FullHD LCD display on iMX7

toradex.questioner · August 28, 2017, 10:09am

A 1920x1080 24bit RGB LCD is connected to Colibri iMX7D with v2.7b3 LinuxImage. Within device tree, the LCD pinout is set.

&lcdif {
	display = <&display0>;
	status = "okay";

	display0: lcd-display {
		bits-per-pixel = <16>;
		bus-width = <24>;

		display-timings {
			native-mode = <&timing_fullhd>;

			timing_fullhd: 1920x1080 {
                clock-frequency = <148500000>;
                hactive = <1920>;
                vactive = <1080>;
                hback-porch = <148>;
                hfront-porch = <88>;
                vback-porch = <36>;
                vfront-porch = <4>;
                hsync-len = <44>;
                vsync-len = <5>;

                de-active = <1>;
                hsync-active = <0>;
                vsync-active = <0>;
                pixelclk-active = <0>;
            };
		};
	};
};

&lcdif {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_lcdif_dat
		     &pinctrl_lcdif_ctrl
		     &pinctrl_lcdif_dat_24>;
	//pinctrl-assert-gpios = <&gpio_spi 7 GPIO_ACTIVE_HIGH>;
};

&iomuxc {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_hog_1 &pinctrl_hog_2 &pinctrl_hog_4 &pinctrl_hog_5>;

But the color of the display is not right.

Clock polarity has been changed, but it seems make no difference. Could is fbmem too small for fullhd display? But I can’t find fbmem setting in device tree.

stefan.tx · August 28, 2017, 10:56pm

Check whether hardware wiring is setup correctly. Note that only the 18 bit mode is compatible across the Colibri module family. The 24-bit color arrangement is not compatible across the Colibri module family since SoC align the colors differently to pads… The Colibri Compatibility Guide available in the Colibri Module article has a excellent overview (table RGB Display Color Mapping).