1 files changed, 463 insertions, 0 deletions

diff --git a/drivers/leds/trigger/ledtrig-pattern.c b/drivers/leds/trigger/ledtrig-pattern.c
new file mode 100644
index 000000000..43a265dc4
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-pattern.c
@@ -0,0 +1,463 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * LED pattern trigger
+ *
+ * Idea discussed with Pavel Machek. Raphael Teysseyre implemented
+ * the first version, Baolin Wang simplified and improved the approach.
+ */
+
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+
+#define MAX_PATTERNS		1024
+/*
+ * When doing gradual dimming, the led brightness will be updated
+ * every 50 milliseconds.
+ */
+#define UPDATE_INTERVAL		50
+
+struct pattern_trig_data {
+	struct led_classdev *led_cdev;
+	struct led_pattern patterns[MAX_PATTERNS];
+	struct led_pattern *curr;
+	struct led_pattern *next;
+	struct mutex lock;
+	u32 npatterns;
+	int repeat;
+	int last_repeat;
+	int delta_t;
+	bool is_indefinite;
+	bool is_hw_pattern;
+	struct timer_list timer;
+};
+
+static void pattern_trig_update_patterns(struct pattern_trig_data *data)
+{
+	data->curr = data->next;
+	if (!data->is_indefinite && data->curr == data->patterns)
+		data->repeat--;
+
+	if (data->next == data->patterns + data->npatterns - 1)
+		data->next = data->patterns;
+	else
+		data->next++;
+
+	data->delta_t = 0;
+}
+
+static int pattern_trig_compute_brightness(struct pattern_trig_data *data)
+{
+	int step_brightness;
+
+	/*
+	 * If current tuple's duration is less than the dimming interval,
+	 * we should treat it as a step change of brightness instead of
+	 * doing gradual dimming.
+	 */
+	if (data->delta_t == 0 || data->curr->delta_t < UPDATE_INTERVAL)
+		return data->curr->brightness;
+
+	step_brightness = abs(data->next->brightness - data->curr->brightness);
+	step_brightness = data->delta_t * step_brightness / data->curr->delta_t;
+
+	if (data->next->brightness > data->curr->brightness)
+		return data->curr->brightness + step_brightness;
+	else
+		return data->curr->brightness - step_brightness;
+}
+
+static void pattern_trig_timer_function(struct timer_list *t)
+{
+	struct pattern_trig_data *data = from_timer(data, t, timer);
+
+	for (;;) {
+		if (!data->is_indefinite && !data->repeat)
+			break;
+
+		if (data->curr->brightness == data->next->brightness) {
+			/* Step change of brightness */
+			led_set_brightness(data->led_cdev,
+					   data->curr->brightness);
+			mod_timer(&data->timer,
+				  jiffies + msecs_to_jiffies(data->curr->delta_t));
+			if (!data->next->delta_t) {
+				/* Skip the tuple with zero duration */
+				pattern_trig_update_patterns(data);
+			}
+			/* Select next tuple */
+			pattern_trig_update_patterns(data);
+		} else {
+			/* Gradual dimming */
+
+			/*
+			 * If the accumulation time is larger than current
+			 * tuple's duration, we should go next one and re-check
+			 * if we repeated done.
