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Keep ownership of spi::DriverRegistration #46

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merged 2 commits into from
May 4, 2021
Merged

Keep ownership of spi::DriverRegistration #46

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7d72580
rust-module: Keep ownership of spi::DriverRegistration
CohenArthur May 3, 2021
366dba8
rust-module: Remove use of builder pattern
CohenArthur May 4, 2021
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14 changes: 7 additions & 7 deletions rust-module/mfrc522.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -84,16 +84,15 @@ impl FileOperations for Mfrc522FileOps {
Err(_) => Err(Error::EINVAL),
// FIXME: Once the Command API is reworked, this will make more sense
Ok(CommandSuccess::BytesWritten(amount)) => Ok(amount),
NoAnswer => Ok(0),
Ok(CommandSuccess::NoAnswer) => Ok(0),
_ => Err(Error::EINVAL),
}
}
}

struct Mfrc522Driver {
misc: Pin<Box<miscdev::Registration>>,
// FIXME: We need to keep ownership of our SPI registration, or else it will get dropped
// when we'll return from the init() function
_spi: Pin<Box<spi::DriverRegistration>>,
_misc: Pin<Box<miscdev::Registration>>,
}

impl KernelModule for Mfrc522Driver {
Expand All @@ -104,10 +103,11 @@ impl KernelModule for Mfrc522Driver {
miscdev::Registration::new_pinned::<Mfrc522FileOps>(cstr!("mfrc522_chrdev"), None, ())?;

let mut spi =
spi::DriverRegistration::new(&THIS_MODULE, cstr!("mfrc522")).with_probe(mfrc522_probe);
spi.register()?;
spi::DriverRegistration::new_pinned(&THIS_MODULE, cstr!("mfrc522"))?
.with_probe(mfrc522_probe);
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can't we just call .register here ?

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Yeah, that's why the FIXME is here for now cause I think it's ugly to do spi.as_mut().register().

We have a solution, which helps with cleanliness: remove the builder pattern (which I agree with) and pass all spi methods in the new_pinned function, and register the driver in the new_pinned function (this is what miscdev.rs does). The downside is that the function takes 3 more arguments, which will be None most of the time

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I'm removing the builder pattern

spi.as_mut().register()?; // FIXME: Not really pretty

Ok(Mfrc522Driver { misc })
Ok(Mfrc522Driver { _spi: spi, _misc: misc })
}
}

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