[PATCH V8 06/14] rust: Add bare minimal bindings for clk framework

Viresh Kumar
2025-02-06T09:29:17Z

This adds very basic bindings for the clk framework, implements only
clk_get() and clk_put(). These are the bare minimum bindings required
for many users and are simple enough to add in the first attempt.

These will be used by Rust based cpufreq / OPP core to begin with.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
MAINTAINERS | 1 +
rust/bindings/bindings_helper.h | 1 +
rust/kernel/clk.rs | 48 +++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 2 ++
4 files changed, 52 insertions(+)
create mode 100644 rust/kernel/clk.rs

diff --git a/MAINTAINERS b/MAINTAINERS
index ff4511914e0a..604717065476 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5780,6 +5780,7 @@ F: include/dt-bindings/clock/
F: include/linux/clk-pr*
F: include/linux/clk/
F: include/linux/of_clk.h
+F: rust/kernel/clk.rs
X: drivers/clk/clkdev.c

COMMON INTERNET FILE SYSTEM CLIENT (CIFS and SMB3)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 59b4bc49d039..4eadcf645df0 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -10,6 +10,7 @@
#include <linux/blk-mq.h>
#include <linux/blk_types.h>
#include <linux/blkdev.h>
+#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/cred.h>
diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs
new file mode 100644
index 000000000000..123cdb43b115
--- /dev/null
+++ b/rust/kernel/clk.rs
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Clock abstractions.
+//!
+//! C header: [`include/linux/clk.h`](srctree/include/linux/clk.h)
+
+use crate::{
+ bindings,
+ device::Device,
+ error::{from_err_ptr, Result},
+ prelude::*,
+};
+
+use core::ptr;
+
+/// A simple implementation of `struct clk` from the C code.
+#[repr(transparent)]
+pub struct Clk(*mut bindings::clk);
+
+impl Clk {
+ /// Creates `Clk` instance for a device and a connection id.
+ pub fn new(dev: &Device, name: Option<&CStr>) -> Result<Self> {
+ let con_id = if let Some(name) = name {
+ name.as_ptr() as *const _
+ } else {
+ ptr::null()
+ };
+
+ // SAFETY: It is safe to call `clk_get()`, on a device pointer earlier received from the C
+ // code.
+ Ok(Self(from_err_ptr(unsafe {
+ bindings::clk_get(dev.as_raw(), con_id)
+ })?))
+ }
+
+ /// Obtain the raw `struct clk *`.
+ pub fn as_raw(&self) -> *mut bindings::clk {
+ self.0
+ }
+}
+
+impl Drop for Clk {
+ fn drop(&mut self) {
+ // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to
+ // relinquish it now.
+ unsafe { bindings::clk_put(self.0) };
+ }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index ccbf7fa087a0..77d3b1f82154 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -40,6 +40,8 @@
pub mod block;
#[doc(hidden)]
pub mod build_assert;
+#[cfg(CONFIG_COMMON_CLK)]
+pub mod clk;
pub mod cpu;
pub mod cpumask;
pub mod cred;
--
2.31.1.272.g89b43f80a514