AM625: Configure TSC2046 for custom AM625 SOM

Hi Aditya,

I have assigned your query to the concerned expert, they will get back to you shortly.

Regards,

Nitika

Hi Nick,

This is my dts function

&main_spi0 {
	pinctrl-names = "default";
	pinctrl-0 = <&tsspi0_pins_default>;
	status = "okay";
	#address-cells = <1>;
	#size-cells = <0>;
	ti,pindir-d0-out-d1-in = <0>;

	tsc2046@0 {
		pinctrl-names = "default";
		pinctrl-0 = <&vdd_mmc1_pins_default>;

		reg = <0>;    / CS0 /
	        compatible = "ti,tsc2046";
        	interrupt-parent= <&main_gpio0>;
	        interrupts = <41 GPIO_ACTIVE_LOW>;
        	spi-max-frequency = <1250000>;
		pendown-gpio = <&main_gpio0 41 GPIO_ACTIVE_LOW>;
		vcc-supply = <&vcc_3v3_sys>;

		ti,x-min = /bits/ 16 <0>;
		ti,x-max = /bits/ 16 <800>;
		ti,y-min = /bits/ 16 <0>;
        	ti,y-max = /bits/ 16 <480>;
        	ti,x-plate-ohms = /bits/ 16 <40>;
        	//ti,y-plate-ohms = /bits/ 16 <200>;
        	ti,pressure-max = /bits/ 16 <255>;
/*
        	ti,vref-delay-usecs = <20000>;
        	ti,vref-mv      = <3300>;
		ti,keep-vref-on    =  <1>;

        	ti,debounce-rep =  <1>;
        	ti,debounce-tol =  <30>;
        	ti,debounce-max =  <10>;
        
        	ti,settle-delay-usec  = /bits/ 16 <150>;
		ti,penirq-recheck-delay-usecs = /bits/ 16 <20000>;
            
		touchscreen-x-mm    = <115>;
		touchscreen-y-mm    = <86>;
*/
		wakeup-source;
	};
};

//TOUCH-Start
	tsspi0_pins_default: tsspi0-pins-default {
		pinctrl-single,pins = <
			AM62X_IOPAD(0x1bc, PIN_OUTPUT, 7) / (A14) SPI0_CLK /
			AM62X_IOPAD(0x1c0, PIN_OUTPUT, 0) / (B13) SPI0_D0 /
			AM62X_IOPAD(0x1c4, PIN_INPUT, 0) / (B14) SPI0_D1 /
			AM62X_IOPAD(0x1b4, PIN_OUTPUT, 0) /* (A13) SPI0_CS0 | GPIO1_15*/
		>;
	};

	tsc_Int_Busy_pins_default: tsc-Int-pins-default {
		pinctrl-single,pins = <
			AM62X_IOPAD(0xa8, PIN_INPUT, 7) / (M21) GPIO0_41 /
			AM62X_IOPAD(0xac, PIN_INPUT, 7) / (L21) GPIO0_42 /
		>;
	};
//End

[    1.493093] ads7846 spi3.0: touchscreen, irq 335
[    1.498125] input: ADS7846 Touchscreen as /mailto:devices/platform/bus@f0000/20100000.spi/spi_master/spi3/spi3.0/input/input0

Hello,

Is there any updates on configuring TSC2046 further?

Thanks & Regards,
Aditya Tandulwadkar

Hello Aditya,

Apologies for the delayed response. I do not have one of those devices to test myself, but I will take a closer look at your devicetree settings tomorrow to see if there is anything that you might want to change.

Regards,

Nick

Hello Nick,

I've got success in enabling resistive touch on custom AM625 SOM. But, now I want to calibrate touch for AM625 SOM which is having TSC2046 touch controller IC

Thanks & Regards,
Aditya Tandulwadkar

Hello Aditya,

1) To confirm, you are now able to see touch input events? What did you end up changing to fix it?

In the past, I used evtest to check for touch inputs, as shown in this thread: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/862817/am3358-touchscreen-error/3197806#3197806 

2) What software are you using for the display? Wayland/Weston? EGFLS? tslib? Something else?

Regards,

Nick

Hi Nick,

1) =>The lines, given below worked for me:
         touchscreen-size-x = <4096>;
         touchscreen-size-y = <4096>;

I've also used to evtest tool and it is recognizing touch on all corners of my display, but how to calibrate using that data?

2) => The platform I'm using is linuxfb on the wayland display on X11

Thanks & Regards,
Aditya Tandulwadkar

Edited Feb 28 2024: The information in this response does not seem to apply to AM62x. Please refer to my later response here:
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1322404/am625-configure-tsc2046-for-custom-am625-som/5063378#5063378 

Hello Aditya,

Several years ago, the weston calibration was saved in a calibration file. So you would delete the old calibration data, and then the calibration tool would run at bootup. These old threads may be helpful:
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/723728/linux-am4378-touchscreen-calibration-problem
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/495706/am572x-touch-screen-calibration 

Where the text from the wiki that I linked to is here:

How to Recalibrate the Touchscreen

Weston based Graphic System
Where is the ws-calibrate.rules file?
The Processor SDK Linux moves the Weston calibration file for the touchscreen from the default location of /etc/udev/rules.d/ws-calibrate.rules to instead be placed at /run/media/mmcblk0p1/ws-calibrate.rules if the SD device is present. This was done to allow user's to easily delete this file and force a recalibration without requiring a Linux PC to mount the file system or a serial console to access the device. In this case the ws-calibrate.rules file is now written to a FAT partition of the SD card, which can be mounted on both Windows or Linux.

