Re: [PATCH RFC] media: OF: add field-active and sync-on-green endpointproperties

From: Sylwester Nawrocki
Date: Thu May 16 2013 - 06:43:32 EST


On 05/16/2013 06:53 AM, Prabhakar Lad wrote:
diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt
>> b/Documentation/devicetree/bindings/media/video-interfaces.txt index
>> e022d2d..6bf87d0 100644
>> --- a/Documentation/devicetree/bindings/media/video-interfaces.txt
>> +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt
>> @@ -101,6 +101,10 @@ Optional endpoint properties
>> array contains only one entry.
>> - clock-noncontinuous: a boolean property to allow MIPI CSI-2
>> non-continuous clock mode.
>> +-field-active: a boolean property indicating active high filed ID output
>> + polarity is inverted.
> Looks like we already have field-even-active property to describe the level of
> the field signal. Could you please check whether it fulfills your use cases ?
> Sorry for not pointing you to it earlier.
I had looked at it earlier it only means "field signal level during the even
field data transmission" it only speaks of even filed. Ideally the field ID
output is set to logic 1 for odd field and set to 0 for even field, what I
want is to invert the FID out polarity when "field-active" property is set.

May be we rename "field-active" to "fid-pol" ?

I guess we failed to clearly describe the 'field-even-active' property then.
It seems to be exactly what you need.

It is not enough to say e.g. field-active = <1>;, because it would not have
been clear which field it refers to, odd or even ? Unlike VSYNC, HSYNC both
levels of the FIELD signal are "active", there is no "idle" state for FIELD.

So field-even-active = <1>; means the FIELD signal at logic high level
indicates EVEN field _and_ this implies FIELD = 0 indicates ODD field, i.e.

FIELD = 0 => odd field
FIELD = 1 => even field

For field-even-active = <0>; it is the other way around:

FIELD = 0 => even field
FIELD = 1 => odd field

It looks like only "sync-on-green" property is missing. BTW, is it really
commonly used ? What drivers would need it ?
I'm not against making it a common property, it's just first time I see it.

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