rust: device: Add property_present()

This implements Device::property_present(), which calls C APIs
device_property_present() helper.

The new helper will be used by Rust based cpufreq drivers.

Signed-off-by: Viresh Kumar <[email protected]>
Link: https://lore.kernel.org/r/f43fe3f7b3151a89c261ad728b0f3bb2fc24caef.1736766672.git.viresh.kumar@linaro.org
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: vireshk

rust/bindings/bindings_helper.h

@@ -26,6 +26,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/platform_device.h>
 #include <linux/poll.h>
+#include <linux/property.h>
 #include <linux/refcount.h>
 #include <linux/sched.h>
 #include <linux/security.h>

rust/kernel/device.rs

@@ -6,6 +6,7 @@
 
 use crate::{
     bindings,
+    str::CString,
     types::{ARef, Opaque},
 };
 use core::{fmt, ptr};
@@ -180,6 +181,12 @@ impl Device {
             )
         };
     }
+
+    /// Checks if property is present or not.
+    pub fn property_present(&self, name: &CString) -> bool {
+        // SAFETY: By the invariant of `CString`, `name` is null-terminated.
+        unsafe { bindings::device_property_present(self.as_raw().cast_const(), name.as_ptr() as *const _) }
+    }
 }
 
 // SAFETY: Instances of `Device` are always reference-counted.