[PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Baolin Wang]

Some LED controllers have support for autonomously controlling
brightness over time, according to some preprogrammed pattern or
function.

This patch adds pattern trigger that LED device can configure the
pattern and trigger it.

Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
Changes from v3:
 - Reset pattern number to 0 if user provides incorrect pattern string.
 - Support one pattern.

Changes from v2:
 - Remove hardware_pattern boolen.
 - Chnage the pattern string format.

Changes from v1:
 - Use ATTRIBUTE_GROUPS() to define attributes.
 - Introduce hardware_pattern flag to determine if software pattern
 or hardware pattern.
 - Re-implement pattern_trig_store_pattern() function.
 - Remove pattern_get() interface.
 - Improve comments.
 - Other small optimization.
---
 .../ABI/testing/sysfs-class-led-trigger-pattern    |  21 ++
 drivers/leds/trigger/Kconfig                       |   7 +
 drivers/leds/trigger/Makefile                      |   1 +
 drivers/leds/trigger/ledtrig-pattern.c             | 271 +++++++++++++++++++++
 include/linux/leds.h                               |  16 ++
 5 files changed, 316 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-pattern
 create mode 100644 drivers/leds/trigger/ledtrig-pattern.c

diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
new file mode 100644
index 0000000..40afefe
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
@@ -0,0 +1,21 @@
+What:		/sys/class/leds/<led>/pattern
+Date:		August 2018
+KernelVersion:	4.19
+Description:
+		Specify a pattern for the LED, for LED hardware that support
+		altering the brightness as a function of time.
+
+		The pattern is given by a series of tuples, of brightness and
+		duration (ms). The LED is expected to traverse the series and
+		each brightness value for the specified duration. Duration of
+		0 means brightness should immediately change to new value.
+
+		The format of the pattern values should be:
+		"brightness_1 duration_1 brightness_2 duration_2 brightness_3
+		duration_3 ...".
+
+What:		/sys/class/leds/<led>/repeat
+Date:		August 2018
+KernelVersion:	4.19
+Description:
+		Specify a pattern repeat number. 0 means repeat indefinitely.
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 4018af7..b76fc3c 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 f3cfe19..9bcb64e 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 0000000..e5b90b7
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-pattern.c
@@ -0,0 +1,271 @@
+// 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
+
+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;
+	u32 repeat;
+	bool is_indefinite;
+	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++;
+}
+
+static void pattern_trig_timer_function(struct timer_list *t)
+{
+	struct pattern_trig_data *data = from_timer(data, t, timer);
+
+	mutex_lock(&data->lock);
+
+	if (!data->is_indefinite && !data->repeat) {
+		mutex_unlock(&data->lock);
+		return;
+	}
+
+	led_set_brightness(data->led_cdev, data->curr->brightness);
+	mod_timer(&data->timer, jiffies + msecs_to_jiffies(data->curr->delta_t));
+	pattern_trig_update_patterns(data);
+
+	mutex_unlock(&data->lock);
+}
+
+static int pattern_trig_start_pattern(struct pattern_trig_data *data,
+				      struct led_classdev *led_cdev)
+{
+	if (!data->npatterns)
+		return 0;
+
+	if (led_cdev->pattern_set) {
+		return led_cdev->pattern_set(led_cdev, data->patterns,
+					     data->npatterns, data->repeat);
+	}
+
+	data->curr = data->patterns;
+	data->next = data->npatterns > 1 ? data->patterns + 1 : data->patterns;
+	data->timer.expires = jiffies;
+	add_timer(&data->timer);
+
+	return 0;
+}
+
+static ssize_t pattern_trig_show_repeat(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;
+	u32 repeat;
+
+	mutex_lock(&data->lock);
+
+	repeat = data->repeat;
+
+	mutex_unlock(&data->lock);
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", 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 = dev_get_drvdata(dev);
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+	unsigned long res;
+	int err;
+
+	err = kstrtoul(buf, 10, &res);
+	if (err)
+		return err;
+
+	if (!led_cdev->pattern_set)
+		del_timer_sync(&data->timer);
+
+	mutex_lock(&data->lock);
+
+	data->repeat = res;
+
+	/* 0 means repeat indefinitely */
+	if (!data->repeat)
+		data->is_indefinite = true;
+	else
+		data->is_indefinite = false;
+
+	err = pattern_trig_start_pattern(data, led_cdev);
+
+	mutex_unlock(&data->lock);
+	return err < 0 ? err : count;
+}
+
+static DEVICE_ATTR(repeat, 0644, 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 = dev_get_drvdata(dev);
+	struct pattern_trig_data *data = led_cdev->trigger_data;
+	ssize_t count = 0;
+	int i;
+
+	mutex_lock(&data->lock);
+
+	if (!data->npatterns)
+		goto out;
+
+	for (i = 0; i < data->npatterns; i++) {
+		count += scnprintf(buf + count, PAGE_SIZE - count,
+				   "%d %d ",
+				   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_pattern(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 ccount, cr, offset = 0, err = 0;
+
+	if (!led_cdev->pattern_set)
+		del_timer_sync(&data->timer);
+
+	mutex_lock(&data->lock);
+
+	data->npatterns = 0;
+	while (offset < count - 1 && data->npatterns < MAX_PATTERNS) {
+		cr = 0;
+		ccount = sscanf(buf + offset, "%d %d %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(data, led_cdev);
+
+out:
+	mutex_unlock(&data->lock);
+	return err < 0 ? err : count;
+}
+
+static DEVICE_ATTR(pattern, 0644, pattern_trig_show_pattern,
+		   pattern_trig_store_pattern);
+
+static struct attribute *pattern_trig_attrs[] = {
+	&dev_attr_pattern.attr,
+	&dev_attr_repeat.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(pattern_trig);
+
+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;
+	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);
+	else
+		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");
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 834683d..c54712c 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -22,6 +22,7 @@
 #include <linux/workqueue.h>
 
