Implement AsRef<T::ParentDevice<Bound>> for Device<T, Registered>, providing access to the bound parent bus device for registered DRM devices.
Since a Device<T, Registered> guarantees that the parent bus device is bound, the conversion to T::ParentDevice<Bound> is safe. Signed-off-by: Danilo Krummrich <[email protected]> --- rust/kernel/drm/device.rs | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index 45bacd7b227f..8f63276c9b62 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -462,6 +462,19 @@ fn as_ref(&self) -> &T::ParentDevice<device::Normal> { } } +impl<T: drm::Driver> AsRef<T::ParentDevice<device::Bound>> for Device<T, Registered> { + fn as_ref(&self) -> &T::ParentDevice<device::Bound> { + let dev = (**self).as_ref().as_ref(); + + // SAFETY: A `Device<T, Registered>` guarantees that the parent device is bound. + let dev = unsafe { dev.as_bound() }; + + // SAFETY: By the type invariant of `Device`, the parent device is embedded in + // `T::ParentDevice`. + unsafe { device::AsBusDevice::from_device(dev) } + } +} + // SAFETY: A `drm::Device` can be released from any thread. unsafe impl<T: drm::Driver, C: DeviceContext> Send for Device<T, C> {} -- 2.54.0
