* [PATCH v13 1/2] leds: core: Introduce LED pattern trigger
@ 2018-09-27 5:04 Baolin Wang
2018-09-27 5:04 ` [PATCH v13 2/2] leds: sc27xx: Add pattern_set/clear interfaces for LED controller Baolin Wang
2018-09-30 15:33 ` [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Jacek Anaszewski
0 siblings, 2 replies; 5+ messages in thread
From: Baolin Wang @ 2018-09-27 5:04 UTC (permalink / raw)
To: jacek.anaszewski, pavel
Cc: rteysseyre, bjorn.andersson, baolin.wang, broonie, linus.walleij,
linux-leds, linux-kernel
This patch adds one new led trigger that LED device can configure
the software or hardware pattern and trigger it.
Consumers can write 'pattern' file to enable the software pattern
which alters the brightness for the specified duration with one
software timer.
Moreover consumers can write 'hw_pattern' file to enable the hardware
pattern for some LED controllers which can autonomously control
brightness over time, according to some preprogrammed hardware
patterns.
Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
Changes from v12:
- Add gradual dimming support for software pattern.
Changes from v11:
- Change -1 means repeat indefinitely.
Changes from v10:
- Change 'int' to 'u32' for delta_t field.
Changes from v9:
- None.
Changes from v8:
- None.
Changes from v7:
- Move the SC27XX hardware patterns description into its own ABI file.
Changes from v6:
- Improve commit message.
- Optimize the description of the hw_pattern file.
- Simplify some logics.
Changes from v5:
- Add one 'hw_pattern' file for hardware patterns.
Changes from v4:
- Change the repeat file to return the originally written number.
- Improve comments.
- Fix some build warnings.
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 | 74 ++++
drivers/leds/trigger/Kconfig | 7 +
drivers/leds/trigger/Makefile | 1 +
drivers/leds/trigger/ledtrig-pattern.c | 406 ++++++++++++++++++++
include/linux/leds.h | 15 +
5 files changed, 503 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..e84d42a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
@@ -0,0 +1,74 @@
+What: /sys/class/leds/<led>/pattern
+Date: September 2018
+KernelVersion: 4.20
+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 constant brightness.
+
+ 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.
+
+ 1. The gradual dimming format of the software pattern values
+ should be:
+ "brightness_1 duration_1 brightness_2 duration_2 brightness_3
+ duration_3 ...". For example:
+
+ echo 0 1000 255 2000 > pattern
+
+ It will make the LED go gradually from zero-intensity to max (255)
+ intensity in 1000 milliseconds, then back to zero intensity in 2000
+ milliseconds:
+
+ LED brightness
+ ^
+ 255-| / \ / \ /
+ | / \ / \ /
+ | / \ / \ /
+ | / \ / \ /
+ 0-| / \/ \/
+ +---0----1----2----3----4----5----6------------> time (s)
+
+ 2. To make the LED go instantly from one brigntess value to another,
+ we should use use zero-time lengths. So the format should be:
+ "brightness_1 duration_1 brightness_1 0 brightness_2 duration_2
+ brightness_2 0 ...". For example:
+
+ echo 0 1000 0 0 255 2000 255 0 > pattern
+
+ It will make the LED stay off for one second, then stay at max brightness
+ for two seconds:
+
+ LED brightness
+ ^
+ 255-| +---------+ +---------+
+ | | | | |
+ | | | | |
+ | | | | |
+ 0-| -----+ +----+ +----
+ +---0----1----2----3----4----5----6------------> time (s)
+
+What: /sys/class/leds/<led>/hw_pattern
+Date: September 2018
+KernelVersion: 4.20
+Description:
+ Specify a hardware pattern for the LED, for LED hardware that
+ supports autonomously controlling brightness over time, according
+ to some preprogrammed hardware patterns.
+
+ Since different LED hardware can have different semantics of
+ hardware patterns, each driver is expected to provide its own
+ description for the hardware patterns in their ABI documentation
+ file.
+
+What: /sys/class/leds/<led>/repeat
+Date: September 2018
+KernelVersion: 4.20
+Description:
+ Specify a pattern repeat number. -1 means repeat indefinitely,
+ other negative numbers and number 0 are invalid.
+
+ This file will always return the originally written repeat
+ number.
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..7aba30e
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-pattern.c
@@ -0,0 +1,406 @@
+// 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 (data->delta_t == 0)
+ 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);
+
+try_again:
+ if (!data->is_indefinite && !data->repeat) {
+ mutex_unlock(&data->lock);
+ return;
+ }
+
+ if (data->curr->brightness == data->next->brightness) {
+ /* Constant brightness */
+ led_set_brightness(data->led_cdev, data->curr->brightness);
+ mod_timer(&data->timer,
+ jiffies + msecs_to_jiffies(data->curr->delta_t));
+
+ /* Skip the step with zero duration */
+ pattern_trig_update_patterns(data);
+ /* Select next step */
+ pattern_trig_update_patterns(data);
+ } else {
+ /* Gradual dimming */
+
+ /*
+ * If the accumulation time is larger than current step
+ * 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);
+ goto try_again;
+ }
+
+ /*
+ * If current step duration is less than UPDATE_INTERVAL, we
+ * should go next one and re-check if we repeated done.
