bus: add doc(cfg).

Author: Dirbaio

embedded-hal-bus/Cargo.toml

@@ -19,3 +19,7 @@ std = []
 [dependencies]
 embedded-hal = { version = "=1.0.0-alpha.11", path = "../embedded-hal" }
 critical-section = { version = "1.0" }
+
+[package.metadata.docs.rs]
+features = ["std"]
+rustdoc-args = ["--cfg", "docsrs"]

embedded-hal-bus/src/i2c/mutex.rs

@@ -6,6 +6,7 @@ use std::sync::Mutex;
 /// Sharing is implemented with an `std` [`Mutex`](std::sync::Mutex). It allows a single bus across multiple threads,
 /// with finer-grained locking than [`CriticalSectionDevice`](super::CriticalSectionDevice). The downside is that
 /// it is only available in `std` targets.
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 pub struct MutexDevice<'a, T> {
     bus: &'a Mutex<T>,
 }

embedded-hal-bus/src/lib.rs

@@ -1,6 +1,7 @@
 #![doc = include_str!("../README.md")]
 #![warn(missing_docs)]
 #![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 pub mod i2c;
 pub mod spi;

embedded-hal-bus/src/spi/mutex.rs

@@ -13,6 +13,7 @@ use super::DeviceError;
 /// Sharing is implemented with a `std` [`Mutex`](std::sync::Mutex). It allows a single bus across multiple threads,
 /// with finer-grained locking than [`CriticalSectionDevice`](super::CriticalSectionDevice). The downside is
 /// it is only available in `std` targets.
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 pub struct MutexDevice<'a, BUS, CS, D> {
     bus: &'a Mutex<BUS>,
     cs: CS,