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Date: Fri, 31 Aug 2018 13:50:51 +0800
From: Baolin Wang <baolin.wang@...aro.org>
To: Jacek Anaszewski <jacek.anaszewski@...il.com>
Cc: Pavel Machek <pavel@....cz>, rteysseyre@...il.com,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Mark Brown <broonie@...nel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Linux LED Subsystem <linux-leds@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 1/2] leds: core: Introduce LED pattern trigger
Hi Jacek,
On 31 August 2018 at 03:55, Jacek Anaszewski <jacek.anaszewski@...il.com> wrote:
> Hi Baolin,
>
> On 08/30/2018 09:40 AM, Baolin Wang wrote:
>> Some LED controllers have support for autonomously controlling
>> brightness over time, according to some preprogrammed pattern or
>> function.
>
> I think that this commit message should be rearranged, so that
> the software pattern was mentioned in the first place. Please keep
> in mind that LED triggers are defined as kernel based sources of
> LED events in the first place.
Sure.
>
>>
>> This patch adds pattern trigger that LED device can configure the
>> pattern and trigger it.
>>
>> Signed-off-by: Raphael Teysseyre <rteysseyre@...il.com>
>> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
>> ---
>> 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 | 41 +++
>> drivers/leds/trigger/Kconfig | 7 +
>> drivers/leds/trigger/Makefile | 1 +
>> drivers/leds/trigger/ledtrig-pattern.c | 344 ++++++++++++++++++++
>> include/linux/leds.h | 16 +
>> 5 files changed, 409 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..dda8bbc
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
>> @@ -0,0 +1,41 @@
>> +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.
>> +
>> + 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 software pattern values should be:
>> + "brightness_1 duration_1 brightness_2 duration_2 brightness_3
>> + duration_3 ...".
>> +
>> +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 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 hardware pattern values should be:
>> + "brightness_1 duration_1 brightness_2 duration_2 brightness_3
>> + duration_3 ...".
>
> hw_pattern interface should have separate description for each driver
> supporting it. This is why we are to have a separate file for it.
> So, here I'd just mention that each driver is expected to provide its
> own ABI documentation for hw_pattern.
>
> E.g. in case of sc27xx you should describe the specific semantics of
> each tuple, which will refer to a breathing curve settings.
Sure. Will do.
>
>> +
>> +What: /sys/class/leds/<led>/repeat
>> +Date: September 2018
>> +KernelVersion: 4.20
>> +Description:
>> + Specify a pattern repeat number. 0 means repeat indefinitely.
>> +
>> + 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..efbd5ef
>> --- /dev/null
>> +++ b/drivers/leds/trigger/ledtrig-pattern.c
>> @@ -0,0 +1,344 @@
>> +// 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;
>> + u32 last_repeat;
>> + 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++;
>> +}
>> +
>> +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 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->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;
>> + u32 repeat;
>> +
>> + mutex_lock(&data->lock);
>> +
>> + repeat = data->last_repeat;
>> +
>> + mutex_unlock(&data->lock);
>> +
>> + return scnprintf(buf, PAGE_SIZE, "%u\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;
>> + unsigned long res;
>> + int err;
>> +
>> + err = kstrtoul(buf, 10, &res);
>> + if (err)
>> + return err;
>> +
>> + /*
>> + * 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;
>> +
>> + /* 0 means repeat indefinitely */
>> + if (!data->repeat)
>> + data->is_indefinite = true;
>> + else
>> + data->is_indefinite = false;
>
> data->is_indefinite = !data->repeat;
OK.
>
>> +
>> + 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 %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_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);
>> +
>> + if (hw_pattern)
>> + data->is_hw_pattern = true;
>> + else
>> + data->is_hw_pattern = false;
>
> Why not just:
>
> data->is_hw_pattern = hw_pattern;
Right. Will simplify this logic. Thanks.
--
Baolin Wang
Best Regards
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