+ */
+ if (data->curr->delta_t < UPDATE_INTERVAL) {
+ pattern_trig_update_patterns(data);
+ goto try_again;
+ }
+
+ 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;
+ }
+
+ 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);
+ }
+
+ data->delta_t = 0;
+ 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 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);
+
+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");
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 834683d..7393a31 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 +89,10 @@ struct led_classdev {
unsigned long *delay_on,
unsigned long *delay_off);
+ int (*pattern_set)(struct led_classdev *led_cdev,
+ struct led_pattern *pattern, u32 len, int repeat);
+ int (*pattern_clear)(struct led_classdev *led_cdev);
+
struct device *dev;
const struct attribute_group **groups;
@@ -472,4 +477,14 @@ static inline void led_classdev_notify_brightness_hw_changed(
struct led_classdev *led_cdev, enum led_brightness brightness) { }
#endif
+/**
+ * struct led_pattern - pattern interval settings
+ * @delta_t: pattern interval delay, in milliseconds
+ * @brightness: pattern interval brightness
+ */
+struct led_pattern {
+ u32 delta_t;
+ int brightness;
+};
+
#endif /* __LINUX_LEDS_H_INCLUDED */
--
1.7.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v13 2/2] leds: sc27xx: Add pattern_set/clear interfaces for LED controller
2018-09-27 5:04 [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Baolin Wang
@ 2018-09-27 5:04 ` Baolin Wang
2018-09-30 15:33 ` [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Jacek Anaszewski
1 sibling, 0 replies; 5+ messages in thread
From: Baolin Wang @ 2018-09-27 5:04 UTC (permalink / raw)
To: jacek.anaszewski, pavel
Cc: rteysseyre, bjorn.andersson, baolin.wang, broonie, linus.walleij,
linux-leds, linux-kernel
This patch implements the 'pattern_set'and 'pattern_clear'
interfaces to support SC27XX LED breathing mode.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.c>
---
Changes from v12:
- None.
Changes from v11:
- None.
Changes from v10:
- Add duration alignment function suggested by Jacek.
- Add acked tag from Pavel.
Changes from v9:
- Optimize the ABI documentation file.
- Update the brightness value in hardware pattern mode.
Changes from v8:
- Optimize the ABI documentation file.
Changes from v7:
- Add its own ABI documentation file.
Changes from v6:
- None.
Changes from v5:
- None.
Changes from v4:
- None.
Changes from v3:
- None.
Changes from v2:
- None.
Changes from v1:
- Remove pattern_get interface.
---
.../ABI/testing/sysfs-class-led-driver-sc27xx | 22 ++++
drivers/leds/leds-sc27xx-bltc.c | 121 ++++++++++++++++++++
2 files changed, 143 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
new file mode 100644
index 0000000..45b1e60
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
@@ -0,0 +1,22 @@
+What: /sys/class/leds/<led>/hw_pattern
+Date: September 2018
+KernelVersion: 4.20
+Description:
+ Specify a hardware pattern for the SC27XX LED. For the SC27XX
+ LED controller, it only supports 4 stages to make a single
+ hardware pattern, which is used to configure the rise time,
+ high time, fall time and low time for the breathing mode.
+
+ For the breathing mode, the SC27XX LED only expects one brightness
+ for the high stage. To be compatible with the hardware pattern
+ format, we should set brightness as 0 for rise stage, fall
+ stage and low stage.
+
+ Min stage duration: 125 ms
+ Max stage duration: 31875 ms
+
+ Since the stage duration step is 125 ms, the duration should be
+ a multiplier of 125, like 125ms, 250ms, 375ms, 500ms ... 31875ms.
+
+ Thus the format of the hardware pattern values should be:
+ "0 rise_duration brightness high_duration 0 fall_duration 0 low_duration".
diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-bltc.c
index 9d9b7aa..fecf27f 100644
--- a/drivers/leds/leds-sc27xx-bltc.c
+++ b/drivers/leds/leds-sc27xx-bltc.c
@@ -32,8 +32,18 @@
#define SC27XX_DUTY_MASK GENMASK(15, 0)
#define SC27XX_MOD_MASK GENMASK(7, 0)
+#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
+/* Stage duration step, in milliseconds */
+#define SC27XX_LEDS_STEP 125
+/* Minimum and maximum duration, in milliseconds */
+#define SC27XX_DELTA_T_MIN SC27XX_LEDS_STEP
+#define SC27XX_DELTA_T_MAX (SC27XX_LEDS_STEP * 255)
struct sc27xx_led {
char name[LED_MAX_NAME_SIZE];
@@ -122,6 +132,113 @@ static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
return err;
}
+static void sc27xx_led_clamp_align_delta_t(u32 *delta_t)
+{
+ u32 v, offset, t = *delta_t;
+
+ v = t + SC27XX_LEDS_STEP / 2;
+ v = clamp_t(u32, v, SC27XX_DELTA_T_MIN, SC27XX_DELTA_T_MAX);
+ offset = v - SC27XX_DELTA_T_MIN;
+ offset = SC27XX_LEDS_STEP * (offset / SC27XX_LEDS_STEP);
+
+ *delta_t = SC27XX_DELTA_T_MIN + offset;
+}
+
+static int sc27xx_led_pattern_clear(struct led_classdev *ldev)
+{
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ struct regmap *regmap = leds->priv->regmap;
+ u32 base = sc27xx_led_get_offset(leds);
+ u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
+ u8 ctrl_shift = 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 = regmap_update_bits(regmap, ctrl_base,
+ (SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
+
+ ldev->brightness = LED_OFF;
+
+ mutex_unlock(&leds->priv->lock);
+
+ return err;
+}
+
+static int sc27xx_led_pattern_set(struct led_classdev *ldev,
+ struct led_pattern *pattern,
+ u32 len, int repeat)
+{
+ struct sc27xx_led *leds = to_sc27xx_led(ldev);
+ u32 base = sc27xx_led_get_offset(leds);
+ u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
+ u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
+ struct regmap *regmap = leds->priv->regmap;
+ int err;
+
+ /*
+ * Must contain 4 tuples to configure the rise time, high time, fall
+ * time and low time to enable the breathing mode.