 struct device;
+struct led_pattern;
 /*
  * LED Core
  */
@@ -88,6 +89,11 @@ struct led_classdev {
 				     unsigned long *delay_on,
 				     unsigned long *delay_off);
 
+	int (*pattern_set)(struct led_classdev *led_cdev,
+			   struct led_pattern *pattern, int len,
+			   unsigned repeat);
+	int (*pattern_clear)(struct led_classdev *led_cdev);
+
 	struct device		*dev;
 	const struct attribute_group	**groups;
 
@@ -472,4 +478,14 @@ static inline void led_classdev_notify_brightness_hw_changed(
 	struct led_classdev *led_cdev, enum led_brightness brightness) { }
 #endif
 
+/**
+ * struct led_pattern - brightness value in a pattern
+ * @delta_t: delay until next entry, in milliseconds
+ * @brightness: brightness at time = 0
+ */
+struct led_pattern {
+	int delta_t;
+	int brightness;
+};
+
 #endif		/* __LINUX_LEDS_H_INCLUDED */
-- 
1.9.1

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Jacek Anaszewski]

Hi Baolin,

Thank you for the fix.

I've found few more details to improve, please take a look
at my comments below.

On 08/05/2018 06:04 AM, Baolin Wang wrote:
> Some LED controllers have support for autonomously controlling
> brightness over time, according to some preprogrammed pattern or
> function.
> 
> This patch adds pattern trigger that LED device can configure the
> pattern and trigger it.
> 
> Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
> Changes from v3:
>  - Reset pattern number to 0 if user provides incorrect pattern string.
>  - Support one pattern.
> 
> Changes from v2:
>  - Remove hardware_pattern boolen.
>  - Chnage the pattern string format.
> 
> Changes from v1:
>  - Use ATTRIBUTE_GROUPS() to define attributes.
>  - Introduce hardware_pattern flag to determine if software pattern
>  or hardware pattern.
>  - Re-implement pattern_trig_store_pattern() function.
>  - Remove pattern_get() interface.
>  - Improve comments.
>  - Other small optimization.
> ---
>  .../ABI/testing/sysfs-class-led-trigger-pattern    |  21 ++
>  drivers/leds/trigger/Kconfig                       |   7 +
>  drivers/leds/trigger/Makefile                      |   1 +
>  drivers/leds/trigger/ledtrig-pattern.c             | 271 +++++++++++++++++++++
>  include/linux/leds.h                               |  16 ++
>  5 files changed, 316 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>  create mode 100644 drivers/leds/trigger/ledtrig-pattern.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> new file mode 100644
> index 0000000..40afefe
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> @@ -0,0 +1,21 @@
> +What:		/sys/class/leds/<led>/pattern
> +Date:		August 2018
> +KernelVersion:	4.19
> +Description:
> +		Specify a pattern for the LED, for LED hardware that support
> +		altering the brightness as a function of time.
> +
> +		The pattern is given by a series of tuples, of brightness and
> +		duration (ms). The LED is expected to traverse the series and
> +		each brightness value for the specified duration. Duration of
> +		0 means brightness should immediately change to new value.
> +
> +		The format of the pattern values should be:
> +		"brightness_1 duration_1 brightness_2 duration_2 brightness_3
> +		duration_3 ...".
> +
> +What:		/sys/class/leds/<led>/repeat
> +Date:		August 2018
> +KernelVersion:	4.19
> +Description:
> +		Specify a pattern repeat number. 0 means repeat indefinitely.

