linux-kernel - Re: [PATCH 3/5] leds: Rename brightness_set_sync op to brightness_set

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Message-id: <5602720F.7080405@samsung.com>
Date:	Wed, 23 Sep 2015 11:34:07 +0200
From:	Jacek Anaszewski <j.anaszewski@...sung.com>
To:	Andrew Lunn <andrew@...n.ch>
Cc:	linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org,
	sakari.ailus@...ux.intel.com, stsp@...rs.sourceforge.net,
	pavel@....cz, ospite@...denti.unina.it, davem@...emloft.net,
	linus.walleij@...aro.org, ricardo.ribalda@...il.com,
	p.meerwald@...-electronic.com
Subject: Re: [PATCH 3/5] leds: Rename brightness_set_sync op to
 brightness_set_blocking

On 09/23/2015 10:36 AM, Jacek Anaszewski wrote:
> On 09/22/2015 08:54 PM, Andrew Lunn wrote:
>> On Wed, Sep 16, 2015 at 12:47:42PM +0200, Jacek Anaszewski wrote:
>>> The initial purpose of brightness_set_sync op, introduced along with
>>> the LED flash class extension, was to add a means for setting torch LED
>>> brightness as soon as possible, which couldn't have been guaranteed by
>>> brightness_set op. This patch renames the op to brightness_set_blocking,
>>> which describes its purpose in a more generic way, and is beneficial
>>> in view of the prospective changes in the core related to using
>>> LED core's set_brightness_work for setting brightness for LED class
>>> drivers that can sleep or use delays while setting brightness.
>>
>> ...
>>
>>> -    /*
>>> -     * Set LED brightness level immediately - it can block the
>>> caller for
>>> -     * the time required for accessing a LED device register.
>>> -     */
>>> -    int        (*brightness_set_sync)(struct led_classdev *led_cdev,
>>> -                    enum led_brightness brightness);
>>> +    /* Can sleep or use delays */
>>> +    int (*brightness_set_blocking)(struct led_classdev *led_cdev,
>>
>> I'm no expert when it comes to flash photography with digital
>> cameras.
>
> This op is now not specific to flash LEDs. The last sentence in the
> commit message explains this, but now I see that it is too long.
> Let's change it to:
>
> "This patch renames the op to brightness_set_blocking,
> which describes its purpose in a more generic way. It is beneficial
> in view of the prospective changes in the LED core, aiming at removing
> the need for using work queues in LED class drivers that can sleep
> or use delays while setting brightness."
>
>> But to me the old comment seems better.
>
> I changed it to highlight the essence of how it differs from
> brightness_set.
>
>> Doesn't the caller
>> want to know the flash is now giving out light?
>
> We have strobe_get op for this, but it is in led-class-flash extension.
> This is irrelevant here.

I focused myself on flash mode of flash LED, but you asked
probably about brightness in torch mode, which can be obtained
with brightness_get op, if implemented by the driver.


-- 
Best Regards,
Jacek Anaszewski
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