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Message-id: <56EBFDDF.7000008@samsung.com>
Date: Fri, 18 Mar 2016 14:08:47 +0100
From: Jacek Anaszewski <j.anaszewski@...sung.com>
To: Heiner Kallweit <hkallweit1@...il.com>
Cc: "linux-leds@...r.kernel.org" <linux-leds@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] leds: triggers: heartbeat: add RGB version of the
trigger
On 03/17/2016 09:04 PM, Heiner Kallweit wrote:
> Am 17.03.2016 um 14:41 schrieb Jacek Anaszewski:
>> Hi Heiner,
>>
>> Thanks for the patch. I have a few questions:
>>
>> 1. Why do you want to register another trigger in
>> a ledtrig-heartbeat.c?
> The existing trigger uses the heartbeat and can be used with RGB
> and non-RGB LED's. The new trigger uses color to visualize the load
> and can be used with RGB LED's only.
>
>> 2. heartbeat trigger implements LED blinking timing that
>> resembles human heart beat rhythm, whereas heartbeat_led_rgb_trigger
>> seems not to reuse led_heartbeat_function code, but instead
>> led_heartbeat_rgb_function() sets timer interval to 500ms, after
>> doing some color magic in led_trigger_range_event(). Where is the
>> heartbeat rhythm implemented here?
> It uses a color to display the load instead of a rhythm.
> I have to admit that this trigger might not perfectly fit here as it
> doesn't actually implement a heartbeat. However it visualizes the same
> parameter (system load). If preferrable I can make it a separate trigger.
Having it in the ledtrig-heartbeat.c would make sense if we you applied
also the same blinking pattern. Is there some specific reason for which
you didn't reuse heartbeat blinking pattern, but instead used fixed
period?
>> 3. Why heartbeat_range.end is somehow related to num_online_cpus()?
> Because e.g. 5 is a high load on a single CPU system but more or less
> idle on a 64 CPU system.
I see, thanks for the explanation.
I have also few comments below.
>>
>> On 03/13/2016 06:18 PM, Heiner Kallweit wrote:
>>> Add a RGB version of the heartbeat trigger (heartbeat-rgb). This version of
>>> the trigger can only be used with LED devices supporting the RGB extension.
>>>
>>> It maps the load [0 .. num_online_cpus] to a color between green and red.
>>>
>>> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
>>> ---
>>> drivers/leds/trigger/ledtrig-heartbeat.c | 64 +++++++++++++++++++++++++++++++-
>>> 1 file changed, 63 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c
>>> index 410c39c..510a3c9 100644
>>> --- a/drivers/leds/trigger/ledtrig-heartbeat.c
>>> +++ b/drivers/leds/trigger/ledtrig-heartbeat.c
>>> @@ -22,6 +22,7 @@
>>> #include "../leds.h"
>>>
>>> static int panic_heartbeats;
>>> +static struct led_trigger heartbeat_led_rgb_trigger;
>>>
>>> struct heartbeat_trig_data {
>>> unsigned int phase;
>>> @@ -30,6 +31,14 @@ struct heartbeat_trig_data {
>>> unsigned int invert;
>>> };
>>>
>>> +static struct led_trigger_range led_heartbeat_range = {
>>> + .start = 0,
>>> + /* default, overridden by module init function */
>>> + .end = 4 * FIXED_1,
>>> + .color_start = 0x54ffff, /* GREEN */
>>> + .color_end = 0x00ffff, /* RED */
>>> +};
>>> +
>>> static void led_heartbeat_function(unsigned long data)
>>> {
>>> struct led_classdev *led_cdev = (struct led_classdev *) data;
>>> @@ -85,6 +94,15 @@ static void led_heartbeat_function(unsigned long data)
>>> mod_timer(&heartbeat_data->timer, jiffies + delay);
>>> }
>>>
>>> +static void led_heartbeat_rgb_function(unsigned long data)
>>> +{
>>> + struct led_classdev *led_cdev = (struct led_classdev *) data;
>>> + struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
>>> +
>>> + led_trigger_range_event(&heartbeat_led_rgb_trigger, avenrun[0]);
>>> + mod_timer(&heartbeat_data->timer, jiffies + msecs_to_jiffies(500));
>>> +}
This function could reuse the code from led_heartbeat_function(), that
calculates timer delay. That code could be made reusable by
both monochrome and rgb heartbeat trigger.
