Merge pull request #2068 from barafael/const_usb_config_builder_new

Constify UsbDevice Config::new (and clippy fixes) in embassy-usb

embassy-usb/build.rs

@@ -70,9 +70,11 @@ fn main() {
 
                     // envvars take priority.
                     if !cfg.seen_env {
-                        if cfg.seen_feature {
+                        assert!(
-                            panic!("multiple values set for feature {}: {} and {}", name, cfg.value, value);
+                            !cfg.seen_feature,
-                        }
+                            "multiple values set for feature {}: {} and {}",
+                            name, cfg.value, value
+                        );
 
                         cfg.value = value;
                         cfg.seen_feature = true;

embassy-usb/src/builder.rs

@@ -1,17 +1,17 @@
 use heapless::Vec;
 
-use crate::config::*;
+use crate::config::MAX_HANDLER_COUNT;
 use crate::descriptor::{BosWriter, DescriptorWriter};
 use crate::driver::{Driver, Endpoint, EndpointType};
 #[cfg(feature = "msos-descriptor")]
 use crate::msos::{DeviceLevelDescriptor, FunctionLevelDescriptor, MsOsDescriptorWriter};
-use crate::types::*;
+use crate::types::{InterfaceNumber, StringIndex};
 use crate::{Handler, Interface, UsbDevice, MAX_INTERFACE_COUNT, STRING_INDEX_CUSTOM_START};
 
 #[derive(Debug, Copy, Clone)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[non_exhaustive]
-/// Configuration used when creating [UsbDevice].
+/// Configuration used when creating [`UsbDevice`].
 pub struct Config<'a> {
     pub(crate) vendor_id: u16,
     pub(crate) product_id: u16,
@@ -99,7 +99,7 @@ pub struct Config<'a> {
 
 impl<'a> Config<'a> {
     /// Create default configuration with the provided vid and pid values.
-    pub fn new(vid: u16, pid: u16) -> Self {
+    pub const fn new(vid: u16, pid: u16) -> Self {
         Self {
             device_class: 0x00,
             device_sub_class: 0x00,
@@ -159,9 +159,10 @@ impl<'d, D: Driver<'d>> Builder<'d, D> {
             panic!("if composite_with_iads is set, you must set device_class = 0xEF, device_sub_class = 0x02, device_protocol = 0x01");
         }
 
-        if config.max_power > 500 {
+        assert!(
-            panic!("The maximum allowed value for `max_power` is 500mA");
+            config.max_power <= 500,
-        }
+            "The maximum allowed value for `max_power` is 500mA"
+        );
 
         match config.max_packet_size_0 {
             8 | 16 | 32 | 64 => {}
@@ -260,12 +261,11 @@ impl<'d, D: Driver<'d>> Builder<'d, D> {
     /// The Handler is called on some USB bus events, and to handle all control requests not already
     /// handled by the USB stack.
     pub fn handler(&mut self, handler: &'d mut dyn Handler) {
-        if self.handlers.push(handler).is_err() {
+        assert!(
-            panic!(
+            self.handlers.push(handler).is_ok(),
-                "embassy-usb: handler list full. Increase the `max_handler_count` compile-time setting. Current value: {}",
+            "embassy-usb: handler list full. Increase the `max_handler_count` compile-time setting. Current value: {}",
-                MAX_HANDLER_COUNT
+            MAX_HANDLER_COUNT
-            )
+        );
-        }
     }
 
     /// Allocates a new string index.
@@ -332,12 +332,10 @@ impl<'a, 'd, D: Driver<'d>> FunctionBuilder<'a, 'd, D> {
             num_alt_settings: 0,
         };
 
-        if self.builder.interfaces.push(iface).is_err() {
+        assert!(self.builder.interfaces.push(iface).is_ok(),
-            panic!(
+            "embassy-usb: interface list full. Increase the `max_interface_count` compile-time setting. Current value: {}",
-                "embassy-usb: interface list full. Increase the `max_interface_count` compile-time setting. Current value: {}",
+            MAX_INTERFACE_COUNT
-                MAX_INTERFACE_COUNT
+        );
-            )
-        }
 
         InterfaceBuilder {
             builder: self.builder,
@@ -371,7 +369,7 @@ pub struct InterfaceBuilder<'a, 'd, D: Driver<'d>> {
 
 impl<'a, 'd, D: Driver<'d>> InterfaceBuilder<'a, 'd, D> {
     /// Get the interface number.
-    pub fn interface_number(&self) -> InterfaceNumber {
+    pub const fn interface_number(&self) -> InterfaceNumber {
         self.interface_number
     }
 
