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![Márton Németh](/assets/img/avatar_default.png)
Extends the leds subsystem with a blink_set() callback function which can be optionally implemented by a LED driver. If implemented, the driver can use the hardware acceleration for blinking a LED. Signed-off-by: Márton Németh <nm127@freemail.hu> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
221 lines
5.6 KiB
C
221 lines
5.6 KiB
C
/*
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* LED Kernel Timer Trigger
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*
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* Copyright 2005-2006 Openedhand Ltd.
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*
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* Author: Richard Purdie <rpurdie@openedhand.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/sysdev.h>
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#include <linux/timer.h>
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#include <linux/ctype.h>
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#include <linux/leds.h>
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#include "leds.h"
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struct timer_trig_data {
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unsigned long delay_on; /* milliseconds on */
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unsigned long delay_off; /* milliseconds off */
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struct timer_list timer;
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};
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static void led_timer_function(unsigned long data)
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{
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struct led_classdev *led_cdev = (struct led_classdev *) data;
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struct timer_trig_data *timer_data = led_cdev->trigger_data;
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unsigned long brightness = LED_OFF;
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unsigned long delay = timer_data->delay_off;
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if (!timer_data->delay_on || !timer_data->delay_off) {
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led_set_brightness(led_cdev, LED_OFF);
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return;
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}
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if (!led_cdev->brightness) {
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brightness = LED_FULL;
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delay = timer_data->delay_on;
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}
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led_set_brightness(led_cdev, brightness);
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mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
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}
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static ssize_t led_delay_on_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct timer_trig_data *timer_data = led_cdev->trigger_data;
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sprintf(buf, "%lu\n", timer_data->delay_on);
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return strlen(buf) + 1;
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}
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static ssize_t led_delay_on_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct timer_trig_data *timer_data = led_cdev->trigger_data;
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int ret = -EINVAL;
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char *after;
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unsigned long state = simple_strtoul(buf, &after, 10);
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size_t count = after - buf;
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if (*after && isspace(*after))
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count++;
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if (count == size) {
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if (timer_data->delay_on != state) {
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/* the new value differs from the previous */
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timer_data->delay_on = state;
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/* deactivate previous settings */
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del_timer_sync(&timer_data->timer);
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/* try to activate hardware acceleration, if any */
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if (!led_cdev->blink_set ||
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led_cdev->blink_set(led_cdev,
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&timer_data->delay_on, &timer_data->delay_off)) {
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/* no hardware acceleration, blink via timer */
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mod_timer(&timer_data->timer, jiffies + 1);
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}
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}
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ret = count;
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}
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return ret;
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}
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static ssize_t led_delay_off_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct timer_trig_data *timer_data = led_cdev->trigger_data;
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sprintf(buf, "%lu\n", timer_data->delay_off);
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return strlen(buf) + 1;
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}
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static ssize_t led_delay_off_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct led_classdev *led_cdev = dev_get_drvdata(dev);
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struct timer_trig_data *timer_data = led_cdev->trigger_data;
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int ret = -EINVAL;
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char *after;
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unsigned long state = simple_strtoul(buf, &after, 10);
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size_t count = after - buf;
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if (*after && isspace(*after))
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count++;
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if (count == size) {
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if (timer_data->delay_off != state) {
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/* the new value differs from the previous */
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timer_data->delay_off = state;
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/* deactivate previous settings */
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del_timer_sync(&timer_data->timer);
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/* try to activate hardware acceleration, if any */
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if (!led_cdev->blink_set ||
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led_cdev->blink_set(led_cdev,
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&timer_data->delay_on, &timer_data->delay_off)) {
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/* no hardware acceleration, blink via timer */
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mod_timer(&timer_data->timer, jiffies + 1);
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}
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}
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ret = count;
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}
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return ret;
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}
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static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
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static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
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static void timer_trig_activate(struct led_classdev *led_cdev)
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{
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struct timer_trig_data *timer_data;
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int rc;
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timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
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if (!timer_data)
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return;
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led_cdev->trigger_data = timer_data;
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init_timer(&timer_data->timer);
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timer_data->timer.function = led_timer_function;
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timer_data->timer.data = (unsigned long) led_cdev;
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rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
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if (rc)
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goto err_out;
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rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
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if (rc)
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goto err_out_delayon;
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/* If there is hardware support for blinking, start one
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* user friendly blink rate chosen by the driver.
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*/
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if (led_cdev->blink_set)
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led_cdev->blink_set(led_cdev,
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&timer_data->delay_on, &timer_data->delay_off);
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return;
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err_out_delayon:
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device_remove_file(led_cdev->dev, &dev_attr_delay_on);
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err_out:
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led_cdev->trigger_data = NULL;
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kfree(timer_data);
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}
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static void timer_trig_deactivate(struct led_classdev *led_cdev)
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{
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struct timer_trig_data *timer_data = led_cdev->trigger_data;
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if (timer_data) {
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device_remove_file(led_cdev->dev, &dev_attr_delay_on);
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device_remove_file(led_cdev->dev, &dev_attr_delay_off);
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del_timer_sync(&timer_data->timer);
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kfree(timer_data);
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}
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}
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static struct led_trigger timer_led_trigger = {
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.name = "timer",
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.activate = timer_trig_activate,
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.deactivate = timer_trig_deactivate,
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};
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static int __init timer_trig_init(void)
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{
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return led_trigger_register(&timer_led_trigger);
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}
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static void __exit timer_trig_exit(void)
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{
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led_trigger_unregister(&timer_led_trigger);
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}
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module_init(timer_trig_init);
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module_exit(timer_trig_exit);
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MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
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MODULE_DESCRIPTION("Timer LED trigger");
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MODULE_LICENSE("GPL");
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