diff options
Diffstat (limited to 'drivers/leds/trigger/ledtrig-transient.c')
| -rw-r--r-- | drivers/leds/trigger/ledtrig-transient.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/drivers/leds/trigger/ledtrig-transient.c b/drivers/leds/trigger/ledtrig-transient.c new file mode 100644 index 000000000..80635183f --- /dev/null +++ b/drivers/leds/trigger/ledtrig-transient.c @@ -0,0 +1,198 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// LED Kernel Transient Trigger +// +// Transient trigger allows one shot timer activation. Please refer to +// Documentation/leds/ledtrig-transient.rst for details +// 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> + +#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; + struct led_classdev *led_cdev; +}; + +static void transient_timer_function(struct timer_list *t) +{ + struct transient_trig_data *transient_data = + from_timer(transient_data, t, timer); + struct led_classdev *led_cdev = transient_data->led_cdev; + + transient_data->activate = 0; + led_set_brightness_nosleep(led_cdev, transient_data->restore_state); +} + +static ssize_t transient_activate_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct transient_trig_data *transient_data = + led_trigger_get_drvdata(dev); + + 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 = led_trigger_get_led(dev); + struct transient_trig_data *transient_data = + led_trigger_get_drvdata(dev); + 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_nosleep(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_nosleep(led_cdev, transient_data->state); + transient_data->restore_state = + (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL; + mod_timer(&transient_data->timer, + jiffies + msecs_to_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 transient_trig_data *transient_data = led_trigger_get_drvdata(dev); + + 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 transient_trig_data *transient_data = + led_trigger_get_drvdata(dev); + 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 transient_trig_data *transient_data = + led_trigger_get_drvdata(dev); + 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 transient_trig_data *transient_data = + led_trigger_get_drvdata(dev); + 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 struct attribute *transient_trig_attrs[] = { + &dev_attr_activate.attr, + &dev_attr_duration.attr, + &dev_attr_state.attr, + NULL +}; +ATTRIBUTE_GROUPS(transient_trig); + +static int transient_trig_activate(struct led_classdev *led_cdev) +{ + struct transient_trig_data *tdata; + + tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL); + if (!tdata) + return -ENOMEM; + + led_set_trigger_data(led_cdev, tdata); + tdata->led_cdev = led_cdev; + + timer_setup(&tdata->timer, transient_timer_function, 0); + + return 0; +} + +static void transient_trig_deactivate(struct led_classdev *led_cdev) +{ + struct transient_trig_data *transient_data = led_get_trigger_data(led_cdev); + + del_timer_sync(&transient_data->timer); + led_set_brightness_nosleep(led_cdev, transient_data->restore_state); + kfree(transient_data); +} + +static struct led_trigger transient_trigger = { + .name = "transient", + .activate = transient_trig_activate, + .deactivate = transient_trig_deactivate, + .groups = transient_trig_groups, +}; +module_led_trigger(transient_trigger); + +MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>"); +MODULE_DESCRIPTION("Transient LED trigger"); +MODULE_LICENSE("GPL v2"); |