[PATCH 1/2] drm/panel: simple: Add bus format for HannStar HSD070PWW1 LVDS panel

[Philipp Zabel]

Am Freitag, den 07.08.2015, 14:42 +0200 schrieb Thierry Reding:
> On Fri, Jun 26, 2015 at 12:27:08PM +0200, Lucas Stach wrote:
> > From: Philipp Zabel <p.zabel at pengutronix.de>
> > 
> 
> Can you be more specific here? What kind of bus format is this?

The bus_format contains more information than just the bpc. In this
case, the SPWG default format for RGB666 via 3-pair LVDS specifies how
the 18 color bits are serialized in the 7 time slots for each pixel
clock. See
http://linuxtv.org/downloads/v4l-dvb-apis/subdev.html#v4l2-mbus-pixelcode-rgb-lvds
for details.

> Why is it that .bpc = 6 doesn't work here?

In this case a LVDS driver could indeed still decide itself that
bpc == 6 should be translated to MEDIA_BUS_FMT_RGB666_1X7X3_SPWG (and
not MEDIA_BUS_FMT_RGB666_1X18, or MEDIA_BUS_FMT_RGB666_1X24_CPADHI, for
example). But in the bpc == 8 case there are two different standard ways
to order the bits (SPWG/VESA vs JEIDA).
For consistency, I'd prefer to set bus_format to the correct value
everywhere.

regards
Philipp