1 /* 2 * LED Heartbeat Trigger 3 * 4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 5 * 6 * Based on Richard Purdie's ledtrig-timer.c and some arch's 7 * CONFIG_HEARTBEAT code. 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 */ 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/slab.h> 18 #include <linux/timer.h> 19 #include <linux/sched.h> 20 #include <linux/sched/loadavg.h> 21 #include <linux/leds.h> 22 #include <linux/reboot.h> 23 #include <linux/suspend.h> 24 #include "../leds.h" 25 26 static int panic_heartbeats; 27 28 struct heartbeat_trig_data { 29 unsigned int phase; 30 unsigned int period; 31 struct timer_list timer; 32 unsigned int invert; 33 }; 34 35 static void led_heartbeat_function(unsigned long data) 36 { 37 struct led_classdev *led_cdev = (struct led_classdev *) data; 38 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 39 unsigned long brightness = LED_OFF; 40 unsigned long delay = 0; 41 42 if (unlikely(panic_heartbeats)) { 43 led_set_brightness_nosleep(led_cdev, LED_OFF); 44 return; 45 } 46 47 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags)) 48 led_cdev->blink_brightness = led_cdev->new_blink_brightness; 49 50 /* acts like an actual heart beat -- ie thump-thump-pause... */ 51 switch (heartbeat_data->phase) { 52 case 0: 53 /* 54 * The hyperbolic function below modifies the 55 * heartbeat period length in dependency of the 56 * current (1min) load. It goes through the points 57 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300. 58 */ 59 heartbeat_data->period = 300 + 60 (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT)); 61 heartbeat_data->period = 62 msecs_to_jiffies(heartbeat_data->period); 63 delay = msecs_to_jiffies(70); 64 heartbeat_data->phase++; 65 if (!heartbeat_data->invert) 66 brightness = led_cdev->blink_brightness; 67 break; 68 case 1: 69 delay = heartbeat_data->period / 4 - msecs_to_jiffies(70); 70 heartbeat_data->phase++; 71 if (heartbeat_data->invert) 72 brightness = led_cdev->blink_brightness; 73 break; 74 case 2: 75 delay = msecs_to_jiffies(70); 76 heartbeat_data->phase++; 77 if (!heartbeat_data->invert) 78 brightness = led_cdev->blink_brightness; 79 break; 80 default: 81 delay = heartbeat_data->period - heartbeat_data->period / 4 - 82 msecs_to_jiffies(70); 83 heartbeat_data->phase = 0; 84 if (heartbeat_data->invert) 85 brightness = led_cdev->blink_brightness; 86 break; 87 } 88 89 led_set_brightness_nosleep(led_cdev, brightness); 90 mod_timer(&heartbeat_data->timer, jiffies + delay); 91 } 92 93 static ssize_t led_invert_show(struct device *dev, 94 struct device_attribute *attr, char *buf) 95 { 96 struct led_classdev *led_cdev = dev_get_drvdata(dev); 97 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 98 99 return sprintf(buf, "%u\n", heartbeat_data->invert); 100 } 101 102 static ssize_t led_invert_store(struct device *dev, 103 struct device_attribute *attr, const char *buf, size_t size) 104 { 105 struct led_classdev *led_cdev = dev_get_drvdata(dev); 106 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 107 unsigned long state; 108 int ret; 109 110 ret = kstrtoul(buf, 0, &state); 111 if (ret) 112 return ret; 113 114 heartbeat_data->invert = !!state; 115 116 return size; 117 } 118 119 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store); 120 121 static void heartbeat_trig_activate(struct led_classdev *led_cdev) 122 { 123 struct heartbeat_trig_data *heartbeat_data; 124 int rc; 125 126 heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); 127 if (!heartbeat_data) 128 return; 129 130 led_cdev->trigger_data = heartbeat_data; 131 rc = device_create_file(led_cdev->dev, &dev_attr_invert); 132 if (rc) { 133 kfree(led_cdev->trigger_data); 134 return; 135 } 136 137 setup_timer(&heartbeat_data->timer, 138 led_heartbeat_function, (unsigned long) led_cdev); 139 heartbeat_data->phase = 0; 140 if (!led_cdev->blink_brightness) 141 led_cdev->blink_brightness = led_cdev->max_brightness; 142 led_heartbeat_function(heartbeat_data->timer.data); 143 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 144 led_cdev->activated = true; 145 } 146 147 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) 148 { 149 struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data; 150 151 if (led_cdev->activated) { 152 del_timer_sync(&heartbeat_data->timer); 153 device_remove_file(led_cdev->dev, &dev_attr_invert); 154 kfree(heartbeat_data); 155 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 156 led_cdev->activated = false; 157 } 158 } 159 160 static struct led_trigger heartbeat_led_trigger = { 161 .name = "heartbeat", 162 .activate = heartbeat_trig_activate, 163 .deactivate = heartbeat_trig_deactivate, 164 }; 165 166 static int heartbeat_pm_notifier(struct notifier_block *nb, 167 unsigned long pm_event, void *unused) 168 { 169 int rc; 170 171 switch (pm_event) { 172 case PM_SUSPEND_PREPARE: 173 case PM_HIBERNATION_PREPARE: 174 case PM_RESTORE_PREPARE: 175 led_trigger_unregister(&heartbeat_led_trigger); 176 break; 177 case PM_POST_SUSPEND: 178 case PM_POST_HIBERNATION: 179 case PM_POST_RESTORE: 180 rc = led_trigger_register(&heartbeat_led_trigger); 181 if (rc) 182 pr_err("could not re-register heartbeat trigger\n"); 183 break; 184 default: 185 break; 186 } 187 return NOTIFY_DONE; 188 } 189 190 static int heartbeat_reboot_notifier(struct notifier_block *nb, 191 unsigned long code, void *unused) 192 { 193 led_trigger_unregister(&heartbeat_led_trigger); 194 return NOTIFY_DONE; 195 } 196 197 static int heartbeat_panic_notifier(struct notifier_block *nb, 198 unsigned long code, void *unused) 199 { 200 panic_heartbeats = 1; 201 return NOTIFY_DONE; 202 } 203 204 static struct notifier_block heartbeat_pm_nb = { 205 .notifier_call = heartbeat_pm_notifier, 206 }; 207 208 static struct notifier_block heartbeat_reboot_nb = { 209 .notifier_call = heartbeat_reboot_notifier, 210 }; 211 212 static struct notifier_block heartbeat_panic_nb = { 213 .notifier_call = heartbeat_panic_notifier, 214 }; 215 216 static int __init heartbeat_trig_init(void) 217 { 218 int rc = led_trigger_register(&heartbeat_led_trigger); 219 220 if (!rc) { 221 atomic_notifier_chain_register(&panic_notifier_list, 222 &heartbeat_panic_nb); 223 register_reboot_notifier(&heartbeat_reboot_nb); 224 register_pm_notifier(&heartbeat_pm_nb); 225 } 226 return rc; 227 } 228 229 static void __exit heartbeat_trig_exit(void) 230 { 231 unregister_pm_notifier(&heartbeat_pm_nb); 232 unregister_reboot_notifier(&heartbeat_reboot_nb); 233 atomic_notifier_chain_unregister(&panic_notifier_list, 234 &heartbeat_panic_nb); 235 led_trigger_unregister(&heartbeat_led_trigger); 236 } 237 238 module_init(heartbeat_trig_init); 239 module_exit(heartbeat_trig_exit); 240 241 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 242 MODULE_DESCRIPTION("Heartbeat LED trigger"); 243 MODULE_LICENSE("GPL"); 244