simple LED Tigger Interface */ 204 205 void led_trigger_event(struct led_trigger *trigger, 206 enum led_brightness brightness) 207 { 208 struct list_head *entry; 209 210 if (!trigger) 211 return; 212 213 read_lock(&trigger->leddev_list_lock); 214 list_for_each(entry, &trigger->led_cdevs) { 215 struct led_classdev *led_cdev; 216 217 led_cdev = list_entry(entry, struct led_classdev, trig_list); 218 led_set_brightness(led_cdev, brightness); 219 } 220 read_unlock(&trigger->leddev_list_lock); 221 } 222 EXPORT_SYMBOL_GPL(led_trigger_event); 223 224 void led_trigger_register_simple(const char *name, struct led_trigger **tp) 225 { 226 struct led_trigger *trigger; 227 int err; 228 229 trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL); 230 231 if (trigger) { 232 trigger->name = name; 233 err = led_trigger_register(trigger); 234 if (err < 0) 235 printk(KERN_WARNING "LED trigger %s failed to register" 236 " (%d)\n", name, err); 237 } else 238 printk(KERN_WARNING "LED trigger %s failed to register" 239 " (no memory)\n", name); 240 241 *tp = trigger; 242 } 243 EXPORT_SYMBOL_GPL(led_trigger_register_simple); 244 245 void led_trigger_unregister_simple(struct led_trigger *trigger) 246 { 247 if (trigger) 248 led_trigger_unregister(trigger); 249 kfree(trigger); 250 } 251 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); 252 253 MODULE_AUTHOR("Richard Purdie"); 254 MODULE_LICENSE("GPL"); 255 MODULE_DESCRIPTION("LED Triggers Core"); 256