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Date: Mon, 30 Mar 2015 14:20:03 +0100
From: Mark Rutland <mark.rutland@arm.com>
To: Jacek Anaszewski <j.anaszewski@samsung.com>
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Subject: Re: [PATCH v3] DT: Add documentation for the mfd Maxim max77693
Message-ID: <20150330132002.GA29200@leverpostej>
References: <1427709149-15014-1-git-send-email-j.anaszewski@samsung.com>
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Hi,

> >> +Optional properties:
> >> +- maxim,trigger-type : Flash trigger type.
> >> +	Possible trigger types:
> >> +		LEDS_TRIG_TYPE_EDGE (0) - Rising edge of the signal triggers
> >> +			the flash,
> >> +		LEDS_TRIG_TYPE_LEVEL (1) - Strobe pulse length controls duration
> >> +			of the flash.
> >
> > Surely this is required? What should be assumed if this property isn't
> > present?
> 
> LEDS_TRIG_TYPE_LEVEL allows for an ISP to do e.g. short flash blink
> before the actual strobe - it is used for eliminating photographs with
> closed eyes, or can serve for probing ambient light conditions.
> 
> With LEDS_TRIG_TYPE_EDGE flash strobe is triggered on rising edge
> and lasts until programmed timeout expires.
> 
> This setting is tightly related to a camera sensor, which generates
> the strobe signal. Effectively it depends on board configuration.

My comment wasn't to do with the semantics of eitehr option but rather
the optionality of the property.

Surely it's vital to know what this should be, and hence this property
should be required rather than optional?

If it isn't required, what would the assumed default be?

Mark.