+ */
+ if (len != SC27XX_LEDS_PATTERN_CNT)
+ return -EINVAL;
+
+ mutex_lock(&leds->priv->lock);
+
+ sc27xx_led_clamp_align_delta_t(&pattern[0].delta_t);
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+ SC27XX_CURVE_L_MASK,
+ pattern[0].delta_t / SC27XX_LEDS_STEP);
+ if (err)
+ goto out;
+
+ sc27xx_led_clamp_align_delta_t(&pattern[1].delta_t);
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+ SC27XX_CURVE_L_MASK,
+ pattern[1].delta_t / SC27XX_LEDS_STEP);
+ if (err)
+ goto out;
+
+ sc27xx_led_clamp_align_delta_t(&pattern[2].delta_t);
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
+ SC27XX_CURVE_H_MASK,
+ (pattern[2].delta_t / SC27XX_LEDS_STEP) <<
+ SC27XX_CURVE_SHIFT);
+ if (err)
+ goto out;
+
+ sc27xx_led_clamp_align_delta_t(&pattern[3].delta_t);
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
+ SC27XX_CURVE_H_MASK,
+ (pattern[3].delta_t / SC27XX_LEDS_STEP) <<
+ SC27XX_CURVE_SHIFT);
+ if (err)
+ goto out;
+
+ err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
+ SC27XX_DUTY_MASK,
+ (pattern[1].brightness << SC27XX_DUTY_SHIFT) |
+ SC27XX_MOD_MASK);
+ if (err)
+ goto out;
+
+ /* Enable the LED breathing mode */
+ err = regmap_update_bits(regmap, ctrl_base,
+ SC27XX_LED_RUN << ctrl_shift,
+ SC27XX_LED_RUN << ctrl_shift);
+ if (!err)
+ ldev->brightness = pattern[1].brightness;
+
+out:
+ mutex_unlock(&leds->priv->lock);
+
+ return err;
+}
+
static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
{
int i, err;
@@ -140,6 +257,9 @@ static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
led->priv = priv;
led->ldev.name = led->name;
led->ldev.brightness_set_blocking = sc27xx_led_set;
+ led->ldev.pattern_set = sc27xx_led_pattern_set;
+ led->ldev.pattern_clear = sc27xx_led_pattern_clear;
+ led->ldev.default_trigger = "pattern";
err = devm_led_classdev_register(dev, &led->ldev);
if (err)
@@ -241,4 +361,5 @@ static int sc27xx_led_remove(struct platform_device *pdev)
MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@spreadtrum.com>");
+MODULE_AUTHOR("Baolin Wang <baolin.wang@linaro.org>");
MODULE_LICENSE("GPL v2");
--
1.7.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v13 1/2] leds: core: Introduce LED pattern trigger
2018-09-27 5:04 [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Baolin Wang
2018-09-27 5:04 ` [PATCH v13 2/2] leds: sc27xx: Add pattern_set/clear interfaces for LED controller Baolin Wang
@ 2018-09-30 15:33 ` Jacek Anaszewski
2018-10-01 13:18 ` Baolin Wang
1 sibling, 1 reply; 5+ messages in thread
From: Jacek Anaszewski @ 2018-09-30 15:33 UTC (permalink / raw)
To: Baolin Wang, pavel
Cc: rteysseyre, bjorn.andersson, broonie, linus.walleij, linux-leds,
linux-kernel
Hi Baolin,
Thank you for adding the dimming support.
I've tested it and detected severe problem when
delta_t is lower than 50, i.e. UPDATE_INTERVAL.
echo "10 49 20 49" > pattern
results after a while in a system wide freeze, see the following
kernel log:
[ 210.593592] rcu: INFO: rcu_sched self-detected stall on CPU
[ 210.593601] rcu: 4-....: (21134 ticks this GP) idle=5b6/0/0x3
softirq=4843/4843 fqs=5250
[ 210.593602] rcu: (t=21000 jiffies g=25697 q=79)
[ 210.593605] NMI backtrace for cpu 4
[ 210.593608] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.19.0-rc1+ #156
[ 210.593609] Hardware name: Gigabyte Technology Co., Ltd.
Z97-HD3/Z97-HD3, BIOS F6 06/11/2014
[ 210.593609] Call Trace:
[ 210.593612] <IRQ>
[ 210.593618] dump_stack+0x46/0x5b
[ 210.593621] nmi_cpu_backtrace+0x90/0xa0
[ 210.593625] ? lapic_can_unplug_cpu+0x90/0x90
[ 210.593627] nmi_trigger_cpumask_backtrace+0x8d/0xc0
[ 210.593630] rcu_dump_cpu_stacks+0x83/0xb3
[ 210.593632] rcu_check_callbacks+0x5aa/0x710
[ 210.593636] ? tick_sched_do_timer+0x50/0x50
[ 210.593638] update_process_times+0x23/0x50
[ 210.593640] tick_sched_handle+0x2f/0x40
[ 210.593642] tick_sched_timer+0x32/0x70
[ 210.593644] __hrtimer_run_queues+0xf7/0x270
[ 210.593646] hrtimer_interrupt+0x11d/0x270
[ 210.593649] smp_apic_timer_interrupt+0x5d/0x130
[ 210.593651] apic_timer_interrupt+0xf/0x20
[ 210.593655] RIP: 0010:pattern_trig_timer_function+0x23/0x100
[ 210.593657] Code: ff ff eb f6 0f 1f 00 41 54 4c 8d a7 b0 df ff ff 55
53 48 89 fb 49 8d ac 24 18 20 00 00 48 89 ef e8 f2 d3 29 00 eb 16 8b 53
f4 <8b> 08 39 ca 77 05 83 f9 31 77 6d 4c 89 e7 e8 aa f9 ff ff 80 7b f8
[ 210.593658] RSP: 0018:ffff8d1017903eb8 EFLAGS: 00000216 ORIG_RAX:
ffffffffffffff13
[ 210.593659] RAX: ffff8d0fe7330010 RBX: ffff8d0fe7332050 RCX:
0000000000000031
[ 210.593660] RDX: 0000000000000000 RSI: 0000000000000014 RDI:
000000000000000a
[ 210.593661] RBP: ffff8d0fe7332018 R08: ffff8d1017903f08 R09:
ffff8d1017903f08
[ 210.593662] R10: 0000002c1cd5e92f R11: 0000000000000000 R12:
ffff8d0fe7330000
[ 210.593663] R13: ffffffffaa738a70 R14: 0000000000000000 R15:
0000000000000001
[ 210.593665] ? apic_timer_interrupt+0xa/0x20
[ 210.593666] ? pattern_trig_activate+0xc0/0xc0
[ 210.593669] ? pattern_trig_timer_function+0x36/0x100
[ 210.593671] call_timer_fn+0x26/0x130
[ 210.593672] run_timer_softirq+0x1cc/0x400
[ 210.593674] ? enqueue_hrtimer+0x35/0x90
[ 210.593676] ? __hrtimer_run_queues+0x127/0x270
[ 210.593679] ? recalibrate_cpu_khz+0x10/0x10
[ 210.593681] __do_softirq+0x104/0x2a5
