rust: regulator: add regulator consumer abstractions

Add a rust abstraction for the regulator consumer API.

Signed-off-by: Fabien Parent <[email protected]>

rust/bindings/bindings_helper.h

@@ -24,6 +24,7 @@
 #include <linux/poll.h>
 #include <linux/refcount.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/sched.h>
 #include <linux/security.h>
 #include <linux/slab.h>

rust/kernel/lib.rs

@@ -55,6 +55,8 @@ pub mod prelude;
 pub mod print;
 #[cfg(CONFIG_REGMAP)]
 pub mod regmap;
+#[cfg(CONFIG_REGULATOR)]
+pub mod regulator;
 pub mod security;
 mod static_assert;
 #[doc(hidden)]

rust/kernel/regulator.rs

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! SoC Regulators
+
+pub mod consumer;
+
+use crate::{
+    bindings,
+    error::{code::*, Error, Result},
+};
+
+/// [`consumer::Regulator`] and [`driver::Regulator`] operating modes
+#[derive(Copy, Clone)]
+#[repr(u32)]
+pub enum Mode {
+    /// Invalid mode
+    Invalid = bindings::REGULATOR_MODE_INVALID,
+    /// Regulator can handle fast changes in it's load
+    Fast = bindings::REGULATOR_MODE_FAST,
+    /// Normal regulator power supply mode
+    Normal = bindings::REGULATOR_MODE_NORMAL,
+    /// Regulator runs in a more efficient mode for light loads
+    Idle = bindings::REGULATOR_MODE_IDLE,
+    /// Regulator runs in the most efficient mode for very light loads
+    Standby = bindings::REGULATOR_MODE_STANDBY,
+}
+
+impl TryFrom<core::ffi::c_uint> for Mode {
+    type Error = Error;
+
+    /// Convert a mode represented as an unsigned integer into its Rust enum equivalent
+    ///
+    /// If the integer does not match any of the [`Mode`], then [`EINVAL`] is returned
+    fn try_from(mode: core::ffi::c_uint) -> Result<Self> {
+        match mode {
+            bindings::REGULATOR_MODE_FAST => Ok(Self::Fast),
+            bindings::REGULATOR_MODE_NORMAL => Ok(Self::Normal),
+            bindings::REGULATOR_MODE_IDLE => Ok(Self::Idle),
+            bindings::REGULATOR_MODE_STANDBY => Ok(Self::Standby),
+            bindings::REGULATOR_MODE_INVALID => Ok(Self::Invalid),
+            _ => Err(EINVAL),
+        }
+    }
+}