iMX6s Split-Mode LVDS FDT

[grim]

I've been upgrading our system from kernel version 3.10.15 to 3.14.28.

I used to be able to set the display up in drivers/video/mxc/ldb.c but now it looks like it's all handled in the device tree.

We have a 1280X1024 display that's intended to use split-mode LVDS.

I'm able to get the display to run but it's not correct..... the Linux penguin and the console text looks like it's twice as wide as it needs to be.

I'm passing 'ldb=spl0' in the boot args but it doesn't seem to make a difference which 'ldb' mode I specify, the display never seems to change.

Here's my parameters for the display in imx6qdl-sabresd.dtsi (it's just been modified from the default).

&ldb {

    status = "okay";

    split-mode;

    primary;

    /* AUO */

    lvds-channel@0 {

        fsl,data-mapping = "spwg";

        fsl,data-width = <18>;

        status = "okay";

        display-timings {

            native-mode = <&timing0>;

            timing0: hsd100pxn1 {

                clock-frequency = <53995680>;

                hactive = <1280>;

                vactive = <1024>;

                hback-porch = <102>;

                hfront-porch = <100>;

                vback-porch = <20>;

                vfront-porch = <20>;

                hsync-len = <2>;

                vsync-len = <2>;

            };

        };

    };

Could anybody help guide me in the proper direction on this issue?

Thanks in advance!

[igorpadykov]

Hi Bob

for 3.14.28 .dtsi example for split mode one can look at boundarydevices

sources (attached), as it supports such lcd:

Buildroot (busybox) - [PATCH 00/14] Update Freescale packages to 3.14.28-1.0.0_ga

For changing lcd timings one can look at

iMX6QD How to Add 24-bit LVDS Support in Android

Best regards

igor

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[grim · Accepted solution]

Thank you very much for the example file Igor.

I modified my ldb structures to more closely follow the structures in your example file..... nothing changed.

I looked more closely at the example you provided and I noticed that the 'clock-frequency' for what they intended to be the split-mode LVDS display.... it's a VERY large value. I thought that was unusual.

I ended up doubling the clock-frequency I specified in my dtsi file and the display now looks correct.

This issue is now closed.

Thank you again Igor!