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Date:   Tue, 24 Jul 2018 13:41:47 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Baolin Wang <baolin.wang@linaro.org>
Cc:     Jacek Anaszewski <jacek.anaszewski@gmail.com>,
        David Lechner <david@lechnology.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        Linux LED Subsystem <linux-leds@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] leds: core: Introduce generic pattern interface
Message-ID: <20180724114147.GA26036@amd>
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Hi!

> >> > >Please keep in mind that this is ABI documentation for the pattern =
file
> >> > >to be exposed by LED core, and not by the pattern trigger, that, as=
 we
> >> > >agreed, will be implemented later. In this case, I'd go for
> >> >
> >> > Gosh, I got completely distracted by the recent discussion about
> >> > pattern synchronization.
> >> >
> >> > So, to recap, we need to decide if we are taking Baolin's solution
> >> > or we're opting for implementing pattern trigger.
> >> >
> >> > If we choose the latter, then we will also need some software
> >> > pattern engine in the trigger, to be applied as a software pattern
> >> > fallback for the devices without hardware pattern support.
> >> > It will certainly delay the contribution process, provided that Baol=
in
> >> > would find time for this work at all.
> >>
> >> I'd recommend the latter. Yes, software pattern as a fallback would be
> >> nice, but I have that code already... let me get it back to running
> >> state, and figure out where to add interface for "hardware
> >> acceleration". I'd like to have same interface to userland, whether
> >> pattern can be done by hardware or by software.
> >
> > For the record, I'd like something like this. (Software pattern should
> > work. Hardware pattern... needs more work).
>=20
> Thanks for showing your thoughts. But I failed to compile your code,
> would you like to send out formal patches (Or only including software
> pattern, I will help to add hardware pattern part and do some testing
> with our driver)? Thanks.

This should be a bit better. I attempted to compile it with your
driver, but whether it works is an open question.

Signed-off-by: Pavel Machek <pavel@ucw.cz>


diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-blt=
c.c
index 9d9b7aa..898f92d 100644
--- a/drivers/leds/leds-sc27xx-bltc.c
+++ b/drivers/leds/leds-sc27xx-bltc.c
@@ -6,6 +6,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <linux/slab.h>
 #include <uapi/linux/uleds.h>
=20
 /* PMIC global control register definition */
@@ -32,8 +33,13 @@
 #define SC27XX_DUTY_MASK	GENMASK(15, 0)
 #define SC27XX_MOD_MASK		GENMASK(7, 0)
=20
+#define SC27XX_CURVE_SHIFT	8
+#define SC27XX_CURVE_L_MASK	GENMASK(7, 0)
+#define SC27XX_CURVE_H_MASK	GENMASK(15, 8)
+
 #define SC27XX_LEDS_OFFSET	0x10
 #define SC27XX_LEDS_MAX		3
+#define SC27XX_LEDS_PATTERN_CNT	4
=20
 struct sc27xx_led {
 	char name[LED_MAX_NAME_SIZE];
@@ -122,6 +128,157 @@ static int sc27xx_led_set(struct led_classdev *ldev, =
enum led_brightness value)
 	return err;
 }
=20
+static int sc27xx_led_pattern_clear(struct led_classdev *ldev)
+{
+	struct sc27xx_led *leds =3D to_sc27xx_led(ldev);
+	struct regmap *regmap =3D leds->priv->regmap;
+	u32 base =3D sc27xx_led_get_offset(leds);
+	u32 ctrl_base =3D leds->priv->base + SC27XX_LEDS_CTRL;
+	u8 ctrl_shift =3D SC27XX_CTRL_SHIFT * leds->line;
+	int err;
+
+	mutex_lock(&leds->priv->lock);
+
+	/* Reset the rise, high, fall and low time to zero. */
+	regmap_write(regmap, base + SC27XX_LEDS_CURVE0, 0);
+	regmap_write(regmap, base + SC27XX_LEDS_CURVE1, 0);
+
+	err =3D regmap_update_bits(regmap, ctrl_base,
+			(SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
+
+	mutex_unlock(&leds->priv->lock);
+
+	return err;
+}
+
+static int sc27xx_led_pattern_set(struct led_classdev *ldev,
+				  struct led_pattern *pattern,
+				  int len)
+{
+	struct sc27xx_led *leds =3D to_sc27xx_led(ldev);
+	u32 base =3D sc27xx_led_get_offset(leds);
+	u32 ctrl_base =3D leds->priv->base + SC27XX_LEDS_CTRL;
+	u8 ctrl_shift =3D SC27XX_CTRL_SHIFT * leds->line;
+	struct regmap *regmap =3D leds->priv->regmap;
+	int err;
+
+	/*
+	 * Must contain 4 patterns to configure the rise time, high time, fall
+	 * time and low time to enable the breathing mode.