In current implementation this file on read returns the number
of remaining repeat intervals. I'd add that to this description.

> diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
> index 4018af7..b76fc3c 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 f3cfe19..9bcb64e 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 0000000..e5b90b7
> --- /dev/null
> +++ b/drivers/leds/trigger/ledtrig-pattern.c
> @@ -0,0 +1,271 @@
> +// 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
> +
> +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;
> +	u32 repeat;
> +	bool is_indefinite;
> +	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++;
> +}
> +
> +static void pattern_trig_timer_function(struct timer_list *t)
> +{
> +	struct pattern_trig_data *data = from_timer(data, t, timer);
> +
> +	mutex_lock(&data->lock);
> +
> +	if (!data->is_indefinite && !data->repeat) {
> +		mutex_unlock(&data->lock);
> +		return;
> +	}
> +
> +	led_set_brightness(data->led_cdev, data->curr->brightness);
> +	mod_timer(&data->timer, jiffies + msecs_to_jiffies(data->curr->delta_t));
> +	pattern_trig_update_patterns(data);
> +
> +	mutex_unlock(&data->lock);
> +}
> +
> +static int pattern_trig_start_pattern(struct pattern_trig_data *data,
> +				      struct led_classdev *led_cdev)
> +{
> +	if (!data->npatterns)
> +		return 0;
> +
> +	if (led_cdev->pattern_set) {
> +		return led_cdev->pattern_set(led_cdev, data->patterns,
> +					     data->npatterns, data->repeat);
> +	}
> +
> +	data->curr = data->patterns;
> +	data->next = data->npatterns > 1 ? data->patterns + 1 : data->patterns;
> +	data->timer.expires = jiffies;
> +	add_timer(&data->timer);
> +
> +	return 0;
> +}
> +
> +static ssize_t pattern_trig_show_repeat(struct device *dev,
> +					struct device_attribute *attr,
> +					char *buf)

Please fix checkpatch.pl warnings:

WARNING: Consider renaming function(s) 'pattern_trig_show_repeat' to
'repeat_show' 'pattern_trig_store_repeat' to 'repeat_store'
#209: FILE: drivers/leds/trigger/ledtrig-pattern.c:127:
+}

WARNING: Consider renaming function(s) 'pattern_trig_show_pattern' to
'pattern_show' 'pattern_trig_store_pattern' to 'pattern_store'
#276: FILE: drivers/leds/trigger/ledtrig-pattern.c:194:
+}


> +{
> +	struct led_classdev *led_cdev = dev_get_drvdata(dev);
> +	struct pattern_trig_data *data = led_cdev->trigger_data;
> +	u32 repeat;
> +
> +	mutex_lock(&data->lock);
> +
> +	repeat = data->repeat;
> +
> +	mutex_unlock(&data->lock);
> +
> +	return scnprintf(buf, PAGE_SIZE, "%u\n", 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 = dev_get_drvdata(dev);
> +	struct pattern_trig_data *data = led_cdev->trigger_data;
> +	unsigned long res;
> +	int err;
> +
> +	err = kstrtoul(buf, 10, &res);
> +	if (err)
> +		return err;
> +
> +	if (!led_cdev->pattern_set)
> +		del_timer_sync(&data->timer);

Is there a reason for not having this check under mutex?

