topic Re: IMX8M MINI LVDS in i.MX Processors

IMX8M MINI LVDS

VinithNama — Fri, 09 Jul 2021 11:34:08 GMT

Hi,

I'm working on IM8M MINI EVK Linux platform, we are working on integration of panasys LVDS display and we are using SN65DSI83 as an bridge converter.

I 'have applied below patch at the directory kernel-sourcr/.../git/drivers/gpu/drm/bridge.

and i have updated in my device tree file build/tmp/work-shared/imx8qmevk/kernel-source/arch/arm64/boot/dts/freescale/imx8mm-evk.dts as below

&lcdif{

max-res = <1280>, <1024>;

status = "okay";

};

&mipi_dsi {

status = "okay";

port@1 {

dsim_to_sn65dsi8: endpoint {

remote-endpoint = <&sn65dsi83_in>;

};

&i2c2 {

clock-frequency = <100000>;

pinctrl-names = "default";

status = "okay";

lvds_bridge: sn65dsi83@2c {

compatible = "ti,sn65dsi83";

reg = <0x2c>;

ti,dsi-lanes = <4>;

ti,lvds-format = <2>;

ti,lvds-bpp = <24>;

ti,width-mm = <376>;

ti,height-mm = <301>;

enable-gpios = <&gpio1 14 GPIO_ACTIVE_HIGH>;

pinctrl-names = "default";

pinctrl-0 = <&pinctrl_dsi_lvds_bridge>;

status = "okay";

display-timings {

lvds {

clock-frequency = <90000000>;

hactive = <1280>;

hsync-len = <54>;

hback-porch = <75>;

hfront-porch = <75>;

vactive = <1024>;

vsync-len = <10>;

vback-porch = <10>;

vfront-porch = <22>;

vsync-active = <0>;

hsync-active =<0>;

de-active =<0>;

pixelclk-active =<0>;

clock-frequency = <108000000>;

hactive = <1280>;

hsync-len = <28>;

hback-porch = <200>;

hfront-porch = <180>;

vactive = <1023>;

vsync-len = <7>;

vback-porch = <30>;

vfront-porch = <5>;

vsync-active = <0>;

hsync-active =<0>;

de-active =<0>;

pixelclk-active =<0>;

};

port {

sn65dsi83_in: endpoint {

remote-endpoint = <&dsim_to_sn65dsi8>;

};

after compiling and deploying the kernel using

bitbake -c compile -f linux-imx and bitbake -c deploy -f linux-imx then I have built entire image using bitbake imx-image-full. I cannot see any display on the LVDS ,can you help me where i was struck.

Re: IMX8M MINI LVDS

Zhiming_Liu — Mon, 12 Jul 2021 02:28:51 GMT

Please kindly check the error in your log...reset pin

[ 2.762593] Call trace:
[ 2.765042] __reset_control_get_internal+0x64/0x110
[ 2.770008] __of_reset_control_get+0x158/0x1b0
[ 2.774539] of_reset_control_array_get+0xac/0x1a0
[ 2.779334] imx_sec_dsim_bind+0x208/0x348
[ 2.783433] component_bind_all+0xfc/0x258
[ 2.787532] imx_drm_bind+0xb8/0x150
[ 2.791106] try_to_bring_up_master+0x164/0x1c8
[ 2.795636] __component_add+0xa0/0x168
[ 2.799475] component_add+0x10/0x18
[ 2.803051] imx_sec_dsim_probe+0x4c/0x70
[ 2.807062] platform_drv_probe+0x50/0xa0
[ 2.811072] really_probe+0xd4/0x318
[ 2.814648] driver_probe_device+0x54/0xe8
[ 2.818746] __device_attach_driver+0x80/0xb8
[ 2.823105] bus_for_each_drv+0x74/0xc0
[ 2.826939] __device_attach+0xdc/0x138
[ 2.830776] device_initial_probe+0x10/0x18
[ 2.834959] bus_probe_device+0x90/0x98
[ 2.838796] deferred_probe_work_func+0x64/0x98
[ 2.843331] process_one_work+0x198/0x320
[ 2.847342] worker_thread+0x1f0/0x420
[ 2.851092] kthread+0xf0/0x120
[ 2.854235] ret_from_fork+0x10/0x18

Re: IMX8M MINI LVDS

paul_geurts — Fri, 18 Nov 2022 08:01:19 GMT

Hi,

I have run into the same issue with the DSI interface (and the same MIPI/LVDS bridge) using the latest 5.15.32_2.0.0 kernel. I have looked around a bit and found the problem in the DSIM driver. I don't know whether this is still an issue for you, but it might be useful for other people finding this ticket. The problem occurs because the dsim driver probe is deferred as the SN65DSI83 initialization was not done yet. When retrying the probe an error occurs because the first try didn't release the aquired resources.

Please apply the attached patch to overcome the issue.

Re: IMX8M MINI LVDS

dianapredescu — Fri, 18 Nov 2022 11:35:45 GMT

Hi @paul_geurts,

Thank you very much for the feedback! Indeed, this issue was already reported and a patch has been developed, tested and will be integrated in Q4 BSP release.

Best regards,

Diana