This is a demonstration of the capabilities of doing bindings with
subsystems that may or may not be statically linked.

Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
v2 -> v3:
- Generate bindings for USB.
v1 -> v2:
- Added this patch.

 drivers/usb/core/Kconfig        |  7 +++++++
 drivers/usb/core/Makefile       |  3 +++
 drivers/usb/core/usb.rs         | 13 +++++++++++++
 rust/bindings/bindings_helper.h |  1 +
 samples/rust/Kconfig            | 10 ++++++++++
 samples/rust/Makefile           |  3 +++
 samples/rust/rust_usb_simple.rs | 22 ++++++++++++++++++++++
 7 files changed, 59 insertions(+)
 create mode 100644 drivers/usb/core/usb.rs
 create mode 100644 samples/rust/rust_usb_simple.rs

diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index 351ede4b5de2..4b5604282129 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -116,3 +116,10 @@ config USB_AUTOSUSPEND_DELAY
 	  The default value Linux has always had is 2 seconds.  Change
 	  this value if you want a different delay and cannot modify
 	  the command line or module parameter.
+
+config USB_RUST
+	bool "Rust USB bindings"
+	depends on USB && RUST
+	default n
+	help
+	  Enables Rust bindings for USB.
diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index 7d338e9c0657..00e116913591 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile
@@ -11,6 +11,7 @@ usbcore-y += phy.o port.o
 usbcore-$(CONFIG_OF)		+= of.o
 usbcore-$(CONFIG_USB_PCI)		+= hcd-pci.o
 usbcore-$(CONFIG_ACPI)		+= usb-acpi.o
+usbcore-$(CONFIG_USB_RUST)		+= libusb.rlib
 
 ifdef CONFIG_USB_ONBOARD_HUB
 usbcore-y			+= ../misc/onboard_usb_hub_pdevs.o
@@ -18,4 +19,6 @@ endif
 
 obj-$(CONFIG_USB)		+= usbcore.o
 
+rust-libs			:= ./usb
+
 obj-$(CONFIG_USB_LEDS_TRIGGER_USBPORT)	+= ledtrig-usbport.o
diff --git a/drivers/usb/core/usb.rs b/drivers/usb/core/usb.rs
new file mode 100644
index 000000000000..3f7ad02153f5
--- /dev/null
+++ b/drivers/usb/core/usb.rs
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! USB devices and drivers.
+//!
+//! C header: [`include/linux/usb.h`](../../../../include/linux/usb.h)
+
+use kernel::bindings;
+
+/// Check if USB is disabled.
+pub fn disabled() -> bool {
+    // SAFETY: FFI call.
+    unsafe { bindings::usb_disabled() != 0 }
+}
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index c41eaab4ddb2..845cdd856981 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -10,6 +10,7 @@
 #include <linux/errname.h>
 #include <linux/slab.h>
 #include <linux/refcount.h>
+#include <linux/usb.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/workqueue.h>
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index b0f74a81c8f9..12116f6fb526 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -30,6 +30,16 @@ config SAMPLE_RUST_PRINT
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_USB_SIMPLE
+	tristate "USB simple device driver"
+	help
+	  This option builds the Rust USB simple driver sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_usb_simple.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_HOSTPROGS
 	bool "Host programs"
 	help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 03086dabbea4..f1ab58a9ecdd 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -2,5 +2,8 @@
 
 obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
 obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_USB_SIMPLE)		+= rust_usb_simple.o
+
+rust-libs					:= ../../drivers/usb/core/usb
 
 subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
diff --git a/samples/rust/rust_usb_simple.rs b/samples/rust/rust_usb_simple.rs
new file mode 100644
index 000000000000..3523f81d5eb8
--- /dev/null
+++ b/samples/rust/rust_usb_simple.rs
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust USB sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: UsbSimple,
+    name: "rust_usb_simple",
+    author: "Martin Rodriguez Reboredo",
+    description: "Rust USB sample",
+    license: "GPL v2",
+}
+
+struct UsbSimple;
+
+impl kernel::Module for UsbSimple {
+    fn init(_module: &'static ThisModule) -> Result<Self> {
+        pr_info!("usb enabled: {}", !usb::disabled());
+        Ok(UsbSimple)
+    }
+}
-- 
2.42.1

On Sat, Nov 04, 2023 at 06:11:59PM -0300, Martin Rodriguez Reboredo wrote:
> This is a demonstration of the capabilities of doing bindings with
> subsystems that may or may not be statically linked.
> 
> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> ---
> v2 -> v3:
> - Generate bindings for USB.
> v1 -> v2:
> - Added this patch.

I know you are just using this for an example, but here's some
USB-specific things that you might want to clean up for when you submit
this as a "real" binding sometime in the future:

> +config USB_RUST
> +	bool "Rust USB bindings"

This is a "USB Host" binding.  We have both USB host mode (when you plug
a USB device into a system running Linux), and USB gadget mode (when
Linux is running on the USB device you plug into any other USB system).

So please be specific here, this should be "USB_HOST_RUST" and then
later, "USB_GADGET_RUST".

> +	depends on USB && RUST
> +	default n

Again, "default n" is the default, never list it again.


> +	help
> +	  Enables Rust bindings for USB.

USB Host, not all of USB.

> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
> index 7d338e9c0657..00e116913591 100644
> --- a/drivers/usb/core/Makefile
> +++ b/drivers/usb/core/Makefile
> @@ -11,6 +11,7 @@ usbcore-y += phy.o port.o
>  usbcore-$(CONFIG_OF)		+= of.o
>  usbcore-$(CONFIG_USB_PCI)		+= hcd-pci.o
>  usbcore-$(CONFIG_ACPI)		+= usb-acpi.o
> +usbcore-$(CONFIG_USB_RUST)		+= libusb.rlib
>  
>  ifdef CONFIG_USB_ONBOARD_HUB
>  usbcore-y			+= ../misc/onboard_usb_hub_pdevs.o
> @@ -18,4 +19,6 @@ endif
>  
>  obj-$(CONFIG_USB)		+= usbcore.o
>  
> +rust-libs			:= ./usb

Why the "./", why not just ":= usb" ?

> +config SAMPLE_RUST_USB_SIMPLE
> +	tristate "USB simple device driver"
> +	help
> +	  This option builds the Rust USB simple driver sample.

Rust USB simple host driver sample.

>  subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
> diff --git a/samples/rust/rust_usb_simple.rs b/samples/rust/rust_usb_simple.rs
> new file mode 100644
> index 000000000000..3523f81d5eb8
> --- /dev/null
> +++ b/samples/rust/rust_usb_simple.rs
> @@ -0,0 +1,22 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! Rust USB sample.
> +
> +use kernel::prelude::*;
> +
> +module! {
> +    type: UsbSimple,

"USBSimple" please.  I thought I said that before.

thanks,

greg k-h