@@ -12,6 +12,16 @@ Description:
The exact format is described in:
Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
+What: /sys/class/leds/<led>/hr_pattern
+Date: June 2023
+Description:
+ Specify a software pattern for the LED, that supports altering
+ the brightness for the specified duration with one software
+ timer. It can do gradual dimming and step change of brightness.
+
+ Unlike the /sys/class/leds/<led>/pattern, this attribute runs
+ a pattern on high-resolution timer (hrtimer).
+
What: /sys/class/leds/<led>/hw_pattern
Date: September 2018
KernelVersion: 4.20
@@ -13,6 +13,7 @@
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/timer.h>
+#include <linux/hrtimer.h>
#define MAX_PATTERNS 1024
/*
@@ -21,6 +22,12 @@
*/
#define UPDATE_INTERVAL 50
+enum pattern_type {
+ PATTERN_TYPE_SW, /* Use standard timer for software pattern */
+ PATTERN_TYPE_HR, /* Use hrtimer for software pattern */
+ PATTERN_TYPE_HW, /* Hardware pattern */
+};
+
struct pattern_trig_data {
struct led_classdev *led_cdev;
struct led_pattern patterns[MAX_PATTERNS];
@@ -32,8 +39,9 @@ struct pattern_trig_data {
int last_repeat;
int delta_t;
bool is_indefinite;
- bool is_hw_pattern;
+ enum pattern_type type;
struct timer_list timer;
+ struct hrtimer hrtimer;
};
static void pattern_trig_update_patterns(struct pattern_trig_data *data)
@@ -71,10 +79,35 @@ static int pattern_trig_compute_brightness(struct pattern_trig_data *data)
return data->curr->brightness - step_brightness;
}
-static void pattern_trig_timer_function(struct timer_list *t)
+static void pattern_trig_timer_start(struct pattern_trig_data *data)
{
- struct pattern_trig_data *data = from_timer(data, t, timer);
+ if (data->type == PATTERN_TYPE_HR) {
+ hrtimer_start(&data->hrtimer, ns_to_ktime(0), HRTIMER_MODE_REL);
+ } else {
+ data->timer.expires = jiffies;
+ add_timer(&data->timer);
+ }
+}
+static void pattern_trig_timer_cancel(struct pattern_trig_data *data)
+{
+ if (data->type == PATTERN_TYPE_HR)
+ hrtimer_cancel(&data->hrtimer);
+ else
+ del_timer_sync(&data->timer);
+}
+
+static void pattern_trig_timer_restart(struct pattern_trig_data *data,
+ unsigned long interval)
+{
+ if (data->type == PATTERN_TYPE_HR)
+ hrtimer_forward_now(&data->hrtimer, ms_to_ktime(interval));
+ else
+ mod_timer(&data->timer, jiffies + msecs_to_jiffies(interval));
+}
+
+static void pattern_trig_timer_common_function(struct pattern_trig_data *data)
+{
for (;;) {
if (!data->is_indefinite && !data->repeat)
break;
@@ -83,8 +116,7 @@ static void pattern_trig_timer_function(struct timer_list *t)
/* 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));
+ pattern_trig_timer_restart(data, data->curr->delta_t);
if (!data->next->delta_t) {
/* Skip the tuple with zero duration */
pattern_trig_update_patterns(data);
@@ -106,8 +138,7 @@ static void pattern_trig_timer_function(struct timer_list *t)
led_set_brightness(data->led_cdev,
pattern_trig_compute_brightness(data));
- mod_timer(&data->timer,
- jiffies + msecs_to_jiffies(UPDATE_INTERVAL));
+ pattern_trig_timer_restart(data, UPDATE_INTERVAL);
/* Accumulate the gradual dimming time */
data->delta_t += UPDATE_INTERVAL;
@@ -117,6 +148,25 @@ static void pattern_trig_timer_function(struct timer_list *t)
}
}
+static void pattern_trig_timer_function(struct timer_list *t)
+{
+ struct pattern_trig_data *data = from_timer(data, t, timer);
+
+ return pattern_trig_timer_common_function(data);
+}
+
+static enum hrtimer_restart pattern_trig_hrtimer_function(struct hrtimer *t)
+{
+ struct pattern_trig_data *data =
+ container_of(t, struct pattern_trig_data, hrtimer);
+
+ pattern_trig_timer_common_function(data);
+ if (!data->is_indefinite && !data->repeat)
+ return HRTIMER_NORESTART;
+
+ return HRTIMER_RESTART;
+}
+
static int pattern_trig_start_pattern(struct led_classdev *led_cdev)
{
struct pattern_trig_data *data = led_cdev->trigger_data;
@@ -124,7 +174,7 @@ static int pattern_trig_start_pattern(struct led_classdev *led_cdev)
if (!data->npatterns)
return 0;
- if (data->is_hw_pattern) {
+ if (data->type == PATTERN_TYPE_HW) {
return led_cdev->pattern_set(led_cdev, data->patterns,
data->npatterns, data->repeat);
}
@@ -136,8 +186,7 @@ static int pattern_trig_start_pattern(struct led_classdev *led_cdev)
data->delta_t = 0;
data->curr = data->patterns;
data->next = data->patterns + 1;
- data->timer.expires = jiffies;
- add_timer(&data->timer);
+ pattern_trig_timer_start(data);
return 0;
}
