rust: driver: introduce a DriverLayout trait

The DriverLayout trait describes the layout of a specific driver
structure, such as `struct pci_driver` or `struct platform_driver`.

In a first step, this replaces the associated type RegType of the
RegistrationOps with the DriverLayout::DriverType associated type.

Acked-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Igor Korotin <igor.korotin.linux@gmail.com>
Link: https://patch.msgid.link/20260107103511.570525-4-dakr@kernel.org
[ Rename driver::Driver to driver::DriverLayout, as it represents the
  layout of a driver structure rather than the driver structure itself.
  - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 11 insertions, 7 deletions

diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index d10b65e9fb6a..60b761c06fbd 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -27,13 +27,17 @@ use core::{
 /// An adapter for the registration of USB drivers.
 pub struct Adapter<T: Driver>(T);
 
-// SAFETY: A call to `unregister` for a given instance of `RegType` is guaranteed to be valid if
+// SAFETY:
+// - `bindings::usb_driver` is a C type declared as `repr(C)`.
+unsafe impl<T: Driver + 'static> driver::DriverLayout for Adapter<T> {
+    type DriverType = bindings::usb_driver;
+}
+
+// SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if
 // a preceding call to `register` has been successful.
 unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
-    type RegType = bindings::usb_driver;
-
     unsafe fn register(
-        udrv: &Opaque<Self::RegType>,
+        udrv: &Opaque<Self::DriverType>,
         name: &'static CStr,
         module: &'static ThisModule,
     ) -> Result {
@@ -45,14 +49,14 @@ unsafe impl<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
             (*udrv.get()).id_table = T::ID_TABLE.as_ptr();
         }
 
-        // SAFETY: `udrv` is guaranteed to be a valid `RegType`.
+        // SAFETY: `udrv` is guaranteed to be a valid `DriverType`.
         to_result(unsafe {
             bindings::usb_register_driver(udrv.get(), module.0, name.as_char_ptr())
         })
     }
 
-    unsafe fn unregister(udrv: &Opaque<Self::RegType>) {
-        // SAFETY: `udrv` is guaranteed to be a valid `RegType`.
+    unsafe fn unregister(udrv: &Opaque<Self::DriverType>) {
+        // SAFETY: `udrv` is guaranteed to be a valid `DriverType`.
         unsafe { bindings::usb_deregister(udrv.get()) };
     }
 }