+	 */
+	if (len !=3D SC27XX_LEDS_PATTERN_CNT)
+		return -EINVAL;
+
+	mutex_lock(&leds->priv->lock);
+
+	err =3D regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+				 SC27XX_CURVE_L_MASK, pattern[0].delta_t);
+	if (err)
+		goto out;
+
+	err =3D regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+				 SC27XX_CURVE_L_MASK, pattern[1].delta_t);
+	if (err)
+		goto out;
+
+	err =3D regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+				 SC27XX_CURVE_H_MASK,
+				 pattern[2].delta_t << SC27XX_CURVE_SHIFT);
+	if (err)
+		goto out;
+
+
+	err =3D regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+				 SC27XX_CURVE_H_MASK,
+				 pattern[3].delta_t << SC27XX_CURVE_SHIFT);
+	if (err)
+		goto out;
+
+
+	err =3D regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
+				 SC27XX_DUTY_MASK,
+				 (pattern[0].brightness << SC27XX_DUTY_SHIFT) |
+				 SC27XX_MOD_MASK);
+	if (err)
+		goto out;
+
+	/* Enable the LED breathing mode */
+	err =3D regmap_update_bits(regmap, ctrl_base,
+				 SC27XX_LED_RUN << ctrl_shift,
+				 SC27XX_LED_RUN << ctrl_shift);
+
+out:
+	mutex_unlock(&leds->priv->lock);
+
+	return err;
+}
+
+static struct led_pattern *sc27xx_led_pattern_get(struct led_classdev *lde=
v,
+						  int *len)
+{
+	struct sc27xx_led *leds =3D to_sc27xx_led(ldev);
+	u32 base =3D sc27xx_led_get_offset(leds);
+	struct regmap *regmap =3D leds->priv->regmap;
+	struct led_pattern *pattern;
+	int i, err;
+	u32 val;
+
+	/*
+	 * Must allocate 4 patterns to show the rise time, high time, fall time
+	 * and low time.
+	 */
+	pattern =3D kcalloc(SC27XX_LEDS_PATTERN_CNT, sizeof(*pattern),
+			  GFP_KERNEL);
+	if (!pattern)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&leds->priv->lock);
+
+	err =3D regmap_read(regmap, base + SC27XX_LEDS_CURVE0, &val);
+	if (err)
+		goto out;
+
+	pattern[0].delta_t =3D val & SC27XX_CURVE_L_MASK;
+
+	err =3D regmap_read(regmap, base + SC27XX_LEDS_CURVE1, &val);
+	if (err)
+		goto out;
+
+	pattern[1].delta_t =3D val & SC27XX_CURVE_L_MASK;
+
+	err =3D regmap_read(regmap, base + SC27XX_LEDS_CURVE0, &val);
+	if (err)
+		goto out;
+
+	pattern[2].delta_t =3D (val & SC27XX_CURVE_H_MASK) >> SC27XX_CURVE_SHIFT;
+
+	err =3D regmap_read(regmap, base + SC27XX_LEDS_CURVE1, &val);
+	if (err)
+		goto out;
+
+	pattern[3].delta_t =3D (val & SC27XX_CURVE_H_MASK) >> SC27XX_CURVE_SHIFT;
+
+	err =3D regmap_read(regmap, base + SC27XX_LEDS_DUTY, &val);
+	if (err)
+		goto out;
+
+	mutex_unlock(&leds->priv->lock);
+
+	val =3D (val & SC27XX_DUTY_MASK) >> SC27XX_DUTY_SHIFT;
+	for (i =3D 0; i < SC27XX_LEDS_PATTERN_CNT; i++)
+		pattern[i].brightness =3D val;
+
+	*len =3D SC27XX_LEDS_PATTERN_CNT;
+
+	return pattern;
+
+out:
+	mutex_unlock(&leds->priv->lock);
+	kfree(pattern);
+
+	return ERR_PTR(err);
+}
+
 static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv =
*priv)
 {
 	int i, err;
@@ -140,6 +297,9 @@ static int sc27xx_led_register(struct device *dev, stru=
