Re: [PATCH 3/3] leds: triggers: heartbeat: add RGB version of the trigger

[Heiner Kallweit]

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.

> 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.

Regards, Heiner

> 
> Best regards,
> Jacek Anaszewski
> 
> 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@xxxxxxxxx>
>> ---
>>   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));
>> +}
>> +
>>   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;
>> +
>> +    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;
>>
>> +    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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