REQUEST: Implement AXP20X + ANALOGIX ANX6345 drivers in linux-lts/edge for OLIMEX Teres-I

Context: I don't know how you manage your linux-lts/edge and i don't want to disrupt that so submitting it in this way.

These drivers are needed for OLIMEX Teres-I to work on Alpine and subsequently on postmarketOS without issues, currently the device fails to set voltages for the card and get a functional display

Card did not respond to voltage select! : -110

..after the u-boot phase (using u-boot that was previously tested with a working kernel to work without issues):

U-Boot SPL 2024.01 (Jan 18 2024 - 19:32:49 +0100)
DRAM: 2048 MiB
Trying to boot from MMC1
NOTICE:  BL31: v2.10.0  (debug):
NOTICE:  BL31: Built : 01:25:38, Dec  4 2023
NOTICE:  BL31: Detected Allwinner A64/H64/R18 SoC (1689)
NOTICE:  BL31: Found U-Boot DTB at 0x20a2d98, model: Olimex A64 Teres-I
INFO:    ARM GICv2 driver initialized
INFO:    Configuring SPC Controller
INFO:    PMIC: Probing AXP803 on RSB
INFO:    PMIC: aldo1 voltage: 2.800V
INFO:    PMIC: dcdc1 voltage: 3.300V
INFO:    PMIC: dcdc5 voltage: 1.500V
INFO:    PMIC: dcdc6 voltage: 1.100V
INFO:    PMIC: dldo1 voltage: 3.300V
INFO:    PMIC: dldo2 voltage: 2.500V
INFO:    PMIC: dldo3 voltage: 1.200V
INFO:    PMIC: dldo4 voltage: 3.300V
INFO:    PMIC: fldo1 voltage: 1.200V
INFO:    PMIC: Enabling DC SW
INFO:    BL31: Platform setup done
INFO:    BL31: Initializing runtime services
INFO:    BL31: cortex_a53: CPU workaround for erratum 843419 was applied
INFO:    BL31: cortex_a53: CPU workaround for erratum 855873 was applied
INFO:    BL31: cortex_a53: CPU workaround for erratum 1530924 was applied
INFO:    PSCI: Suspend is unavailable
INFO:    BL31: Preparing for EL3 exit to normal world
INFO:    Entry point address = 0x4a000000
INFO:    SPSR = 0x3c9


U-Boot 2024.01 (Jan 18 2024 - 19:32:49 +0100) Allwinner Technology

CPU:   Allwinner A64 (SUN50I)
Model: Olimex A64 Teres-I
DRAM:  2 GiB
Core:  74 devices, 24 uclasses, devicetree: separate
WDT:   Not starting watchdog@1c20ca0
MMC:   mmc@1c0f000: 0, mmc@1c10000: 2, mmc@1c11000: 1
Loading Environment from FAT... Unable to read "uboot.env" from mmc0:1... 
In:    serial,usbkbd
Out:   serial,vidconsole
Err:   serial,vidconsole
Net:   No ethernet found.
starting USB...
Bus usb@1c1b000: USB EHCI 1.00
scanning bus usb@1c1b000 for devices... EHCI timed out on TD - token=0x80008c80
4 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Card did not respond to voltage select! : -110
BootOrder not defined
EFI boot manager: Cannot load any image
Found EFI removable media binary efi/boot/bootaa64.efi
83456 bytes read in 6 ms (13.3 MiB/s)
Booting /efi\boot\bootaa64.efi
EFI stub: Decompressing Linux Kernel...
EFI stub: Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path
EFI stub: Using DTB from configuration table
EFI stub: Exiting boot services...
<<Unknown what it's doing, no serial console output and black screen on the device>>

Expected additions:

CONFIG_BATTERY_AXP20X=m # Battery Gauge
CONFIG_AXP20X_ADC=m # Battery
CONFIG_DRM_ANALOGIX_ANX6345=m # Display bridge drivers (important!)

# These should be automatically enabled
CONFIG_PINCTRL_AXP209=y
CONFIG_INPUT_AXP20X_PEK=y

Consider also CONFIG_PREEMPT_DYNAMIC to enable the change of preemption model bcs e.g. teres prefers low-latency over the current desktop and CONFIG_EFI_ZBOOT as it's supposed to speed up the boot (https://gitlab.com/postmarketOS/pmaports/-/merge_requests/4774#note_1748507441)

If you know of any missing configuration then feel free to propose additions e.g. I don't know what's needed to address INFO: PSCI: Suspend is unavailable atm, but i assume it's the lack of crust firmware complied in the testing u-boot.

Blocks: https://gitlab.com/postmarketOS/pmaports/-/merge_requests/4743

CC @ncopa - The Linux-LTS/Edge Maintainer in Alpine Linux

CC @mps - The Device Maintainer in Alpine Linux