@@ -422,12 +420,12 @@ pub struct InterfaceAltBuilder<'a, 'd, D: Driver<'d>> {
 
 impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
     /// Get the interface number.
-    pub fn interface_number(&self) -> InterfaceNumber {
+    pub const fn interface_number(&self) -> InterfaceNumber {
         self.interface_number
     }
 
     /// Get the alternate setting number.
-    pub fn alt_setting_number(&self) -> u8 {
+    pub const fn alt_setting_number(&self) -> u8 {
         self.alt_setting_number
     }
 
@@ -436,7 +434,7 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
     /// Descriptors are written in the order builder functions are called. Note that some
     /// classes care about the order.
     pub fn descriptor(&mut self, descriptor_type: u8, descriptor: &[u8]) {
-        self.builder.config_descriptor.write(descriptor_type, descriptor)
+        self.builder.config_descriptor.write(descriptor_type, descriptor);
     }
 
     fn endpoint_in(&mut self, ep_type: EndpointType, max_packet_size: u16, interval_ms: u8) -> D::EndpointIn {

embassy-usb/src/class/cdc_acm.rs

@@ -11,7 +11,7 @@ use embassy_sync::waitqueue::WakerRegistration;
 
 use crate::control::{self, InResponse, OutResponse, Recipient, Request, RequestType};
 use crate::driver::{Driver, Endpoint, EndpointError, EndpointIn, EndpointOut};
-use crate::types::*;
+use crate::types::InterfaceNumber;
 use crate::{Builder, Handler};
 
 /// This should be used as `device_class` when building the `UsbDevice`.
@@ -39,12 +39,18 @@ pub struct State<'a> {
     shared: ControlShared,
 }
 
+impl<'a> Default for State<'a> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<'a> State<'a> {
     /// Create a new `State`.
     pub fn new() -> Self {
         Self {
             control: MaybeUninit::uninit(),
-            shared: Default::default(),
+            shared: ControlShared::default(),
         }
     }
 }
@@ -55,9 +61,9 @@ impl<'a> State<'a> {
 /// writing USB packets with no intermediate buffers, but it will not act like a stream-like serial
 /// port. The following constraints must be followed if you use this class directly:
 ///
-/// - `read_packet` must be called with a buffer large enough to hold max_packet_size bytes.
+/// - `read_packet` must be called with a buffer large enough to hold `max_packet_size` bytes.
-/// - `write_packet` must not be called with a buffer larger than max_packet_size bytes.
+/// - `write_packet` must not be called with a buffer larger than `max_packet_size` bytes.
-/// - If you write a packet that is exactly max_packet_size bytes long, it won't be processed by the
+/// - If you write a packet that is exactly `max_packet_size` bytes long, it won't be processed by the
 ///   host operating system until a subsequent shorter packet is sent. A zero-length packet (ZLP)
 ///   can be sent if there is no other data to send. This is because USB bulk transactions must be
 ///   terminated with a short packet, even if the bulk endpoint is used for stream-like data.
@@ -103,17 +109,16 @@ impl Default for ControlShared {
 
 impl ControlShared {
     async fn changed(&self) {
-        poll_fn(|cx| match self.changed.load(Ordering::Relaxed) {
+        poll_fn(|cx| {
-            true => {
+            if self.changed.load(Ordering::Relaxed) {
                 self.changed.store(false, Ordering::Relaxed);
                 Poll::Ready(())
-            }
+            } else {
-            false => {
                 self.waker.borrow_mut().register(cx.waker());
                 Poll::Pending
             }
         })
-        .await
+        .await;
     }
 }
 
@@ -192,7 +197,7 @@ impl<'d> Handler for Control<'d> {
             // REQ_GET_ENCAPSULATED_COMMAND is not really supported - it will be rejected below.
             REQ_GET_LINE_CODING if req.length == 7 => {
                 debug!("Sending line coding");
-                let coding = self.shared().line_coding.lock(|x| x.get());
+                let coding = self.shared().line_coding.lock(Cell::get);
                 assert!(buf.len() >= 7);
                 buf[0..4].copy_from_slice(&coding.data_rate.to_le_bytes());
                 buf[4] = coding.stop_bits as u8;
@@ -206,8 +211,8 @@ impl<'d> Handler for Control<'d> {
 }
 
 impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
-    /// Creates a new CdcAcmClass with the provided UsbBus and max_packet_size in bytes. For
+    /// Creates a new CdcAcmClass with the provided UsbBus and `max_packet_size` in bytes. For
-    /// full-speed devices, max_packet_size has to be one of 8, 16, 32 or 64.
+    /// full-speed devices, `max_packet_size` has to be one of 8, 16, 32 or 64.
     pub fn new(builder: &mut Builder<'d, D>, state: &'d mut State<'d>, max_packet_size: u16) -> Self {
         assert!(builder.control_buf_len() >= 7);
 
