1 files changed, 79 insertions, 0 deletions
diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs
new file mode 100644
index 000000000000..1ec478d96abc
--- /dev/null
+++ b/rust/kernel/clk.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Common clock framework.
+//!
+//! C header: [`include/linux/clk.h`](../../../../include/linux/clk.h)
+
+use crate::{bindings, error::Result, to_result};
+use core::mem::ManuallyDrop;
+
+/// Represents `struct clk *`.
+///
+/// # Invariants
+///
+/// The pointer is valid.
+pub struct Clk(*mut bindings::clk);
+
+impl Clk {
+    /// Creates new clock structure from a raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// The pointer must be valid.
+    pub unsafe fn new(clk: *mut bindings::clk) -> Self {
+        Self(clk)
+    }
+
+    /// Returns value of the rate field of `struct clk`.
+    pub fn get_rate(&self) -> usize {
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_get_rate(self.0) as usize }
+    }
+
+    /// Prepares and enables the underlying hardware clock.
+    ///
+    /// This function should not be called in atomic context.
+    pub fn prepare_enable(self) -> Result<EnabledClk> {
+        // SAFETY: The pointer is valid by the type invariant.
+        to_result(unsafe { bindings::clk_prepare_enable(self.0) })?;
+        Ok(EnabledClk(self))
+    }
+}
+
+impl Drop for Clk {
+    fn drop(&mut self) {
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_put(self.0) };
+    }
+}
+
+// SAFETY: `Clk` is not restricted to a single thread so it is safe
+// to move it between threads.
+unsafe impl Send for Clk {}
+
+/// A clock variant that is prepared and enabled.
+pub struct EnabledClk(Clk);
+
+impl EnabledClk {
+    /// Returns value of the rate field of `struct clk`.
+    pub fn get_rate(&self) -> usize {
+        self.0.get_rate()
+    }
+
+    /// Disables and later unprepares the underlying hardware clock prematurely.
+    ///
+    /// This function should not be called in atomic context.
+    pub fn disable_unprepare(self) -> Clk {
+        let mut clk = ManuallyDrop::new(self);
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_disable_unprepare(clk.0 .0) };
+        core::mem::replace(&mut clk.0, Clk(core::ptr::null_mut()))
+    }
+}
+
+impl Drop for EnabledClk {
+    fn drop(&mut self) {
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_disable_unprepare(self.0 .0) };
+    }
+}