PWM & SAR

[mboehmer]

Hi,

 

as the "huge eMMC" patch for Odroid C2 seems to work, I want to proceed now on PWM and SAR.

I just installed a fresh system, and try to get both things working.

 

Can someone give me a hint on which modules I need, and if some tweaking in device tree is needed?

 

lsmod shows me that the SAR module seems to be present (meson_saradc), but I can't find the corresponding files on /sys/class/...

Moreover, the meson_pwm.ko is present and can be modprobe'd, but I don't get any files unter /sys/class/pwm/

 

Any help is appreciated.

 

Thanks in advance, Michael

[mboehmer]

Come on, no one except me wants to use PWM on Odroid C2?

I tried meanwhile to figure out which settings in Device Tree to add to get the pwm-meson kernel driver recognize it, but so far I failed.

 

ANY help is appreciated!

[Jojo]

Dear Michael,

 

sorry for digging out this ol' thread, but recently I faced the same problem like you. I like to use PWM on the C2. I can load the pwm-meson module, but the (required?) pmw-ctrl module seems to be missing. I don't find anything in my file system, which looks like a PWM compatible pin.

 

Have you come any further?

 

Thanks a lot,

greetings,

 

Jojo

[mboehmer]

It's working perfectly. You need the correct files for dts/dtb, otherwise it will not work.

As my systems are deployed already (no access, 2650m deep), I have other issues now to solve. 

I recommend to kindly address Neil Armstrong (no, not the one who was on Moon ) and ask for the correct files, and... to check them into to official branch

In case you need help, please let me know, I can try to help, but my time is at the moment severily limited.

 

Michael

[Jojo]

Ok, thank you! I will contact him.

 

Greetings

 

Edited July 19, 2018 by Jojo

[picosoft]

Hi, 

I have the same problems.

If you got the PWM working, please share how to do.

Thanks, 

[TonyMac32]

@picosoft please don't double post if possible.  That said, please see the response to your other post.

[picosoft]

On 12/26/2018 at 12:31 PM, TonyMac32 said:

@picosoft please don't double post if possible.  That said, please see the response to your other post.

I read the answer of the other post.( that is your answer.)

"If you know how to make overlays, you can give nightly dev images a try, I haven't made PWM overlays yet though."

This means there is no solution.

 

But, in this post says "It's working perfectly. You need the correct files for dts/dtb, otherwise it will not work." from mbohmer.

So, I asked how to correct files for dts/dtb.

I really want to know the method.

[TonyMac32]

3 minutes ago, picosoft said:

I read the answer of the other post.( that is your answer.)

"If you know how to make overlays, you can give nightly dev images a try, I haven't made PWM overlays yet though."

This means there is no solution.

 

The solution is to make an overlay.

 

3 minutes ago, picosoft said:

But, in this post says "It's working perfectly. You need the correct files for dts/dtb, otherwise it will not work." from mbohmer.

So, I asked how to correct files for dts/dtb.

I really want to know the method.

 

The correct dts/dtb is the overlay mentioned in my response.

 

The method is to make a device tree overlay and compile it, then, in the armbianEnv.txt file, specify it for inclusion at boot.  I'm afraid I don't have time to give you a tutorial on this at the moment, if you look at our build system you might be able to pick it up.  You also need to recognize the differences between kernel versions, I'm uncertain if mboehmer was using a 4.x kernel.

 

This page http://www.linux-meson.com/doku.php?id=start

Says pwm works with modern kernels, so, simply enabling it should be sufficient in the device tree overlay, and making sure the driver is compiled with the kernel.  If you are unable to do it, I may be able to by the end of the week, since it will benefit 3 boards.  No promise though, I have quite a few projects I'm working on simultaneously.