@@ -242,7 +247,7 @@ impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
             &[
                 CDC_TYPE_UNION, // bDescriptorSubtype
                 comm_if.into(), // bControlInterface
-                data_if.into(), // bSubordinateInterface
+                data_if,        // bSubordinateInterface
             ],
         );
 
@@ -283,7 +288,7 @@ impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
     /// Gets the current line coding. The line coding contains information that's mainly relevant
     /// for USB to UART serial port emulators, and can be ignored if not relevant.
     pub fn line_coding(&self) -> LineCoding {
-        self.control.line_coding.lock(|x| x.get())
+        self.control.line_coding.lock(Cell::get)
     }
 
     /// Gets the DTR (data terminal ready) state
@@ -308,7 +313,7 @@ impl<'d, D: Driver<'d>> CdcAcmClass<'d, D> {
 
     /// Waits for the USB host to enable this interface
     pub async fn wait_connection(&mut self) {
-        self.read_ep.wait_enabled().await
+        self.read_ep.wait_enabled().await;
     }
 
     /// Split the class into a sender and receiver.
@@ -356,7 +361,7 @@ pub struct ControlChanged<'d> {
 impl<'d> ControlChanged<'d> {
     /// Return a future for when the control settings change
     pub async fn control_changed(&self) {
-        self.control.changed().await
+        self.control.changed().await;
     }
 }
 
@@ -378,7 +383,7 @@ impl<'d, D: Driver<'d>> Sender<'d, D> {
     /// Gets the current line coding. The line coding contains information that's mainly relevant
     /// for USB to UART serial port emulators, and can be ignored if not relevant.
     pub fn line_coding(&self) -> LineCoding {
-        self.control.line_coding.lock(|x| x.get())
+        self.control.line_coding.lock(Cell::get)
     }
 
     /// Gets the DTR (data terminal ready) state
@@ -398,7 +403,7 @@ impl<'d, D: Driver<'d>> Sender<'d, D> {
 
     /// Waits for the USB host to enable this interface
     pub async fn wait_connection(&mut self) {
-        self.write_ep.wait_enabled().await
+        self.write_ep.wait_enabled().await;
     }
 }
 
@@ -420,7 +425,7 @@ impl<'d, D: Driver<'d>> Receiver<'d, D> {
     /// Gets the current line coding. The line coding contains information that's mainly relevant
     /// for USB to UART serial port emulators, and can be ignored if not relevant.
     pub fn line_coding(&self) -> LineCoding {
-        self.control.line_coding.lock(|x| x.get())
+        self.control.line_coding.lock(Cell::get)
     }
 
     /// Gets the DTR (data terminal ready) state
@@ -440,7 +445,7 @@ impl<'d, D: Driver<'d>> Receiver<'d, D> {
 
     /// Waits for the USB host to enable this interface
     pub async fn wait_connection(&mut self) {
-        self.read_ep.wait_enabled().await
+        self.read_ep.wait_enabled().await;
     }
 }
 
@@ -514,17 +519,17 @@ impl LineCoding {
     }
 
     /// Gets the number of data bits for UART communication.
-    pub fn data_bits(&self) -> u8 {
+    pub const fn data_bits(&self) -> u8 {
         self.data_bits
     }
 
     /// Gets the parity type for UART communication.
-    pub fn parity_type(&self) -> ParityType {
+    pub const fn parity_type(&self) -> ParityType {
         self.parity_type
     }
 
     /// Gets the data rate in bits per second for UART communication.
-    pub fn data_rate(&self) -> u32 {
+    pub const fn data_rate(&self) -> u32 {
         self.data_rate
     }
 }

embassy-usb/src/class/cdc_ncm/mod.rs

@@ -16,10 +16,11 @@
 
 use core::intrinsics::copy_nonoverlapping;
 use core::mem::{size_of, MaybeUninit};
+use core::ptr::addr_of;
 
 use crate::control::{self, InResponse, OutResponse, Recipient, Request, RequestType};
 use crate::driver::{Driver, Endpoint, EndpointError, EndpointIn, EndpointOut};
-use crate::types::*;
+use crate::types::{InterfaceNumber, StringIndex};
 use crate::{Builder, Handler};
 
 pub mod embassy_net;
@@ -62,9 +63,9 @@ const REQ_SET_NTB_INPUT_SIZE: u8 = 0x86;
 //const NOTIF_POLL_INTERVAL: u8 = 20;
 