ct sc27xx_led_priv *priv)
 		led->priv =3D priv;
 		led->ldev.name =3D led->name;
 		led->ldev.brightness_set_blocking =3D sc27xx_led_set;
+		led->ldev.pattern_set =3D sc27xx_led_pattern_set;
+		led->ldev.pattern_get =3D sc27xx_led_pattern_get;
+		led->ldev.pattern_clear =3D sc27xx_led_pattern_clear;
=20
 		err =3D devm_led_classdev_register(dev, &led->ldev);
 		if (err)
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index a2559b4..91ae5b0 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -125,6 +125,16 @@ config LEDS_TRIGGER_CAMERA
 	  This enables direct flash/torch on/off by the driver, kernel space.
 	  If unsure, say Y.
=20
+config LEDS_TRIGGER_PATTERN
+	tristate "LED Pattern Trigger"
+	depends on LEDS_TRIGGERS
+	help
+	  This allows LEDs blinking with an arbitrary pattern. Can be useful
+	  on embedded systems with no screen to give out a status code to
+	  a human.
+
+	  If unsure, say N
+
 config LEDS_TRIGGER_PANIC
 	bool "LED Panic Trigger"
 	depends on LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index f3cfe19..ba6f3b9 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -11,5 +11,6 @@ obj-$(CONFIG_LEDS_TRIGGER_ACTIVITY)	+=3D ledtrig-activity=
=2Eo
 obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)	+=3D ledtrig-default-on.o
 obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)	+=3D ledtrig-transient.o
 obj-$(CONFIG_LEDS_TRIGGER_CAMERA)	+=3D ledtrig-camera.o
+obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+=3D ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_PANIC)	+=3D ledtrig-panic.o
 obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+=3D ledtrig-netdev.o
diff --git a/drivers/leds/trigger/ledtrig-pattern.c b/drivers/leds/trigger/=
ledtrig-pattern.c
new file mode 100644
index 0000000..3dab050
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-pattern.c
@@ -0,0 +1,395 @@
+/*
+ * Arbitrary pattern trigger
+ *
+ * Copyright 2015, Epsiline
+ *
+ * Author : Rapha=EBl Teysseyre <rteysseyre@gmail.com>
+ *
+ * Idea discussed with Pavel Machek <pavel@ucw.cz> on
+ * <linux-leds@vger.kernel.org> (march 2015, thread title
+ * [PATCH RFC] leds: Add status code trigger)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/timer.h>
+#include "../leds.h"
+
+struct pattern_trig_data {
+	struct led_classdev *led_cdev;
+
+	struct led_pattern *steps; /* Array describing the pattern */
+	struct mutex lock;
+	char is_sane;
+	struct led_pattern *curr;
+	struct led_pattern *next;
+	int delta_t; /* Time in current step */
+	int nsteps;  /* Number of steps */
+	int repeat;  /* < 0 means repeat indefinitely */
+	struct timer_list timer;
+};
+
+#define MAX_NSTEPS (PAGE_SIZE/4)
+/* The "pattern" attribute contains at most PAGE_SIZE characters.
+   Each line in this attribute is at least 4 characters long
+   (a 1-digit number for the led brighntess, a space,
+   a 1-digit number for the time, a semi-colon).
