Re: [PATCH] leds: triggers: add invert to heartbeat

["Jiří Prchal" <jiri.prchal@aksignal.cz>]

Hi Jacek,
comments below...

On 7.10.2015 15:32, Jacek Anaszewski wrote:
> Hi Jiri,
>
> Thanks for the patch. It's nice in general, but please see my
> comments below.
>
> On 10/07/2015 11:31 AM, Jiri Prchal wrote:
>> This patcht adds possibility to invert heartbeat blinking. The inverted LED is
>> more time ON then OFF.
>> It's because it looks better when the heartbeat LED is next to other LED which
>> is most time ON.
>> The invert value is exported same way via sysfs in file invert like oneshot. I
>> get inspiration from this trigger.
>
> Please adjust commit message so as it wouldn't exceed 75 characters line
> length limit. scripts/checkpatch.pl is useful for  catching this kind of
> problems.
>
>> Signed-off-by: Jiri Prchal <jiri.prchal@aksignal.cz>
>> ---
>>   drivers/leds/trigger/ledtrig-heartbeat.c | 49 ++++++++++++++++++++++++++++++--
>>   1 file changed, 47 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c
>> index fea6871..c09c30b 100644
>> --- a/drivers/leds/trigger/ledtrig-heartbeat.c
>> +++ b/drivers/leds/trigger/ledtrig-heartbeat.c
>> @@ -27,6 +27,7 @@ struct heartbeat_trig_data {
>>       unsigned int phase;
>>       unsigned int period;
>>       struct timer_list timer;
>> +    unsigned int invert;
>>   };
>>
>>   static void led_heartbeat_function(unsigned long data)
>> @@ -56,21 +57,27 @@ static void led_heartbeat_function(unsigned long data)
>>               msecs_to_jiffies(heartbeat_data->period);
>>           delay = msecs_to_jiffies(70);
>>           heartbeat_data->phase++;
>> -        brightness = led_cdev->max_brightness;
>> +        if (!heartbeat_data->invert)
>> +            brightness = led_cdev->max_brightness;
>>           break;
>>       case 1:
>>           delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
>>           heartbeat_data->phase++;
>> +        if (heartbeat_data->invert)
>> +            brightness = led_cdev->max_brightness;
>
> As you are at it, could you change, in a separate patch,
> led_cdev->max_brightness to led_cdev->brightness? I think there is no
> reason for which we shouldn't allow other values than max.
I changed it but it doesn't blink at all.

>
>>           break;
>>       case 2:
>>           delay = msecs_to_jiffies(70);
>>           heartbeat_data->phase++;
>> -        brightness = led_cdev->max_brightness;
>> +        if (!heartbeat_data->invert)
>> +            brightness = led_cdev->max_brightness;
>>           break;
>>       default:
>>           delay = heartbeat_data->period - heartbeat_data->period / 4 -
>>               msecs_to_jiffies(70);
>>           heartbeat_data->phase = 0;
>> +        if (heartbeat_data->invert)
>> +            brightness = led_cdev->max_brightness;
>>           break;
>>       }
>>
>> @@ -78,15 +85,50 @@ static void led_heartbeat_function(unsigned long data)
>>       mod_timer(&heartbeat_data->timer, jiffies + delay);
>>   }
>>
>> +static ssize_t led_invert_show(struct device *dev,
>> +        struct device_attribute *attr, char *buf)
>> +{
>> +    struct led_classdev *led_cdev = dev_get_drvdata(dev);
>> +    struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
>> +
>> +    return sprintf(buf, "%u\n", heartbeat_data->invert);
>> +}
>> +
>> +static ssize_t led_invert_store(struct device *dev,
>> +        struct device_attribute *attr, const char *buf, size_t size)
>> +{
>> +    struct led_classdev *led_cdev = dev_get_drvdata(dev);
>> +    struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
>> +    unsigned long state;
>> +    int ret;
>> +
>> +    ret = kstrtoul(buf, 0, &state);
>> +    if (ret)
>> +        return ret;
>> +
>> +    heartbeat_data->invert = !!state;
>> +
>> +    return size;
>> +}
>> +
>> +static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
>> +
>>   static void heartbeat_trig_activate(struct led_classdev *led_cdev)
>>   {
>>       struct heartbeat_trig_data *heartbeat_data;
>> +    int rc;
>>
>>       heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
>>       if (!heartbeat_data)
>>           return;
>>
>>       led_cdev->trigger_data = heartbeat_data;
>> +    rc = device_create_file(led_cdev->dev, &dev_attr_invert);
>> +    if (rc) {
>> +        kfree(led_cdev->trigger_data);
>> +        return;
>> +    }
>> +
>>       setup_timer(&heartbeat_data->timer,
>>               led_heartbeat_function, (unsigned long) led_cdev);
>>       heartbeat_data->phase = 0;
>> @@ -100,9 +142,12 @@ static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
>>
>>       if (led_cdev->activated) {
>>           del_timer_sync(&heartbeat_data->timer);
>> +        device_remove_file(led_cdev->dev, &dev_attr_invert);
>>           kfree(heartbeat_data);
>>           led_cdev->activated = false;
>>       }
>> +
>> +    led_set_brightness(led_cdev, LED_OFF);
>
> I believe this is a fix. Could you split it into a separate patch
> and explain its merit?
I'm not sure of necessity of it, I copied it from oneshot.
Without it could leave LED in ON state. But never happens to me.
Should I produce separate patch to discuss it in separate thread?

>
>>   }
>>
>>   static struct led_trigger heartbeat_led_trigger = {
>>
>
>