Update Board info for Pi 5 #2145

pjgpetecodes · 2023-10-08T21:16:52Z

The Board info for the new Raspberry Pi 5 is missing.

Microsoft Reviewers: Open in CodeFlow

pgrawehr · 2023-10-09T06:28:05Z

src/System.Device.Gpio/System/Device/Gpio/Drivers/RaspberryPi3Driver.cs

+            RaspberryBoardInfo.Model.RaspberryPi5 or
            RaspberryBoardInfo.Model.RaspberryPi400 => new RaspberryPi3LinuxDriver(),


The GPIO Hardware of the RPi5 seems to be quite different from previous versions. Is the RaspberryPi3LinuxDriver really working correctly?

Fair point... I'll see if I can build it all locally and try it on my Pi5 and see what's what. :-)

I read the pre-release datasheet for the new custom IC called RP1 which is new to the RPi5.
It governs all the I/O, serial ports, I2C, SPI, PWM, video and USB communications. The HW architecture is very different from the previous boards even if they apparently maintained the external pin compatibility (They also use MUXes for the I/O, meaning that you can remap the ping assignments).

The main point about that IC is to offload the communications from the main processor to support low-power communication while the rest of the board is in sleep mode. It also supports 1.8V levels but they have to be carefully used because, once set any voltage higher than 1.8V can damage the board.

Said that, the libgpiod could be enough to decouple the new functionalities but since there are more features, it will probably deserve a new separate RasperryPi5LinuxDriver to support them.

I don't have a new RPi5, but any test you could do is more than welcome :)

Is there a recommended workflow for development / debugging for GPIO? Are we able to debug directly on the Pi? @pgrawehr @raffaeler ...

Is there a recommended workflow for development / debugging for GPIO? Are we able to debug directly on the Pi?

The point here is that there is no direct access for the C# code to the GPIO, therefore debugging the GPIO access does not help much. The dotnet/iot library provides two "drivers": sysfs (GPIOs mapped on files) and libgpiod. They are just the C# code accessing the file system or the libgpiod api.

sysfs is the simpler (and slower) way. If you can successfully access the GPIOs using the default tools, it should work from dotnet/iot as well. Even if this works, it is not the best solution as file mapped GPIOs have a number of issues.

libgpiod provides access to the GPIOs via APIs. I understood that there is no current version for libgpiod for the RPi5. In this case there is nothing you can do from dotnet. A soon as the Raspberry Foundation should provide it, we will have to see if the APIs are exactly the same or not.

Alternate solutions are:

fork libgpiod and provide support for the RPi5, you should download and implement the RP1 specifications inside the libgpiod source code. This step is definitely not trivial.

implement the RP1 specs directly in C# bypassing libgpiod. It is doable but, again, not trivial.
AFAIK we never did this for any other board.

P.S. As I mentioned in the previous message the RP1 specs have a number of new features that may not fit in the current libgpiod API. This is why I believe we need something different on the C# wrapper side as well.

@pjgpetecodes There are two options to work with the library:

Variant 1

Check out the repo on the PC, build

Create / update an example

Publish it for arm64 and copy to the pi

Run on the Pi, use SSH for remote debugging, if needed

Variant 2

Checkout on the PI

Build on the Pi

Execute the examples / Integration tests

I'm normally going with 1, unless I'm running the GPIO testbench. Then I check out on the Pi and run dotnet test System.Device.Gpio.sln. (For the GPIO tests to work, you need to have pins 5 and 6 connected with a resistor)

I'm guessing I'll have to clone, switch to my working branch, and build this on the pi, then manually add the system.device.gpio dlls to my project to begin with...?

You can just cross-compiling everything on Windows and then copy to the RPi5. Your test code could be any basic binding. I suggest you to directly reference the dotnet/iot libraries so that you recompile the libraries as well.

This is the typical way to cross-compile using self-contained to avoid any dependency and being able to sync the sources as suggested by Patrick.

Release vs Debug: pick Debug if you want to avoid optimizations and sync the sources

linx-arm vs linux-arm64. This depends on the OS on the RPi

dotnet deploy -c Release -r linux-arm --self-contained=true

Please note that the pdbs will point to sources that you just compiled.

In any case, if you just want to make a test, you don't need to debug. You can just deploy the release version as self-contained and see if if works (you can write on the console some message to have detailed info).

HTH

Arghhh... My comments above (#2145 (comment)) were stuck in pending... Apologies @raffaeler and @pgrawehr ... Thanks for the help mind you!

As you can see it seems to work at a high level at least...

Need to figure out the best way to move forward now eh!

Hey, that's good news, at least we have one driver that works for the Pi5. Can you (just for reference) do the same test with using the RaspberryPi3Driver and the SysFsDriver?

