diff options
Diffstat (limited to 'drivers/leds/ledtrig-transient.c')
| -rw-r--r-- | drivers/leds/ledtrig-transient.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/drivers/leds/ledtrig-transient.c b/drivers/leds/ledtrig-transient.c new file mode 100644 index 000000000000..83179f435e1e --- /dev/null +++ b/drivers/leds/ledtrig-transient.c @@ -0,0 +1,237 @@ +/* + * LED Kernel Transient Trigger + * + * Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com> + * + * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's + * ledtrig-heartbeat.c + * Design and use-case input from Jonas Bonn <jonas@southpole.se> and + * Neil Brown <neilb@suse.de> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ +/* + * Transient trigger allows one shot timer activation. Please refer to + * Documentation/leds/ledtrig-transient.txt for details +*/ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/device.h> +#include <linux/slab.h> +#include <linux/timer.h> +#include <linux/leds.h> +#include "leds.h" + +struct transient_trig_data { + int activate; + int state; + int restore_state; + unsigned long duration; + struct timer_list timer; +}; + +static void transient_timer_function(unsigned long data) +{ + struct led_classdev *led_cdev = (struct led_classdev *) data; + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + transient_data->activate = 0; + led_set_brightness(led_cdev, transient_data->restore_state); +} + +static ssize_t transient_activate_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + return sprintf(buf, "%d\n", transient_data->activate); +} + +static ssize_t transient_activate_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + unsigned long state; + ssize_t ret; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + if (state != 1 && state != 0) + return -EINVAL; + + /* cancel the running timer */ + if (state == 0 && transient_data->activate == 1) { + del_timer(&transient_data->timer); + transient_data->activate = state; + led_set_brightness(led_cdev, transient_data->restore_state); + return size; + } + + /* start timer if there is no active timer */ + if (state == 1 && transient_data->activate == 0 && + transient_data->duration != 0) { + transient_data->activate = state; + led_set_brightness(led_cdev, transient_data->state); + transient_data->restore_state = + (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL; + mod_timer(&transient_data->timer, + jiffies + transient_data->duration); + } + + /* state == 0 && transient_data->activate == 0 + timer is not active - just return */ + /* state == 1 && transient_data->activate == 1 + timer is already active - just return */ + + return size; +} + +static ssize_t transient_duration_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + return sprintf(buf, "%lu\n", transient_data->duration); +} + +static ssize_t transient_duration_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + unsigned long state; + ssize_t ret; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + transient_data->duration = state; + return size; +} + +static ssize_t transient_state_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + int state; + + state = (transient_data->state == LED_FULL) ? 1 : 0; + return sprintf(buf, "%d\n", state); +} + +static ssize_t transient_state_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct transient_trig_data *transient_data = led_cdev->trigger_data; + unsigned long state; + ssize_t ret; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + if (state != 1 && state != 0) + return -EINVAL; + + transient_data->state = (state == 1) ? LED_FULL : LED_OFF; + return size; +} + +static DEVICE_ATTR(activate, 0644, transient_activate_show, + transient_activate_store); +static DEVICE_ATTR(duration, 0644, transient_duration_show, + transient_duration_store); +static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store); + +static void transient_trig_activate(struct led_classdev *led_cdev) +{ + int rc; + struct transient_trig_data *tdata; + + tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL); + if (!tdata) { + dev_err(led_cdev->dev, + "unable to allocate transient trigger\n"); + return; + } + led_cdev->trigger_data = tdata; + + rc = device_create_file(led_cdev->dev, &dev_attr_activate); + if (rc) + goto err_out; + + rc = device_create_file(led_cdev->dev, &dev_attr_duration); + if (rc) + goto err_out_duration; + + rc = device_create_file(led_cdev->dev, &dev_attr_state); + if (rc) + goto err_out_state; + + setup_timer(&tdata->timer, transient_timer_function, + (unsigned long) led_cdev); + led_cdev->activated = true; + + return; + +err_out_state: + device_remove_file(led_cdev->dev, &dev_attr_duration); +err_out_duration: + device_remove_file(led_cdev->dev, &dev_attr_activate); +err_out: + dev_err(led_cdev->dev, "unable to register transient trigger\n"); + led_cdev->trigger_data = NULL; + kfree(tdata); +} + +static void transient_trig_deactivate(struct led_classdev *led_cdev) +{ + struct transient_trig_data *transient_data = led_cdev->trigger_data; + + if (led_cdev->activated) { + del_timer_sync(&transient_data->timer); + led_set_brightness(led_cdev, transient_data->restore_state); + device_remove_file(led_cdev->dev, &dev_attr_activate); + device_remove_file(led_cdev->dev, &dev_attr_duration); + device_remove_file(led_cdev->dev, &dev_attr_state); + led_cdev->trigger_data = NULL; + led_cdev->activated = false; + kfree(transient_data); + } +} + +static struct led_trigger transient_trigger = { + .name = "transient", + .activate = transient_trig_activate, + .deactivate = transient_trig_deactivate, +}; + +static int __init transient_trig_init(void) +{ + return led_trigger_register(&transient_trigger); +} + +static void __exit transient_trig_exit(void) +{ + led_trigger_unregister(&transient_trigger); +} + +module_init(transient_trig_init); +module_exit(transient_trig_exit); + +MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>"); +MODULE_DESCRIPTION("Transient LED trigger"); +MODULE_LICENSE("GPL"); |