video: imxfb: Add DT support

Add devicetree support for imx framebuffer driver. It uses the generic
display bindings and helper functions.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>

Documentation/devicetree/bindings/video/fsl,imx-fb.txt

@@ -0,0 +1,51 @@
+Freescale imx21 Framebuffer
+
+This framebuffer driver supports devices imx1, imx21, imx25, and imx27.
+
+Required properties:
+- compatible : "fsl,<chip>-fb", chip should be imx1 or imx21
+- reg : Should contain 1 register ranges(address and length)
+- interrupts : One interrupt of the fb dev
+
+Required nodes:
+- display: Phandle to a display node as described in
+	Documentation/devicetree/bindings/video/display-timing.txt
+	Additional, the display node has to define properties:
+	- bits-per-pixel: Bits per pixel
+	- fsl,pcr: LCDC PCR value
+
+Optional properties:
+- fsl,dmacr: DMA Control Register value. This is optional. By default, the
+	register is not modified as recommended by the datasheet.
+- fsl,lscr1: LCDC Sharp Configuration Register value.
+
+Example:
+
+	imxfb: fb@10021000 {
+		compatible = "fsl,imx21-fb";
+		interrupts = <61>;
+		reg = <0x10021000 0x1000>;
+		display = <&display0>;
+	};
+
+	...
+
+	display0: display0 {
+		model = "Primeview-PD050VL1";
+		native-mode = <&timing_disp0>;
+		bits-per-pixel = <16>;
+		fsl,pcr = <0xf0c88080>;	/* non-standard but required */
+		display-timings {
+			timing_disp0: 640x480 {
+				hactive = <640>;
+				vactive = <480>;
+				hback-porch = <112>;
+				hfront-porch = <36>;
+				hsync-len = <32>;
+				vback-porch = <33>;
+				vfront-porch = <33>;
+				vsync-len = <2>;
+				clock-frequency = <25000000>;
+			};
+		};
+	};

drivers/video/Kconfig

@@ -367,6 +367,8 @@ config FB_IMX
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT
+	select FB_MODE_HELPERS
+	select VIDEOMODE_HELPERS
 
 config FB_CYBER2000
 	tristate "CyberPro 2000/2010/5000 support"