Shuah Khan | 44e1e9f | 2012-05-29 15:07:30 -0700 | [diff] [blame] | 1 | /* |
| 2 | * LED Kernel Transient Trigger |
| 3 | * |
| 4 | * Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com> |
| 5 | * |
| 6 | * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's |
| 7 | * ledtrig-heartbeat.c |
| 8 | * Design and use-case input from Jonas Bonn <jonas@southpole.se> and |
| 9 | * Neil Brown <neilb@suse.de> |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License version 2 as |
| 13 | * published by the Free Software Foundation. |
| 14 | * |
| 15 | */ |
| 16 | /* |
| 17 | * Transient trigger allows one shot timer activation. Please refer to |
| 18 | * Documentation/leds/ledtrig-transient.txt for details |
| 19 | */ |
| 20 | |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/kernel.h> |
| 23 | #include <linux/init.h> |
| 24 | #include <linux/device.h> |
| 25 | #include <linux/slab.h> |
| 26 | #include <linux/timer.h> |
| 27 | #include <linux/leds.h> |
| 28 | #include "leds.h" |
| 29 | |
| 30 | struct transient_trig_data { |
| 31 | int activate; |
| 32 | int state; |
| 33 | int restore_state; |
| 34 | unsigned long duration; |
| 35 | struct timer_list timer; |
| 36 | }; |
| 37 | |
| 38 | static void transient_timer_function(unsigned long data) |
| 39 | { |
| 40 | struct led_classdev *led_cdev = (struct led_classdev *) data; |
| 41 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 42 | |
| 43 | transient_data->activate = 0; |
| 44 | led_set_brightness(led_cdev, transient_data->restore_state); |
| 45 | } |
| 46 | |
| 47 | static ssize_t transient_activate_show(struct device *dev, |
| 48 | struct device_attribute *attr, char *buf) |
| 49 | { |
| 50 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 51 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 52 | |
| 53 | return sprintf(buf, "%d\n", transient_data->activate); |
| 54 | } |
| 55 | |
| 56 | static ssize_t transient_activate_store(struct device *dev, |
| 57 | struct device_attribute *attr, const char *buf, size_t size) |
| 58 | { |
| 59 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 60 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 61 | unsigned long state; |
| 62 | ssize_t ret; |
| 63 | |
| 64 | ret = kstrtoul(buf, 10, &state); |
| 65 | if (ret) |
| 66 | return ret; |
| 67 | |
| 68 | if (state != 1 && state != 0) |
| 69 | return -EINVAL; |
| 70 | |
| 71 | /* cancel the running timer */ |
| 72 | if (state == 0 && transient_data->activate == 1) { |
| 73 | del_timer(&transient_data->timer); |
| 74 | transient_data->activate = state; |
| 75 | led_set_brightness(led_cdev, transient_data->restore_state); |
| 76 | return size; |
| 77 | } |
| 78 | |
| 79 | /* start timer if there is no active timer */ |
| 80 | if (state == 1 && transient_data->activate == 0 && |
| 81 | transient_data->duration != 0) { |
| 82 | transient_data->activate = state; |
| 83 | led_set_brightness(led_cdev, transient_data->state); |
| 84 | transient_data->restore_state = |
| 85 | (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL; |
| 86 | mod_timer(&transient_data->timer, |
| 87 | jiffies + transient_data->duration); |
| 88 | } |
| 89 | |
| 90 | /* state == 0 && transient_data->activate == 0 |
| 91 | timer is not active - just return */ |
| 92 | /* state == 1 && transient_data->activate == 1 |
| 93 | timer is already active - just return */ |
| 94 | |
| 95 | return size; |
| 96 | } |
| 97 | |
| 98 | static ssize_t transient_duration_show(struct device *dev, |
| 99 | struct device_attribute *attr, char *buf) |
| 100 | { |
| 101 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 102 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 103 | |
| 104 | return sprintf(buf, "%lu\n", transient_data->duration); |
| 105 | } |
| 106 | |
| 107 | static ssize_t transient_duration_store(struct device *dev, |
| 108 | struct device_attribute *attr, const char *buf, size_t size) |
| 109 | { |
| 110 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 111 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 112 | unsigned long state; |
| 113 | ssize_t ret; |
| 114 | |
| 115 | ret = kstrtoul(buf, 10, &state); |
| 116 | if (ret) |
| 117 | return ret; |
| 118 | |
