This version (24 Jul 2020 11:05) was approved by Sunny Feng.
Table of Contents
Linux LCD Touchscreen
Introduction
This section describes the steps required to build and use SPI Touchscreen device on Linux using an ADSP-SC58x board and a WVGA/LCD EI3 extender board.
Hardware Setup
- ADSP-SC58x EZ-KIT: ADSP-SC589/SC584 EZ-Board
- A WVGA/LCD EI3 Extender Board
Connect the J1 connector on the LCD EI3 Extender Board to the P1A connector on the SC58x-EZKIT
Software Configuration
The following configuration should be done on top of the sc589-ezkit/sc584-ezkit default configuration.
Configure Linux Kernel
Run bitbake linux-adi -c menuconfig and configure the kernel as follows:
There are two things to enable in the Linux kernel. First, you need the common code for the event interface. Then you need the specific driver for the touchscreen device you're using.
Device Drivers ---> Input device support ---> [*] Generic input layer (needed for keyboard, mouse, ...) <*> Event interface
The touchscreen drivers will be in the same place. Enable the driver for the device you're using.
Device Drivers --->
Input device support --->
[*] Touchscreens --->
<*> Analog Devices AD7879-1/AD7889-1 touchscreen interface
<*> support SPI bus connection
Don't forget to enable LCD and disable CAN driver for touch screen calibraion.
Device Drivers --->
Graphics support --->
Frame buffer Devices --->
<*> Support for frame buffer devices --->
<*> NEC NL8048HL WVGA LCD for ADI SC5XX boards
[*] Networking support --->
< > CAN bus subsystem support ---->
Enable Packages
Add the touchscreen test program in the filesystem images, it's enabled in adsp-sc5xx-full image by default.
vim build/conf/local.conf IMAGE_INSTALL_append = "tslib tslib-calibrate evtest"
Example
Enable LCD Back-light
Look for the right gpio number of target boards:
# cat /sys/kernel/debug/gpio gpiochip0: GPIOs 0-15, adi-gpio: gpiochip1: GPIOs 16-31, adi-gpio: gpio-30 ( |mdio-reset ) out hi gpiochip2: GPIOs 32-47, adi-gpio: gpio-32 ( |spi0.32 ) out hi gpio-38 ( |spi2.38 ) out hi gpio-39 ( |spi0.39 ) out hi gpio-44 ( |spi0.44 ) out hi gpiochip3: GPIOs 48-63, adi-gpio: gpiochip4: GPIOs 64-79, adi-gpio: gpiochip5: GPIOs 80-95, adi-gpio: gpiochip6: GPIOs 96-101, adi-gpio: gpiochip9: GPIOs 479-479, parent: spi/spi0.32, AD7879-GPIO, can sleep: gpiochip8: GPIOs 480-495, parent: i2c/0-0022, mcp23017, can sleep: gpiochip7: GPIOs 496-511, parent: i2c/0-0021, mcp23017, can sleep: gpio-498 P0.2 (adi-uart4.0 ) out lo gpio-499 P0.3 (3100c000.ethernet) out lo gpio-500 P0.4 (3100e000.ethernet) out lo gpio-507 P0.11 (31010000.mmc) out lo gpio-508 P0.12 (spi2.38 ) out lo gpio-509 P0.13 (spi2.38 ) out lo
As above showed, GPIO 479 is what we are looking for.
# echo 479 > /sys/class/gpio/export # echo high > /sys/class/gpio/gpio479/direction
Make sure your LCD screen becomes white at this point.
Soft Switch Configuration
The settings in this section is only apply to ADSP-SC584 EZ-Board.
# echo 484 > /sys/class/gpio/export # echo high > /sys/class/gpio/gpio484/direction # echo 491 > /sys/class/gpio/export # echo high > /sys/class/gpio/gpio491/direction
Runtime Config
Before you can use the touchscreen, you need to export a few environment variables. You may want to put these into a file so you can easily source it at runtime.
# vi /etc/tslib.env export TSLIB_FBDEVICE=/dev/fb0 export TSLIB_CONSOLEDEVICE=none export TSLIB_CONFFILE=/etc/ts.conf export TSLIB_CALIBFILE=/etc/pointercal export TSLIB_TSDEVICE=/dev/input/event0 # . /etc/tslib.env
Calibration
Before you start using the touchscreen, you should calibrate it. This can be easily accomplished with the ts_calibrate application on the EI3 LCD extender. Just follow the on-screen directions.
