[PATCH v2 3/6] rust: device: Support testing devices for equality

[Matthew Maurer <mmaurer@google.com>]

This allows device drivers to check if, for example, an auxiliary
devices is one of its children by comparing the parent field, or
checking if a device parameter is its own device.

Also convert existing `.as_raw() != .as_raw()` to  use this new
implementation.

Signed-off-by: Matthew Maurer <mmaurer@google.com>
---
 rust/kernel/device.rs     | 8 ++++++++
 rust/kernel/devres.rs     | 2 +-
 rust/kernel/drm/driver.rs | 2 +-
 rust/kernel/pwm.rs        | 2 +-
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 94e0548e76871d8b7de309c1f1c7b77bb49738ed..aa10359d3ebdd1c99cc567a35b89f52ddb2ee050 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -516,6 +516,14 @@ unsafe impl Send for Device {}
 // synchronization in `struct device`.
 unsafe impl Sync for Device {}
 
+impl<Ctx: DeviceContext, Ctx2: DeviceContext> PartialEq<Device<Ctx2>> for Device<Ctx> {
+    fn eq(&self, other: &Device<Ctx2>) -> bool {
+        self.as_raw() == other.as_raw()
+    }
+}
+
+impl<Ctx: DeviceContext> Eq for Device<Ctx> {}
+
 /// Marker trait for the context or scope of a bus specific device.
 ///
 /// [`DeviceContext`] is a marker trait for types representing the context of a bus specific
diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index cdc49677022a6b466e771d9d8cf3818ab9b9112d..20126daad193370868661b9412937937eda6d3c4 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -281,7 +281,7 @@ pub fn device(&self) -> &Device {
     /// }
     /// ```
     pub fn access<'a>(&'a self, dev: &'a Device<Bound>) -> Result<&'a T> {
-        if self.dev.as_raw() != dev.as_raw() {
+        if self.dev.as_ref() != dev {
             return Err(EINVAL);
         }
 
diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs
index f30ee4c6245cda72ac72852bf9362736d8fe992f..497ef46028d560bc9649dbbdf69316ce4fce8199 100644
--- a/rust/kernel/drm/driver.rs
+++ b/rust/kernel/drm/driver.rs
@@ -139,7 +139,7 @@ pub fn new_foreign_owned(
     where
         T: 'static,
     {
-        if drm.as_ref().as_raw() != dev.as_raw() {
+        if drm.as_ref() != dev {
             return Err(EINVAL);
         }
 
diff --git a/rust/kernel/pwm.rs b/rust/kernel/pwm.rs
index cb00f8a8765c8ec58ed78a73275b022b02bf7aa3..033f778909a2633acbc25d5a21a1c8a7b8e41a70 100644
--- a/rust/kernel/pwm.rs
+++ b/rust/kernel/pwm.rs
@@ -680,7 +680,7 @@ impl<T: 'static + PwmOps + Send + Sync> Registration<T> {
     /// calling `pwmchip_remove`. This function should be called from the driver's `probe`.
     pub fn register(dev: &device::Device<Bound>, chip: ARef<Chip<T>>) -> Result {
         let chip_parent = chip.device().parent().ok_or(EINVAL)?;
-        if dev.as_raw() != chip_parent.as_raw() {
+        if dev != chip_parent {
             return Err(EINVAL);
         }
 

-- 
2.53.0.rc2.204.g2597b5adb4-goog