Re: [PATCH v6 15/16] samples: rust: add Rust platform sample driver

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Dec 12, 2024 at 05:33:46PM +0100, 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.
> 
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---
>  MAINTAINERS                                  |  1 +
>  drivers/of/unittest-data/tests-platform.dtsi |  5 ++
>  samples/rust/Kconfig                         | 10 ++++
>  samples/rust/Makefile                        |  1 +
>  samples/rust/rust_driver_platform.rs         | 49 ++++++++++++++++++++
>  5 files changed, 66 insertions(+)
>  create mode 100644 samples/rust/rust_driver_platform.rs
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fec876068c40..95bd7dc88ad8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7037,6 +7037,7 @@ F:	rust/kernel/device_id.rs
>  F:	rust/kernel/devres.rs
>  F:	rust/kernel/driver.rs
>  F:	rust/kernel/platform.rs
> +F:	samples/rust/rust_driver_platform.rs
>  
>  DRIVERS FOR OMAP ADAPTIVE VOLTAGE SCALING (AVS)
>  M:	Nishanth Menon <nm@ti.com>
> diff --git a/drivers/of/unittest-data/tests-platform.dtsi b/drivers/of/unittest-data/tests-platform.dtsi
> index fa39611071b3..2caaf1c10ee6 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/Kconfig b/samples/rust/Kconfig
> index 6d468193cdd8..70126b750426 100644
> --- a/samples/rust/Kconfig
> +++ b/samples/rust/Kconfig
> @@ -41,6 +41,16 @@ config SAMPLE_RUST_DRIVER_PCI
>  
>  	  If unsure, say N.
>  
> +config SAMPLE_RUST_DRIVER_PLATFORM
> +	tristate "Platform Driver"
> +	help
> +	  This option builds the Rust Platform driver sample.
> +
> +	  To compile this as a module, choose M here:
> +	  the module will be called rust_driver_platform.
> +
> +	  If unsure, say N.
> +
>  config SAMPLE_RUST_HOSTPROGS
>  	bool "Host programs"
>  	help
> diff --git a/samples/rust/Makefile b/samples/rust/Makefile
> index 2f5b6bdb2fa5..761d13fff018 100644
> --- a/samples/rust/Makefile
> +++ b/samples/rust/Makefile
> @@ -4,6 +4,7 @@ ccflags-y += -I$(src)				# needed for trace events
>  obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
>  obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
>  obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI)		+= rust_driver_pci.o
> +obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM)	+= rust_driver_platform.o
>  
>  rust_print-y := rust_print_main.o rust_print_events.o
>  
> diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_driver_platform.rs
> new file mode 100644
> index 000000000000..8120609e2940
> --- /dev/null
> +++ b/samples/rust/rust_driver_platform.rs
> @@ -0,0 +1,49 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! Rust Platform driver sample.

Nit, I think your employer will want a copyright line on these, but hey,
I could be wrong!  Your call...

> +use kernel::{c_str, of, platform, prelude::*};
> +
> +struct SampleDriver {
> +    pdev: platform::Device,
> +}
> +
> +struct Info(u32);
> +
> +kernel::of_device_table!(
> +    OF_TABLE,
> +    MODULE_OF_TABLE,
> +    <SampleDriver as platform::Driver>::IdInfo,
> +    [(of::DeviceId::new(c_str!("test,rust-device")), Info(42))]
> +);
> +
> +impl platform::Driver for SampleDriver {
> +    type IdInfo = Info;
> +    const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
> +
> +    fn probe(pdev: &mut platform::Device, info: Option<&Self::IdInfo>) -> Result<Pin<KBox<Self>>> {
> +        dev_dbg!(pdev.as_ref(), "Probe Rust Platform driver sample.\n");
> +
> +        if let Some(info) = info {
> +            dev_info!(pdev.as_ref(), "Probed with info: '{}'.\n", info.0);
> +        }
> +
> +        let drvdata = KBox::new(Self { pdev: pdev.clone() }, GFP_KERNEL)?;
> +
> +        Ok(drvdata.into())
> +    }
> +}
> +
> +impl Drop for SampleDriver {
> +    fn drop(&mut self) {
> +        dev_dbg!(self.pdev.as_ref(), "Remove Rust Platform driver sample.\n");
> +    }
> +}
> +
> +kernel::module_platform_driver! {
> +    type: SampleDriver,
> +    name: "rust_driver_platform",
> +    author: "Danilo Krummrich",
> +    description: "Rust Platform driver",
> +    license: "GPL v2",
> +}

That is almost too simple.  Seriously nice work, let's wait a few days
for some others to review the series and I'll be glad to apply it to my
tree!

greg k-h