[PATCH v2 1/3] DONOTMERGE: rust: prelude: add bit function

[Christina Quast]

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

Do not merge this commit, because rust/kernel/types.rs in Rust-for-Linux
already contains this functionality and will be merged into next-net
soon.
But this driver does not compile without this commit, so I am adding it
to the patchset to get more feedback on the actual driver.

Signed-off-by: Christina Quast <contact@xxxxxxxxxxxxxxxxxx>
---
 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
+}

-- 
2.43.0