Compiling an LCD driver for armbian on Allwinner A33.

[Patrick 42]

Hi, I'am Patrick from France, it is my first post on the forum.

 

I am porting the Zortrax m200 plus 3D printer to Armbian and my last important step would be to have the LCD screen working.

I cross compiled my module but I have this message when installing it:

# insmod panel-himax-hx8394.ko 
[ 1760.189919] BPF: [120533] Invalid name_offset:2238391
[ 1760.195183] failed to validate module [panel_himax_hx8394] BTF: -22
insmod: ERROR: could not insert module panel-himax-hx8394.ko: Invalid parameters

 

Then I added the module source code to the sources, but calling ./compile.sh seems to update the repo and revert my changes such as I do not see my module in there.

 

The next possibility would be to create an image with the kernel headers included. I will try to compile the driver on the system.

And is there another way?

 

 

Edited Thursday at 03:42 PM by Patrick 42

[robertoj]

You dont need to cross-compile. You need to select the in-kernel-source option: https://www.kernelconfig.io/config_drm_panel_himax_hx8394 within the armbian build process.

 

Then you need to create a DTS like: https://forum.armbian.com/topic/47971-driving-the-ili9488-lcd-40-inch-cheap-chinese-clone/

 

 

And also dig through the experience in this thread: https://forum.armbian.com/topic/50963-dsi-display-does-not-work-on-raspberry-pi-5/#comment-216030

 

 

Send photo of the a33 and LCD

[Patrick 42]

I have managed to compile the driver on the target with a brand new image compiled using "./compile.sh INSTALL_HEADERS=yes". Yet I would like to cross compile it. If you know how, I will greatly appreciate if you give the method.

Edited Thursday at 06:12 PM by Patrick 42

[Patrick 42]

Thanks  Robertoj

All the documentation for the board is here https://github.com/zharijs/zmxxxp-re

But the LCD is not an himax-hx8394. The screen is a "MTF0397SWI-06" using the chip OTM8019A.

It just that I am starting from this driver to port the sunxi driver: sl698ph_720p.

 

I will now look at your links.

[Patrick 42]

I am strugling withthe AXP223 gpio LDO configuration to initialise properly, otherwise the i2C lines to the touchscreen controller are unpowered. Therefore I will add traces in the axP223 rsb (reduced signal bus) driver code.

And I try to not be annoying here, but I am a bit lost. What is the common method for driver debugging/development in armbian?

I mean how to recompile the kernel without rebuilding all the image?

 

For now I changed the kernel configuration for the rsb driver to module. And I will compile it on the target to add my traces.

 

In case someone has the solution to my problem,  my dts looks like this:

&axp_gpio {
	gpio1_ldo_pin: gpio1-ldo-pin {
		pins = "GPIO1";
		function = "ldo";
	};
};

&reg_ldo_io1 {
	pinctrl-names = "default";
	pinctrl-0 = <&gpio1_ldo_pin>;
	regulator-always-on;
	regulator-min-microvolt = <3000000>;
	regulator-max-microvolt = <3000000>;
	regulator-name = "i2C0-iovcc";
 	status = "okay";
 };

 

And while the regulator initialises for the AXP223 GPIO1/LDO, I have nothing but GND on the pin.

 

[    1.223696] i2C0-iovcc: Bringing 3800000uV into 3000000-3000000uV

 

Because the driver configures the pin in the regulators, it seems like the axp_gpio and pinctrl definitions are useless.

[Patrick 42]

I fixed my i2c gpio ldo regulator issue by disabling the axp_gpio in the device tree.

 

&axp_gpio {
	status = "disabled";
};

 

The separate driver must have been rewriting the registers configured by the regulators driver.

 

Now back to the LCD

Edited 8 hours ago by Patrick 42