SPI TFT ILI9488

Out Of Tree DRM Driver for ILI9488 Driver Chip Based TFT 3.5" 480x320 LCDs that utilize the SPI protocol.

NOTE: There is already a kernel driver that was being moved upstream by Kamlesh Gurudasani. This is just my implementation that works with the udoo-bolt.

Development is done with kernel version 6.1.9. Utilizing the yocto project and a BitBake recipe called ili9488.bb. One can build the driver via.

Building

Compile Kernel Module

# On target
$ KSRC="/lib/modules/$(uname -r)/build" make

$ source openembedded-core/oe-init-build-env $(pwd)/build
$ bitbake ili9488

# cd into working directory + git folder
# May look something like bellow
$ cd tmp/work/udoo_bolt_emmc-northstar-linux/ili9488/0.0.1-git+b9d43fbe2a6a05a29bfa13d244a8573a3ade20c3-r0/git
$ ../temp/run.do_compile

Compile DTS/ASL

# Compile Device Tree Source to Device Tree Blob
$ KSRC="/lib/modules/$(uname -r)/build" make dtb

# Compile ACPI Source Language to ACPI Machine Language
$ make aml

Testing AML file

# First Gather, Extract, & Disassemble ACPI Tables
$ acpidump > acpi.log
$ acpixtract acpi.log

# To get source of all DSDT/SSDT
$ iasl -d *.dat > /dev/null 2>&1

# Execute
$ acpiexec *.{dat,aml}

SSDT overlays: Run-time ConfigFS approach

# If desire alias for loading and unloading ACPI SSDT
$ source devutils/compile-load-alias

# Mount ConfigFS
$ mount -t configfs none /sys/kernel/config

# Load ACPI ConfigFS support (if it’s a module)
$ modprobe acpi-configfs

# Load SSDT
$ mkdir -p /sys/kernel/config/acpi/table/ili9488
$ cat "ili9488.aml" > "/sys/kernel/config/acpi/table/ili9488/aml"
# OR
$ load_ili9488_aml

# Unload SSDT
$ ./devutils/unload-acpi-table /sys/kernel/config/acpi/table/ili9488
# OR
$ unload_ili9488_aml