+   Therefore, there is at most PAGE_SIZE/4 steps. */
+
+#define UPDATE_INTERVAL 50
+/* When doing gradual dimming, the led brightness
+   will be updated every UPDATE_INTERVAL milliseconds */
+
+#define PATTERN_SEPARATOR ","
+
+static int pattern_trig_initialize_data(struct pattern_trig_data *data)
+{
+	mutex_init(&data->lock);
+	mutex_lock(&data->lock);
+
+	data->is_sane =3D 0;
+	data->steps =3D kzalloc(MAX_NSTEPS*sizeof(struct led_pattern),
+			GFP_KERNEL);
+	if (!data->steps)
+		return -ENOMEM;
+
+	data->curr =3D NULL;
+	data->next =3D NULL;
+	data->delta_t =3D 0;
+	data->nsteps =3D 0;
+	data->repeat =3D -1;
+	//data->timer =3D __TIMER_INITIALIZER(NULL, 0);
+
+	mutex_unlock(&data->lock);
+	return 0;
+}
+
+static void pattern_trig_clear_data(struct pattern_trig_data *data)
+{
+	data->is_sane =3D 0;
+	kfree(data->steps);
+}
+
+/*
+ *  is_sane : pattern checking.
+ *  A pattern satisfying these three conditions is reported as sane :
+ *    - At least two steps
+ *    - At least one step with time >=3D UPDATE_INTERVAL
+ *    - At least two steps with differing brightnesses
+ *  When @data isn't sane, a sensible brightness
+ *  default is suggested in @brightness
+ *
+ * DO NOT call pattern_trig_update on a not-sane pattern,
+ * you'll be punished with an infinite loop in the kernel.
+ */
+static int is_sane(struct pattern_trig_data *data, int *brightness)
+{
+	int i;
+	char stept_ok =3D 0;
+	char stepb_ok =3D 0;
+
+	*brightness =3D 0;
+	if (data->nsteps < 1)
+		return 0;
+
+	*brightness =3D data->steps[0].brightness;
+	if (data->nsteps < 2)
+		return 0;
+
+	for (i =3D 0; i < data->nsteps; i++) {
+		if (data->steps[i].delta_t >=3D UPDATE_INTERVAL) {
+			/* FIXME: this is wrong */
+			if (stepb_ok)
+				return 1;
+			stept_ok =3D 1;
+		}
+		if (data->steps[i].brightness !=3D data->steps[0].brightness) {
+			if (stept_ok)
+				return 1;
+			stepb_ok =3D 1;
+		}
+	}
+
+	return 0;
+}
+
+static void reset_pattern(struct pattern_trig_data *data,
+			struct led_classdev *led_cdev)
+{
+	int brightness;
+
+	if (led_cdev->pattern_clear) {
+		led_cdev->pattern_clear(led_cdev);
+	}
+
+	del_timer_sync(&data->timer);
+
+	if (led_cdev->pattern_set && led_cdev->pattern_set(led_cdev, data->steps,=
 data->nsteps)) {
+		return;
+	}
+
+	if (!is_sane(data, &brightness)) {
+		led_set_brightness(led_cdev, brightness);
+		return;
+	}
+
+	data->curr =3D data->steps;
+	data->next =3D data->steps + 1;
+	data->delta_t =3D 0;
+	data->is_sane =3D 1;
+
+	data->timer.expires =3D jiffies;
+	add_timer(&data->timer);
+}
+
+/* --- Sysfs handling --- */
+
+static ssize_t pattern_trig_show_repeat(
+	struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev =3D dev_get_drvdata(dev);
+	struct pattern_trig_data *data =3D led_cdev->trigger_data;
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", data->repeat);
+}
+
+static ssize_t pattern_trig_store_repeat(
+	struct device *dev, struct device_attribute *attr,
+	const char *buf, size_t count)
+{
+	struct led_classdev *led_cdev =3D dev_get_drvdata(dev);
+	struct pattern_trig_data *data =3D led_cdev->trigger_data;
+	long res;
+	int err;
+
+	err =3D kstrtol(buf, 10, &res);
+	if (err)
+		return err;
+
+	data->repeat =3D res < 0 ? -1 : res;
+	reset_pattern(data, led_cdev);
+
+	return count;
+}
+
+DEVICE_ATTR(repeat, S_IRUGO | S_IWUSR,
