Message-id: <5486F5A0.9060700@samsung.com>
Date: Tue, 09 Dec 2014 14:14:08 +0100
From: Jacek Anaszewski <j.anaszewski@samsung.com>
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To: Sakari Ailus <sakari.ailus@iki.fi>
Cc: linux-leds@vger.kernel.org, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, kyungmin.park@samsung.com,
        b.zolnierkie@samsung.com, pavel@ucw.cz, cooloney@gmail.com,
        rpurdie@rpsys.net, s.nawrocki@samsung.com, robh+dt@kernel.org,
        pawel.moll@arm.com, mark.rutland@arm.com,
        ijc+devicetree@hellion.org.uk, galak@codeaurora.org
Subject: Re: [PATCH/RFC v9 02/19] Documentation: leds: Add description of LED
 Flash class extension
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 <20141203170818.GN14746@valkosipuli.retiisi.org.uk>
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Hi Sakari,

On 12/09/2014 01:38 PM, Sakari Ailus wrote:

[...]

>>> How does the user btw. figure out which flash LEDs may be strobed
>>> synchronously using the LED flash interface?
>>
>> The flash_sync_strobe argument is absent if synchronized strobe
>> is not available for a LED. The driver defines this by setting
>> newly added LED_DEV_CAP_COMPOUND flag.
>
> I meant that how does the user figure out which LEDs may be strobed
> synchronously, together. Say, if you have two of these chips and four LEDs,
> then how does it work? :-)
>

User can figure it out by checking the existence of the
flash_sync_strobe attribute. Sub-leds can by synchronized only
when are driven by common chip. It is assumed that sub-leds of
one chip will have common segment in their name, defined in
DT 'label' property. Maybe we should enforce it by adding another
property to the leds/common.txt DT binding, e.g. 'device-prefix'?

Best Regards,
Jacek Anaszewski

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