> +	mutex_lock(&data->lock);
> +
> +	data->repeat = res;
> +
> +	/* 0 means repeat indefinitely */
> +	if (!data->repeat)
> +		data->is_indefinite = true;
> +	else
> +		data->is_indefinite = false;
> +
> +	err = pattern_trig_start_pattern(data, led_cdev);
> +
> +	mutex_unlock(&data->lock);
> +	return err < 0 ? err : count;
> +}
> +
> +static DEVICE_ATTR(repeat, 0644, 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 = dev_get_drvdata(dev);
> +	struct pattern_trig_data *data = led_cdev->trigger_data;
> +	ssize_t count = 0;
> +	int i;
> +
> +	mutex_lock(&data->lock);
> +
> +	if (!data->npatterns)
> +		goto out;
> +
> +	for (i = 0; i < data->npatterns; i++) {
> +		count += scnprintf(buf + count, PAGE_SIZE - count,
> +				   "%d %d ",
> +				   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_pattern(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 ccount, cr, offset = 0, err = 0;
> +
> +	if (!led_cdev->pattern_set)
> +		del_timer_sync(&data->timer);

Ditto.

> +	mutex_lock(&data->lock);
> +
> +	data->npatterns = 0;
> +	while (offset < count - 1 && data->npatterns < MAX_PATTERNS) {
> +		cr = 0;
> +		ccount = sscanf(buf + offset, "%d %d %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(data, led_cdev);
> +
> +out:
> +	mutex_unlock(&data->lock);
> +	return err < 0 ? err : count;
> +}
> +
> +static DEVICE_ATTR(pattern, 0644, pattern_trig_show_pattern,
> +		   pattern_trig_store_pattern);
> +
> +static struct attribute *pattern_trig_attrs[] = {
> +	&dev_attr_pattern.attr,
> +	&dev_attr_repeat.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(pattern_trig);
> +
> +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;
> +	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);
> +	else
> +		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");
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 834683d..c54712c 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -22,6 +22,7 @@
>  #include <linux/workqueue.h>
>  
>  struct device;
> +struct led_pattern;
>  /*
>   * LED Core
>   */
> @@ -88,6 +89,11 @@ struct led_classdev {
>  				     unsigned long *delay_on,
>  				     unsigned long *delay_off);
>  
> +	int (*pattern_set)(struct led_classdev *led_cdev,
> +			   struct led_pattern *pattern, int len,
> +			   unsigned repeat);
> +	int (*pattern_clear)(struct led_classdev *led_cdev);
> +
>  	struct device		*dev;
>  	const struct attribute_group	**groups;
>  
> @@ -472,4 +478,14 @@ static inline void led_classdev_notify_brightness_hw_changed(
>  	struct led_classdev *led_cdev, enum led_brightness brightness) { }
>  #endif
>  
> +/**
> + * struct led_pattern - brightness value in a pattern

Since this structure describes single pattern interval and not
the whole pattern, please change its description to:

pattern interval settings

> + * @delta_t: delay until next entry, in milliseconds

@delta_t: pattern interval delay, in milliseconds

> + * @brightness: brightness at time = 0

@brightness: pattern interval brightness

> + */
> +struct led_pattern {
> +	int delta_t;
> +	int brightness;
> +};
> +
>  #endif		/* __LINUX_LEDS_H_INCLUDED */
> 

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 687 bytes --]

Hi!

> > +What:		/sys/class/leds/<led>/repeat
> > +Date:		August 2018
> > +KernelVersion:	4.19
> > +Description:
> > +		Specify a pattern repeat number. 0 means repeat indefinitely.
> 
> In current implementation this file on read returns the number
> of remaining repeat intervals. I'd add that to this description.

Lets not do this.

LEDs such as the one on N900 can do repeats automatically, in
hardware. But in such case we may not be able to determine how many
repetitions were done (and how many are left).

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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Baolin Wang]

