Re: [PATCH v3 3/3] samples: rust: add Rust I2C sample driver

["Danilo Krummrich" <dakr@kernel.org>]

On Fri Aug 1, 2025 at 5:45 PM CEST, Igor Korotin wrote:
> +#[kernel::prelude::pin_data]

Can just be #[pin_data].

> +struct DriverModule {
> +    #[pin]
> +    _driver: kernel::driver::Registration<Ops<SampleDriver>>,
> +    _reg: i2c::Registration,
> +}
> +
> +impl kernel::InPlaceModule for DriverModule {
> +    fn init(
> +        module: &'static kernel::ThisModule,
> +    ) -> impl ::pin_init::PinInit<Self, kernel::error::Error> {
> +        let adapter = i2c::I2cAdapterRef::get(SAMPLE_I2C_ADAPTER_INDEX);
> +
> +        kernel::try_pin_init!(Self {
> +            _reg <- i2c::Registration::new(&adapter.unwrap(), &BOARD_INFO),

Please don't use unwrap(), this panics the kernel in case of failure. Please see
below for a better solution.

> +            _driver<-kernel::driver::Registration::new(<Self as kernel::ModuleMetadata>::NAME,module,),
> +        })
> +    }
> +}
> +kernel::prelude::module! {
> +    type:DriverModule,name:"rust_driver_i2c",authors:["Igor Korotin"],description:"Rust I2C driver",license:"GPL v2",
> +}

I suggest to write this like this:

	#[pin_data]
	struct DriverModule {
	    #[pin]
	    _driver: kernel::driver::Registration<Ops<SampleDriver>>,
	    _reg: i2c::Registration,
	}
	
	impl kernel::InPlaceModule for DriverModule {
	    fn init(
	        module: &'static kernel::ThisModule,
	    ) -> impl ::pin_init::PinInit<Self, Error> {
	        try_pin_init!(Self {
	            _reg <- {
	                let adapter = i2c::I2cAdapterRef::get(SAMPLE_I2C_ADAPTER_INDEX).ok_or(ENOENT)?;
	
	                i2c::Registration::new(&adapter, &BOARD_INFO)
	            },
	            _driver <- kernel::driver::Registration::new(<Self as kernel::ModuleMetadata>::NAME, module),
	        })
	    }
	}

	kernel::prelude::module! {
	    type:DriverModule,
	    name:"rust_driver_i2c",
	    authors:["Igor Korotin"],
	    description:"Rust I2C driver",
	    license:"GPL v2",
	}