Re: [PATCH v3 16/16] samples: rust: add Rust platform sample driver

[Danilo Krummrich <dakr@kernel.org>]

On Wed, Oct 23, 2024 at 10:37:03AM -0500, Rob Herring wrote:
> On Wed, Oct 23, 2024 at 08:59:48AM +0200, Danilo Krummrich wrote:
> > On Tue, Oct 22, 2024 at 07:04:08PM -0500, Rob Herring wrote:
> > > On Tue, Oct 22, 2024 at 11:31:53PM +0200, Danilo Krummrich wrote:
> > > > Add a sample Rust platform driver illustrating the usage of the platform
> > > > bus abstractions.
> > > > 
> > > > This driver probes through either a match of device / driver name or a
> > > > match within the OF ID table.
> > > 
> > > I know if rust compiles it works, but how does one actually use/test 
> > > this? (I know ways, but I might be in the minority. :) )
> > 
> > For testing a name match I just used platform_device_register_simple() in a
> > separate module.
> > 
> > Probing through the OF table is indeed a bit more tricky. Since I was too lazy
> > to pull out a random ARM device of my cupboard I just used QEMU on x86 and did
> > what drivers/of/unittest.c does. If you're smart you can also just enable those
> > unit tests and change the compatible string to "unittest". :)
> > 
> > > 
> > > The DT unittests already define test platform devices. I'd be happy to 
> > > add a device node there. Then you don't have to muck with the DT on some 
> > > device and it even works on x86 or UML.
> > 
> > Sounds good, I'll add one in there for this sample driver -- any preferences?
> 
> I gave this a spin and added the patch below in. Feel free to squash it 
> into this one.

Looks good -- it only works if the sample driver is built-in though, but I think
that should be fine.

> 
> 8<----------------------------------------------------------------
> From: "Rob Herring (Arm)" <robh@kernel.org>
> Date: Wed, 23 Oct 2024 10:29:47 -0500
> Subject: [PATCH] of: unittest: Add a platform device node for rust platform
>  driver sample
> 
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> 
> diff --git a/drivers/of/unittest-data/tests-platform.dtsi b/drivers/of/unittest-data/tests-platform.dtsi
> index fa39611071b3..575ea260a877 100644
> --- a/drivers/of/unittest-data/tests-platform.dtsi
> +++ b/drivers/of/unittest-data/tests-platform.dtsi
> @@ -33,6 +33,11 @@ dev@100 {
>                                         reg = <0x100>;
>                                 };
>                         };
> +
> +                       test-device@2 {
> +                               compatible = "test,rust-device";
> +                               reg = <0x2>;
> +                       };
>                 };
>         };
>  };
> diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_driver_platform.rs
> index 55caaaa4f216..5cf4a8f86c13 100644
> --- a/samples/rust/rust_driver_platform.rs
> +++ b/samples/rust/rust_driver_platform.rs
> @@ -15,7 +15,7 @@ struct SampleDriver {
>      MODULE_OF_TABLE,
>      <SampleDriver as platform::Driver>::IdInfo,
>      [(
> -        of::DeviceId::new(c_str!("redhat,rust-sample-platform-driver")),
> +        of::DeviceId::new(c_str!("test,rust-device")),
>          Info(42)
>      )]
>  );
>