[ 210.593685] irq_exit+0x9d/0xa0
[ 210.593687] smp_apic_timer_interrupt+0x67/0x130
[ 210.593688] apic_timer_interrupt+0xf/0x20
[ 210.593689] </IRQ>
[ 210.593693] RIP: 0010:cpuidle_enter_state+0xf8/0x2a0
[ 210.593694] Code: c7 0f 1f 44 00 00 31 ff e8 65 69 95 ff 80 7c 24 03
00 74 12 9c 58 f6 c4 02 0f 85 8c 01 00 00 31 ff e8 7c 41 9a ff fb 4d 29
e7 <48> ba cf f7 53 e3 a5 9b c4 20 4c 89 f8 4c 89 fd 48 f7 ea 48 c1 fd
[ 210.593695] RSP: 0018:ffffb0fc00cf7e88 EFLAGS: 00000206 ORIG_RAX:
ffffffffffffff13
[ 210.593696] RAX: ffff8d1017920dc0 RBX: ffff8d1014b49c00 RCX:
000000000000001f
[ 210.593697] RDX: 0000000000000000 RSI: 000000c1514cc3a0 RDI:
0000000000000000
[ 210.593698] RBP: 0000000000000001 R08: fffffffbcf10adc2 R09:
000000000000afc7
[ 210.593699] R10: 000000000000003c R11: ffff8d101791fe68 R12:
0000002c1d11a32d
[ 210.593700] R13: 0000000000000001 R14: 0000000000000004 R15:
0000000000011a82
[ 210.593703] ? cpuidle_enter_state+0xdb/0x2a0
[ 210.593705] do_idle+0x1f5/0x250
[ 210.593707] cpu_startup_entry+0x6a/0x70
[ 210.593709] start_secondary+0x183/0x1b0
[ 210.593711] secondary_startup_64+0xa4/0xb0
Probably the best solution would be to avoid the dimming if
delta_t is lower than UPDATE_INTERVAL.
Besides the above, please refer also to my comments below.
On 09/27/2018 07:04 AM, Baolin Wang wrote:
> This patch adds one new led trigger that LED device can configure
> the software or hardware pattern and trigger it.
>
> Consumers can write 'pattern' file to enable the software pattern
> which alters the brightness for the specified duration with one
> software timer.
>
> Moreover consumers can write 'hw_pattern' file to enable the hardware
> pattern for some LED controllers which can autonomously control
> brightness over time, according to some preprogrammed hardware
> patterns.
>
> Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
> Changes from v12:
> - Add gradual dimming support for software pattern.
>
> Changes from v11:
> - Change -1 means repeat indefinitely.
>
> Changes from v10:
> - Change 'int' to 'u32' for delta_t field.
>
> Changes from v9:
> - None.
>
> Changes from v8:
> - None.
>
> Changes from v7:
> - Move the SC27XX hardware patterns description into its own ABI file.
>
> Changes from v6:
> - Improve commit message.
> - Optimize the description of the hw_pattern file.
> - Simplify some logics.
>
> Changes from v5:
> - Add one 'hw_pattern' file for hardware patterns.
>
> Changes from v4:
> - Change the repeat file to return the originally written number.
> - Improve comments.
> - Fix some build warnings.
>
> 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 | 74 ++++
> drivers/leds/trigger/Kconfig | 7 +
> drivers/leds/trigger/Makefile | 1 +
> drivers/leds/trigger/ledtrig-pattern.c | 406 ++++++++++++++++++++
> include/linux/leds.h | 15 +
> 5 files changed, 503 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..e84d42a
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> @@ -0,0 +1,74 @@
> +What: /sys/class/leds/<led>/pattern
> +Date: September 2018
> +KernelVersion: 4.20
> +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 constant brightness.
> +
> + 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.
> +
> + 1. The gradual dimming format of the software pattern values
> + should be:
> + "brightness_1 duration_1 brightness_2 duration_2 brightness_3
> + duration_3 ...". For example:
> +
> + echo 0 1000 255 2000 > pattern
> +
> + It will make the LED go gradually from zero-intensity to max (255)
> + intensity in 1000 milliseconds, then back to zero intensity in 2000
> + milliseconds:
> +
> + LED brightness
> + ^
> + 255-| / \ / \ /
> + | / \ / \ /
> + | / \ / \ /
> + | / \ / \ /
> + 0-| / \/ \/
> + +---0----1----2----3----4----5----6------------> time (s)
> +
> + 2. To make the LED go instantly from one brigntess value to another,
> + we should use use zero-time lengths. So the format should be:
> + "brightness_1 duration_1 brightness_1 0 brightness_2 duration_2
> + brightness_2 0 ...". For example:
> +
> + echo 0 1000 0 0 255 2000 255 0 > pattern
> +
> + It will make the LED stay off for one second, then stay at max brightness
> + for two seconds:
> +
> + LED brightness
> + ^
> + 255-| +---------+ +---------+
> + | | | | |
> + | | | | |
> + | | | | |
> + 0-| -----+ +----+ +----
> + +---0----1----2----3----4----5----6------------> time (s)
> +
> +What: /sys/class/leds/<led>/hw_pattern
> +Date: September 2018
> +KernelVersion: 4.20
> +Description:
> + Specify a hardware pattern for the LED, for LED hardware that
> + supports autonomously controlling brightness over time, according
> + to some preprogrammed hardware patterns.
> +
> + Since different LED hardware can have different semantics of
> + hardware patterns, each driver is expected to provide its own
> + description for the hardware patterns in their ABI documentation
> + file.
> +
> +What: /sys/class/leds/<led>/repeat
> +Date: September 2018
> +KernelVersion: 4.20
> +Description:
> + Specify a pattern repeat number. -1 means repeat indefinitely,
> + other negative numbers and number 0 are invalid.
> +
> + This file will always return the originally written repeat
> + number.
