// 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");