linux-kernel - Re: [PATCH v2 6/6] leds: netdev trigger: allow setting initial values in device tree

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Message-ID: <ddc53d4c-3da8-3f00-12dc-51df4a149bcf@gmail.com>
Date:   Thu, 14 Mar 2019 16:36:45 +0100
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        Pavel Machek <pavel@....cz>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2 6/6] leds: netdev trigger: allow setting initial values
 in device tree

On 3/14/19 4:05 PM, Rasmus Villemoes wrote:
> On 14/03/2019 15.24, Jacek Anaszewski wrote:
>> Rasmus,
>>
>> Thank you for the update.
>> Still, there is one thing to improve.
>>
> 
>>>    static int netdev_trig_activate(struct led_classdev *led_cdev)
>>>    {
>>>        struct led_netdev_data *trigger_data;
>>> @@ -423,6 +451,8 @@ static int netdev_trig_activate(struct
>>> led_classdev *led_cdev)
>>>        trigger_data->mode = 0;
>>>        atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
>>>        trigger_data->last_activity = 0;
>>> +    if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER)
>>> +        netdev_trig_of_init(led_cdev, trigger_data);
>>
>> We don't necessarily want OF settings to be used for initialization on
>> each LED trigger activation for the LED class device, but only on the
>> first one. That's why the triggers using this flags clean it here:
>>
>> led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
> 
> Right, I noticed that pattern, but wondered about it. If this is
> supposed to be a general thing, why isn't it just done by the trigger
> core after the call of led_trigger_set() in the two places the bit gets
> set? I.e.
> 
> 		led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
> 		led_trigger_set(led_cdev, trig);
> +		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
> 
> I can certainly add clearing the flag to my code, just wondering.

Good point. It would have to be applied in both
led_trigger_set_default() and led_trigger_register(). So you either
need to add generic support for clearing the flag (and update the three
users) or update your patch alone.

-- 
Best regards,
Jacek Anaszewski