+	pattern_trig_show_repeat, pattern_trig_store_repeat);
+
+static ssize_t pattern_trig_show_pattern(
+	struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev =3D dev_get_drvdata(dev);
+	struct pattern_trig_data *data =3D led_cdev->trigger_data;
+	ssize_t count =3D 0;
+	int i;
+
+	if (!data->steps || !data->nsteps)
+		return 0;
+
+	for (i =3D 0; i < data->nsteps; i++)
+		count +=3D scnprintf(buf + count, PAGE_SIZE - count,
+				"%d %d" PATTERN_SEPARATOR,
+				data->steps[i].brightness,
+				data->steps[i].delta_t);
+	buf[count - 1] =3D '\n';
+	buf[count] =3D '\0';
+
+	return count + 1;
+}
+
+static ssize_t pattern_trig_store_pattern(
+	struct device *dev, struct device_attribute *attr,
+	const char *buf, size_t count)
+{
+	struct led_classdev *led_cdev =3D dev_get_drvdata(dev);
+	struct pattern_trig_data *data =3D led_cdev->trigger_data;
+	int cr =3D 0; /* Characters read on one conversion */
+	int tcr =3D 0; /* Total characters read */
+	int ccount; /* Number of successful conversions */
+
+	mutex_lock(&data->lock);
+	data->is_sane =3D 0;
+
+	for (data->nsteps =3D 0; data->nsteps < MAX_NSTEPS; data->nsteps++) {
+		cr =3D 0;
+		ccount =3D sscanf(buf + tcr, "%d %d " PATTERN_SEPARATOR "%n",
+			&data->steps[data->nsteps].brightness,
+			&data->steps[data->nsteps].delta_t, &cr);
+
+		if (!cr) { /* Invalid syntax or end of pattern */
+			if (ccount =3D=3D 2)
+				data->nsteps++;
+			mutex_unlock(&data->lock);
+			reset_pattern(data, led_cdev);
+			return count;
+		}
+
+		tcr +=3D cr;
+	}
+
+	/* Shouldn't reach that */
+	WARN(1, "MAX_NSTEP too small. Please report\n");
+	mutex_unlock(&data->lock);
+	return count;
+}
+
+DEVICE_ATTR(pattern, S_IRUGO | S_IWUSR,
+	pattern_trig_show_pattern, pattern_trig_store_pattern);
+
+static int pattern_trig_create_sysfs_files(struct device *dev)
+{
+	int err;
+
+	err =3D device_create_file(dev, &dev_attr_repeat);
+	if (err)
+		return err;
+
+	err =3D device_create_file(dev, &dev_attr_pattern);
+	if (err)
+		device_remove_file(dev, &dev_attr_repeat);
+
+	return err;
+}
+
+static void pattern_trig_remove_sysfs_files(struct device *dev)
+{
+	device_remove_file(dev, &dev_attr_pattern);
+	device_remove_file(dev, &dev_attr_repeat);
+}
+
+/* --- Led intensity updating --- */
+
+static int compute_brightness(struct pattern_trig_data *data)
+{
+	if (data->delta_t =3D=3D 0)
+		return data->curr->brightness;
+
+	if (data->curr->delta_t =3D=3D 0)
+		return data->next->brightness;
+
+	return data->curr->brightness + data->delta_t
+		* (data->next->brightness - data->curr->brightness)
+		/ data->curr->delta_t;
+}
+
+static void update_to_next_step(struct pattern_trig_data *data)
+{
+	data->curr =3D data->next;
+	if (data->curr =3D=3D data->steps)
+		data->repeat--;
+
+	if (data->next =3D=3D data->steps + data->nsteps - 1)
+		data->next =3D data->steps;
+	else
+		data->next++;
+
+	data->delta_t =3D 0;
+}
+
+static void pattern_trig_update(struct timer_list *t)
+{
+	struct pattern_trig_data *data =3D from_timer(data, t, timer);
+
+	mutex_lock(&data->lock);
+
+	if (!data->is_sane || !data->repeat) {
+		mutex_unlock(&data->lock);
+		return;
+	}
+
+	if (data->delta_t > data->curr->delta_t)
+		update_to_next_step(data);
+
+	/* is_sane() checked that there is at least
+	   one step with delta_t >=3D UPDATE_INTERVAL
