Hi Peter, On Sun, Sep 04, 2016 at 10:03:06PM +0200, Peter Korsgaard wrote: > >>>>> "Maxime" == Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> writes: > > Hi, > > > The A33 pipeline also has some new components called SAT and DRC. Even > > though their exact features and programming model is not known (or > > documented), they need to be clocked for the pipeline to carry the video > > signal all the way. > > > Add minimal drivers for those that just claim the needed resources for the > > pipeline to operate properly. > > > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> > > --- > > .../bindings/display/sunxi/sun4i-drm.txt | 37 +++++++ > > drivers/gpu/drm/sun4i/Makefile | 3 +- > > drivers/gpu/drm/sun4i/sun6i_drc.c | 117 +++++++++++++++++++++ > > drivers/gpu/drm/sun4i/sun8i_sat.c | 105 ++++++++++++++++++ > > 4 files changed, 261 insertions(+), 1 deletion(-) > > create mode 100644 drivers/gpu/drm/sun4i/sun6i_drc.c > > create mode 100644 drivers/gpu/drm/sun4i/sun8i_sat.c > > > diff --git a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt > > index d467ea93ac08..87c3c8dd34cb 100644 > > --- a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt > > +++ b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt > > @@ -51,6 +51,43 @@ Required properties: > > second the block connected to the TCON channel 1 (usually the TV > > encoder) > > > +SAT > > +--- > > + > > +The SAT, found in the A33, allows to do some color correction. > > + > > +Required properties: > > + - compatible: value must be one of: > > + * allwinner,sun8i-a33-sat > > + - reg: base address and size of the memory-mapped region. > > + - clock: phandles to bus clock feeding the SAT > > + - resets: phandles to the reset line driving the SAT > > + > > +- ports: A ports node with endpoint definitions as defined in > > + Documentation/devicetree/bindings/media/video-interfaces.txt. The > > + first port should be the input endpoints, the second one the outputs > > + > > +DRC > > +--- > > + > > +The DRC, found in the latest Allwinner SoCs (A31, A23, A33), allows to > > +do some backlight control to enhance the power consumption. > > 'Enhance the power consumption'? That doesn't sound like something you > would want ;) Presumably it is something to allow you to save power by > dynamically adjusting LCD backlight and pixel brightness/contrast > depending on screen content? I believe this is typically called content > adaptive backlight control: > > https://www.ecnmag.com/article/2010/04/content-adaptive-lcd-backlight-control > > You spell out what DRC and SAT stands for in the driver source code, > perhaps it also makes sense to do it here? > > Perhaps rewording it to something like this is clearer: > > .. allows to dynamically adjust pixel brightness/contrast based on > histogram measurements for LCD content adaptive backlight control. You're right, I changed it. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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