summaryrefslogtreecommitdiffstats
path: root/drivers/leds/trigger/ledtrig-transient.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/leds/trigger/ledtrig-transient.c')
-rw-r--r--drivers/leds/trigger/ledtrig-transient.c198
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 0000000000..f111fa7635
--- /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);
+
+ timer_shutdown_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");