Hi Jacek,

On 6 August 2018 at 00:10, Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:
> Hi Baolin,
>
> Thank you for the fix.
>
> I've found few more details to improve, please take a look
> at my comments below.
>
> On 08/05/2018 06:04 AM, Baolin Wang wrote:
>> Some LED controllers have support for autonomously controlling
>> brightness over time, according to some preprogrammed pattern or
>> function.
>>
>> This patch adds pattern trigger that LED device can configure the
>> pattern and trigger it.
>>
>> Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> ---
>> Changes from v3:
>>  - Reset pattern number to 0 if user provides incorrect pattern string.
>>  - Support one pattern.
>>
>> Changes from v2:
>>  - Remove hardware_pattern boolen.
>>  - Chnage the pattern string format.
>>
>> Changes from v1:
>>  - Use ATTRIBUTE_GROUPS() to define attributes.
>>  - Introduce hardware_pattern flag to determine if software pattern
>>  or hardware pattern.
>>  - Re-implement pattern_trig_store_pattern() function.
>>  - Remove pattern_get() interface.
>>  - Improve comments.
>>  - Other small optimization.
>> ---
>>  .../ABI/testing/sysfs-class-led-trigger-pattern    |  21 ++
>>  drivers/leds/trigger/Kconfig                       |   7 +
>>  drivers/leds/trigger/Makefile                      |   1 +
>>  drivers/leds/trigger/ledtrig-pattern.c             | 271 +++++++++++++++++++++
>>  include/linux/leds.h                               |  16 ++
>>  5 files changed, 316 insertions(+)
>>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>>  create mode 100644 drivers/leds/trigger/ledtrig-pattern.c
>>
>> diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>> new file mode 100644
>> index 0000000..40afefe
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>> @@ -0,0 +1,21 @@
>> +What:                /sys/class/leds/<led>/pattern
>> +Date:                August 2018
>> +KernelVersion:       4.19
>> +Description:
>> +             Specify a pattern for the LED, for LED hardware that support
>> +             altering the brightness as a function of time.
>> +
>> +             The pattern is given by a series of tuples, of brightness and
>> +             duration (ms). The LED is expected to traverse the series and
>> +             each brightness value for the specified duration. Duration of
>> +             0 means brightness should immediately change to new value.
>> +
>> +             The format of the pattern values should be:
>> +             "brightness_1 duration_1 brightness_2 duration_2 brightness_3
>> +             duration_3 ...".
>> +
>> +What:                /sys/class/leds/<led>/repeat
>> +Date:                August 2018
>> +KernelVersion:       4.19
>> +Description:
>> +             Specify a pattern repeat number. 0 means repeat indefinitely.
>
> In current implementation this file on read returns the number
> of remaining repeat intervals. I'd add that to this description.

I saw Pavel's comments that he did not suggest do this. So I will keep
the original description?

>
>> diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
>> index 4018af7..b76fc3c 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 f3cfe19..9bcb64e 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 0000000..e5b90b7
>> --- /dev/null
>> +++ b/drivers/leds/trigger/ledtrig-pattern.c
>> @@ -0,0 +1,271 @@
>> +// 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
>> +
>> +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;
>> +     u32 repeat;
>> +     bool is_indefinite;
>> +     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++;
>> +}
>> +
>> +static void pattern_trig_timer_function(struct timer_list *t)
>> +{
>> +     struct pattern_trig_data *data = from_timer(data, t, timer);
>> +
>> +     mutex_lock(&data->lock);
>> +
>> +     if (!data->is_indefinite && !data->repeat) {
>> +             mutex_unlock(&data->lock);
>> +             return;
>> +     }
>> +
>> +     led_set_brightness(data->led_cdev, data->curr->brightness);
>> +     mod_timer(&data->timer, jiffies + msecs_to_jiffies(data->curr->delta_t));
>> +     pattern_trig_update_patterns(data);
>> +
>> +     mutex_unlock(&data->lock);
>> +}
>> +
>> +static int pattern_trig_start_pattern(struct pattern_trig_data *data,
>> +                                   struct led_classdev *led_cdev)
>> +{
>> +     if (!data->npatterns)
>> +             return 0;
>> +
>> +     if (led_cdev->pattern_set) {
>> +             return led_cdev->pattern_set(led_cdev, data->patterns,
>> +                                          data->npatterns, data->repeat);
>> +     }
>> +
>> +     data->curr = data->patterns;
>> +     data->next = data->npatterns > 1 ? data->patterns + 1 : data->patterns;
>> +     data->timer.expires = jiffies;
>> +     add_timer(&data->timer);
>> +
>> +     return 0;
>> +}
>> +
>> +static ssize_t pattern_trig_show_repeat(struct device *dev,
>> +                                     struct device_attribute *attr,
>> +                                     char *buf)
>
> Please fix checkpatch.pl warnings:
>
> WARNING: Consider renaming function(s) 'pattern_trig_show_repeat' to
> 'repeat_show' 'pattern_trig_store_repeat' to 'repeat_store'
> #209: FILE: drivers/leds/trigger/ledtrig-pattern.c:127:
> +}
>
> WARNING: Consider renaming function(s) 'pattern_trig_show_pattern' to
> 'pattern_show' 'pattern_trig_store_pattern' to 'pattern_store'
> #276: FILE: drivers/leds/trigger/ledtrig-pattern.c:194:
> +}

Yes, I saw the warning, but I just follow other trigger‘s custom.
Sure, I can fix this.

