[libgpiod][PATCH V10 1/6] bindings: rust: Add libgpiod-sys rust crate

[Viresh Kumar <viresh.kumar@xxxxxxxxxx>]

This adds libgpiod-sys rust crate, which provides FFI (foreign function
interface) bindings for libgpiod APIs.

Reviewed-by: Kent Gibson <warthog618@xxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
 bindings/rust/.gitignore              |  4 +++
 bindings/rust/Cargo.toml              |  9 ++++++
 bindings/rust/libgpiod-sys/Cargo.toml | 21 ++++++++++++++
 bindings/rust/libgpiod-sys/README.md  | 14 +++++++++
 bindings/rust/libgpiod-sys/build.rs   | 41 +++++++++++++++++++++++++++
 bindings/rust/libgpiod-sys/src/lib.rs | 11 +++++++
 6 files changed, 100 insertions(+)
 create mode 100644 bindings/rust/.gitignore
 create mode 100644 bindings/rust/Cargo.toml
 create mode 100644 bindings/rust/libgpiod-sys/Cargo.toml
 create mode 100644 bindings/rust/libgpiod-sys/README.md
 create mode 100644 bindings/rust/libgpiod-sys/build.rs
 create mode 100644 bindings/rust/libgpiod-sys/src/lib.rs

diff --git a/bindings/rust/.gitignore b/bindings/rust/.gitignore
new file mode 100644
index 000000000000..95054d9da312
--- /dev/null
+++ b/bindings/rust/.gitignore
@@ -0,0 +1,4 @@
+# Added by cargo
+
+target
+Cargo.lock
diff --git a/bindings/rust/Cargo.toml b/bindings/rust/Cargo.toml
new file mode 100644
index 000000000000..e3e253a4cf5e
--- /dev/null
+++ b/bindings/rust/Cargo.toml
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2022 Linaro Ltd.
+# SPDX-FileCopyrightTest: 2022 Viresh Kumar <viresh.kumar@xxxxxxxxxx>
+
+[workspace]
+
+members = [
+    "libgpiod-sys"
+]
diff --git a/bindings/rust/libgpiod-sys/Cargo.toml b/bindings/rust/libgpiod-sys/Cargo.toml
new file mode 100644
index 000000000000..479184da3f7b
--- /dev/null
+++ b/bindings/rust/libgpiod-sys/Cargo.toml
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2022 Linaro Ltd.
+# SPDX-FileCopyrightTest: 2022 Viresh Kumar <viresh.kumar@xxxxxxxxxx>
+
+[package]
+name = "libgpiod-sys"
+version = "0.1.0"
+authors = ["Viresh Kumar <viresh.kumar@xxxxxxxxxx>"]
+description = "libgpiod public header bindings"
+repository = "https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git";
+categories = ["external-ffi-bindings", "os::linux-apis"]
+rust-version = "1.56"
+keywords = ["libgpiod", "gpio"]
+license = "Apache-2.0 OR BSD-3-Clause"
+edition = "2021"
+
+[dependencies]
+
+[build-dependencies]
+bindgen = "0.59.1"
+cc = "1.0.46"
diff --git a/bindings/rust/libgpiod-sys/README.md b/bindings/rust/libgpiod-sys/README.md
new file mode 100644
index 000000000000..7e6e643ab2ab
--- /dev/null
+++ b/bindings/rust/libgpiod-sys/README.md
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2022 Linaro Ltd.
+# SPDX-FileCopyrightTest: 2022 Viresh Kumar <viresh.kumar@xxxxxxxxxx>
+
+# Generated libgpiod-sys Rust FFI bindings
+Automatically generated Rust FFI bindings via
+	[bindgen](https://github.com/rust-lang/rust-bindgen).
+
+## License
+
+This project is licensed under either of
+
+- [Apache License](http://www.apache.org/licenses/LICENSE-2.0), Version 2.0
+- [BSD-3-Clause License](https://opensource.org/licenses/BSD-3-Clause)
diff --git a/bindings/rust/libgpiod-sys/build.rs b/bindings/rust/libgpiod-sys/build.rs
new file mode 100644
index 000000000000..274069eb9e9d
--- /dev/null
+++ b/bindings/rust/libgpiod-sys/build.rs
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
+// SPDX-FileCopyrightText: 2022 Linaro Ltd.
+// SPDX-FileCopyrightTest: 2022 Viresh Kumar <viresh.kumar@xxxxxxxxxx>
+
+extern crate bindgen;
+
+use std::env;
+use std::path::PathBuf;
+
+fn generate_bindings() {
+    // Tell cargo to invalidate the built crate whenever following files change
+    println!("cargo:rerun-if-changed=../../../include/gpiod.h");
+
+    // The bindgen::Builder is the main entry point
+    // to bindgen, and lets you build up options for
+    // the resulting bindings.
+    let bindings = bindgen::Builder::default()
+        // The input header we would like to generate
+        // bindings for.
+        .header("../../../include/gpiod.h")
+        // Tell cargo to invalidate the built crate whenever any of the
+        // included header files changed.
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
+        // Finish the builder and generate the bindings.
+        .generate()
+        // Unwrap the Result and panic on failure.
+        .expect("Unable to generate bindings");
+
+    // Write the bindings to the $OUT_DIR/bindings.rs file.
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Couldn't write bindings!");
+}
+
+fn main() {
+    generate_bindings();
+
+    println!("cargo:rustc-link-search=./../../lib/.libs/");
+    println!("cargo:rustc-link-lib=static=gpiod");
+}
diff --git a/bindings/rust/libgpiod-sys/src/lib.rs b/bindings/rust/libgpiod-sys/src/lib.rs
new file mode 100644
index 000000000000..68526910c8ee
--- /dev/null
+++ b/bindings/rust/libgpiod-sys/src/lib.rs
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
+// SPDX-FileCopyrightText: 2022 Linaro Ltd.
+// SPDX-FileCopyrightTest: 2022 Viresh Kumar <viresh.kumar@xxxxxxxxxx>
+
+#[allow(non_camel_case_types, non_upper_case_globals)]
+#[cfg_attr(test, allow(deref_nullptr, non_snake_case))]
+
+mod bindings_raw {
+    include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
+}
+pub use bindings_raw::*;
-- 
2.31.1.272.g89b43f80a514