> 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..7aba30e
> --- /dev/null
> +++ b/drivers/leds/trigger/ledtrig-pattern.c
> @@ -0,0 +1,406 @@
> +// 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 (data->delta_t == 0)
> + 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);
> +
> +try_again:
> + if (!data->is_indefinite && !data->repeat) {
> + mutex_unlock(&data->lock);
> + return;
> + }
Let's change try_again label to "for (;;) {" here (it seems that
above condition needs to be evaluated only on enter to this function).
> + if (data->curr->brightness == data->next->brightness) {
> + /* Constant brightness */
> + led_set_brightness(data->led_cdev, data->curr->brightness);
> + mod_timer(&data->timer,
> + jiffies + msecs_to_jiffies(data->curr->delta_t));
> +
> + /* Skip the step with zero duration */
> + pattern_trig_update_patterns(data);
> + /* Select next step */
> + pattern_trig_update_patterns(data);
> + } else {
> + /* Gradual dimming */
> +
> + /*
> + * If the accumulation time is larger than current step
> + * 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);
> + goto try_again;
When in for (;;) loop, we can "continue" here instead.
> + }
> +
> + /*
> + * If current step duration is less than UPDATE_INTERVAL, we
> + * should go next one and re-check if we repeated done.
> + */
> + if (data->curr->delta_t < UPDATE_INTERVAL) {
> + pattern_trig_update_patterns(data);
> + goto try_again;
Ditto.
> + }
> +
> + 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;
> + }
When in for (;;) loop we should "break" here.
> + 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);
> + }
> +
> + data->delta_t = 0;
> + 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 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;
I'm not sure if we discussed it earlier, but currently repeat_show
always reports initially requested repeat number, instead of the
number of remaining iterations. IMHO the latter approach would be
more useful.
> +
> + 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);
> +
> +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");
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 834683d..7393a31 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 +89,10 @@ struct led_classdev {
> unsigned long *delay_on,
> unsigned long *delay_off);
>
> + int (*pattern_set)(struct led_classdev *led_cdev,
> + struct led_pattern *pattern, u32 len, int repeat);
> + int (*pattern_clear)(struct led_classdev *led_cdev);
> +
> struct device *dev;
> const struct attribute_group **groups;
>
> @@ -472,4 +477,14 @@ static inline void led_classdev_notify_brightness_hw_changed(
> struct led_classdev *led_cdev, enum led_brightness brightness) { }
> #endif
>
> +/**
> + * struct led_pattern - pattern interval settings
> + * @delta_t: pattern interval delay, in milliseconds
> + * @brightness: pattern interval brightness
> + */
> +struct led_pattern {
> + u32 delta_t;
> + int brightness;
> +};
> +
> #endif /* __LINUX_LEDS_H_INCLUDED */
>
--
Best regards,
Jacek Anaszewski
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v13 1/2] leds: core: Introduce LED pattern trigger
2018-09-30 15:33 ` [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Jacek Anaszewski
@ 2018-10-01 13:18 ` Baolin Wang
2018-10-01 18:26 ` Jacek Anaszewski
0 siblings, 1 reply; 5+ messages in thread
From: Baolin Wang @ 2018-10-01 13:18 UTC (permalink / raw)
To: Jacek Anaszewski
Cc: Pavel Machek, rteysseyre, Bjorn Andersson, Mark Brown,
Linus Walleij, Linux LED Subsystem, LKML
Hi Jacek,
On 30 September 2018 at 23:33, Jacek Anaszewski
<jacek.anaszewski@gmail.com> wrote:
> Hi Baolin,
>
> Thank you for adding the dimming support.
>
> I've tested it and detected severe problem when
> delta_t is lower than 50, i.e. UPDATE_INTERVAL.
>
> echo "10 49 20 49" > pattern
>
> results after a while in a system wide freeze, see the following
> kernel log:
>
> [ 210.593592] rcu: INFO: rcu_sched self-detected stall on CPU
> [ 210.593601] rcu: 4-....: (21134 ticks this GP) idle=5b6/0/0x3
> softirq=4843/4843 fqs=5250
> [ 210.593602] rcu: (t=21000 jiffies g=25697 q=79)
> [ 210.593605] NMI backtrace for cpu 4
> [ 210.593608] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.19.0-rc1+ #156
> [ 210.593609] Hardware name: Gigabyte Technology Co., Ltd.