>>> static ssize_t led_invert_show(struct device *dev,
>>> struct device_attribute *attr, char *buf)
>>> {
>>> @@ -136,6 +154,22 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev)
>>> led_cdev->activated = true;
>>> }
>>>
>>> +static void heartbeat_trig_rgb_activate(struct led_classdev *led_cdev)
>>> +{
>>> + struct heartbeat_trig_data *heartbeat_data;
>>> +
>>> + heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
>>> + if (!heartbeat_data)
>>> + return;
>>> +
>>> + led_cdev->trigger_data = heartbeat_data;
How about adding struct rgb_heartbeat_trig_data comprising
two properties of types struct heartbeat_trig_data and
struct led_trigger_range respectively?
It would be used by the new led_heartbeat_rgb_function to
store blinking and color related data.
>>> + setup_timer(&heartbeat_data->timer,
>>> + led_heartbeat_rgb_function, (unsigned long) led_cdev);
>>> + led_heartbeat_rgb_function(heartbeat_data->timer.data);
>>> + led_cdev->activated = true;
>>> +}
>>> +
>>> static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
>>> {
>>> struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
>>> @@ -148,12 +182,31 @@ static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
>>> }
>>> }
>>>
>>> +static void heartbeat_trig_rgb_deactivate(struct led_classdev *led_cdev)
>>> +{
>>> + struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
>>> +
>>> + if (led_cdev->activated) {
>>> + del_timer_sync(&heartbeat_data->timer);
>>> + kfree(heartbeat_data);
>>> + led_cdev->activated = false;
>>> + }
>>> +}
>>> +
>>> static struct led_trigger heartbeat_led_trigger = {
>>> .name = "heartbeat",
>>> .activate = heartbeat_trig_activate,
>>> .deactivate = heartbeat_trig_deactivate,
>>> };
>>>
>>> +static struct led_trigger heartbeat_led_rgb_trigger = {
>>> + .flags = LED_TRIG_CAP_RGB,
>>> + .name = "heartbeat-rgb",
>>> + .range = &led_heartbeat_range,
>>> + .activate = heartbeat_trig_rgb_activate,
>>> + .deactivate = heartbeat_trig_rgb_deactivate,
>>> +};
>>> +
>>> static int heartbeat_reboot_notifier(struct notifier_block *nb,
>>> unsigned long code, void *unused)
>>> {
>>> @@ -178,9 +231,17 @@ static struct notifier_block heartbeat_panic_nb = {
>>>
>>> static int __init heartbeat_trig_init(void)
>>> {
>>> - int rc = led_trigger_register(&heartbeat_led_trigger);
>>> + int rc;
>>> +
>>> + led_heartbeat_range.end = num_online_cpus() * FIXED_1;
>>> +
>>> + rc = led_trigger_register(&heartbeat_led_rgb_trigger);
>>> + if (rc)
>>> + return rc;
With inherited blinking pattern rgb version will also have to
register the same notifiers as the monochrome one.
>>> + rc = led_trigger_register(&heartbeat_led_trigger);
>>> if (!rc) {
>>> + led_trigger_unregister(&heartbeat_led_rgb_trigger);
>>> atomic_notifier_chain_register(&panic_notifier_list,
>>> &heartbeat_panic_nb);
>>> register_reboot_notifier(&heartbeat_reboot_nb);
>>> @@ -194,6 +255,7 @@ static void __exit heartbeat_trig_exit(void)
>>> atomic_notifier_chain_unregister(&panic_notifier_list,
>>> &heartbeat_panic_nb);
>>> led_trigger_unregister(&heartbeat_led_trigger);
>>> + led_trigger_unregister(&heartbeat_led_rgb_trigger);
>>> }
>>>
>>> module_init(heartbeat_trig_init);
>>>
>>
>>
>> --
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>>
>
>
>
--
Best regards,
Jacek Anaszewski
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