| 119 | transient_data->duration = state; |
| 120 | return size; |
| 121 | } |
| 122 | |
| 123 | static ssize_t transient_state_show(struct device *dev, |
| 124 | struct device_attribute *attr, char *buf) |
| 125 | { |
| 126 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 127 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 128 | int state; |
| 129 | |
| 130 | state = (transient_data->state == LED_FULL) ? 1 : 0; |
| 131 | return sprintf(buf, "%d\n", state); |
| 132 | } |
| 133 | |
| 134 | static ssize_t transient_state_store(struct device *dev, |
| 135 | struct device_attribute *attr, const char *buf, size_t size) |
| 136 | { |
| 137 | struct led_classdev *led_cdev = dev_get_drvdata(dev); |
| 138 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 139 | unsigned long state; |
| 140 | ssize_t ret; |
| 141 | |
| 142 | ret = kstrtoul(buf, 10, &state); |
| 143 | if (ret) |
| 144 | return ret; |
| 145 | |
| 146 | if (state != 1 && state != 0) |
| 147 | return -EINVAL; |
| 148 | |
| 149 | transient_data->state = (state == 1) ? LED_FULL : LED_OFF; |
| 150 | return size; |
| 151 | } |
| 152 | |
| 153 | static DEVICE_ATTR(activate, 0644, transient_activate_show, |
| 154 | transient_activate_store); |
| 155 | static DEVICE_ATTR(duration, 0644, transient_duration_show, |
| 156 | transient_duration_store); |
| 157 | static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store); |
| 158 | |
| 159 | static void transient_trig_activate(struct led_classdev *led_cdev) |
| 160 | { |
| 161 | int rc; |
| 162 | struct transient_trig_data *tdata; |
| 163 | |
| 164 | tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL); |
| 165 | if (!tdata) { |
| 166 | dev_err(led_cdev->dev, |
| 167 | "unable to allocate transient trigger\n"); |
| 168 | return; |
| 169 | } |
| 170 | led_cdev->trigger_data = tdata; |
| 171 | |
| 172 | rc = device_create_file(led_cdev->dev, &dev_attr_activate); |
| 173 | if (rc) |
| 174 | goto err_out; |
| 175 | |
| 176 | rc = device_create_file(led_cdev->dev, &dev_attr_duration); |
| 177 | if (rc) |
| 178 | goto err_out_duration; |
| 179 | |
| 180 | rc = device_create_file(led_cdev->dev, &dev_attr_state); |
| 181 | if (rc) |
| 182 | goto err_out_state; |
| 183 | |
| 184 | setup_timer(&tdata->timer, transient_timer_function, |
| 185 | (unsigned long) led_cdev); |
| 186 | led_cdev->activated = true; |
| 187 | |
| 188 | return; |
| 189 | |
| 190 | err_out_state: |
| 191 | device_remove_file(led_cdev->dev, &dev_attr_duration); |
| 192 | err_out_duration: |
| 193 | device_remove_file(led_cdev->dev, &dev_attr_activate); |
| 194 | err_out: |
| 195 | dev_err(led_cdev->dev, "unable to register transient trigger\n"); |
| 196 | led_cdev->trigger_data = NULL; |
| 197 | kfree(tdata); |
| 198 | } |
| 199 | |
| 200 | static void transient_trig_deactivate(struct led_classdev *led_cdev) |
| 201 | { |
| 202 | struct transient_trig_data *transient_data = led_cdev->trigger_data; |
| 203 | |
| 204 | if (led_cdev->activated) { |
| 205 | del_timer_sync(&transient_data->timer); |
| 206 | led_set_brightness(led_cdev, transient_data->restore_state); |
| 207 | device_remove_file(led_cdev->dev, &dev_attr_activate); |
| 208 | device_remove_file(led_cdev->dev, &dev_attr_duration); |
| 209 | device_remove_file(led_cdev->dev, &dev_attr_state); |
| 210 | led_cdev->trigger_data = NULL; |
| 211 | led_cdev->activated = false; |
| 212 | kfree(transient_data); |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | static struct led_trigger transient_trigger = { |
| 217 | .name = "transient", |
| 218 | .activate = transient_trig_activate, |
| 219 | .deactivate = transient_trig_deactivate, |
| 220 | }; |
| 221 | |
| 222 | static int __init transient_trig_init(void) |
| 223 | { |
| 224 | return led_trigger_register(&transient_trigger); |
| 225 | } |
| 226 | |
| 227 | static void __exit transient_trig_exit(void) |
| 228 | { |
| 229 | led_trigger_unregister(&transient_trigger); |
| 230 | } |
| 231 | |
| 232 | module_init(transient_trig_init); |
| 233 | module_exit(transient_trig_exit); |
| 234 | |
| 235 | MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>"); |
| 236 | MODULE_DESCRIPTION("Transient LED trigger"); |
| 237 | MODULE_LICENSE("GPL"); |