lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 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 | if(NULL==led_cdev) |
| 38 | return -EINVAL; |
| 39 | |
| 40 | /* no lock needed for this */ |
| 41 | led_update_brightness(led_cdev); |
| 42 | |
| 43 | return sprintf(buf, "%u\n", led_cdev->brightness); |
| 44 | } |
| 45 | |
| 46 | static ssize_t led_brightness_store(struct device *dev, |
| 47 | struct device_attribute *attr, const char *buf, size_t size) |
| 48 | { |
| 49 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 50 | ssize_t ret = -EINVAL; |
| 51 | char *after; |
| 52 | unsigned long state = simple_strtoul(buf, &after, 10); |
| 53 | size_t count = after - buf; |
| 54 | |
| 55 | if(NULL==led_cdev) |
| 56 | return -EINVAL; |
| 57 | |
| 58 | if (isspace(*after)) |
| 59 | count++; |
| 60 | |
| 61 | if (count == size) { |
| 62 | ret = count; |
| 63 | |
| 64 | if (state == LED_OFF) |
| 65 | led_trigger_remove(led_cdev); |
| 66 | led_set_brightness(led_cdev, state); |
| 67 | } |
| 68 | |
| 69 | return ret; |
| 70 | } |
| 71 | |
| 72 | static ssize_t led_max_brightness_show(struct device *dev, |
| 73 | struct device_attribute *attr, char *buf) |
| 74 | { |
| 75 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 76 | |
| 77 | if(NULL==led_cdev) |
| 78 | return -EINVAL; |
| 79 | |
| 80 | return sprintf(buf, "%u\n", led_cdev->max_brightness); |
| 81 | } |
| 82 | |
| 83 | static struct device_attribute led_class_attrs[] = { |
| 84 | __ATTR(brightness, 0644, led_brightness_show, led_brightness_store), |
| 85 | __ATTR(max_brightness, 0444, led_max_brightness_show, NULL), |
| 86 | #ifdef CONFIG_LEDS_TRIGGERS |
| 87 | __ATTR(trigger, 0644, led_trigger_show, led_trigger_store), |
| 88 | #endif |
| 89 | __ATTR_NULL, |
| 90 | }; |
| 91 | |
| 92 | static void led_timer_function(unsigned long data) |
| 93 | { |
| 94 | struct led_classdev *led_cdev = (void *)data; |
| 95 | unsigned long brightness; |
| 96 | unsigned long delay; |
| 97 | |
| 98 | if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { |
| 99 | led_set_brightness(led_cdev, LED_OFF); |
| 100 | return; |
| 101 | } |
| 102 | |
| 103 | brightness = led_get_brightness(led_cdev); |
| 104 | if (!brightness) { |
| 105 | /* Time to switch the LED on. */ |
| 106 | brightness = led_cdev->blink_brightness; |
| 107 | delay = led_cdev->blink_delay_on; |
| 108 | } else { |
| 109 | /* Store the current brightness value to be able |
| 110 | * to restore it when the delay_off period is over. |
| 111 | */ |
| 112 | led_cdev->blink_brightness = brightness; |
| 113 | brightness = LED_OFF; |
| 114 | delay = led_cdev->blink_delay_off; |
| 115 | } |
| 116 | |
| 117 | led_set_brightness(led_cdev, brightness); |
| 118 | |
| 119 | mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * led_classdev_suspend - suspend an led_classdev. |
| 124 | * @led_cdev: the led_classdev to suspend. |
| 125 | */ |
| 126 | void led_classdev_suspend(struct led_classdev *led_cdev) |
| 127 | { |
| 128 | led_cdev->flags |= LED_SUSPENDED; |
| 129 | led_cdev->brightness_set(led_cdev, 0); |
| 130 | } |
| 131 | EXPORT_SYMBOL_GPL(led_classdev_suspend); |
| 132 | |
| 133 | /** |
| 134 | * led_classdev_resume - resume an led_classdev. |
| 135 | * @led_cdev: the led_classdev to resume. |
| 136 | */ |
| 137 | void led_classdev_resume(struct led_classdev *led_cdev) |
| 138 | { |
| 139 | led_cdev->brightness_set(led_cdev, led_cdev->brightness); |
| 140 | led_cdev->flags &= ~LED_SUSPENDED; |
| 141 | } |
| 142 | EXPORT_SYMBOL_GPL(led_classdev_resume); |
| 143 | |
| 144 | static int led_suspend(struct device *dev, pm_message_t state) |