@@ -175,9 +224,9 @@ static ssize_t repeat_store(struct device *dev, struct device_attribute *attr,
mutex_lock(&data->lock);
- del_timer_sync(&data->timer);
+ pattern_trig_timer_cancel(data);
- if (data->is_hw_pattern)
+ if (data->type == PATTERN_TYPE_HW)
led_cdev->pattern_clear(led_cdev);
data->last_repeat = data->repeat = res;
@@ -196,14 +245,14 @@ static ssize_t repeat_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_RW(repeat);
static ssize_t pattern_trig_show_patterns(struct pattern_trig_data *data,
- char *buf, bool hw_pattern)
+ char *buf, enum pattern_type type)
{
ssize_t count = 0;
int i;
mutex_lock(&data->lock);
- if (!data->npatterns || (data->is_hw_pattern ^ hw_pattern))
+ if (!data->npatterns || data->type != type)
goto out;
for (i = 0; i < data->npatterns; i++) {
@@ -260,19 +309,19 @@ static int pattern_trig_store_patterns_int(struct pattern_trig_data *data,
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)
+ size_t count, enum pattern_type type)
{
struct pattern_trig_data *data = led_cdev->trigger_data;
int err = 0;
mutex_lock(&data->lock);
- del_timer_sync(&data->timer);
+ pattern_trig_timer_cancel(data);
- if (data->is_hw_pattern)
+ if (data->type == PATTERN_TYPE_HW)
led_cdev->pattern_clear(led_cdev);
- data->is_hw_pattern = hw_pattern;
+ data->type = type;
data->npatterns = 0;
if (buf)
@@ -297,7 +346,7 @@ static ssize_t pattern_show(struct device *dev, struct device_attribute *attr,
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);
+ return pattern_trig_show_patterns(data, buf, PATTERN_TYPE_SW);
}
static ssize_t pattern_store(struct device *dev, struct device_attribute *attr,
@@ -305,7 +354,8 @@ static ssize_t pattern_store(struct device *dev, struct device_attribute *attr,
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
- return pattern_trig_store_patterns(led_cdev, buf, NULL, count, false);
+ return pattern_trig_store_patterns(led_cdev, buf, NULL, count,
+ PATTERN_TYPE_SW);
}
static DEVICE_ATTR_RW(pattern);
@@ -316,7 +366,7 @@ static ssize_t hw_pattern_show(struct device *dev,
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);
+ return pattern_trig_show_patterns(data, buf, PATTERN_TYPE_HW);
}
static ssize_t hw_pattern_store(struct device *dev,
@@ -325,11 +375,33 @@ static ssize_t hw_pattern_store(struct device *dev,
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
- return pattern_trig_store_patterns(led_cdev, buf, NULL, count, true);
+ return pattern_trig_store_patterns(led_cdev, buf, NULL, count,
+ PATTERN_TYPE_HW);
}
static DEVICE_ATTR_RW(hw_pattern);
+static ssize_t hr_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, PATTERN_TYPE_HR);
+}
+
+static ssize_t hr_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,
+ PATTERN_TYPE_HR);
+}
+
+static DEVICE_ATTR_RW(hr_pattern);
+
static umode_t pattern_trig_attrs_mode(struct kobject *kobj,
struct attribute *attr, int index)
{
@@ -338,6 +410,8 @@ static umode_t pattern_trig_attrs_mode(struct kobject *kobj,
if (attr == &dev_attr_repeat.attr || attr == &dev_attr_pattern.attr)
return attr->mode;
+ else if (attr == &dev_attr_hr_pattern.attr)
+ return attr->mode;
else if (attr == &dev_attr_hw_pattern.attr && led_cdev->pattern_set)
return attr->mode;
@@ -347,6 +421,7 @@ static umode_t pattern_trig_attrs_mode(struct kobject *kobj,
static struct attribute *pattern_trig_attrs[] = {
&dev_attr_pattern.attr,
&dev_attr_hw_pattern.attr,
+ &dev_attr_hr_pattern.attr,
&dev_attr_repeat.attr,
NULL
};
@@ -376,7 +451,8 @@ static void pattern_init(struct led_classdev *led_cdev)
goto out;
}
- err = pattern_trig_store_patterns(led_cdev, NULL, pattern, size, false);
+ err = pattern_trig_store_patterns(led_cdev, NULL, pattern, size,
+ PATTERN_TYPE_SW);
if (err < 0)
dev_warn(led_cdev->dev,
"Pattern initialization failed with error %d\n", err);
@@ -400,12 +476,15 @@ static int pattern_trig_activate(struct led_classdev *led_cdev)
led_cdev->pattern_clear = NULL;
}
+ data->type = PATTERN_TYPE_SW;
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);
+ hrtimer_init(&data->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ data->hrtimer.function = pattern_trig_hrtimer_function;
led_cdev->activated = true;
if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
@@ -431,6 +510,7 @@ static void pattern_trig_deactivate(struct led_classdev *led_cdev)
led_cdev->pattern_clear(led_cdev);
timer_shutdown_sync(&data->timer);
+ hrtimer_cancel(&data->hrtimer);
led_set_brightness(led_cdev, LED_OFF);
kfree(data);