Then run following commands and touch the appropriate location according to screen`s prompts .
# ts_calibrate xres = 800, yres = 480 Took 3 samples... Top left : X = 261 Y = 648 Took 5 samples... Top right : X = 3631 Y = 657 Took 6 samples... Bot right : X = 3633 Y = 3407 Took 5 samples... Bot left : X = 236 Y = 3467 Took 2 samples... Center : X = 1970 Y = 2001 -4.445068 0.206877 0.000894 -39.800293 0.001046 0.136427 Calibration constants: -291312 13557 58 -2608352 68 8940 65536
Event Test
After run following the command, start using the touchscreen. The application should decode the input immediately.
# evtest /dev/input/event0 Input driver version is 1.0.1 Input device ID: bus 0x1c vendor 0x0 product 0x7a version 0x3 Input device name: "AD7879 Touchscreen" Supported events: Event type 0 (EV_SYN) Event type 1 (EV_KEY) Event code 330 (BTN_TOUCH) Event type 3 (EV_ABS) Event code 0 (ABS_X) Value 0 Min 0 Max 4095 Event code 1 (ABS_Y) Value 0 Min 0 Max 4095 Event code 24 (ABS_PRESSURE) Value 0 Min 0 Max 10000 Properties: Testing ... (interrupt to exit) Event: time 1572578217.819961, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1 Event: time 1572578217.819961, type 3 (EV_ABS), code 0 (ABS_X), value 1552 Event: time 1572578217.819961, type 3 (EV_ABS), code 1 (ABS_Y), value 2577 Event: time 1572578217.819961, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 446 Event: time 1572578217.819961, -------------- SYN_REPORT ------------ Event: time 1572578217.832117, type 3 (EV_ABS), code 0 (ABS_X), value 1565 Event: time 1572578217.832117, type 3 (EV_ABS), code 1 (ABS_Y), value 2564 Event: time 1572578217.832117, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 644 Event: time 1572578217.832117, -------------- SYN_REPORT ------------ Event: time 1572578217.844232, type 3 (EV_ABS), code 0 (ABS_X), value 1571 Event: time 1572578217.844232, type 3 (EV_ABS), code 1 (ABS_Y), value 2563 Event: time 1572578217.844232, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 383 Event: time 1572578217.844232, -------------- SYN_REPORT ------------ Event: time 1572578217.856371, type 3 (EV_ABS), code 0 (ABS_X), value 1557 Event: time 1572578217.856371, type 3 (EV_ABS), code 1 (ABS_Y), value 2572 Event: time 1572578217.856371, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 326 Event: time 1572578217.856371, -------------- SYN_REPORT ------------ Event: time 1572578217.868511, type 3 (EV_ABS), code 0 (ABS_X), value 1551 Event: time 1572578217.868511, type 3 (EV_ABS), code 1 (ABS_Y), value 2588 Event: time 1572578217.868511, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 298 Event: time 1572578217.868511, -------------- SYN_REPORT ------------ Event: time 1572578217.880664, type 3 (EV_ABS), code 0 (ABS_X), value 1554 Event: time 1572578217.880664, type 3 (EV_ABS), code 1 (ABS_Y), value 2613 Event: time 1572578217.880664, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 286 Event: time 1572578217.880664, -------------- SYN_REPORT ------------ Event: time 1572578217.892814, type 3 (EV_ABS), code 0 (ABS_X), value 1559 Event: time 1572578217.892814, type 3 (EV_ABS), code 1 (ABS_Y), value 2624 Event: time 1572578217.892814, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 288 Event: time 1572578217.892814, -------------- SYN_REPORT ------------ Event: time 1572578217.904947, type 3 (EV_ABS), code 0 (ABS_X), value 1562 Event: time 1572578217.904947, type 3 (EV_ABS), code 1 (ABS_Y), value 2626 Event: time 1572578217.904947, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 300 Event: time 1572578217.904947, -------------- SYN_REPORT ------------ Event: time 1572578217.917082, type 3 (EV_ABS), code 1 (ABS_Y), value 2611 Event: time 1572578217.917082, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 334 Event: time 1572578217.917082, -------------- SYN_REPORT ------------ Event: time 1572578217.969468, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 0 Event: time 1572578217.969468, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0 Event: time 1572578217.969468, -------------- SYN_REPORT ------------
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resources/tools-software/linuxdsp/docs/linux-kernel-and-drivers/lcd/lcd_touchscreen.txt · Last modified: 03 Jul 2020 09:02 by Sunny Feng