Feature-gate HID over USB functionality

Cargo.toml

@@ -11,10 +11,14 @@ categories = ["embedded", "no-std"]
 license = "MIT"
 readme = "README.md"
 
+[features]
+default = ["usb"]
+usb = ["dep:usb-device"]
+
 [dependencies]
 keyberon-macros = { version = "0.1.0", path = "./keyberon-macros" }
 either = { version = "1.9.0", default-features = false }
 embedded-hal = { version = "1.0" }
-usb-device = "0.3"
+usb-device = { version = "0.3", optional = true }
 heapless = "0.8"
 arraydeque = { version = "0.5.1", default-features = false }

src/lib.rs

@@ -10,54 +10,24 @@
 //! a given MCU, you need GPIO throw the [embedded hal
 //! crate](https://crates.io/crates/embedded-hal) to read the key
 //! states, and the [usb-device
-//! crate](https://crates.io/crates/usb-device) for USB communication.
+//! crate](https://crates.io/crates/usb-device) for USB communication
+//! if the `usb` feature is enabled.
 
 #![no_std]
 #![deny(missing_docs)]
 
-use usb_device::bus::UsbBusAllocator;
-use usb_device::device::StringDescriptors;
-use usb_device::prelude::*;
-
 pub mod action;
 pub mod chording;
 pub mod debounce;
+#[cfg(feature = "usb")]
 pub mod hid;
 pub mod key_code;
+#[cfg(feature = "usb")]
 pub mod keyboard;
 pub mod layout;
 pub mod matrix;
+#[cfg(feature = "usb")]
+mod usb;
 
-/// A handly shortcut for the keyberon USB class type.
-pub type Class<'a, B, L> = hid::HidClass<'a, B, keyboard::Keyboard<L>>;
-
-/// USB VIP for a generic keyboard from
-/// https://github.com/obdev/v-usb/blob/master/usbdrv/USB-IDs-for-free.txt
-const VID: u16 = 0x16c0;
-
-/// USB PID for a generic keyboard from
-/// https://github.com/obdev/v-usb/blob/master/usbdrv/USB-IDs-for-free.txt
-const PID: u16 = 0x27db;
-
-/// Constructor for `Class`.
-pub fn new_class<B, L>(bus: &UsbBusAllocator<B>, leds: L) -> Class<'_, B, L>
-where
-    B: usb_device::bus::UsbBus,
-    L: keyboard::Leds,
-{
-    hid::HidClass::new(keyboard::Keyboard::new(leds), bus)
-}
-
-/// Constructor for a keyberon USB device.
-pub fn new_device<B>(bus: &UsbBusAllocator<B>) -> usb_device::device::UsbDevice<'_, B>
-where
-    B: usb_device::bus::UsbBus,
-{
-    UsbDeviceBuilder::new(bus, UsbVidPid(VID, PID))
-        .strings(&[StringDescriptors::default()
-            .manufacturer("RIIR Task Force")
-            .product("Keyberon")
-            .serial_number(env!("CARGO_PKG_VERSION"))])
-        .expect("Failed to configure UsbDeviceBuilder")
-        .build()
-}
+#[cfg(feature = "usb")]
+pub use usb::{new_class, new_device, Class};

src/usb.rs

@@ -0,0 +1,40 @@
+//! Keyberon USB constructors.
+
+use crate::{hid, keyboard};
+use usb_device::bus::UsbBusAllocator;
+use usb_device::device::StringDescriptors;
+use usb_device::prelude::*;
+
+/// A handly shortcut for the keyberon USB class type.
+pub type Class<'a, B, L> = hid::HidClass<'a, B, keyboard::Keyboard<L>>;
+
+/// USB VIP for a generic keyboard from
+/// https://github.com/obdev/v-usb/blob/master/usbdrv/USB-IDs-for-free.txt
+const VID: u16 = 0x16c0;
+
+/// USB PID for a generic keyboard from
+/// https://github.com/obdev/v-usb/blob/master/usbdrv/USB-IDs-for-free.txt
+const PID: u16 = 0x27db;
+
+/// Constructor for `Class`.
+pub fn new_class<B, L>(bus: &UsbBusAllocator<B>, leds: L) -> Class<'_, B, L>
+where
+    B: usb_device::bus::UsbBus,
+    L: keyboard::Leds,
+{
+    hid::HidClass::new(keyboard::Keyboard::new(leds), bus)
+}
+
+/// Constructor for a keyberon USB device.
+pub fn new_device<B>(bus: &UsbBusAllocator<B>) -> usb_device::device::UsbDevice<'_, B>
+where
+    B: usb_device::bus::UsbBus,
+{
+    UsbDeviceBuilder::new(bus, UsbVidPid(VID, PID))
+        .strings(&[StringDescriptors::default()
+            .manufacturer("RIIR Task Force")
+            .product("Keyberon")
+            .serial_number(env!("CARGO_PKG_VERSION"))])
+        .expect("Failed to configure UsbDeviceBuilder")
+        .build()
+}