 const NTB_MAX_SIZE: usize = 2048;
-const SIG_NTH: u32 = 0x484d434e;
+const SIG_NTH: u32 = 0x484d_434e;
-const SIG_NDP_NO_FCS: u32 = 0x304d434e;
+const SIG_NDP_NO_FCS: u32 = 0x304d_434e;
-const SIG_NDP_WITH_FCS: u32 = 0x314d434e;
+const SIG_NDP_WITH_FCS: u32 = 0x314d_434e;
 
 const ALTERNATE_SETTING_DISABLED: u8 = 0x00;
 const ALTERNATE_SETTING_ENABLED: u8 = 0x01;
@@ -111,7 +112,7 @@ struct NtbParametersDir {
 
 fn byteify<T>(buf: &mut [u8], data: T) -> &[u8] {
     let len = size_of::<T>();
-    unsafe { copy_nonoverlapping(&data as *const _ as *const u8, buf.as_mut_ptr(), len) }
+    unsafe { copy_nonoverlapping(addr_of!(data).cast(), buf.as_mut_ptr(), len) }
     &buf[..len]
 }
 
@@ -121,27 +122,28 @@ pub struct State<'a> {
     shared: ControlShared,
 }
 
+impl<'a> Default for State<'a> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<'a> State<'a> {
     /// Create a new `State`.
     pub fn new() -> Self {
         Self {
             control: MaybeUninit::uninit(),
-            shared: Default::default(),
+            shared: ControlShared::default(),
         }
     }
 }
 
-/// Shared data between Control and CdcAcmClass
+/// Shared data between Control and `CdcAcmClass`
+#[derive(Default)]
 struct ControlShared {
     mac_addr: [u8; 6],
 }
 
-impl Default for ControlShared {
-    fn default() -> Self {
-        ControlShared { mac_addr: [0; 6] }
-    }
-}
-
 struct Control<'a> {
     mac_addr_string: StringIndex,
     shared: &'a ControlShared,
@@ -377,12 +379,12 @@ impl<'d, D: Driver<'d>> Sender<'d, D> {
     ///
     /// This waits until the packet is successfully stored in the CDC-NCM endpoint buffers.
     pub async fn write_packet(&mut self, data: &[u8]) -> Result<(), EndpointError> {
-        let seq = self.seq;
-        self.seq = self.seq.wrapping_add(1);
-
         const OUT_HEADER_LEN: usize = 28;
         const ABS_MAX_PACKET_SIZE: usize = 512;
 
+        let seq = self.seq;
+        self.seq = self.seq.wrapping_add(1);
+
         let header = NtbOutHeader {
             nth_sig: SIG_NTH,
             nth_len: 0x0c,
@@ -416,7 +418,7 @@ impl<'d, D: Driver<'d>> Sender<'d, D> {
             self.write_ep.write(&buf[..self.max_packet_size]).await?;
 
             for chunk in d2.chunks(self.max_packet_size) {
-                self.write_ep.write(&chunk).await?;
+                self.write_ep.write(chunk).await?;
             }
 
             // Send ZLP if needed.
@@ -459,12 +461,9 @@ impl<'d, D: Driver<'d>> Receiver<'d, D> {
             let ntb = &ntb[..pos];
 
             // Process NTB header (NTH)
-            let nth = match ntb.get(..12) {
+            let Some(nth) = ntb.get(..12) else {
-                Some(x) => x,
+                warn!("Received too short NTB");
-                None => {
+                continue;
-                    warn!("Received too short NTB");
-                    continue;
-                }
             };
             let sig = u32::from_le_bytes(nth[0..4].try_into().unwrap());
             if sig != SIG_NTH {
@@ -474,12 +473,9 @@ impl<'d, D: Driver<'d>> Receiver<'d, D> {
             let ndp_idx = u16::from_le_bytes(nth[10..12].try_into().unwrap()) as usize;
 
             // Process NTB Datagram Pointer (NDP)
-            let ndp = match ntb.get(ndp_idx..ndp_idx + 12) {
+            let Some(ndp) = ntb.get(ndp_idx..ndp_idx + 12) else {
-                Some(x) => x,
+                warn!("NTH has an NDP pointer out of range.");
-                None => {
+                continue;
-                    warn!("NTH has an NDP pointer out of range.");
-                    continue;
-                }
             };
             let sig = u32::from_le_bytes(ndp[0..4].try_into().unwrap());
             if sig != SIG_NDP_NO_FCS && sig != SIG_NDP_WITH_FCS {
@@ -495,12 +491,9 @@ impl<'d, D: Driver<'d>> Receiver<'d, D> {
             }
 
