On Thu, Aug 25, 2016 at 7:03 AM, Jyri Sarha jsarha@ti.com wrote:
Add "blue-and-red-crossed"-device tree property and update devicetree binding document. The red and blue components are reversed between 24 and 16 bit modes on am335x LCDC output pins. To get 24 RGB format the red and blue wires has to be crossed and this in turn causes 16 colors output to be in BGR format. With straight wiring the 16 color is RGB and 24 bit is BGR. The new property describes whether the red and blue wires are crossed or not. If the wires are crossed this boolean property should be present in the relevant devicetree node.
The am335x-evm and am335x-evm have the blue and red wires crossed for 24 bit RGB mode and after this patch their LCDC nodes should have this property to get correct colors in the display.
For more details see section 3.1.1 in AM335x Silicon Errata: http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=sp...
Signed-off-by: Jyri Sarha jsarha@ti.com
.../devicetree/bindings/display/tilcdc/tilcdc.txt | 12 +++++++++++ drivers/gpu/drm/tilcdc/tilcdc_drv.c | 24 ++++++++++++++++++++++ drivers/gpu/drm/tilcdc/tilcdc_drv.h | 4 ++++ drivers/gpu/drm/tilcdc/tilcdc_plane.c | 9 +++----- 4 files changed, 43 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt b/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt index 6efa4c5..48a660a 100644 --- a/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt +++ b/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt @@ -17,6 +17,8 @@ Optional properties: the lcd controller.
- max-pixelclock: The maximum pixel clock that can be supported by the lcd controller in KHz.
- blue-and-red-crossed: Boolean property, set this of blue and red wires
- for LCD_DATA are crossed for 24-bit RGB support (and 16-bit BGR mode). [1]
Doesn't this need to be blue-and-red-straight for compatibility?
Optional nodes:
@@ -28,6 +30,14 @@ Optional nodes: Documentation/devicetree/bindings/display/tilcdc/tfp410.txt for connecting tfp410 DVI encoder or lcd panel to lcdc
+[1] There is an errata about AM335x color wiring. For 16-bit color mode
- the wires work as they should (LCD_DATA[0:4] is for Blue[3:7]),
- but for 24 bit color modes the wiring of blue and red components is
- crossed and LCD_DATA[0:4] is for Red[3:7] and LCD_DATA[11:15] is
- for Blue[3-7]. For more details see section 3.1.1 in AM335x
- Silicon Errata:
- http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=sp...
Example:
fb: fb@4830e000 {@@ -37,6 +47,8 @@ Example: interrupts = <36>; ti,hwmods = "lcdc";
blue-and-red-wiring = "crossed";
This needs to be updated.
Rob