On 2012-12-07 16:12, Philipp Zabel wrote:
Hi,
Am Montag, den 26.11.2012, 18:56 +0200 schrieb Tomi Valkeinen:
So what does the pixelclk-inverted mean? Normally the SoC drives pixel data on rising edge, and the panel samples it at falling edge? And vice-versa for inverted? Or the other way around?
When is hsync/vsync set? On rising or falling edge of pclk?
My point here is that the pixelclk-inverted is not crystal clear thing, like the hsync/vsync/de-active values are.
And while thinking about this, I realized that the meaning of pixelclk-inverted depends on what component is it applied to. Presuming normal pixclk means "pixel data on rising edge", the meaning of that depends on do we consider the SoC or the panel. The panel needs to sample the data on the other edge from the one the SoC uses to drive the data.
Does the videomode describe the panel, or does it describe the settings programmed to the SoC?
How about calling this property pixelclk-active, active high meaning driving pixel data on rising edges and sampling on falling edges (the pixel clock is high between driving and sampling the data), and active low meaning driving on falling edges and sampling on rising edges? It is the same from the SoC perspective and from the panel perspective, and it mirrors the usage of the other *-active properties.
This sounds good to me. It's not quite correct, as neither pixelclock or pixel data are not really "active" when the clock is high/low, but it still makes sense and is clear (at least with a short description).
Tomi