rust: device: implement impl_device_context_deref!

The Deref hierarchy for device context generics is the same for every
(bus specific) device.

Implement those with a generic macro to avoid duplicated boiler plate
code and ensure the correct Deref hierarchy for every device
implementation.

Co-developed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Christian Schrefl <chrisi.schrefl@gmail.com>
Link: https://lore.kernel.org/r/20250413173758.12068-2-dakr@kernel.org
[ Add missing `::` prefix in macros. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 3 insertions, 14 deletions

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 4917cb34e2fe..22590bdff7bb 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -16,7 +16,6 @@ use crate::{
 
 use core::{
     marker::PhantomData,
-    ops::Deref,
     ptr::{addr_of_mut, NonNull},
 };
 
@@ -190,19 +189,9 @@ impl Device {
     }
 }
 
-impl Deref for Device<device::Core> {
-    type Target = Device;
-
-    fn deref(&self) -> &Self::Target {
-        let ptr: *const Self = self;
-
-        // CAST: `Device<Ctx>` is a transparent wrapper of `Opaque<bindings::platform_device>`.
-        let ptr = ptr.cast::<Device>();
-
-        // SAFETY: `ptr` was derived from `&self`.
-        unsafe { &*ptr }
-    }
-}
+// SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic
+// argument.
+kernel::impl_device_context_deref!(unsafe { Device });
 
 impl From<&Device<device::Core>> for ARef<Device> {
     fn from(dev: &Device<device::Core>) -> Self {