| 145 | { |
| 146 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 147 | |
| 148 | if(NULL==led_cdev) |
| 149 | return 0; |
| 150 | if (led_cdev->flags & LED_CORE_SUSPENDRESUME) |
| 151 | led_classdev_suspend(led_cdev); |
| 152 | |
| 153 | return 0; |
| 154 | } |
| 155 | |
| 156 | static int led_resume(struct device *dev) |
| 157 | { |
| 158 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 159 | |
| 160 | if(NULL==led_cdev) |
| 161 | return 0; |
| 162 | if (led_cdev->flags & LED_CORE_SUSPENDRESUME) |
| 163 | led_classdev_resume(led_cdev); |
| 164 | |
| 165 | return 0; |
| 166 | } |
| 167 | |
| 168 | /** |
| 169 | * led_classdev_register - register a new object of led_classdev class. |
| 170 | * @parent: The device to register. |
| 171 | * @led_cdev: the led_classdev structure for this device. |
| 172 | */ |
| 173 | int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) |
| 174 | { |
| 175 | led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, |
| 176 | "%s", led_cdev->name); |
| 177 | if (IS_ERR(led_cdev->dev)) |
| 178 | return PTR_ERR(led_cdev->dev); |
| 179 | |
| 180 | #ifdef CONFIG_LEDS_TRIGGERS |
| 181 | init_rwsem(&led_cdev->trigger_lock); |
| 182 | #endif |
| 183 | /* add to the list of leds */ |
| 184 | down_write(&leds_list_lock); |
| 185 | list_add_tail(&led_cdev->node, &leds_list); |
| 186 | up_write(&leds_list_lock); |
| 187 | |
| 188 | if (!led_cdev->max_brightness) |
| 189 | led_cdev->max_brightness = LED_FULL; |
| 190 | |
| 191 | led_update_brightness(led_cdev); |
| 192 | |
| 193 | init_timer(&led_cdev->blink_timer); |
| 194 | led_cdev->blink_timer.function = led_timer_function; |
| 195 | led_cdev->blink_timer.data = (unsigned long)led_cdev; |
| 196 | |
| 197 | #ifdef CONFIG_LEDS_TRIGGERS |
| 198 | led_trigger_set_default(led_cdev); |
| 199 | #endif |
| 200 | |
| 201 | printk(KERN_DEBUG "Registered led device: %s\n", |
| 202 | led_cdev->name); |
| 203 | |
| 204 | return 0; |
| 205 | } |
| 206 | EXPORT_SYMBOL_GPL(led_classdev_register); |
| 207 | |
| 208 | /** |
| 209 | * led_classdev_unregister - unregisters a object of led_properties class. |
| 210 | * @led_cdev: the led device to unregister |
| 211 | * |
| 212 | * Unregisters a previously registered via led_classdev_register object. |
| 213 | */ |
| 214 | void led_classdev_unregister(struct led_classdev *led_cdev) |
| 215 | { |
| 216 | #ifdef CONFIG_LEDS_TRIGGERS |
| 217 | down_write(&led_cdev->trigger_lock); |
| 218 | if (led_cdev->trigger) |
| 219 | led_trigger_set(led_cdev, NULL); |
| 220 | up_write(&led_cdev->trigger_lock); |
| 221 | #endif |
| 222 | |
| 223 | /* Stop blinking */ |
| 224 | led_brightness_set(led_cdev, LED_OFF); |
| 225 | |
| 226 | device_unregister(led_cdev->dev); |
| 227 | |
| 228 | down_write(&leds_list_lock); |
| 229 | list_del(&led_cdev->node); |
| 230 | up_write(&leds_list_lock); |
| 231 | } |
| 232 | EXPORT_SYMBOL_GPL(led_classdev_unregister); |
| 233 | |
| 234 | static int __init leds_init(void) |
| 235 | { |
| 236 | leds_class = class_create(THIS_MODULE, "leds"); |
| 237 | if (IS_ERR(leds_class)) |
| 238 | return PTR_ERR(leds_class); |
| 239 | leds_class->suspend = led_suspend; |
| 240 | leds_class->resume = led_resume; |
| 241 | leds_class->dev_attrs = led_class_attrs; |
| 242 | return 0; |
| 243 | } |
| 244 | |
| 245 | static void __exit leds_exit(void) |
| 246 | { |
| 247 | class_destroy(leds_class); |
| 248 | } |
| 249 | |
| 250 | subsys_initcall(leds_init); |
| 251 | module_exit(leds_exit); |
| 252 | |
| 253 | MODULE_AUTHOR("John Lenz, Richard Purdie"); |
| 254 | MODULE_LICENSE("GPL"); |
| 255 | MODULE_DESCRIPTION("LED Class Interface"); |