Issue 951: Fix remaining issues for v5.10 on jz4730 mipsbook

Reported by Nikolaus Schaller, Dec 23, 2020

The following areas (highest priority first) are not yet working:
- µs timer
- boot speed
- i2c
- lcd and backlight pwm
- keyboard, buttons
- rtc
- powerdown/reboot/suspend?
- dma for mmc
- ethernet
- sound
- nand

working is:
* boot to login:
* mmc
* usb incl. wifi and touchpad

Comment 1 by Nikolaus Schaller, Dec 30, 2020

working is:
+ mmc
+ boot to login: and run shell
+ caps lock, scroll lock
+ usb incl. built-in wifi (can be used to apt-get upgrade) and 
touchpad peripherals

now working with latest git tree:
+ matrix keyboard and buttons
+ powerdown (if i2c available)
+ external PCF RTC (if i2c available)
+ num-lock LED

work in progress:
* new i2c driver

still broken:
- µs timer (sched_clock seems to work but hrtimer is too slow)
- boot speed
- sleep 10 waits 20 real time seconds and heartbeat appears to run 
at half speed
- i2c (new driver works but is not 100% reliable)
- backlight pwm (basically works but does not become enabled)
- lcd (no display even if pwm is enabled through devmem2)
- reboot
[   38.221657] reboot: Restarting system
[   38.235240] Reboot failed -- System halted
- suspend (not implemented, no rtc-wake)
- dma for mmc (currently disabled)
- ethernet
- sound
- nand

Comment 2 by Nikolaus Schaller, Jan 19, 2021

status update for 5.11-rc4:

working is:
+ mmc
+ boot to login: and run shell
+ caps lock, scroll lock
+ usb incl. built-in wifi (can be used to apt-get upgrade) and 
touchpad peripherals
+ matrix keyboard and buttons
+ powerdown (if i2c available)
+ external PCF RTC (if i2c available)
+ num-lock LED
+ backlight pwm
+ lcd
+ X11 startup (very slow)

already fixed but not yet integrated:
* µs timer (sched_clock seems to work but hrtimer is too slow)
* boot speed
* sleep 10 waits 20 real time seconds and heartbeat appears to run 
at half speed

work in progress:
* new i2c driver
* X11 setup (left/right mouse button not triggering xevents)

still broken:
- i2c (new driver works but is not 100% reliable)
- reboot
[   38.221657] reboot: Restarting system
[   38.235240] Reboot failed -- System halted
- suspend (not implemented, no rtc-wake)
- dma for mmc (currently disabled)
- ethernet
- sound
- nand
- sysbench --test=cpu --num-threads=4 run very very slow

Comment 3 by Nikolaus Schaller, Apr 27, 2021

status update 5.12.0:

working is:
+ mmc
+ boot to login: and run shell
+ caps lock, scroll lock
+ usb incl. built-in wifi (can be used to apt-get upgrade) and 
touchpad peripherals
+ matrix keyboard and buttons
+ powerdown (if i2c available)
+ external PCF RTC (if i2c available)
+ num-lock LED
+ backlight pwm
+ lcd
+ X11 startup (very slow)
+ clocksources
+ boot speed
+ ethernet (a little unreliable)

work in progress (not yet fully integrated in letux-current):
* new i2c driver
* X11 setup (left/right mouse button are not triggering xevents)
* headset detect

still broken:
- i2c (new driver works but is not 100% reliable)
- sound (aplay, arecord)
- "sysbench --test=cpu --num-threads=4 run" is very very 
slow
- dma for mmc (currently disabled)
- nand
- suspend (not implemented, no rtc-wake)
- reboot (need user to press Fn+L-Shift)

Letux Kernel