Add SPI Abstraction

rust/bindings/bindings_helper.h

@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
+#include <linux/spi/spi.h>
 
 /* `bindgen` gets confused at certain things. */
 const size_t RUST_CONST_HELPER_ARCH_SLAB_MINALIGN = ARCH_SLAB_MINALIGN;

rust/helpers.c

@@ -31,6 +31,7 @@
 #include <linux/spinlock.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
+#include <linux/spi/spi.h>
 
 __noreturn void rust_helper_BUG(void)
 {
@@ -157,6 +158,13 @@ void rust_helper_init_work_with_key(struct work_struct *work, work_func_t func,
 }
 EXPORT_SYMBOL_GPL(rust_helper_init_work_with_key);
 
+void rust_helper_spi_message_init(struct spi_message *m)
+{
+	memset(m, 0, sizeof *m);
+	spi_message_init_no_memset(m);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spi_message_init);
+
 /*
  * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
  * use it in contexts where Rust expects a `usize` like slice (array) indices.

rust/kernel/lib.rs

@@ -59,6 +59,9 @@ pub use uapi;
 #[doc(hidden)]
 pub use build_error::build_error;
 
+#[cfg(CONFIG_SPI)]
+pub mod spi;
+
 /// Prefix to appear before log messages printed from within the `kernel` crate.
 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";