If the ws-calibrate.rules file is created at /run/media/mmcblk0p1/ws-calibrate.rules, and there is not already a file in /etc/udev/rules.d/ws-calibrate.rules then the file is also copied to the old default location.

In the case that there is no SD card available then the ws-calibrate.rules file will be written to the default /etc/udev/rules.d/ws-calibrate.rules.

Recalibrating by Deleting ws-calibrate.rules
To trigger touchscreen re-calibration, both ws-calbration.rules files need to be deleted. The ws-calbration.rules file which is now written to the FAT partition of the SD card can be deleted by simply inserting the SD card into a PC and deleting the ws-calbration.rules file found on the first partition (assuming the first partition is a FAT partition) and we also need to delete /etc/udev/rules.d/ws-calibrate.rules from the filesystem. After both ws-calibration.rules files are removed, you will be asked to calibrate the touchscreen when the Weston is launched at the first time or relaunched by issuing "/etc/init.d/weston start" command at the console.

Alternatively, you may delete the above listed files directly from the EVM's console by issuing the following commands at EVM's Linux prompt, and reboot the EVM to allow recalibration of the LCD.

 rm /etc/udev/rules.d/ws-calibrate.rules
 rm /run/media/mmcblk0p1/ws-calibrate.rules
 reboot
 
 Non-Weston based Graphic System
Where is the pointercal file?
The Processor SDK Linux moves the calibration file for the touchscreen from the default location of /etc/pointercal to instead be placed at /run/media/mmcblk0p1/pointercal if the SD device is present. This was done to allow user's to easily delete this file and force a recalibration without requiring a Linux PC to mount the file system or a serial console to access the device. In this case the pointercal file is now written to a FAT partition of the SD card, which can be mounted on both Windows or Linux.

If the pointercal file is created at /run/media/mmcblk0p1/pointercal, and there is not already a file in /etc/pointercal then the file is also copied to the old default location. This is to prevent requiring the export of the TSLIB_CALIBFILE variable as described in later sections of this document.

In the case that there is no SD card available then the pointercal file will be written to the default /etc/pointercal location.

Recalibrating by Deleting pointercal
Because the pointercal file is now written to the FAT partition of the SD card recalibrating the touchscreen can be done by simply inserting the SD card into a PC and deleting the pointercal file found on the first partition (assuming the first partition is a FAT partition). When the system is then rebooted you will be asked to calibrate the touchscreen.

Recalibrating over Serial Console
If you do have access to the serial console you can always recalibrate the touchscreen using the ts_calibrate command as normal. However, in this case if you already have a pointercal file on the SD card you will need to export the TSLIB_CALIBFILE variable to point to that location before you run ts_calibrate. i.e.

target# export TSLIB_CALIBFILE=/run/media/mmcblk0p1/pointercal
target# ts_calibrate
NOTE: If you have Matrix or any other GUI application already running you should stop that application (How to Stop Matrix) before running ts_calibrate so that you can see the calibration screen.

Exporting TSLIB_CALIBFILE
The environment variable TSLIB_CALIBFILE is used by the tslib package to indicate the location of the pointercal file. The default value for TSLIB_CALIBFILE is /etc/pointercal. If you are writing a program that uses tslib you should make sure that you export TSLIB_CALIBFILE to point to the location of your pointercal file (as indicated in the previous section), or that you place a copy of the pointercal file at the default /etc/pointercal location.

I'm not sure if that information still applies nowadays on AM62x?

Regards,

Nick

Hi Nick,

Thanks for providing above information. but it didn't helped me much.
Still I'm getting wrong touch co-ordinates

Thanks & Regards,
Aditya Tandulwadkar

Hello Aditya,

I am in the process of setting up a screen on my side that I can run tests on (not the same as yours, it's the one documented here: https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/09_01_00_08/exports/docs/linux/How_to_Guides/Target/How_to_enable_Microtips_LVDS_Panel_on_AM62_SK_EVM.html).

While I get that set up, please provide me with more information about what you have tried for calibration, and what results you are observing.

Regards,

Nick

Hi Nick,

The display I'm working on is 7" TFT RGB display, with 800×480 pixels. It supports 24 bit data i.e. RGB888.

On the other side, after running the evtest utility I'm able to recognize touch on all corners as well as different points on display, but when I want to execute a QT application on it, with linuxfb platform or any other platform like

eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, xcb 

On any of these platforms after clicking any of button which is made using QT it is getting wrong touch recognized.

Now, I'm not understanding that how to set right parameters of touch events?

Thanks & Regards,

Aditya Tandulwadkar 

Hello Aditya,

I will continue working this on my side. I'm on vacation Monday, and then my hardware setup will be ready by Wednesday. However, I would encourage you to try to search the web for other resources on calibrating a touchscreen with whatever software platform you are interested in.

I can provide guidance on how to get the TI EVM with the Microtips display panel calibrated, using the default software enabled in the SDK. But your solution may be different than what I can test here.

Either way, this will go faster with both of us running tests, instead of waiting for me to make progress on my side.

Regards,

Nick

Hi Nick,

Yes, I'm trying from my side to calibrate the touch and will update here, if any progress on it

Thanks & Regards,
Aditya Tandulwadkar