2025-06-18 1:37 AM - edited 2025-06-18 1:39 AM
Dear ST Developer Support,
I want to enable LVDS panel on STM32MP257F-EV1 based on Android OS.
I tried to modify device tree stm32mp257f-ev1.dts and stm32mp257f-ev1-overlay.dts to enable LVDS panel.
But I could not enable it. When I revert the device fdt file, I saw that the LVDS related device tree nodes
lvds
panel-lvds
panel-lvds-backlight
display-controller
status were "disabled".
In stm32mp257f-ev1.dts and stm32mp257f-ev1-overlay.dts file, the LVDS related device note are status="okay".
So, I confuse on this problem. Maybe somewhere dts overlay this device node, but I cannot find it.
Would you help me solve this problem?
Thanks.
Solved! Go to Solution.
2025-07-03 1:32 AM
Hi,
to modify uboot/bootloader, you need to follow this documentation:
https://wiki.st.com/stm32mpu/wiki/How_to_build_bootloaders_for_Android
And in order to use another LVDS screen than the standard one (etml0700z9ndha) delivered with Eval board, you have comment the following section in
"./device/stm/stm32mp2-bootloader/u-boot-stm32mp2/board/st/stm32mp2/stm32mp2.c" file (line 784)
//if (board_is_stm32mp257_eval()) {
// ret = fixup_stm32mp257_eval_panel(blob);
// if (ret)
// log_err("Error during panel fixup ! (%d)\n", ret);
//}
This will avoid to disable the DT node when another LVDS screen is used.
As explained in documentation, rebuild bootloader (build_bootloader), update it (build_bootloader -i), build full image (make -j) and reflash (flash-device).
Let me know if you have trouble,
BR,
Philippe.
2025-06-18 5:05 AM
Hi,
by default the LVDS panel is activated in our Android Package, you don't have to modify the device tree (stm32mp257f-ev1-overlay.dts)
If you don't have any display on LVDS screen , please check again documentation ( connection ?, ...)
https://wiki.st.com/stm32mpu/wiki/STM32MP25_Evaluation_boards_-_Starter_Package_for_Android
BR,
Philippe
2025-06-23 12:55 AM
Hi Philippe,
If I want to enable other LVDS panel on STM32MP257F-EV1 based on Android, I need to modify the device tree to meet my panel-timing. But I found the problem is that I set the LVDS related device tree node to status="okay". The LVDS still cannot enable. Would you have any idea?
Thanks.
2025-06-24 1:41 AM
Hi Philippe,
I use st-android-13.0.0-2024-07-31-stm32mp257f-ev1-emmc-starter to flash device. But I check lvds related node in device, I cannot see lvds node and device-tree status is disabled.
Would you help me resolve this problem?
Thanks.
2025-06-25 5:16 AM
Hi,
could you please check your dmesg output when driver is loaded?
thanks,
Philippe.
2025-06-25 6:25 PM
Hi Philippe,
I have checked dmesg log, I cannot see any message about lvds driver.
But I check my .config, the lvds driver has built in.
Thanks.
2025-06-27 12:12 AM
Hi Tim,
is the issue fixed on your side or you still face problem managing the dt. I am ot sure of the status of your last message.
BR,
Philippe.
2025-06-27 1:47 AM
Hi Philippe,
This issue is still exist. I means that I cannot see any about lvds driver log on dmesg output when driver is loaded.
2025-06-30 5:28 AM
Hi,
could you please list the modifications you did on DT "stm32mp257f-ev1-overlay.dts" file (and other files ?) to adapt the setup for your specific LVDS screen?
And what is the new LVDS screen model?
BR,
Philippe.
2025-06-30 5:49 AM
You will have to adapt the following parameters to fit with your LVDS screen specification:
panel-timing {
clock-frequency = <54000000>;
hactive = <1024>;
vactive = <600>;
hfront-porch = <150>;
hback-porch = <150>;
hsync-len = <21>;
vfront-porch = <24>;
vback-porch = <24>;
vsync-len = <21>;
};