diff options
Diffstat (limited to 'drivers/leds')
| -rw-r--r-- | drivers/leds/trigger/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/leds/trigger/Makefile | 1 | ||||
| -rw-r--r-- | drivers/leds/trigger/ledtrig-pattern.c | 411 |
3 files changed, 419 insertions, 0 deletions
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig index 4018af769969..b76fc3cdc8f8 100644 --- a/drivers/leds/trigger/Kconfig +++ b/drivers/leds/trigger/Kconfig @@ -129,4 +129,11 @@ config LEDS_TRIGGER_NETDEV This allows LEDs to be controlled by network device activity. If unsure, say Y. +config LEDS_TRIGGER_PATTERN + tristate "LED Pattern Trigger" + help + This allows LEDs to be controlled by a software or hardware pattern + which is a series of tuples, of brightness and duration (ms). + If unsure, say N + endif # LEDS_TRIGGERS diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile index f3cfe1950538..9bcb64ee8123 100644 --- a/drivers/leds/trigger/Makefile +++ b/drivers/leds/trigger/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT) += ledtrig-transient.o obj-$(CONFIG_LEDS_TRIGGER_CAMERA) += ledtrig-camera.o obj-$(CONFIG_LEDS_TRIGGER_PANIC) += ledtrig-panic.o obj-$(CONFIG_LEDS_TRIGGER_NETDEV) += ledtrig-netdev.o +obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o diff --git a/drivers/leds/trigger/ledtrig-pattern.c b/drivers/leds/trigger/ledtrig-pattern.c new file mode 100644 index 000000000000..ce7acd115dd8 --- /dev/null +++ b/drivers/leds/trigger/ledtrig-pattern.c @@ -0,0 +1,411 @@ +// 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); + + mutex_lock(&data->lock); + + 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)); + + /* 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; + } + + mutex_unlock(&data->lock); +} + +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; + + /* + * Clear previous patterns' performence firstly, and remove the timer + * without mutex lock to avoid dead lock. + */ + del_timer_sync(&data->timer); + + mutex_lock(&data->lock); + + 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 ssize_t pattern_trig_store_patterns(struct led_classdev *led_cdev, + const char *buf, size_t count, + bool hw_pattern) +{ + struct pattern_trig_data *data = led_cdev->trigger_data; + int ccount, cr, offset = 0, err = 0; + + /* + * Clear previous patterns' performence firstly, and remove the timer + * without mutex lock to avoid dead lock. + */ + del_timer_sync(&data->timer); + + mutex_lock(&data->lock); + + if (data->is_hw_pattern) + led_cdev->pattern_clear(led_cdev); + + data->is_hw_pattern = hw_pattern; + data->npatterns = 0; + + while (offset < count - 1 && data->npatterns < MAX_PATTERNS) { + cr = 0; + ccount = sscanf(buf + offset, "%d %u %n", + &data->patterns[data->npatterns].brightness, + &data->patterns[data->npatterns].delta_t, &cr); + if (ccount != 2) { + data->npatterns = 0; + err = -EINVAL; + goto out; + } + + offset += cr; + data->npatterns++; + } + + 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, 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, 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 = container_of(kobj, struct device, 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 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; + + 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"); |