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

[Danilo Krummrich <dakr@kernel.org>]

On Sun, Dec 15, 2024 at 01:25:45PM +0100, Greg KH wrote:
> 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!

Thanks! If nothing else comes up, I'll send you a v7 end of this week addressing
the two minor things I just replied to (remove wrong return statement in
iounmap() helper, `pci::DeviceId` naming and `Deref` impl).

- Danilo

> 
> greg k-h