topic Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm in i.MX Processors

Adding LVDS Bridge (sn65dsi84) to iMX8mm

injaneer1 — Thu, 29 Oct 2020 15:38:48 GMT

I am trying to add the LVDS bridge snd65dsi84 to our custom board based on the iMX8mm processor. I am having difficulty finding the right information on how to configure the DTS files for both PWM and for 2 enable lines for the backlight, and where to make changes for the LVDS.

Thanks,

Chris

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

igorpadykov — Fri, 30 Oct 2020 01:19:16 GMT

Hi injaneer1

one can look at below example

https://github.com/TechNexion-customization/linux-imx-tn/blob/tn-imx_4.14.98_2.0.0_ga-wip-mipi2lvds/arch/arm64/boot/dts/freescale/imx8mm-pico-pi-sn65dsi84-hj070na.dts

Best regards
igor

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

injaneer1 — Fri, 30 Oct 2020 15:12:56 GMT

Thanks, Where can I get the driver Or is one not necessary ? Also I am running Android 10, will the above example apply the same way for that ?

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

igorpadykov — Sun, 01 Nov 2020 00:10:03 GMT

technexion linux already includes driver

https://github.com/TechNexion-customization/linux-imx-tn/tree/tn-imx_4.14.98_2.0.0_ga-wip-mipi2lvds

drivers/gpu/drm/bridge/sn65dsi84-dsi2lvds.c

https://github.com/TechNexion-customization/linux-imx-tn/blob/tn-imx_4.14.98_2.0.0_ga-wip-mipi2lvds/drivers/gpu/drm/bridge/sn65dsi84-dsi2lvds.c

General description on linux video subsystem can be found in i.MX Linux Reference Manual

Best regards
igor

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

injaneer1 — Sat, 31 Oct 2020 14:27:33 GMT

This is not actually an example. Just pointed me to a dts file. However, I have been able to find the settings in here and the included dts, I found a driver I think (no readme or anything can be found). I have managed to get the backlight working with this post.

We are running Android 10 not linux so really need a copy of the kernel-imx folder with these settings.

When I run our board I get this.

[ 1.371688] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 1.378324] [drm] No driver support for vblank timestamp query.
[ 1.384326] imx-drm soc@0:bus@32c00000:display-subsystem: bound imx-lcdif-crtc.0 (ops lcdif_crtc_ops)
[ 1.394252] imx_sec_dsim_drv 32e10000.mipi_dsi: version number is 0x1060200
[ 1.402541] imx_sec_dsim_drv 32e10000.mipi_dsi: Failed to attach bridge: 32e10000.mipi_dsi
[ 1.410878] imx_sec_dsim_drv 32e10000.mipi_dsi: failed to bind sec dsim bridge: -517
[ 1.418669] imx-drm soc@0:bus@32c00000:display-subsystem: failed to bind 32e10000.mipi_dsi (ops imx_sec_dsim_ops): -517
[ 1.429543] imx-drm soc@0:bus@32c00000:display-subsystem: master bind failed: -517

Thanks

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

injaneer1 — Sun, 01 Nov 2020 18:26:42 GMT

I also get this message after adding this line to my config file.

CONFIG_DRM_TI_SN65DSI84=y

Value requested for CONFIG_DRM_TI_SN65DSI84 not in final .config

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

igorpadykov — Mon, 02 Nov 2020 00:25:56 GMT

specific timings for used lcd can be added to dts as in above example:

&mipi_dsi {

status = "okay";

panel@0 {

reg = <0>;

compatible = "tn,dsi2lvds-panel";

dsi,flags = <0x0007>;

dsi,format = <0>;

dsi,lanes = <4>;

panel-width-mm = <153>;

panel-height-mm = <90>;

bus-flags = <1>;

refresh-rate = <60>;

rotate = <0>;

/* horz-flip; */

/* vert-flip; */

display-timings {

native-mode = <&timing0>;

timing0: hj070na {

clock-frequency = <51000000>;

hactive = <1024>;

vactive = <600>;

hfront-porch = <120>;

hsync-len = <100>;

hback-porch = <90>;

vfront-porch = <1>;

vsync-len = <33>;

vback-porch = <1>;

hsync-active = <1>;

vsync-active = <1>;

};

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

injaneer1 — Mon, 02 Nov 2020 15:26:27 GMT

Yes, I have this already configured, but the traces below is the bigger issue ?

Re: Adding LVDS Bridge (sn65dsi84) to iMX8mm

igorpadykov — Tue, 03 Nov 2020 01:29:30 GMT

one can check with lcd manufacturer what should be correct initialization for

used lcd and add it in driver.

Best regards
igor