PinNumberingScheme.Board is only supported with the RaspberryPi3Driver, because it needs to know the mapping from the logical pins to the physical pins. Because most boards and drivers don't support that either, we've mostly given up support for that anyway and stick to the logical numbering.

So...

With the original code;

RaspberryPi3Driver driver gives Not a supported Raspberry Pi type: (Fairly obviously)`

SysFSDriver just works!

With Raspberry Pi 5 added in the boardInfo.BoardModel switch in the CreateInternalRaspberryPi3LinuxDriver function, creating the RaspberryPi3Driver and passing it into the GpioController gives An unhandled exception of type 'System.IO.IOException' occurred in System.Device.Gpio.dll: 'Error 13 Initializing the Gpio driver'

Interestingly, doing a sudo dotnet run, gives Error 22 instead of Error 13 (But still System.IO.IOException)... Not sure of the difference.

Also, doing an ls /dev/gpiomem (as I see that mentioned in the RaspberryPiLinuxDriver.cs) gives No such file or directory, same with sudo ls /dev/gpiomem.

sudo adduser <myusername> gpio gives adduser: The user '<myusername>' is already a member of 'gpio'

ls /dev/mem gives:

crw-r----- 1 root kmem 1, 1 Oct 10 21:11

This is all no doubt because the new RP1 IO chip does GPIO entirely differently.

For reference, standing up something like a PWM Servo means that we can't pass in which GPIO Driver we use, so this needs to be done behind the scenes I guess.

I mean, ideally we'd write a driver specifically for this, but I'm not sure what's involved in that of course.

krwq · 2023-10-12T15:42:31Z

src/System.Device.Gpio/System/Device/Gpio/Drivers/RaspberryPi3Driver.cs

@@ -141,6 +141,7 @@ RaspberryBoardInfo.Model.RaspberryPi3BPlus or
            RaspberryBoardInfo.Model.RaspberryPiZeroW or
            RaspberryBoardInfo.Model.RaspberryPiZero2W or
            RaspberryBoardInfo.Model.RaspberryPi4 or
+            RaspberryBoardInfo.Model.RaspberryPi5 or


[Triage] Please remove this line to avoid using that driver for Raspberry Pi 5 because it's not fully working and as a next step right after this PR consider creating a separate PR/issue for Raspberry 5 driver.

Thanks... Done... I've also added the Pi5 Board reference to the GpioController class along with a switch choosing the LibGpiodDriver when on windows.

However, I guess this will only be used if running on Windows 10 or the now (pretty much) defunct Windows 10 IoT?

Do let me know if you think this should be removed though?

I'll definitely go with a new PR for for any work on a Pi5 driver.

Add Pi 5 OProduct to GpioDriver.

pgrawehr · 2023-10-12T17:10:02Z

src/System.Device.Gpio/System/Device/Gpio/GpioController.cs

@@ -506,6 +507,11 @@ private static GpioDriver GetBestDriverForBoardOnWindows()
            return new RaspberryPi3Driver();
        }

+        if (baseBoardProduct == RaspberryPi5Product || baseBoardProduct.StartsWith($"{RaspberryPi5Product} "))
+        {
+            return new LibGpiodDriver();


Shouldn't this be in the Linux method? AFAIK there's no supported windows version for rpi at this time and libgpiod is not for windows.

I absolutely agree... Only, that function doesn't detect the board type nor does this class for Unix, where that code is within the RaspberryPi3Driver class sadly...

So, I figure, if I'm going to need to bring that code in to this class, or modify the RaspberryPi3Driver class, then I should submit a new PR for that as @krwq suggests perhaps?

Absolutely happy to take some direction though!

For now, let's keep this simple. As you've already noticed above, Windows isn't really supported any more (the defunct Windows 10 Iot is only supported on the Raspberry Pi 3, and for Windows 11, there are no officially supported versions for any Pi at all at this time).

So for now, move this code to GetBestDriverForLinux() so at least we get a valid driver there. If I understand correctly, you need to do new LibGpiodDriver(4) though. After this, I would say this PR is ready to get merged.

After that, investigation is needed onto the next steps. We probably need a fully new RaspberryPi5Driver then, that handles the GPIO device for the new RP1 chip. Don't forget to take a look at the RaspberryPiBoard class, which contains the logic to program the mux for the different GPIO alternate functions. This logic will likely also change.

Ok done...

(Ignoring the brain farts of commits - Amazing how much trouble an errant semi-colon can cause - We can squash)... It works...

Of course, if you use a Pin Numbering scheme of Board instead of Logical it throws a Platform Not Supported error (I like the board numbering scheme personally).

I tried PWM and a Servo out of interest and it doesn't seem to work interestingly... I wonder is this a limitation of the LibGpioDriver?