             // Process actual datagram, finally.
-            let datagram = match ntb.get(datagram_index..datagram_index + datagram_len) {
+            let Some(datagram) = ntb.get(datagram_index..datagram_index + datagram_len) else {
-                Some(x) => x,
+                warn!("NDP has a datagram pointer out of range.");
-                None => {
+                continue;
-                    warn!("NDP has a datagram pointer out of range.");
-                    continue;
-                }
             };
             buf[..datagram_len].copy_from_slice(datagram);
 

embassy-usb/src/class/hid.rs

@@ -63,7 +63,7 @@ pub enum ReportId {
 }
 
 impl ReportId {
-    fn try_from(value: u16) -> Result<Self, ()> {
+    const fn try_from(value: u16) -> Result<Self, ()> {
         match value >> 8 {
             1 => Ok(ReportId::In(value as u8)),
             2 => Ok(ReportId::Out(value as u8)),
@@ -79,9 +79,15 @@ pub struct State<'d> {
     out_report_offset: AtomicUsize,
 }
 
+impl<'d> Default for State<'d> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<'d> State<'d> {
     /// Create a new `State`.
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         State {
             control: MaybeUninit::uninit(),
             out_report_offset: AtomicUsize::new(0),
@@ -148,7 +154,7 @@ fn build<'d, D: Driver<'d>>(
 }
 
 impl<'d, D: Driver<'d>, const READ_N: usize, const WRITE_N: usize> HidReaderWriter<'d, D, READ_N, WRITE_N> {
-    /// Creates a new HidReaderWriter.
+    /// Creates a new `HidReaderWriter`.
     ///
     /// This will allocate one IN and one OUT endpoints. If you only need writing (sending)
     /// HID reports, consider using [`HidWriter::new`] instead, which allocates an IN endpoint only.
@@ -171,7 +177,7 @@ impl<'d, D: Driver<'d>, const READ_N: usize, const WRITE_N: usize> HidReaderWrit
     }
 
     /// Waits for both IN and OUT endpoints to be enabled.
-    pub async fn ready(&mut self) -> () {
+    pub async fn ready(&mut self) {
         self.reader.ready().await;
         self.writer.ready().await;
     }
@@ -224,7 +230,7 @@ pub enum ReadError {
 
 impl From<EndpointError> for ReadError {
     fn from(val: EndpointError) -> Self {
-        use EndpointError::*;
+        use EndpointError::{BufferOverflow, Disabled};
         match val {
             BufferOverflow => ReadError::BufferOverflow,
             Disabled => ReadError::Disabled,
@@ -251,17 +257,16 @@ impl<'d, D: Driver<'d>, const N: usize> HidWriter<'d, D, N> {
     }
 
     /// Waits for the interrupt in endpoint to be enabled.
-    pub async fn ready(&mut self) -> () {
+    pub async fn ready(&mut self) {
-        self.ep_in.wait_enabled().await
+        self.ep_in.wait_enabled().await;
     }
 
     /// Writes an input report by serializing the given report structure.
     #[cfg(feature = "usbd-hid")]
     pub async fn write_serialize<IR: AsInputReport>(&mut self, r: &IR) -> Result<(), EndpointError> {
         let mut buf: [u8; N] = [0; N];
-        let size = match serialize(&mut buf, r) {
+        let Ok(size) = serialize(&mut buf, r) else {
-            Ok(size) => size,
+            return Err(EndpointError::BufferOverflow);
-            Err(_) => return Err(EndpointError::BufferOverflow),
         };
         self.write(&buf[0..size]).await
     }
@@ -286,8 +291,8 @@ impl<'d, D: Driver<'d>, const N: usize> HidWriter<'d, D, N> {
 
 impl<'d, D: Driver<'d>, const N: usize> HidReader<'d, D, N> {
     /// Waits for the interrupt out endpoint to be enabled.
-    pub async fn ready(&mut self) -> () {
+    pub async fn ready(&mut self) {
-        self.ep_out.wait_enabled().await
+        self.ep_out.wait_enabled().await;
     }
 
     /// Delivers output reports from the Interrupt Out pipe to `handler`.
@@ -344,9 +349,8 @@ impl<'d, D: Driver<'d>, const N: usize> HidReader<'d, D, N> {
                         if size < max_packet_size || total == N {
                             self.offset.store(0, Ordering::Release);
                             break;
-                        } else {
-                            self.offset.store(total, Ordering::Release);
                         }
+                        self.offset.store(total, Ordering::Release);
                     }
                     Err(err) => {
                         self.offset.store(0, Ordering::Release);
@@ -466,7 +470,7 @@ impl<'d> Handler for Control<'d> {
             HID_REQ_SET_IDLE => {
                 if let Some(handler) = self.request_handler {
                     let id = req.value as u8;
-                    let id = (id != 0).then(|| ReportId::In(id));
+                    let id = (id != 0).then_some(ReportId::In(id));
                     let dur = u32::from(req.value >> 8);
                     let dur = if dur == 0 { u32::MAX } else { 4 * dur };
                     handler.set_idle_ms(id, dur);
@@ -522,7 +526,7 @@ impl<'d> Handler for Control<'d> {
                     HID_REQ_GET_IDLE => {
                         if let Some(handler) = self.request_handler {
                             let id = req.value as u8;
-                            let id = (id != 0).then(|| ReportId::In(id));
+                            let id = (id != 0).then_some(ReportId::In(id));
                             if let Some(dur) = handler.get_idle_ms(id) {
                                 let dur = u8::try_from(dur / 4).unwrap_or(0);
                                 buf[0] = dur;

