i.MX ProcessorsのトピックRe: IMX6 Quad LVDS display support

IMX6 Quad LVDS display support

dhrumildoshi — Tue, 23 Jan 2018 12:12:34 GMT

Hello,

I am trying to interface 1920X1200 LVDS display onto imx6 Quad custom board. We use LVDS0 channel to interface with display,
I am unable to find the following answers :

Does IMX6 Quad platform support 1920X1200 LVDS output on single channel?
Which are the u-boot arguments needed to be set?
What are the changes required to be done in driver or device tree?
Which mode I need to use for 1920x1200 resolution? LVDS split mode or single mode?

Please provide answers to above questions.

Thanks,

Dhrumil

Re: IMX6 Quad LVDS display support

igorpadykov — Tue, 23 Jan 2018 23:19:45 GMT

Hi Dhrumil

single channel supports1366x768@60fps, overal LDB supports
1920x1200@ 60fps. For 1920x1200 one needs to use split mode similar

to patch below

imx6q and lvds.

Best regards
igor
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Re: IMX6 Quad LVDS display support

dhrumildoshi — Wed, 24 Jan 2018 09:29:40 GMT

Hi Igor,

Thanks for your reply. I will try your patch and will let you know the result.

Till then, can you please tell me what is the maximum resolution I can get using on single LVDS channel (LVDS0)?

And if I want to use only single channel, then what should be the clock frequency?

As per my knowledge, If I want to get LVDS output 1920*1200 @30Hz, then I should be able to do it using single LVDS channel (LVDS0) instead of split mode. As frame rate is low, the LVDS clock needs to be 79.7 MHz (<85 MHz limitation LVDS channel).

To set above configuration, I have done below changes. Please confirm the changes and let me know if any other change is required to be done.

In board's .dtsi file,
&ldb {
status = "okay";
lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
primary;
status = "okay";
display-timings {
native-mode = <&timing0>;
timing0: hj070na {
clock-frequency = <79795320>;
hactive = <1920>;
vactive = <1200>;
hback-porch = <60>;
hfront-porch = <81>;
vback-porch = <25>;
vfront-porch = <35>;
hsync-len = <1>;
vsync-len = <1>;
};
};
};
};
In boot commands file,

console=ttymxc0,115200 init=/init video=mxcfb0:dev=ldb,1920x1200@30,if=RGB24,bpp=32 video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off androidboot.console=ttymxc0 androidboot.hardware=freescale vmalloc=300M androidboot.selinux=disabled consoleblank=0 cma=256M androidboot.dm_verity=disabled

Thanks,

Dhrumil

Re: IMX6 Quad LVDS display support

igorpadykov — Wed, 24 Jan 2018 23:22:51 GMT

Hi Dhrumil

for supported resolutions please refer to sect.39.4.1 Input Parallel Display Ports
i.MX6DQ Reference Manual
http://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf

Best regards
igor

Re: IMX6 Quad LVDS display support

dhrumildoshi — Thu, 25 Jan 2018 06:05:28 GMT

Hi Igor,

What about the changes I have mentioned for 1920x1200 @30Hz on single channel LVDS (LVDS0)?

Are they correct or not?

Regards,

Dhrumil

Re: IMX6 Quad LVDS display support

igorpadykov — Thu, 25 Jan 2018 09:11:53 GMT

Hi Dhrumil

please use lcd datasheet and below links for display timings changes:

Documentation/devicetree/bindings/video/display-timing.txt · 0bbdbb89b92a70997d3a33075bc34e948eea8d9d · ARM / qmx6_kerne…

Display Output, Resolution and Timings (Linux)

how to support WSVGA output in imx6sdq

Best regards
igor

Re: IMX6 Quad LVDS display support

aurelienbouin — Mon, 07 May 2018 10:13:19 GMT

Hi Dhrumil,

Finally have you succeed in using one single LVDS channel working on a 1920x1200@30Hz ?

Because I don't really see an answer to the question

Are your changes in the dts and boot loader corrects ?

Thank you by advance for your answers

Regards,

Re: IMX6 Quad LVDS display support

dhrumildoshi — Thu, 04 Oct 2018 12:25:30 GMT

Hi AURELIEN,

Yes, the changes in dts and boot loader files are correct and it is working at maximum of 40 Hz refresh rate.

Thanks,

Dhrumil