With Python and gpiozero I get jittery servo movement from BCM18... But there's movement...

Could you re-try with C# after running the Python code?

Nothing sadly... gpiozero, while jittery, works... I'm sure it's bit bashed PWM in gpiozero by default given that its jitterry and gives this warning;

/usr/lib/python3/dist-packages/gpiozero/output_devices.py:1509: PWMSoftwareFallback: To reduce servo jitter, use the pigpio pin factory.See https://gpiozero.readthedocs.io/en/stable/api_output.html#servo for more info warnings.warn(PWMSoftwareFallback(

No movement at all for .NET... Which will be trying to use Hardware PWM.

With that in mind... When I try software PWM from the bindings it works... But not ideal...

using SoftwarePwmChannel pwmChannel1 = new SoftwarePwmChannel(18, 50, 0.5, true); using ServoMotor servoMotor1 = new ServoMotor( pwmChannel1, 180, 900, 2100);

There is probably some new initialization stuff needed to make it work on the RPi5 but it's hard to say.

I'll have a dig around and a play.... See what I can turn up...

BTW... I tried adding the following to the config.txt file and rebooting;

dtoverlay=pwm-2chan,pin=18,func=2,pin2=13,func2=4

But, no dice.

Worth trying eh.

I've also asked the question around Pi 5 docs in the Raspberry pi Forums, see if there's some more info out there other than the RP1 Datasheet.

pjgpetecodes · 2023-10-16T10:17:33Z

Looks like this is stuck for some reason... Not sure why...

raffaeler · 2023-10-16T10:41:09Z

Looks like this is stuck for some reason... Not sure why...

No worries, we just have to review the changes this week during the triage.

pgrawehr · 2023-10-16T10:53:37Z

/azp run dotnet.iot

azure-pipelines · 2023-10-16T10:53:47Z

Azure Pipelines successfully started running 1 pipeline(s).

pjgpetecodes · 2023-10-16T11:36:36Z

Looks like this is stuck for some reason... Not sure why...

No worries, we just have to review the changes this week during the triage.

Ahhh... Gotcha... Makes sense... Thanks.

I thought I'd done something wrong!

Interestingly it looks like something failed with the build though?

pgrawehr · 2023-10-16T13:42:05Z

@pjgpetecodes No, it's all fine with the build now. Because you're a first-time contributor, the build doesn't start automatically, though. Therefore I had to force it to run.

raffaeler · 2023-10-16T13:50:38Z

Interestingly it looks like something failed with the build though?

Yes, a couple of builds failed because there are random (known) issues happening in the pipelines that makes some tests fail. The issues on the pipeline will be hopefully fixed soon.
Anyway, I forced re-running the failed platforms and now they are all green.

pjgpetecodes · 2023-10-16T14:29:21Z

Wahoo... Awesome... Thanks!

In the meanwhile... I'm doing some learning on how the current driver works and how to create a new one for the Pi 5!

Update Board info for Pi 5

7659c7c

ghost added the area-System.Device.Gpio Contains types for using general-purpose I/O (GPIO) pins label Oct 8, 2023

pjgpetecodes added 2 commits October 8, 2023 22:36

Rename pi5

8676ab2

Add Pi 5 for driver

f70fbc1

pgrawehr reviewed Oct 9, 2023

View reviewed changes

Remove Whitespace from Pi3 driver

bcb9cad

krwq reviewed Oct 12, 2023

View reviewed changes

Remove Raspberry pi 5 switch case from Pi driver.

89a6947

Add Pi 5 OProduct to GpioDriver.

pgrawehr reviewed Oct 12, 2023

View reviewed changes

pjgpetecodes added 4 commits October 13, 2023 12:02

Initial Version of the check for Raspberry Pi 5

5e049cf

Fixes for Raspberry Pi 5 board check

4735a9c

More fixes

e738e0a

More fixes

da852b7

pgrawehr approved these changes Oct 13, 2023

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raffaeler approved these changes Oct 16, 2023

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krwq approved these changes Oct 19, 2023

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krwq merged commit f7cbec0 into dotnet:main Oct 19, 2023
9 checks passed

pgrawehr added this to the v3.1.0 milestone Nov 9, 2023

raffaeler mentioned this pull request Nov 22, 2023

libgpiod v2 support #2179

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Update Board info for Pi 5 #2145

Update Board info for Pi 5 #2145

pjgpetecodes commented Oct 8, 2023 •

edited by ghost

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		RaspberryBoardInfo.Model.RaspberryPi5 or
		RaspberryBoardInfo.Model.RaspberryPi400 => new RaspberryPi3LinuxDriver(),

Update Board info for Pi 5 #2145

Update Board info for Pi 5 #2145

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pjgpetecodes commented Oct 8, 2023 • edited by ghost Loading

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Variant 1

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