embassy-usb/src/class/midi.rs

@@ -27,9 +27,9 @@ const MIDI_OUT_SIZE: u8 = 0x09;
 /// writing USB packets with no intermediate buffers, but it will not act like a stream-like port.
 /// The following constraints must be followed if you use this class directly:
 ///
-/// - `read_packet` must be called with a buffer large enough to hold max_packet_size bytes.
+/// - `read_packet` must be called with a buffer large enough to hold `max_packet_size` bytes.
-/// - `write_packet` must not be called with a buffer larger than max_packet_size bytes.
+/// - `write_packet` must not be called with a buffer larger than `max_packet_size` bytes.
-/// - If you write a packet that is exactly max_packet_size bytes long, it won't be processed by the
+/// - If you write a packet that is exactly `max_packet_size` bytes long, it won't be processed by the
 ///   host operating system until a subsequent shorter packet is sent. A zero-length packet (ZLP)
 ///   can be sent if there is no other data to send. This is because USB bulk transactions must be
 ///   terminated with a short packet, even if the bulk endpoint is used for stream-like data.
@@ -39,8 +39,8 @@ pub struct MidiClass<'d, D: Driver<'d>> {
 }
 
 impl<'d, D: Driver<'d>> MidiClass<'d, D> {
-    /// Creates a new MidiClass with the provided UsbBus, number of input and output jacks and max_packet_size in bytes.
+    /// Creates a new `MidiClass` with the provided UsbBus, number of input and output jacks and `max_packet_size` in bytes.
-    /// For full-speed devices, max_packet_size has to be one of 8, 16, 32 or 64.
+    /// For full-speed devices, `max_packet_size` has to be one of 8, 16, 32 or 64.
     pub fn new(builder: &mut Builder<'d, D>, n_in_jacks: u8, n_out_jacks: u8, max_packet_size: u16) -> Self {
         let mut func = builder.function(USB_AUDIO_CLASS, USB_AUDIOCONTROL_SUBCLASS, PROTOCOL_NONE);
 
@@ -160,7 +160,7 @@ impl<'d, D: Driver<'d>> MidiClass<'d, D> {
 
     /// Waits for the USB host to enable this interface
     pub async fn wait_connection(&mut self) {
-        self.read_ep.wait_enabled().await
+        self.read_ep.wait_enabled().await;
     }
 
     /// Split the class into a sender and receiver.
@@ -197,7 +197,7 @@ impl<'d, D: Driver<'d>> Sender<'d, D> {
 
     /// Waits for the USB host to enable this interface
     pub async fn wait_connection(&mut self) {
-        self.write_ep.wait_enabled().await
+        self.write_ep.wait_enabled().await;
     }
 }
 
@@ -222,6 +222,6 @@ impl<'d, D: Driver<'d>> Receiver<'d, D> {
 
     /// Waits for the USB host to enable this interface
     pub async fn wait_connection(&mut self) {
-        self.read_ep.wait_enabled().await
+        self.read_ep.wait_enabled().await;
     }
 }

embassy-usb/src/control.rs

@@ -120,7 +120,7 @@ impl Request {
     }
 
     /// Gets the descriptor type and index from the value field of a GET_DESCRIPTOR request.
-    pub fn descriptor_type_index(&self) -> (u8, u8) {
+    pub const fn descriptor_type_index(&self) -> (u8, u8) {
         ((self.value >> 8) as u8, self.value as u8)
     }
 }

embassy-usb/src/descriptor.rs

@@ -2,7 +2,7 @@
 
 use crate::builder::Config;
 use crate::driver::EndpointInfo;
-use crate::types::*;
+use crate::types::{InterfaceNumber, StringIndex};
 use crate::CONFIGURATION_VALUE;
 
 /// Standard descriptor types
@@ -59,7 +59,7 @@ impl<'a> DescriptorWriter<'a> {
     }
 
     /// Gets the current position in the buffer, i.e. the number of bytes written so far.
-    pub fn position(&self) -> usize {
+    pub const fn position(&self) -> usize {
         self.position
     }
 