+			 */
+			if (data->delta_t > data->curr->delta_t) {
+				pattern_trig_update_patterns(data);
+				continue;
+			}
+
+			led_set_brightness(data->led_cdev,
+					   pattern_trig_compute_brightness(data));
+			mod_timer(&data->timer,
+				  jiffies + msecs_to_jiffies(UPDATE_INTERVAL));
+
+			/* Accumulate the gradual dimming time */
+			data->delta_t += UPDATE_INTERVAL;
+		}
+
+		break;
+	}
+}
+
+static int pattern_trig_start_pattern(struct led_classdev *led_cdev)
+{
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+
+	if (!data->npatterns)
+		return 0;
+
+	if (data->is_hw_pattern) {
+		return led_cdev->pattern_set(led_cdev, data->patterns,
+					     data->npatterns, data->repeat);
+	}
+
+	/* At least 2 tuples for software pattern. */
+	if (data->npatterns < 2)
+		return -EINVAL;
+
+	data->delta_t = 0;
+	data->curr = data->patterns;
+	data->next = data->patterns + 1;
+	data->timer.expires = jiffies;
+	add_timer(&data->timer);
+
+	return 0;
+}
+
+static ssize_t repeat_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+	int repeat;
+
+	mutex_lock(&data->lock);
+
+	repeat = data->last_repeat;
+
+	mutex_unlock(&data->lock);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", repeat);
+}
+
+static ssize_t repeat_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+	int err, res;
+
+	err = kstrtos32(buf, 10, &res);
+	if (err)
+		return err;
+
+	/* Number 0 and negative numbers except -1 are invalid. */
+	if (res < -1 || res == 0)
+		return -EINVAL;
+
+	mutex_lock(&data->lock);
+
+	del_timer_sync(&data->timer);
+
+	if (data->is_hw_pattern)
+		led_cdev->pattern_clear(led_cdev);
+
+	data->last_repeat = data->repeat = res;
+	/* -1 means repeat indefinitely */
+	if (data->repeat == -1)
+		data->is_indefinite = true;
+	else
+		data->is_indefinite = false;
+
+	err = pattern_trig_start_pattern(led_cdev);
+
+	mutex_unlock(&data->lock);
+	return err < 0 ? err : count;
+}
+
+static DEVICE_ATTR_RW(repeat);
+
+static ssize_t pattern_trig_show_patterns(struct pattern_trig_data *data,
+					  char *buf, bool hw_pattern)
+{
+	ssize_t count = 0;
+	int i;
+
+	mutex_lock(&data->lock);
+
+	if (!data->npatterns || (data->is_hw_pattern ^ hw_pattern))
+		goto out;
+
+	for (i = 0; i < data->npatterns; i++) {
+		count += scnprintf(buf + count, PAGE_SIZE - count,
+				   "%d %u ",
+				   data->patterns[i].brightness,
+				   data->patterns[i].delta_t);
+	}
+
+	buf[count - 1] = '\n';
+
+out:
+	mutex_unlock(&data->lock);
+	return count;
+}
+
+static int pattern_trig_store_patterns_string(struct pattern_trig_data *data,
+					      const char *buf, size_t count)
+{
+	int ccount, cr, offset = 0;
+
+	while (offset < count - 1 && data->npatterns < MAX_PATTERNS) {
+		cr = 0;
+		ccount = sscanf(buf + offset, "%u %u %n",
+				&data->patterns[data->npatterns].brightness,
+				&data->patterns[data->npatterns].delta_t, &cr);
+
+		if (ccount != 2 ||
+		    data->patterns[data->npatterns].brightness > data->led_cdev->max_brightness) {
+			data->npatterns = 0;
+			return -EINVAL;
+		}
+
+		offset += cr;
+		data->npatterns++;
+	}
+
+	return 0;
+}
+
+static int pattern_trig_store_patterns_int(struct pattern_trig_data *data,
+					   const u32 *buf, size_t count)
+{
+	unsigned int i;
+
+	for (i = 0; i < count; i += 2) {
+		data->patterns[data->npatterns].brightness = buf[i];
+		data->patterns[data->npatterns].delta_t = buf[i + 1];
+		data->npatterns++;
+	}
+
+	return 0;
+}
+
+static ssize_t pattern_trig_store_patterns(struct led_classdev *led_cdev,
+					   const char *buf, const u32 *buf_int,
+					   size_t count, bool hw_pattern)
+{
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+	int err = 0;
+
+	mutex_lock(&data->lock);
+
+	del_timer_sync(&data->timer);
+
+	if (data->is_hw_pattern)
+		led_cdev->pattern_clear(led_cdev);
+
+	data->is_hw_pattern = hw_pattern;
+	data->npatterns = 0;
+
+	if (buf)
+		err = pattern_trig_store_patterns_string(data, buf, count);
+	else
+		err = pattern_trig_store_patterns_int(data, buf_int, count);
+	if (err)
+		goto out;