> Z97-HD3/Z97-HD3, BIOS F6 06/11/2014
> [ 210.593609] Call Trace:
> [ 210.593612] <IRQ>
> [ 210.593618] dump_stack+0x46/0x5b
> [ 210.593621] nmi_cpu_backtrace+0x90/0xa0
> [ 210.593625] ? lapic_can_unplug_cpu+0x90/0x90
> [ 210.593627] nmi_trigger_cpumask_backtrace+0x8d/0xc0
> [ 210.593630] rcu_dump_cpu_stacks+0x83/0xb3
> [ 210.593632] rcu_check_callbacks+0x5aa/0x710
> [ 210.593636] ? tick_sched_do_timer+0x50/0x50
> [ 210.593638] update_process_times+0x23/0x50
> [ 210.593640] tick_sched_handle+0x2f/0x40
> [ 210.593642] tick_sched_timer+0x32/0x70
> [ 210.593644] __hrtimer_run_queues+0xf7/0x270
> [ 210.593646] hrtimer_interrupt+0x11d/0x270
> [ 210.593649] smp_apic_timer_interrupt+0x5d/0x130
> [ 210.593651] apic_timer_interrupt+0xf/0x20
> [ 210.593655] RIP: 0010:pattern_trig_timer_function+0x23/0x100
> [ 210.593657] Code: ff ff eb f6 0f 1f 00 41 54 4c 8d a7 b0 df ff ff 55
> 53 48 89 fb 49 8d ac 24 18 20 00 00 48 89 ef e8 f2 d3 29 00 eb 16 8b 53
> f4 <8b> 08 39 ca 77 05 83 f9 31 77 6d 4c 89 e7 e8 aa f9 ff ff 80 7b f8
> [ 210.593658] RSP: 0018:ffff8d1017903eb8 EFLAGS: 00000216 ORIG_RAX:
> ffffffffffffff13
> [ 210.593659] RAX: ffff8d0fe7330010 RBX: ffff8d0fe7332050 RCX:
> 0000000000000031
> [ 210.593660] RDX: 0000000000000000 RSI: 0000000000000014 RDI:
> 000000000000000a
> [ 210.593661] RBP: ffff8d0fe7332018 R08: ffff8d1017903f08 R09:
> ffff8d1017903f08
> [ 210.593662] R10: 0000002c1cd5e92f R11: 0000000000000000 R12:
> ffff8d0fe7330000
> [ 210.593663] R13: ffffffffaa738a70 R14: 0000000000000000 R15:
> 0000000000000001
> [ 210.593665] ? apic_timer_interrupt+0xa/0x20
> [ 210.593666] ? pattern_trig_activate+0xc0/0xc0
> [ 210.593669] ? pattern_trig_timer_function+0x36/0x100
> [ 210.593671] call_timer_fn+0x26/0x130
> [ 210.593672] run_timer_softirq+0x1cc/0x400
> [ 210.593674] ? enqueue_hrtimer+0x35/0x90
> [ 210.593676] ? __hrtimer_run_queues+0x127/0x270
> [ 210.593679] ? recalibrate_cpu_khz+0x10/0x10
> [ 210.593681] __do_softirq+0x104/0x2a5
> [ 210.593685] irq_exit+0x9d/0xa0
> [ 210.593687] smp_apic_timer_interrupt+0x67/0x130
> [ 210.593688] apic_timer_interrupt+0xf/0x20
> [ 210.593689] </IRQ>
> [ 210.593693] RIP: 0010:cpuidle_enter_state+0xf8/0x2a0
> [ 210.593694] Code: c7 0f 1f 44 00 00 31 ff e8 65 69 95 ff 80 7c 24 03
> 00 74 12 9c 58 f6 c4 02 0f 85 8c 01 00 00 31 ff e8 7c 41 9a ff fb 4d 29
> e7 <48> ba cf f7 53 e3 a5 9b c4 20 4c 89 f8 4c 89 fd 48 f7 ea 48 c1 fd
> [ 210.593695] RSP: 0018:ffffb0fc00cf7e88 EFLAGS: 00000206 ORIG_RAX:
> ffffffffffffff13
> [ 210.593696] RAX: ffff8d1017920dc0 RBX: ffff8d1014b49c00 RCX:
> 000000000000001f
> [ 210.593697] RDX: 0000000000000000 RSI: 000000c1514cc3a0 RDI:
> 0000000000000000
> [ 210.593698] RBP: 0000000000000001 R08: fffffffbcf10adc2 R09:
> 000000000000afc7
> [ 210.593699] R10: 000000000000003c R11: ffff8d101791fe68 R12:
> 0000002c1d11a32d
> [ 210.593700] R13: 0000000000000001 R14: 0000000000000004 R15:
> 0000000000011a82
> [ 210.593703] ? cpuidle_enter_state+0xdb/0x2a0
> [ 210.593705] do_idle+0x1f5/0x250
> [ 210.593707] cpu_startup_entry+0x6a/0x70
> [ 210.593709] start_secondary+0x183/0x1b0
> [ 210.593711] secondary_startup_64+0xa4/0xb0
>
> Probably the best solution would be to avoid the dimming if
> delta_t is lower than UPDATE_INTERVAL.
Thanks for your testing. Yes, I will valid the delta_t value when user
use the gradual dimming, and add some comments in ABI to make it
clear, that we should not set delta_t lower than UPDATE_INTERVAL for
gradual dimming.
>
> Besides the above, please refer also to my comments below.
>
> On 09/27/2018 07:04 AM, Baolin Wang wrote:
>> This patch adds one new led trigger that LED device can configure
>> the software or hardware pattern and trigger it.
>>
>> Consumers can write 'pattern' file to enable the software pattern
>> which alters the brightness for the specified duration with one
>> software timer.
>>
>> Moreover consumers can write 'hw_pattern' file to enable the hardware
>> pattern for some LED controllers which can autonomously control
>> brightness over time, according to some preprogrammed hardware
>> patterns.
>>
>> Signed-off-by: Raphael Teysseyre <rteysseyre@gmail.com>
>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> ---
>> Changes from v12:
>> - Add gradual dimming support for software pattern.
>>
>> Changes from v11:
>> - Change -1 means repeat indefinitely.
>>
>> Changes from v10:
>> - Change 'int' to 'u32' for delta_t field.
>>
>> Changes from v9:
>> - None.
>>
>> Changes from v8:
>> - None.
>>
>> Changes from v7:
>> - Move the SC27XX hardware patterns description into its own ABI file.
>>
>> Changes from v6:
>> - Improve commit message.
>> - Optimize the description of the hw_pattern file.
>> - Simplify some logics.
>>
>> Changes from v5:
>> - Add one 'hw_pattern' file for hardware patterns.
>>
>> Changes from v4:
>> - Change the repeat file to return the originally written number.
>> - Improve comments.
>> - Fix some build warnings.
>>
>> 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 | 74 ++++
>> drivers/leds/trigger/Kconfig | 7 +
>> drivers/leds/trigger/Makefile | 1 +
>> drivers/leds/trigger/ledtrig-pattern.c | 406 ++++++++++++++++++++
>> include/linux/leds.h | 15 +
>> 5 files changed, 503 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..e84d42a
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>> @@ -0,0 +1,74 @@
>> +What: /sys/class/leds/<led>/pattern
>> +Date: September 2018
>> +KernelVersion: 4.20
>> +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 constant brightness.
>> +
>> + 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.