@@ -67,9 +67,10 @@ impl<'a> DescriptorWriter<'a> {
     pub fn write(&mut self, descriptor_type: u8, descriptor: &[u8]) {
         let length = descriptor.len();
 
-        if (self.position + 2 + length) > self.buf.len() || (length + 2) > 255 {
+        assert!(
-            panic!("Descriptor buffer full");
+            (self.position + 2 + length) <= self.buf.len() && (length + 2) <= 255,
-        }
+            "Descriptor buffer full"
+        );
 
         self.buf[self.position] = (length + 2) as u8;
         self.buf[self.position + 1] = descriptor_type;
@@ -102,7 +103,7 @@ impl<'a> DescriptorWriter<'a> {
                 config.serial_number.map_or(0, |_| 3), // iSerialNumber
                 1,                                     // bNumConfigurations
             ],
-        )
+        );
     }
 
     pub(crate) fn configuration(&mut self, config: &Config) {
@@ -120,7 +121,7 @@ impl<'a> DescriptorWriter<'a> {
                     | if config.supports_remote_wakeup { 0x20 } else { 0x00 }, // bmAttributes
                 (config.max_power / 2) as u8, // bMaxPower
             ],
-        )
+        );
     }
 
     #[allow(unused)]
@@ -248,9 +249,7 @@ impl<'a> DescriptorWriter<'a> {
     pub(crate) fn string(&mut self, string: &str) {
         let mut pos = self.position;
 
-        if pos + 2 > self.buf.len() {
+        assert!(pos + 2 <= self.buf.len(), "Descriptor buffer full");
-            panic!("Descriptor buffer full");
-        }
 
         self.buf[pos] = 0; // length placeholder
         self.buf[pos + 1] = descriptor_type::STRING;
@@ -258,9 +257,7 @@ impl<'a> DescriptorWriter<'a> {
         pos += 2;
 
         for c in string.encode_utf16() {
-            if pos >= self.buf.len() {
+            assert!(pos < self.buf.len(), "Descriptor buffer full");
-                panic!("Descriptor buffer full");
-            }
 
             self.buf[pos..pos + 2].copy_from_slice(&c.to_le_bytes());
             pos += 2;
@@ -279,9 +276,9 @@ pub struct BosWriter<'a> {
 }
 
 impl<'a> BosWriter<'a> {
-    pub(crate) fn new(writer: DescriptorWriter<'a>) -> Self {
+    pub(crate) const fn new(writer: DescriptorWriter<'a>) -> Self {
         Self {
-            writer: writer,
+            writer,
             num_caps_mark: None,
         }
     }
@@ -314,9 +311,10 @@ impl<'a> BosWriter<'a> {
         let mut start = self.writer.position;
         let blen = data.len();
 
-        if (start + blen + 3) > self.writer.buf.len() || (blen + 3) > 255 {
+        assert!(
-            panic!("Descriptor buffer full");
+            (start + blen + 3) <= self.writer.buf.len() && (blen + 3) <= 255,
-        }
+            "Descriptor buffer full"
+        );
 
         self.writer.buf[start] = (blen + 3) as u8;
         self.writer.buf[start + 1] = descriptor_type::CAPABILITY;

embassy-usb/src/descriptor_reader.rs

@@ -11,11 +11,11 @@ pub struct Reader<'a> {
 }
 
 impl<'a> Reader<'a> {
-    pub fn new(data: &'a [u8]) -> Self {
+    pub const fn new(data: &'a [u8]) -> Self {
         Self { data }
     }
 
-    pub fn eof(&self) -> bool {
+    pub const fn eof(&self) -> bool {
         self.data.is_empty()
     }
 
@@ -102,7 +102,7 @@ pub fn foreach_endpoint(data: &[u8], mut f: impl FnMut(EndpointInfo)) -> Result<
             }
             descriptor_type::ENDPOINT => {
                 ep.ep_address = EndpointAddress::from(r.read_u8()?);
-                f(ep)
+                f(ep);
             }
             _ => {}
         }

embassy-usb/src/lib.rs

@@ -24,12 +24,12 @@ use embassy_futures::select::{select, Either};
 use heapless::Vec;
 
 pub use crate::builder::{Builder, Config, FunctionBuilder, InterfaceAltBuilder, InterfaceBuilder};
-use crate::config::*;
+use crate::config::{MAX_HANDLER_COUNT, MAX_INTERFACE_COUNT};
-use crate::control::*;
+use crate::control::{InResponse, OutResponse, Recipient, Request, RequestType};
-use crate::descriptor::*;
+use crate::descriptor::{descriptor_type, lang_id};
 use crate::descriptor_reader::foreach_endpoint;
 use crate::driver::{Bus, ControlPipe, Direction, Driver, EndpointAddress, Event};
-use crate::types::*;
+use crate::types::{InterfaceNumber, StringIndex};
 
