after doing more research it seems you have to compile the dts files into a pre processed file with cpp command before you can compile into a dtb file with the dtc command. so i got that figured out and can change the io pullups.

however im still struggling with the wakeup from suspend conditions. I enabled several of them but none seem to work. usb hubs are suspended so usb wakeup doesnt work, the Uart0 wakeup condition is enabled but doesnt wakeup the processor either. ill have to keep digging, but if you are anyone knows how to wakeup from a source other than the power button that would be great to know. as it stands ill have to add a secondary microprocessor to the system to ground the power button contact physically to wake up the board.

@george so here is where I am at. Ive spent a lot of time trying to figure this out but nothing is making sense so maybe you can give me a direct file of what will work. I have done this:

1. navigate to folder of rk3588s-cp4.dtb (/boot/firmware/rk3588s-cp4.dtb)
2. converted the dtb file to dts file using command: sudo dtc -I dtb -O dts rk3588s-cp4.dtb -o rk3588s-cp4.dts
3. nano to open the file: sudo nano rk3588s-cp4.dts

heres where im stuck...theres nothing in that file that resembles the syntax you have sent me. I will attach the dts file in txt format here. can you edit it with the correction to change pin 32 from pull up to pull down? thanks!
rk3588s-cp4.txt

alternatively, on line 1562 i find there is an entry for wake from suspend such as below.

rockchip,wakeup-config = <0x100>;

can you tell me how to change this line to enable GPIO wake from suspend? then I can use whatever GPIO I wish to wake the cool-pi 4b up when suspended without physically pushing the button. I have tried the syntax below but i get a syntax error when i try to convert it back to dtb file:

rockchip,wakeup-config = <
(0
| RKPM_GPIO_WKUP_EN
)
>;

@george ok this explains things better. I have a HAT that was designed for the raspberry pi 4 and it has a power detection pin on pin 32. it needs to be pulled down in order to function because the hat sends 3.3v to the pin as long as incoming power is detected on the power in lines of the HAT. then when the incoming power dissapears from the hat incoming lines, pin 32 will be pulled low by the pull down resistor and the pi can execute some code. If i can figue out how to edit the dts file and recompile to dtb to change pin 32 to an internal pull down resistor i will do it that way. otherwise i guess i am stuck.

@george thanks for the info george...i tried adding a 2k resistor to ground on pin 32 to change it to change it from pull up to pull down as you mentioned, however that does not work and the pin voltage on 32 reads 1.034 volts. ill try other values of resistors and report which one works.

@george and can i do the same thing with an overlay in the config.txt or something? if so how? thx

@george ok George where can i find this file to modify?

@george have logged into root but only see certain gpio as i still try to piece the missing parts together. How can I then change the pull up and pull down resistors for certain input pins?

@george im trying to access the gpio because i have a custom hardware hat that needs gpio105 (pin 32) to be pulled down and i dont see any other way to pull down the input even though the documentation on the gpio page says that all IO can be set up with pull up or pull down resistors. pin 32 seems only to be pull up

@george yes from the very start: echo 128 > /sys/class/gpio/export does not create a node

ugh per usual on this site none of these commands work :rolls eyes:

it says in the GPIO page that all gpio are configurable with pullup or pulldown mode. How can we access the pull down resistor on a input pin say pin 32 GPIO105 that is default set to pullup? I tried the same convention as raspberry pi python access which is

GPIO.setup([pin#], GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

and i get the error no PUD_DOWN in the module. Can you post the entire documentation with included commands in this module?

@george ok so i just figured something out. I removed my power supply hat that i have on my pi so i could connect my serial terminal pins and get you a log, and behold the suspend function works when i powered it on with the usb c port. so seems that for some reason supplying power through the gpio pins for some reason wont let me use the suspend function.

@george that is very strange ive been chasing the issue for last 12 hours. mine definitely doesnt act that way. i have the 20230424 ubuntu image....i also see ive downloaded the 20230306 image. i cant say which is running on the micro sd card though. does the 20230306 behave the same way?

@george also can you test on the latest ubuntu 22.04 release as well? The software im developing is having issues on ubuntu 23.04 but works well on 22.04

@george thanks!

@george im on cp4b. any tips on making it work? since the power button just reboots even though i have it set to suspend function.

@george when i sett the power button to suspend mode and press it, it reboots the board it doesnt actually suspend it. tried changing the systemd sleep file as well with the same results in every case. I think its sufficient to say that currently it does not actually support suspend mode. at least not ubuntu. have you tried any of the other images?

@george is the new kernel used in the ubuntu 23.04 image? I have tried the ubuntu 22.04 image and the 23.04 image but when i run $ cat /sys/power/state it returns "freeze mem" not "freeze mem disk" indicating that theres no kernel level support for actually saving the ram swap to the disk to reboot from.

if no, Can someone build a kernel with power management enabled via swap partition or swap file? Is it possible to put the cool pi 4b into suspend or hibernate mode?

@jack_admin i used the most recent debian image on the drive linked here. i burned the image to 2 diferent usb drives. they are nvme ssd's connected over usb. this method works on my other raspberry pi-like sbc's just not the cool-pi