linux-kernel - [PATCH v3 2/3] rust: clk: add devres-managed clks

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Message-Id: <20260107-clk-type-state-v3-2-77d3e3ee59c2@collabora.com>
Date: Wed, 07 Jan 2026 12:09:53 -0300
From: Daniel Almeida <daniel.almeida@...labora.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, 
 Viresh Kumar <viresh.kumar@...aro.org>, Danilo Krummrich <dakr@...nel.org>, 
 Alice Ryhl <aliceryhl@...gle.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Drew Fustini <fustini@...nel.org>, Guo Ren <guoren@...nel.org>, 
 Fu Wei <wefu@...hat.com>, 
 Uwe Kleine-König <ukleinek@...nel.org>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Miguel Ojeda <ojeda@...nel.org>, 
 Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
 Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
 Benno Lossin <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, 
 Trevor Gross <tmgross@...ch.edu>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
 dri-devel@...ts.freedesktop.org, linux-riscv@...ts.infradead.org, 
 linux-pwm@...r.kernel.org, linux-clk@...r.kernel.org, 
 rust-for-linux@...r.kernel.org, 
 Daniel Almeida <daniel.almeida@...labora.com>
Subject: [PATCH v3 2/3] rust: clk: add devres-managed clks

The clk API allows fine-grained control, but some drivers might be
more interested in a "set and forget" API.

Expand the current API to support this. The clock will automatically be
disabled, unprepared and freed when the device is unbound from the bus
without further intervention by the driver.

Signed-off-by: Daniel Almeida <daniel.almeida@...labora.com>
---
 rust/kernel/clk.rs | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs
index 6323b40dc7ba..e840e7c20af7 100644
--- a/rust/kernel/clk.rs
+++ b/rust/kernel/clk.rs
@@ -95,6 +95,49 @@ impl Sealed for super::Prepared {}
         impl Sealed for super::Enabled {}
     }

+    /// Obtains and enables a [`devres`]-managed [`Clk`] for a bound device.
+    ///
+    /// [`devres`]: crate::devres::Devres
+    pub fn devm_enable(dev: &Device<Bound>, name: Option<&CStr>) -> Result {
+        let name = name.map_or(ptr::null(), |n| n.as_char_ptr());
+
+        // SAFETY: It is safe to call [`devm_clk_get_enabled`] with a valid
+        // device pointer.
+        from_err_ptr(unsafe { bindings::devm_clk_get_enabled(dev.as_raw(), name) })?;
+        Ok(())
+    }
+
+    /// Obtains and enables a [`devres`]-managed [`Clk`] for a bound device.
+    ///
+    /// This does not print any error messages if the clock is not found.
+    ///
+    /// [`devres`]: crate::devres::Devres
+    pub fn devm_enable_optional(dev: &Device<Bound>, name: Option<&CStr>) -> Result {
+        let name = name.map_or(ptr::null(), |n| n.as_char_ptr());
+
+        // SAFETY: It is safe to call [`devm_clk_get_optional_enabled`] with a
+        // valid device pointer.
+        from_err_ptr(unsafe { bindings::devm_clk_get_optional_enabled(dev.as_raw(), name) })?;
+        Ok(())
+    }
+
+    /// Same as [`devm_enable_optional`], but also sets the rate.
+    pub fn devm_enable_optional_with_rate(
+        dev: &Device,
+        name: Option<&CStr>,
+        rate: Hertz,
+    ) -> Result {
+        let name = name.map_or(ptr::null(), |n| n.as_char_ptr());
+
+        // SAFETY: It is safe to call
+        // [`devm_clk_get_optional_enabled_with_rate`] with a valid device
+        // pointer.
+        from_err_ptr(unsafe {
+            bindings::devm_clk_get_optional_enabled_with_rate(dev.as_raw(), name, rate.as_hz())
+        })?;
+        Ok(())
+    }
+
     /// A trait representing the different states that a [`Clk`] can be in.
     pub trait ClkState: private::Sealed {
         /// Whether the clock should be disabled when dropped.

-- 
2.52.0