drivers/leds/ledtrig-timer.c

   1 /*
   2  * LED Kernel Timer Trigger
   3  *
   4  * Copyright 2005-2006 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/jiffies.h>
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18 #include <linux/list.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/device.h>
  21 #include <linux/sysdev.h>
  22 #include <linux/timer.h>
  23 #include <linux/ctype.h>
  24 #include <linux/leds.h>
  25 #include <linux/slab.h>
  26 #include "leds.h"
  27
  28 struct timer_trig_data {
  29         int brightness_on;              /* LED brightness during "on" period.
  30                                          * (LED_OFF < brightness_on <= LED_FULL)
  31                                          */
  32         unsigned long delay_on;         /* milliseconds on */
  33         unsigned long delay_off;        /* milliseconds off */
  34         struct timer_list timer;
  35 };
  36
  37 static void led_timer_function(unsigned long data)
  38 {
  39         struct led_classdev *led_cdev = (struct led_classdev *) data;
  40         struct timer_trig_data *timer_data = led_cdev->trigger_data;
  41         unsigned long brightness;
  42         unsigned long delay;
  43
  44         if (!timer_data->delay_on || !timer_data->delay_off) {
  45                 led_set_brightness(led_cdev, LED_OFF);
  46                 return;
  47         }
  48
  49         brightness = led_get_brightness(led_cdev);
  50         if (!brightness) {
  51                 /* Time to switch the LED on. */
  52                 brightness = timer_data->brightness_on;
  53                 delay = timer_data->delay_on;
  54         } else {
  55                 /* Store the current brightness value to be able
  56                  * to restore it when the delay_off period is over.
  57                  */
  58                 timer_data->brightness_on = brightness;
  59                 brightness = LED_OFF;
  60                 delay = timer_data->delay_off;
  61         }
  62
  63         led_set_brightness(led_cdev, brightness);
  64
  65         mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
  66 }
  67
  68 static ssize_t led_delay_on_show(struct device *dev,
  69                 struct device_attribute *attr, char *buf)
  70 {
  71         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  72         struct timer_trig_data *timer_data = led_cdev->trigger_data;
  73
  74         return sprintf(buf, "%lu\n", timer_data->delay_on);
  75 }
  76
  77 static ssize_t led_delay_on_store(struct device *dev,
  78                 struct device_attribute *attr, const char *buf, size_t size)
  79 {
  80         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  81         struct timer_trig_data *timer_data = led_cdev->trigger_data;
  82         int ret = -EINVAL;
  83         char *after;
  84         unsigned long state = simple_strtoul(buf, &after, 10);
  85         size_t count = after - buf;
  86
  87         if (isspace(*after))
  88                 count++;
  89
  90         if (count == size) {
  91                 if (timer_data->delay_on != state) {
  92                         /* the new value differs from the previous */
  93                         timer_data->delay_on = state;
  94
  95                         /* deactivate previous settings */
  96                         del_timer_sync(&timer_data->timer);
  97
  98                         /* try to activate hardware acceleration, if any */
  99                         if (!led_cdev->blink_set ||
 100                             led_cdev->blink_set(led_cdev,
 101                               &timer_data->delay_on, &timer_data->delay_off)) {
 102                                 /* no hardware acceleration, blink via timer */
 103                                 mod_timer(&timer_data->timer, jiffies + 1);
 104                         }
 105                 }
 106                 ret = count;
 107         }
 108
 109         return ret;
 110 }
 111
 112 static ssize_t led_delay_off_show(struct device *dev,
 113                 struct device_attribute *attr, char *buf)
 114 {
 115         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 116         struct timer_trig_data *timer_data = led_cdev->trigger_data;
 117
 118         return sprintf(buf, "%lu\n", timer_data->delay_off);
 119 }
 120
 121 static ssize_t led_delay_off_store(struct device *dev,