>> +
>> + 1. The gradual dimming format of the software pattern values
>> + should be:
>> + "brightness_1 duration_1 brightness_2 duration_2 brightness_3
>> + duration_3 ...". For example:
>> +
>> + echo 0 1000 255 2000 > pattern
>> +
>> + It will make the LED go gradually from zero-intensity to max (255)
>> + intensity in 1000 milliseconds, then back to zero intensity in 2000
>> + milliseconds:
>> +
>> + LED brightness
>> + ^
>> + 255-| / \ / \ /
>> + | / \ / \ /
>> + | / \ / \ /
>> + | / \ / \ /
>> + 0-| / \/ \/
>> + +---0----1----2----3----4----5----6------------> time (s)
>> +
>> + 2. To make the LED go instantly from one brigntess value to another,
>> + we should use use zero-time lengths. So the format should be:
>> + "brightness_1 duration_1 brightness_1 0 brightness_2 duration_2
>> + brightness_2 0 ...". For example:
>> +
>> + echo 0 1000 0 0 255 2000 255 0 > pattern
>> +
>> + It will make the LED stay off for one second, then stay at max brightness
>> + for two seconds:
>> +
>> + LED brightness
>> + ^
>> + 255-| +---------+ +---------+
>> + | | | | |
>> + | | | | |
>> + | | | | |
>> + 0-| -----+ +----+ +----
>> + +---0----1----2----3----4----5----6------------> time (s)
>> +
>> +What: /sys/class/leds/<led>/hw_pattern
>> +Date: September 2018
>> +KernelVersion: 4.20
>> +Description:
>> + Specify a hardware pattern for the LED, for LED hardware that
>> + supports autonomously controlling brightness over time, according
>> + to some preprogrammed hardware patterns.
>> +
>> + Since different LED hardware can have different semantics of
>> + hardware patterns, each driver is expected to provide its own
>> + description for the hardware patterns in their ABI documentation
>> + file.
>> +
>> +What: /sys/class/leds/<led>/repeat
>> +Date: September 2018
>> +KernelVersion: 4.20
>> +Description:
>> + Specify a pattern repeat number. -1 means repeat indefinitely,
>> + other negative numbers and number 0 are invalid.
>> +
>> + This file will always return the originally written repeat
>> + number.
>> 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..7aba30e
>> --- /dev/null
>> +++ b/drivers/leds/trigger/ledtrig-pattern.c
>> @@ -0,0 +1,406 @@
>> +// 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 (data->delta_t == 0)
>> + 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);
>> +
>> +try_again:
>> + if (!data->is_indefinite && !data->repeat) {
>> + mutex_unlock(&data->lock);
>> + return;
>> + }
>
> Let's change try_again label to "for (;;) {" here (it seems that
> above condition needs to be evaluated only on enter to this function).
Sure.
>
>> + if (data->curr->brightness == data->next->brightness) {
>> + /* Constant brightness */
>> + led_set_brightness(data->led_cdev, data->curr->brightness);
>> + mod_timer(&data->timer,
>> + jiffies + msecs_to_jiffies(data->curr->delta_t));
>> +
>> + /* Skip the step with zero duration */
>> + pattern_trig_update_patterns(data);
>> + /* Select next step */
>> + pattern_trig_update_patterns(data);
>> + } else {
>> + /* Gradual dimming */
>> +
>> + /*
>> + * If the accumulation time is larger than current step
>> + * 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);
>> + goto try_again;
>
> When in for (;;) loop, we can "continue" here instead.
Yes.
>
>> + }
>> +
>> + /*
>> + * If current step duration is less than UPDATE_INTERVAL, we
>> + * should go next one and re-check if we repeated done.
>> + */
>> + if (data->curr->delta_t < UPDATE_INTERVAL) {
>> + pattern_trig_update_patterns(data);
>> + goto try_again;
>
> Ditto.
>
>> + }
>> +
>> + 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;
>> + }
>
> When in for (;;) loop we should "break" here.
Yes.
>
>> + 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);
>> + }
>> +
>> + data->delta_t = 0;
>> + 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 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;
>
> I'm not sure if we discussed it earlier, but currently repeat_show
> always reports initially requested repeat number, instead of the
> number of remaining iterations. IMHO the latter approach would be
> more useful.
That's what we discussed before and had a consensus about this. Please see:
https://lore.kernel.org/patchwork/patch/971746/
Thanks.
--
Baolin Wang
Best Regards
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v13 1/2] leds: core: Introduce LED pattern trigger
2018-10-01 13:18 ` Baolin Wang
@ 2018-10-01 18:26 ` Jacek Anaszewski
0 siblings, 0 replies; 5+ messages in thread
From: Jacek Anaszewski @ 2018-10-01 18:26 UTC (permalink / raw)
To: Baolin Wang
Cc: Pavel Machek, rteysseyre, Bjorn Andersson, Mark Brown,
Linus Walleij, Linux LED Subsystem, LKML
Hi Baolin,
On 10/01/2018 03:18 PM, Baolin Wang wrote:
> Hi Jacek,
>
> On 30 September 2018 at 23:33, Jacek Anaszewski
> <jacek.anaszewski@gmail.com> wrote:
>> Hi Baolin,
>>
>> Thank you for adding the dimming support.
>>
>> I've tested it and detected severe problem when
>> delta_t is lower than 50, i.e. UPDATE_INTERVAL.
>>
>> echo "10 49 20 49" > pattern
>>
>> results after a while in a system wide freeze, see the following
>> kernel log:
>>
>> [ 210.593592] rcu: INFO: rcu_sched self-detected stall on CPU
>> [ 210.593601] rcu: 4-....: (21134 ticks this GP) idle=5b6/0/0x3
>> softirq=4843/4843 fqs=5250
>> [ 210.593602] rcu: (t=21000 jiffies g=25697 q=79)
>> [ 210.593605] NMI backtrace for cpu 4
>> [ 210.593608] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.19.0-rc1+ #156
>> [ 210.593609] Hardware name: Gigabyte Technology Co., Ltd.