+
+	err = pattern_trig_start_pattern(led_cdev);
+	if (err)
+		data->npatterns = 0;
+
+out:
+	mutex_unlock(&data->lock);
+	return err < 0 ? err : count;
+}
+
+static ssize_t pattern_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+
+	return pattern_trig_show_patterns(data, buf, false);
+}
+
+static ssize_t pattern_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+	return pattern_trig_store_patterns(led_cdev, buf, NULL, count, false);
+}
+
+static DEVICE_ATTR_RW(pattern);
+
+static ssize_t hw_pattern_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+
+	return pattern_trig_show_patterns(data, buf, true);
+}
+
+static ssize_t hw_pattern_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+	return pattern_trig_store_patterns(led_cdev, buf, NULL, count, true);
+}
+
+static DEVICE_ATTR_RW(hw_pattern);
+
+static umode_t pattern_trig_attrs_mode(struct kobject *kobj,
+				       struct attribute *attr, int index)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+	if (attr == &dev_attr_repeat.attr || attr == &dev_attr_pattern.attr)
+		return attr->mode;
+	else if (attr == &dev_attr_hw_pattern.attr && led_cdev->pattern_set)
+		return attr->mode;
+
+	return 0;
+}
+
+static struct attribute *pattern_trig_attrs[] = {
+	&dev_attr_pattern.attr,
+	&dev_attr_hw_pattern.attr,
+	&dev_attr_repeat.attr,
+	NULL
+};
+
+static const struct attribute_group pattern_trig_group = {
+	.attrs = pattern_trig_attrs,
+	.is_visible = pattern_trig_attrs_mode,
+};
+
+static const struct attribute_group *pattern_trig_groups[] = {
+	&pattern_trig_group,
+	NULL,
+};
+
+static void pattern_init(struct led_classdev *led_cdev)
+{
+	unsigned int size = 0;
+	u32 *pattern;
+	int err;
+
+	pattern = led_get_default_pattern(led_cdev, &size);
+	if (!pattern)
+		return;
+
+	if (size % 2) {
+		dev_warn(led_cdev->dev, "Expected pattern of tuples\n");
+		goto out;
+	}
+
+	err = pattern_trig_store_patterns(led_cdev, NULL, pattern, size, false);
+	if (err < 0)
+		dev_warn(led_cdev->dev,
+			 "Pattern initialization failed with error %d\n", err);
+
+out:
+	kfree(pattern);
+}
+
+static int pattern_trig_activate(struct led_classdev *led_cdev)
+{
+	struct pattern_trig_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	if (!!led_cdev->pattern_set ^ !!led_cdev->pattern_clear) {
+		dev_warn(led_cdev->dev,
+			 "Hardware pattern ops validation failed\n");
+		led_cdev->pattern_set = NULL;
+		led_cdev->pattern_clear = NULL;
+	}
+
+	data->is_indefinite = true;
+	data->last_repeat = -1;
+	mutex_init(&data->lock);
+	data->led_cdev = led_cdev;
+	led_set_trigger_data(led_cdev, data);
+	timer_setup(&data->timer, pattern_trig_timer_function, 0);
+	led_cdev->activated = true;
+
+	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
+		pattern_init(led_cdev);
+		/*
+		 * Mark as initialized even on pattern_init() error because
+		 * any consecutive call to it would produce the same error.
+		 */
+		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
+	}
+
+	return 0;
+}
+
+static void pattern_trig_deactivate(struct led_classdev *led_cdev)
+{
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+
+	if (!led_cdev->activated)
+		return;
+
+	if (led_cdev->pattern_clear)
+		led_cdev->pattern_clear(led_cdev);
+
+	del_timer_sync(&data->timer);
+
+	led_set_brightness(led_cdev, LED_OFF);
+	kfree(data);
+	led_cdev->activated = false;
+}
+
+static struct led_trigger pattern_led_trigger = {
+	.name = "pattern",
+	.activate = pattern_trig_activate,
+	.deactivate = pattern_trig_deactivate,
+	.groups = pattern_trig_groups,
+};
+
+static int __init pattern_trig_init(void)
+{
+	return led_trigger_register(&pattern_led_trigger);
+}
+
+static void __exit pattern_trig_exit(void)
+{
+	led_trigger_unregister(&pattern_led_trigger);
+}
+
+module_init(pattern_trig_init);
+module_exit(pattern_trig_exit);
+
+MODULE_AUTHOR("Raphael Teysseyre <rteysseyre@gmail.com>");
+MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
+MODULE_DESCRIPTION("LED Pattern trigger");
+MODULE_LICENSE("GPL v2");