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