>> Z97-HD3/Z97-HD3, BIOS F6 06/11/2014
>> [ 210.593609] Call Trace:
>> [ 210.593612] <IRQ>
>> [ 210.593618] dump_stack+0x46/0x5b
>> [ 210.593621] nmi_cpu_backtrace+0x90/0xa0
>> [ 210.593625] ? lapic_can_unplug_cpu+0x90/0x90
>> [ 210.593627] nmi_trigger_cpumask_backtrace+0x8d/0xc0
>> [ 210.593630] rcu_dump_cpu_stacks+0x83/0xb3
>> [ 210.593632] rcu_check_callbacks+0x5aa/0x710
>> [ 210.593636] ? tick_sched_do_timer+0x50/0x50
>> [ 210.593638] update_process_times+0x23/0x50
>> [ 210.593640] tick_sched_handle+0x2f/0x40
>> [ 210.593642] tick_sched_timer+0x32/0x70
>> [ 210.593644] __hrtimer_run_queues+0xf7/0x270
>> [ 210.593646] hrtimer_interrupt+0x11d/0x270
>> [ 210.593649] smp_apic_timer_interrupt+0x5d/0x130
>> [ 210.593651] apic_timer_interrupt+0xf/0x20
>> [ 210.593655] RIP: 0010:pattern_trig_timer_function+0x23/0x100
>> [ 210.593657] Code: ff ff eb f6 0f 1f 00 41 54 4c 8d a7 b0 df ff ff 55
>> 53 48 89 fb 49 8d ac 24 18 20 00 00 48 89 ef e8 f2 d3 29 00 eb 16 8b 53
>> f4 <8b> 08 39 ca 77 05 83 f9 31 77 6d 4c 89 e7 e8 aa f9 ff ff 80 7b f8
>> [ 210.593658] RSP: 0018:ffff8d1017903eb8 EFLAGS: 00000216 ORIG_RAX:
>> ffffffffffffff13
>> [ 210.593659] RAX: ffff8d0fe7330010 RBX: ffff8d0fe7332050 RCX:
>> 0000000000000031
>> [ 210.593660] RDX: 0000000000000000 RSI: 0000000000000014 RDI:
>> 000000000000000a
>> [ 210.593661] RBP: ffff8d0fe7332018 R08: ffff8d1017903f08 R09:
>> ffff8d1017903f08
>> [ 210.593662] R10: 0000002c1cd5e92f R11: 0000000000000000 R12:
>> ffff8d0fe7330000
>> [ 210.593663] R13: ffffffffaa738a70 R14: 0000000000000000 R15:
>> 0000000000000001
>> [ 210.593665] ? apic_timer_interrupt+0xa/0x20
>> [ 210.593666] ? pattern_trig_activate+0xc0/0xc0
>> [ 210.593669] ? pattern_trig_timer_function+0x36/0x100
>> [ 210.593671] call_timer_fn+0x26/0x130
>> [ 210.593672] run_timer_softirq+0x1cc/0x400
>> [ 210.593674] ? enqueue_hrtimer+0x35/0x90
>> [ 210.593676] ? __hrtimer_run_queues+0x127/0x270
>> [ 210.593679] ? recalibrate_cpu_khz+0x10/0x10
>> [ 210.593681] __do_softirq+0x104/0x2a5
>> [ 210.593685] irq_exit+0x9d/0xa0
>> [ 210.593687] smp_apic_timer_interrupt+0x67/0x130
>> [ 210.593688] apic_timer_interrupt+0xf/0x20
>> [ 210.593689] </IRQ>
>> [ 210.593693] RIP: 0010:cpuidle_enter_state+0xf8/0x2a0
>> [ 210.593694] Code: c7 0f 1f 44 00 00 31 ff e8 65 69 95 ff 80 7c 24 03
>> 00 74 12 9c 58 f6 c4 02 0f 85 8c 01 00 00 31 ff e8 7c 41 9a ff fb 4d 29
>> e7 <48> ba cf f7 53 e3 a5 9b c4 20 4c 89 f8 4c 89 fd 48 f7 ea 48 c1 fd
>> [ 210.593695] RSP: 0018:ffffb0fc00cf7e88 EFLAGS: 00000206 ORIG_RAX:
>> ffffffffffffff13
>> [ 210.593696] RAX: ffff8d1017920dc0 RBX: ffff8d1014b49c00 RCX:
>> 000000000000001f
>> [ 210.593697] RDX: 0000000000000000 RSI: 000000c1514cc3a0 RDI:
>> 0000000000000000
>> [ 210.593698] RBP: 0000000000000001 R08: fffffffbcf10adc2 R09:
>> 000000000000afc7
>> [ 210.593699] R10: 000000000000003c R11: ffff8d101791fe68 R12:
>> 0000002c1d11a32d
>> [ 210.593700] R13: 0000000000000001 R14: 0000000000000004 R15:
>> 0000000000011a82
>> [ 210.593703] ? cpuidle_enter_state+0xdb/0x2a0
>> [ 210.593705] do_idle+0x1f5/0x250
>> [ 210.593707] cpu_startup_entry+0x6a/0x70
>> [ 210.593709] start_secondary+0x183/0x1b0
>> [ 210.593711] secondary_startup_64+0xa4/0xb0
>>
>> Probably the best solution would be to avoid the dimming if
>> delta_t is lower than UPDATE_INTERVAL.
>
> Thanks for your testing. Yes, I will valid the delta_t value when user
> use the gradual dimming, and add some comments in ABI to make it
> clear, that we should not set delta_t lower than UPDATE_INTERVAL for
> gradual dimming.
Thanks.
[...]
>>> +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;
>>
>> I'm not sure if we discussed it earlier, but currently repeat_show
>> always reports initially requested repeat number, instead of the
>> number of remaining iterations. IMHO the latter approach would be
>> more useful.
>
> That's what we discussed before and had a consensus about this. Please see:
> https://lore.kernel.org/patchwork/patch/971746/
Ah right. I had a vague reminiscence of this discussion, but failed to
track it back.
OK, so no action is required here, let's keep the things as we agreed.
--
Best regards,
Jacek Anaszewski
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2018-10-01 18:26 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-09-27 5:04 [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Baolin Wang
2018-09-27 5:04 ` [PATCH v13 2/2] leds: sc27xx: Add pattern_set/clear interfaces for LED controller Baolin Wang
2018-09-30 15:33 ` [PATCH v13 1/2] leds: core: Introduce LED pattern trigger Jacek Anaszewski
2018-10-01 13:18 ` Baolin Wang
2018-10-01 18:26 ` Jacek Anaszewski
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