Banana pi R3 fan with PWM

Banana Pi Router design BPI-R3/R3 Mini(MT7986)
122

Have you tried the patch i suggested (using different top clock)? Which kernel (5.15 vs. 6.1).

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I thought this patch was included in the last snapshot. Should I build an image with the patch? Otherwise the kernel is 5.15.126.

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No, we have to know first if it solves your issueā€¦have you tried kernel 6.1?

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How to try kernel 6.1? master is 5.15.

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Same problem here with the RC3 And i donā€™t know how to build a firmware, so even less how to apply a patch :rofl:

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You mean PWM doesnā€™t work for you either. Right?

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5.15 is known not working

I guess because backported pwm/clock support is different to mainline

The pwm node i upstreamed works for me in mainline kernel without openwrt. So we need someone who can test pwm with openwrt with kernel 6.1 which (hopefully) does not have any openwrt-specific backports for r3

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129

The fan start runing when i boot the BPI, after 10/15 seconds it stop. i can start/stop the fan by sending some echo commands, so i donā€™t know if it is runing as expected, i mean starting alone when the temp is high.

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Hi @frank-w, I can change the clock in 5.15 dts, but I need some instructions? Do I have to build new image?

Iā€™m experienced in Linux. :grin:

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Yes you have to build openwrt from code and stop after patches are applied and then change the clock in dts and continue build-process. I do not know openwrt build tools enough if this is possible without adding an own patch file in the folder structure

Maybe @dangowrt can explain steps? Or maybe test this and add the patch?

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132

Try

echo 2 > /sys/class/thermal/cooling_device0/cur_state

Does it turn on the fan? Can you post your boot log?

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@Dale Nope. It does not start.

And some more info:

root@openwrt:~# cat /sys/kernel/debug/pwm 
platform/10048000.pwm, 2 PWM devices
 pwm-0   (pwm-fan             ): requested enabled period: 10000 ns duty: 9999 ns polarity: normal
 pwm-1   ((null)              ): period: 0 ns duty: 0 ns polarity: normal
134

Can you run the same command right after you run the command I suggested?

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yes, it turns about 5s and stop.

I use openwrt 23.05.0 RC3 with kernel 5.15.127

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Then you have no problem, the thing is the trip points has changed and the fan will only start at 85cā€¦ it has to be changed

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@Rooot can you also try:

echo 1 > /sys/class/thermal/cooling_device0/cur_state
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Do you use snapshot or 23-rc?

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i did it already and the fan turns indefinitly (i think)

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here it is : https://sharetext.me/209j4zgcdj

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@frank-w , as you can see this guy has the pwm clk error on boot log and it still works for him. Perhaps the init has retries? I havenā€™t looked at the code