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