[PATCH v2 2/3] rust: platform: wire runtime PM callbacks

[Beata Michalska <beata.michalska@arm.com>]

Allow Rust platform drivers to expose runtime PM callbacks to the driver core.

The runtime PM abstraction builds a dev_pm_ops table for the concrete driver
implementation, but the platform bus still needs to receive that table through
struct platform_driver. Add an optional PM_OPS associated constant to
platform::Driver and initialize the coresponding C device_driver struct
accordingly during registration. The platform glue only wires the callback
table into the C driver model; ownership of the callback payload and
runtime PM teardown remain with the pm module.

Signed-off-by: Beata Michalska <beata.michalska@arm.com>
---
 rust/kernel/platform.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index d8d48f60b0b9..b7e422388634 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -72,6 +72,11 @@ unsafe fn register(
             None => core::ptr::null(),
         };
 
+        let pm_ops = match T::PM_OPS {
+            Some(ops) => ops,
+            None => core::ptr::null(),
+        };
+
         // SAFETY: It's safe to set the fields of `struct platform_driver` on initialization.
         unsafe {
             (*pdrv.get()).driver.name = name.as_char_ptr();
@@ -79,6 +84,7 @@ unsafe fn register(
             (*pdrv.get()).remove = Some(Self::remove_callback);
             (*pdrv.get()).driver.of_match_table = of_table;
             (*pdrv.get()).driver.acpi_match_table = acpi_table;
+            (*pdrv.get()).driver.pm = pm_ops;
         }
 
         // SAFETY: `pdrv` is guaranteed to be a valid `DriverType`.
@@ -222,6 +228,9 @@ pub trait Driver {
     /// The table of ACPI device ids supported by the driver.
     const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = None;
 
+    /// Runtime PM callbacks
+    const PM_OPS: Option<&'static bindings::dev_pm_ops> = None;
+
     /// Platform driver probe.
     ///
     /// Called when a new platform device is added or discovered.
-- 
2.43.0