+	   so we won't go in an infinite loop */
+	while (data->curr->delta_t < UPDATE_INTERVAL)
+		update_to_next_step(data);
+
+	if (data->next->brightness =3D=3D data->curr->brightness) {
+		/* Constant brightness for this step */
+		led_set_brightness(data->led_cdev, data->curr->brightness);
+		mod_timer(&data->timer, jiffies
+			+ msecs_to_jiffies(data->curr->delta_t));
+		update_to_next_step(data);
+	} else {
+		/* Gradual dimming */
+		led_set_brightness(data->led_cdev, compute_brightness(data));
+		data->delta_t +=3D UPDATE_INTERVAL;
+		mod_timer(&data->timer, jiffies
+			+ msecs_to_jiffies(UPDATE_INTERVAL));
+	}
+
+	mutex_unlock(&data->lock);
+}
+
+/* --- Trigger activation --- */
+
+static void pattern_trig_activate(struct led_classdev *led_cdev)
+{
+	struct pattern_trig_data *data =3D NULL;
+	int err;
+
+	data =3D kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return;
+
+	err =3D pattern_trig_initialize_data(data);
+	if (err) {
+		kfree(data);
+		return;
+	}
+
+	data->led_cdev =3D led_cdev;
+	led_cdev->trigger_data =3D data;
+	timer_setup(&data->timer, pattern_trig_update, 0);
+	pattern_trig_create_sysfs_files(led_cdev->dev);
+}
+
+static void pattern_trig_deactivate(struct led_classdev *led_cdev)
+{
+	struct pattern_trig_data *data =3D led_cdev->trigger_data;
+
+	if (data) {
+		pattern_trig_remove_sysfs_files(led_cdev->dev);
+		del_timer_sync(&data->timer);
+		led_set_brightness(led_cdev, LED_OFF);
+		pattern_trig_clear_data(data);
+		kfree(data);
+		led_cdev->trigger_data =3D NULL;
+	}
+}
+
+static struct led_trigger pattern_led_trigger =3D {
+	.name =3D "pattern",
+	.activate =3D pattern_trig_activate,
+	.deactivate =3D pattern_trig_deactivate,
+};
+
+/* --- Module loading/unloading --- */
+
+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_DESCRIPTION("Pattern LED trigger");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 2fce962..39908ba 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -22,6 +22,7 @@
 #include <linux/workqueue.h>
=20
 struct device;
+struct led_pattern;
 /*
  * LED Core
  */
@@ -91,6 +92,14 @@ struct led_classdev {
 				     unsigned long *delay_on,
 				     unsigned long *delay_off);
=20
+	int (*pattern_set)(struct led_classdev *led_cdev,
+			   struct led_pattern *pattern, int len);
+
+	int (*pattern_clear)(struct led_classdev *led_cdev);
+
+	struct led_pattern *(*pattern_get)(struct led_classdev *led_cdev,
+					   int *len);
+
 	struct device		*dev;
 	const struct attribute_group	**groups;
=20
@@ -104,7 +113,7 @@ struct led_classdev {
 	void			(*flash_resume)(struct led_classdev *led_cdev);
=20
 	struct work_struct	set_brightness_work;
-	int			delayed_set_value;
+	enum led_brightness     delayed_set_value;
=20
 #ifdef CONFIG_LEDS_TRIGGERS
 	/* Protects the trigger data below */
@@ -471,4 +480,14 @@ static inline void led_classdev_notify_brightness_hw_c=
hanged(
 	struct led_classdev *led_cdev, enum led_brightness brightness) { }
 #endif
=20
+/**
+ * struct led_pattern - brightness value in a pattern
+ * @delta_t: delay until next entry, in milliseconds
+ * @brightness: brightness at time =3D 0
+ */
+struct led_pattern {
+	int delta_t;
+	int brightness;
+};
+
 #endif		/* __LINUX_LEDS_H_INCLUDED */


--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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