 122                 struct device_attribute *attr, const char *buf, size_t size)
 123 {
 124         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 125         struct timer_trig_data *timer_data = led_cdev->trigger_data;
 126         int ret = -EINVAL;
 127         char *after;
 128         unsigned long state = simple_strtoul(buf, &after, 10);
 129         size_t count = after - buf;
 130
 131         if (isspace(*after))
 132                 count++;
 133
 134         if (count == size) {
 135                 if (timer_data->delay_off != state) {
 136                         /* the new value differs from the previous */
 137                         timer_data->delay_off = state;
 138
 139                         /* deactivate previous settings */
 140                         del_timer_sync(&timer_data->timer);
 141
 142                         /* try to activate hardware acceleration, if any */
 143                         if (!led_cdev->blink_set ||
 144                             led_cdev->blink_set(led_cdev,
 145                               &timer_data->delay_on, &timer_data->delay_off)) {
 146                                 /* no hardware acceleration, blink via timer */
 147                                 mod_timer(&timer_data->timer, jiffies + 1);
 148                         }
 149                 }
 150                 ret = count;
 151         }
 152
 153         return ret;
 154 }
 155
 156 static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
 157 static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
 158
 159 static void timer_trig_activate(struct led_classdev *led_cdev)
 160 {
 161         struct timer_trig_data *timer_data;
 162         int rc;
 163
 164         timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
 165         if (!timer_data)
 166                 return;
 167
 168         timer_data->brightness_on = led_get_brightness(led_cdev);
 169         if (timer_data->brightness_on == LED_OFF)
 170                 timer_data->brightness_on = led_cdev->max_brightness;
 171         led_cdev->trigger_data = timer_data;
 172
 173         init_timer(&timer_data->timer);
 174         timer_data->timer.function = led_timer_function;
 175         timer_data->timer.data = (unsigned long) led_cdev;
 176
 177         rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
 178         if (rc)
 179                 goto err_out;
 180         rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
 181         if (rc)
 182                 goto err_out_delayon;
 183
 184         /* If there is hardware support for blinking, start one
 185          * user friendly blink rate chosen by the driver.
 186          */
 187         if (led_cdev->blink_set)
 188                 led_cdev->blink_set(led_cdev,
 189                         &timer_data->delay_on, &timer_data->delay_off);
 190
 191         return;
 192
 193 err_out_delayon:
 194         device_remove_file(led_cdev->dev, &dev_attr_delay_on);
 195 err_out:
 196         led_cdev->trigger_data = NULL;
 197         kfree(timer_data);
 198 }
 199
 200 static void timer_trig_deactivate(struct led_classdev *led_cdev)
 201 {
 202         struct timer_trig_data *timer_data = led_cdev->trigger_data;
 203         unsigned long on = 0, off = 0;
 204
 205         if (timer_data) {
 206                 device_remove_file(led_cdev->dev, &dev_attr_delay_on);
 207                 device_remove_file(led_cdev->dev, &dev_attr_delay_off);
 208                 del_timer_sync(&timer_data->timer);
 209                 kfree(timer_data);
 210         }
 211
 212         /* If there is hardware support for blinking, stop it */
 213         if (led_cdev->blink_set)
 214                 led_cdev->blink_set(led_cdev, &on, &off);
 215 }
 216
 217 static struct led_trigger timer_led_trigger = {
 218         .name     = "timer",
 219         .activate = timer_trig_activate,
 220         .deactivate = timer_trig_deactivate,
 221 };
 222
 223 static int __init timer_trig_init(void)
 224 {
 225         return led_trigger_register(&timer_led_trigger);
 226 }
 227
 228 static void __exit timer_trig_exit(void)
 229 {
 230         led_trigger_unregister(&timer_led_trigger);
 231 }
 232
 233 module_init(timer_trig_init);
 234 module_exit(timer_trig_exit);
 235
 236 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
 237 MODULE_DESCRIPTION("Timer LED trigger");
 238 MODULE_LICENSE("GPL");