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From: Christina Quast <contact@christina-quast.de>
Date: Tue, 30 Jan 2024 20:47:51 +0100
Subject: [PATCH] rust: prelude: add bit function
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Message-Id: <20240130-rust-bit-v1-1-ed2ed6389a58@christina-quast.de>
To: Miguel Ojeda <ojeda@kernel.org>, Alex Gaynor <alex.gaynor@gmail.com>, 
 Wedson Almeida Filho <wedsonaf@gmail.com>, 
 Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>, 
 =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>, 
 Benno Lossin <benno.lossin@proton.me>, 
 Andreas Hindborg <a.hindborg@samsung.com>, 
 Alice Ryhl <aliceryhl@google.com>
Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, 
 Christina Quast <contact@christina-quast.de>

In order to create masks easily, the define BIT() is used in C code.
This commit adds the same functionality to the rust kernel.

To use it, include the following into your rust file:
use kernel::prelude::bit

Signed-off-by: Christina Quast <contact@christina-quast.de>
---
This patch is needed for further patches porting the rockchip phy
driver to rust.
---
 rust/kernel/prelude.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
index ae21600970b3..16e483de2f27 100644
--- a/rust/kernel/prelude.rs
+++ b/rust/kernel/prelude.rs
@@ -38,3 +38,19 @@
 pub use super::init::{InPlaceInit, Init, PinInit};
 
 pub use super::current;
+
+/// Returns a `u32` number that has only the `n`th bit set.
+///
+/// # Arguments
+///
+/// * `n` - A `u32` that specifies the bit position (zero-based index)
+///
+/// # Example
+///
+/// ```
+/// let b = bit(2);
+/// assert_eq!(b, 4);
+#[inline]
+pub const fn bit(n: u32) -> u32 {
+    1 << n
+}

---
base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
change-id: 20240130-rust-bit-99dd6d3a0536

Best regards,
-- 
Christina Quast <contact@christina-quast.de>