>> +{
>> +     struct led_classdev *led_cdev = dev_get_drvdata(dev);
>> +     struct pattern_trig_data *data = led_cdev->trigger_data;
>> +     u32 repeat;
>> +
>> +     mutex_lock(&data->lock);
>> +
>> +     repeat = data->repeat;
>> +
>> +     mutex_unlock(&data->lock);
>> +
>> +     return scnprintf(buf, PAGE_SIZE, "%u\n", 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 = dev_get_drvdata(dev);
>> +     struct pattern_trig_data *data = led_cdev->trigger_data;
>> +     unsigned long res;
>> +     int err;
>> +
>> +     err = kstrtoul(buf, 10, &res);
>> +     if (err)
>> +             return err;
>> +
>> +     if (!led_cdev->pattern_set)
>> +             del_timer_sync(&data->timer);
>
> Is there a reason for not having this check under mutex?

We will hold the mutex in pattern_trig_timer_function(), so if we do
del_timer_sync() under the mutex protection, we may meet dead-lock
issue. Moreover, the del_timer_sync() will make sure deactivating one
timer is safe.

>
>> +     mutex_lock(&data->lock);
>> +
>> +     data->repeat = res;
>> +
>> +     /* 0 means repeat indefinitely */
>> +     if (!data->repeat)
>> +             data->is_indefinite = true;
>> +     else
>> +             data->is_indefinite = false;
>> +
>> +     err = pattern_trig_start_pattern(data, led_cdev);
>> +
>> +     mutex_unlock(&data->lock);
>> +     return err < 0 ? err : count;
>> +}
>> +
>> +static DEVICE_ATTR(repeat, 0644, 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 = dev_get_drvdata(dev);
>> +     struct pattern_trig_data *data = led_cdev->trigger_data;
>> +     ssize_t count = 0;
>> +     int i;
>> +
>> +     mutex_lock(&data->lock);
>> +
>> +     if (!data->npatterns)
>> +             goto out;
>> +
>> +     for (i = 0; i < data->npatterns; i++) {
>> +             count += scnprintf(buf + count, PAGE_SIZE - count,
>> +                                "%d %d ",
>> +                                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_pattern(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 ccount, cr, offset = 0, err = 0;
>> +
>> +     if (!led_cdev->pattern_set)
>> +             del_timer_sync(&data->timer);
>
> Ditto.

See above comments.

>
>> +     mutex_lock(&data->lock);
>> +
>> +     data->npatterns = 0;
>> +     while (offset < count - 1 && data->npatterns < MAX_PATTERNS) {
>> +             cr = 0;
>> +             ccount = sscanf(buf + offset, "%d %d %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(data, led_cdev);
>> +
>> +out:
>> +     mutex_unlock(&data->lock);
>> +     return err < 0 ? err : count;
>> +}
>> +
>> +static DEVICE_ATTR(pattern, 0644, pattern_trig_show_pattern,
>> +                pattern_trig_store_pattern);
>> +
>> +static struct attribute *pattern_trig_attrs[] = {
>> +     &dev_attr_pattern.attr,
>> +     &dev_attr_repeat.attr,
>> +     NULL
>> +};
>> +ATTRIBUTE_GROUPS(pattern_trig);
>> +
>> +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;
>> +     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);
>> +     else
>> +             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");
>> diff --git a/include/linux/leds.h b/include/linux/leds.h
>> index 834683d..c54712c 100644
>> --- a/include/linux/leds.h
>> +++ b/include/linux/leds.h
>> @@ -22,6 +22,7 @@
>>  #include <linux/workqueue.h>
>>
>>  struct device;
>> +struct led_pattern;
>>  /*
>>   * LED Core
>>   */
>> @@ -88,6 +89,11 @@ struct led_classdev {
>>                                    unsigned long *delay_on,
>>                                    unsigned long *delay_off);
>>
>> +     int (*pattern_set)(struct led_classdev *led_cdev,
>> +                        struct led_pattern *pattern, int len,
>> +                        unsigned repeat);
>> +     int (*pattern_clear)(struct led_classdev *led_cdev);
>> +
>>       struct device           *dev;
>>       const struct attribute_group    **groups;
>>
>> @@ -472,4 +478,14 @@ static inline void led_classdev_notify_brightness_hw_changed(
>>       struct led_classdev *led_cdev, enum led_brightness brightness) { }
>>  #endif
>>
>> +/**
>> + * struct led_pattern - brightness value in a pattern
>
> Since this structure describes single pattern interval and not
> the whole pattern, please change its description to:
>
> pattern interval settings
>
>> + * @delta_t: delay until next entry, in milliseconds
>
> @delta_t: pattern interval delay, in milliseconds
>
>> + * @brightness: brightness at time = 0
>
> @brightness: pattern interval brightness

