DESK-MX6UL-L/Peripherals/LCD

History
Version	Issue Date	Notes
1.0.0	Apr 2021	First DESK release

Peripheral LCD

Device tree configuration

Here below an example of device tree configuration used on standard DAVE's kit for the AXEL ULite SOM:

From the imx6ul-axelulite-cb003a.dts where RGB interface has been configured for a LCD panel (800x480 18bit):

&lcdif {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_lcdif_dat
                     &pinctrl_lcdif_ctrl>;
        display = <&display0>;
        status = "okay";

        display0: display {
                bits-per-pixel = <18>;
                bus-width = <18>;

                display-timings {
                        native-mode = <&timing0>;
                        timing0: timing0 {
                                clock-frequency = <33800000>;
                                hactive = <800>;
                                vactive = <480>;
                                hfront-porch = <118>;
                                hback-porch = <10>;
                                hsync-len = <128>;
                                vback-porch = <8>;
                                vfront-porch = <35>;
                                vsync-len = <2>;

                                hsync-active = <0>;
                                vsync-active = <0>;
                                de-active = <1>;
                                pixelclk-active = <1>;
                        };
                };
        };
};
&iomuxc {
...
...
    lcd {
	pinctrl_lcdif_dat: lcdifdatgrp {
		fsl,pins = <
			MX6UL_PAD_LCD_DATA00__LCDIF_DATA00      0x79
			MX6UL_PAD_LCD_DATA01__LCDIF_DATA01      0x79
			MX6UL_PAD_LCD_DATA02__LCDIF_DATA02      0x79
			MX6UL_PAD_LCD_DATA03__LCDIF_DATA03      0x79
			MX6UL_PAD_LCD_DATA04__LCDIF_DATA04      0x79
			MX6UL_PAD_LCD_DATA05__LCDIF_DATA05      0x79
			MX6UL_PAD_LCD_DATA06__LCDIF_DATA06      0x79
			MX6UL_PAD_LCD_DATA07__LCDIF_DATA07      0x79
			MX6UL_PAD_LCD_DATA08__LCDIF_DATA08      0x79
			MX6UL_PAD_LCD_DATA09__LCDIF_DATA09      0x79
			MX6UL_PAD_LCD_DATA10__LCDIF_DATA10      0x79
			MX6UL_PAD_LCD_DATA11__LCDIF_DATA11      0x79
			MX6UL_PAD_LCD_DATA12__LCDIF_DATA12      0x79
			MX6UL_PAD_LCD_DATA13__LCDIF_DATA13      0x79
			MX6UL_PAD_LCD_DATA14__LCDIF_DATA14      0x79
			MX6UL_PAD_LCD_DATA15__LCDIF_DATA15      0x79
			MX6UL_PAD_LCD_DATA16__LCDIF_DATA16      0x79
			MX6UL_PAD_LCD_DATA17__LCDIF_DATA17      0x79
		>;
	};

	pinctrl_lcdif_ctrl: lcdifctrlgrp {
		fsl,pins = <
			MX6UL_PAD_LCD_CLK__LCDIF_CLK            0x79
			MX6UL_PAD_LCD_ENABLE__LCDIF_ENABLE      0x79
			MX6UL_PAD_LCD_DATA20__GPIO3_IO25        0x110b0         /* 5V_BL_EN */
			MX6UL_PAD_LCD_DATA19__GPIO3_IO24        0x110b0         /* 3V3_LCD_EN */
			MX6UL_PAD_GPIO1_IO01__GPIO1_IO01        0x110b0         /* BLEN */
			MX6UL_PAD_LCD_DATA22__GPIO3_IO27        0x110b0         /* LVDS_STDN */
		>;
	};
    };
...
...
};

Accessing the peripheral

Linux messages at boot time

...
...
[    2.021689] mxsfb 21c8000.lcdif: 21c8000.lcdif supply lcd not found, using dummy regulator
[    2.443038] mxsfb 21c8000.lcdif: initialized
...
...

Additional information

LCD framebuffer can be accessed through the standard /dev/fbX fb device.

The configured framebuffer can be checked using standard fbset utility:

root@desk-mx6ul-axelulite:~# fbset

mode "800x480-61"
        # D: 33.801 MHz, H: 32.008 kHz, V: 60.968 Hz
        geometry 800 480 800 480 32
        timings 29585 10 118 8 35 128 2
        accel false
        rgba 8/16,8/8,8/0,0/0
endmode

root@desk-mx6ul-axelulite:~#

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