[PATCH 1/3] drm: Add LCD display clock polarity flags

Marek Vasut marex at denx.de
Mon Dec 2 15:42:10 PST 2013


Hello Russell,

> On Mon, Dec 02, 2013 at 04:39:26PM +0100, Marek Vasut wrote:
> > Add DRM flags for the LCD display clock polarity so the pixelclk-active
> > DT property can be properly handled by drivers using the DRM API.
> 
> I still say that not even this should be part of the DRM mode API to
> userspace.  The hint that you're changing the user API is that you're
> modifying a header file below a 'uapi' directory.

OK, you are right.

> The settings of double scan, sync polarity etc are all part of the
> display mode specification (check CEA-861 documents).  Things like
> pixel clock polarity are not part of the mode specification, they're
> a property of the display itself and are independent of the mode.
> 
> Therefore, they should not be part of struct drm_mode_modeinfo.

Can you please provide me with some more hint here ? As for as I understand, 
using the 'pixelclk-active' DT prop in the 'display-timings' node for this 
purpose is correct, yes ? What I don't quite grok down is how do I get this 
information from DT into the imx-drm driver.

Thanks!

Best regards,
Marek Vasut


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