Sure. Thanks for your comments.

>
>> + */
>> +struct led_pattern {
>> +     int delta_t;
>> +     int brightness;
>> +};
>> +
>>  #endif               /* __LINUX_LEDS_H_INCLUDED */
>>
>
> --
> Best regards,
> Jacek Anaszewski



-- 
Baolin Wang
Best Regards

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 483 bytes --]

Hi!

> > In current implementation this file on read returns the number
> > of remaining repeat intervals. I'd add that to this description.
> 
> I saw Pavel's comments that he did not suggest do this. So I will keep
> the original description?

If that is accepted, the code should return originally written number.

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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Baolin Wang]

Hi Pavel,

On 6 August 2018 at 15:09, Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
>> > In current implementation this file on read returns the number
>> > of remaining repeat intervals. I'd add that to this description.
>>
>> I saw Pavel's comments that he did not suggest do this. So I will keep
>> the original description?
>
> If that is accepted, the code should return originally written number.

But I think it is more reasonable if user can know how many
repetitions were left. So for your hardware case, can we add
pattern_get() interface back to get the repetition number?

-- 
Baolin Wang
Best Regards

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 1116 bytes --]

On Mon 2018-08-06 15:33:12, Baolin Wang wrote:
> Hi Pavel,
> 
> On 6 August 2018 at 15:09, Pavel Machek <pavel@ucw.cz> wrote:
> > Hi!
> >
> >> > In current implementation this file on read returns the number
> >> > of remaining repeat intervals. I'd add that to this description.
> >>
> >> I saw Pavel's comments that he did not suggest do this. So I will keep
> >> the original description?
> >
> > If that is accepted, the code should return originally written number.
> 
> But I think it is more reasonable if user can know how many
> repetitions were left. So for your hardware case, can we add
> pattern_get() interface back to get the repetition number?

Well, I'd say that we are mostly seeing "infinite" repetitions, or one
repetition.

Yes, interface could be added to the lowlever driver -- but I'm not
sure hardware really supports getting that information; could be
tricky on N900 for example.

I'd keep it simple for now.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Baolin Wang]

On 6 August 2018 at 16:06, Pavel Machek <pavel@ucw.cz> wrote:
> On Mon 2018-08-06 15:33:12, Baolin Wang wrote:
>> Hi Pavel,
>>
>> On 6 August 2018 at 15:09, Pavel Machek <pavel@ucw.cz> wrote:
>> > Hi!
>> >
>> >> > In current implementation this file on read returns the number
>> >> > of remaining repeat intervals. I'd add that to this description.
>> >>
>> >> I saw Pavel's comments that he did not suggest do this. So I will keep
>> >> the original description?
>> >
>> > If that is accepted, the code should return originally written number.
>>
>> But I think it is more reasonable if user can know how many
>> repetitions were left. So for your hardware case, can we add
>> pattern_get() interface back to get the repetition number?
>
> Well, I'd say that we are mostly seeing "infinite" repetitions, or one
> repetition.
>
> Yes, interface could be added to the lowlever driver -- but I'm not
> sure hardware really supports getting that information; could be
> tricky on N900 for example.
>
> I'd keep it simple for now.

OK, I also like to keep it simple. I am fine the repeat file returns
originally written number. If Jacek also agrees with this, then I will
update new version.

