[PATCH 1/2 v6] of: add helper to parse display timings

Mitch Bradley wmb at firmworks.com
Mon Oct 8 09:34:12 PDT 2012

On 10/7/2012 11:01 PM, Tomi Valkeinen wrote:
> On Mon, 2012-10-08 at 10:25 +0200, Guennadi Liakhovetski wrote:
>> In general, I might be misunderstanding something, but don't we have to 
>> distinguish between 2 types of information about display timings: (1) is 
>> defined by the display controller requirements, is known to the display 
>> driver and doesn't need to be present in timings DT. We did have some of 
>> these parameters in board data previously, because we didn't have proper 
>> display controller drivers... (2) is board specific configuration, and is 
>> such it has to be present in DT.
>> In that way, doesn't "interlaced" belong to type (1) and thus doesn't need 
>> to be present in DT?
> As I see it, this DT data is about the display (most commonly LCD
> panel), i.e. what video mode(s) the panel supports. If things were done
> my way, the panel's supported timings would be defined in the driver for
> the panel, and DT would be left to describe board specific data, but
> this approach has its benefits.
> Thus, if you connect an interlaced panel to your board,

Do interlaced panels exist?  I have never seen one.

 you need to tell
> the display controller that this panel requires interlace signal. Also,
> pixel clock source doesn't make sense in this context, as this doesn't
> describe the actual used configuration, but only what the panel
> supports.
> Of course, if this is about describing the hardware, the default-mode
> property doesn't really fit in...
>  Tomi
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