refactor(arch): split the rp2040 arch into multiple submodule files

Split the `rp2040` arch to make it more manageable when it keeps growing.

src/riot-rs-embassy/src/arch/rp2040.rs → src/riot-rs-embassy/src/arch/rp2040/mod.rs

@@ -1,3 +1,6 @@
+#[cfg(feature = "usb")]
+pub mod usb;
+
 pub(crate) use embassy_executor::InterruptExecutor as Executor;
 pub use embassy_rp::interrupt;
 pub use embassy_rp::interrupt::SWI_IRQ_1 as SWI;
@@ -12,27 +15,6 @@ unsafe fn SWI_IRQ_1() {
     unsafe { crate::EXECUTOR.on_interrupt() }
 }
 
-#[cfg(feature = "usb")]
-pub mod usb {
-    use embassy_rp::{
-        bind_interrupts, peripherals,
-        usb::{Driver, InterruptHandler},
-    };
-
-    use crate::arch;
-
-    bind_interrupts!(struct Irqs {
-        USBCTRL_IRQ => InterruptHandler<peripherals::USB>;
-    });
-
-    pub type UsbDriver = Driver<'static, peripherals::USB>;
-
-    pub fn driver(peripherals: &mut arch::OptionalPeripherals) -> UsbDriver {
-        let usb = peripherals.USB.take().unwrap();
-        Driver::new(usb, Irqs)
-    }
-}
-
 pub fn init(config: Config) -> OptionalPeripherals {
     // SWI & DMA priority need to match. DMA is hard-coded to P3 by upstream.
     use embassy_rp::interrupt::{InterruptExt, Priority};

src/riot-rs-embassy/src/arch/rp2040/usb.rs

@@ -0,0 +1,17 @@
+use embassy_rp::{
+    bind_interrupts, peripherals,
+    usb::{Driver, InterruptHandler},
+};
+
+use crate::arch;
+
+bind_interrupts!(struct Irqs {
+    USBCTRL_IRQ => InterruptHandler<peripherals::USB>;
+});
+
+pub type UsbDriver = Driver<'static, peripherals::USB>;
+
+pub fn driver(peripherals: &mut arch::OptionalPeripherals) -> UsbDriver {
+    let usb = peripherals.USB.take().unwrap();
+    Driver::new(usb, Irqs)
+}

src/riot-rs-embassy/src/lib.rs

@@ -11,7 +11,7 @@ cfg_if::cfg_if! {
         #[path = "arch/nrf/mod.rs"]
         pub mod arch;
     } else if #[cfg(context = "rp2040")] {
-        #[path = "arch/rp2040.rs"]
+        #[path = "arch/rp2040/mod.rs"]
         pub mod arch;
     } else if #[cfg(context = "esp")] {
         #[path = "arch/esp.rs"]