-- 
Baolin Wang
Best Regards

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Jacek Anaszewski]

Hi Baolin,

On 08/06/2018 03:53 AM, Baolin Wang wrote:
> Hi Jacek,
[...]
>>> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>>> @@ -0,0 +1,21 @@
>>> +What:                /sys/class/leds/<led>/pattern
>>> +Date:                August 2018
>>> +KernelVersion:       4.19
>>> +Description:
>>> +             Specify a pattern for the LED, for LED hardware that support
>>> +             altering the brightness as a function of time.
>>> +
>>> +             The pattern is given by a series of tuples, of brightness and
>>> +             duration (ms). The LED is expected to traverse the series and
>>> +             each brightness value for the specified duration. Duration of
>>> +             0 means brightness should immediately change to new value.
>>> +
>>> +             The format of the pattern values should be:
>>> +             "brightness_1 duration_1 brightness_2 duration_2 brightness_3
>>> +             duration_3 ...".
>>> +
>>> +What:                /sys/class/leds/<led>/repeat
>>> +Date:                August 2018
>>> +KernelVersion:       4.19
>>> +Description:
>>> +             Specify a pattern repeat number. 0 means repeat indefinitely.
>>
>> In current implementation this file on read returns the number
>> of remaining repeat intervals. I'd add that to this description.
> 
> I saw Pavel's comments that he did not suggest do this. So I will keep
> the original description?

Yes, please report always the original value.

[...]
>>> +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 = dev_get_drvdata(dev);
>>> +     struct pattern_trig_data *data = led_cdev->trigger_data;
>>> +     unsigned long res;
>>> +     int err;
>>> +
>>> +     err = kstrtoul(buf, 10, &res);
>>> +     if (err)
>>> +             return err;
>>> +
>>> +     if (!led_cdev->pattern_set)
>>> +             del_timer_sync(&data->timer);
>>
>> Is there a reason for not having this check under mutex?
> 
> We will hold the mutex in pattern_trig_timer_function(), so if we do
> del_timer_sync() under the mutex protection, we may meet dead-lock
> issue. Moreover, the del_timer_sync() will make sure deactivating one
> timer is safe.

Ack.

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH v4 1/2] leds: core: Introduce LED pattern trigger

[Baolin Wang]

Hi Jacek,

On 6 August 2018 at 19:41, Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:
> Hi Baolin,
>
> On 08/06/2018 03:53 AM, Baolin Wang wrote:
>> Hi Jacek,
> [...]
>>>> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>>>> @@ -0,0 +1,21 @@
>>>> +What:                /sys/class/leds/<led>/pattern
>>>> +Date:                August 2018
>>>> +KernelVersion:       4.19
>>>> +Description:
>>>> +             Specify a pattern for the LED, for LED hardware that support
>>>> +             altering the brightness as a function of time.
>>>> +
>>>> +             The pattern is given by a series of tuples, of brightness and
>>>> +             duration (ms). The LED is expected to traverse the series and
>>>> +             each brightness value for the specified duration. Duration of
>>>> +             0 means brightness should immediately change to new value.
>>>> +
>>>> +             The format of the pattern values should be:
>>>> +             "brightness_1 duration_1 brightness_2 duration_2 brightness_3
>>>> +             duration_3 ...".
>>>> +
>>>> +What:                /sys/class/leds/<led>/repeat
>>>> +Date:                August 2018
>>>> +KernelVersion:       4.19
>>>> +Description:
>>>> +             Specify a pattern repeat number. 0 means repeat indefinitely.
>>>
>>> In current implementation this file on read returns the number
>>> of remaining repeat intervals. I'd add that to this description.
>>
>> I saw Pavel's comments that he did not suggest do this. So I will keep
>> the original description?
>
> Yes, please report always the original value.

Sure. Thanks.

>
> [...]
>>>> +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 = dev_get_drvdata(dev);
>>>> +     struct pattern_trig_data *data = led_cdev->trigger_data;
>>>> +     unsigned long res;
>>>> +     int err;
>>>> +
>>>> +     err = kstrtoul(buf, 10, &res);
>>>> +     if (err)
>>>> +             return err;
>>>> +
>>>> +     if (!led_cdev->pattern_set)
>>>> +             del_timer_sync(&data->timer);
>>>
>>> Is there a reason for not having this check under mutex?
>>
>> We will hold the mutex in pattern_trig_timer_function(), so if we do
>> del_timer_sync() under the mutex protection, we may meet dead-lock
>> issue. Moreover, the del_timer_sync() will make sure deactivating one
>> timer is safe.
>
> Ack.
>
> --
> Best regards,
> Jacek Anaszewski



-- 
Baolin Wang
Best Regards