 /// The global state of the USB device.
 ///
@@ -294,7 +294,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
     /// After dropping the future, [`UsbDevice::disable()`] should be called
     /// before calling any other `UsbDevice` methods to fully reset the
     /// peripheral.
-    pub async fn run_until_suspend(&mut self) -> () {
+    pub async fn run_until_suspend(&mut self) {
         while !self.inner.suspended {
             let control_fut = self.control.setup();
             let bus_fut = self.inner.bus.poll();
@@ -364,6 +364,8 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
     }
 
     async fn handle_control_in(&mut self, req: Request) {
+        const DEVICE_DESCRIPTOR_LEN: usize = 18;
+
         let mut resp_length = req.length as usize;
         let max_packet_size = self.control.max_packet_size();
 
@@ -371,19 +373,15 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         // The host doesn't know our EP0 max packet size yet, and might assume
         // a full-length packet is a short packet, thinking we're done sending data.
         // See https://github.com/hathach/tinyusb/issues/184
-        const DEVICE_DESCRIPTOR_LEN: usize = 18;
+        if self.inner.address == 0 && max_packet_size < DEVICE_DESCRIPTOR_LEN && max_packet_size < resp_length {
-        if self.inner.address == 0
-            && max_packet_size < DEVICE_DESCRIPTOR_LEN
-            && (max_packet_size as usize) < resp_length
-        {
             trace!("received control req while not addressed: capping response to 1 packet.");
             resp_length = max_packet_size;
         }
 
-        match self.inner.handle_control_in(req, &mut self.control_buf) {
+        match self.inner.handle_control_in(req, self.control_buf) {
             InResponse::Accepted(data) => {
                 let len = data.len().min(resp_length);
-                let need_zlp = len != resp_length && (len % usize::from(max_packet_size)) == 0;
+                let need_zlp = len != resp_length && (len % max_packet_size) == 0;
 
                 let chunks = data[0..len]
                     .chunks(max_packet_size)
@@ -435,7 +433,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     self.control.accept_set_address(self.inner.address).await;
                     self.inner.set_address_pending = false;
                 } else {
-                    self.control.accept().await
+                    self.control.accept().await;
                 }
             }
             OutResponse::Rejected => self.control.reject().await,
@@ -548,9 +546,8 @@ impl<'d, D: Driver<'d>> Inner<'d, D> {
 
                     OutResponse::Accepted
                 }
-                (Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => match self.device_state {
+                (Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => {
-                    UsbDeviceState::Default => OutResponse::Accepted,
+                    if self.device_state != UsbDeviceState::Default {
-                    _ => {
                         debug!("SET_CONFIGURATION: unconfigured");
                         self.device_state = UsbDeviceState::Addressed;
 
@@ -564,17 +561,15 @@ impl<'d, D: Driver<'d>> Inner<'d, D> {
                         for h in &mut self.handlers {
                             h.configured(false);
                         }
-
-                        OutResponse::Accepted
                     }
-                },
+                    OutResponse::Accepted
+                }
                 _ => OutResponse::Rejected,
             },
             (RequestType::Standard, Recipient::Interface) => {
                 let iface_num = InterfaceNumber::new(req.index as _);
-                let iface = match self.interfaces.get_mut(iface_num.0 as usize) {
+                let Some(iface) = self.interfaces.get_mut(iface_num.0 as usize) else {
-                    Some(iface) => iface,
+                    return OutResponse::Rejected;
-                    None => return OutResponse::Rejected,
                 };
 
                 match req.request {
@@ -650,9 +645,8 @@ impl<'d, D: Driver<'d>> Inner<'d, D> {
                 _ => InResponse::Rejected,
             },
             (RequestType::Standard, Recipient::Interface) => {
-                let iface = match self.interfaces.get_mut(req.index as usize) {
+                let Some(iface) = self.interfaces.get_mut(req.index as usize) else {
-                    Some(iface) => iface,
+                    return InResponse::Rejected;
-                    None => return InResponse::Rejected,
                 };
 
                 match req.request {
@@ -706,7 +700,7 @@ impl<'d, D: Driver<'d>> Inner<'d, D> {
     }
 
     fn handle_control_in_delegated<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
-        unsafe fn extend_lifetime<'x, 'y>(r: InResponse<'x>) -> InResponse<'y> {
+        unsafe fn extend_lifetime<'y>(r: InResponse<'_>) -> InResponse<'y> {
             core::mem::transmute(r)
         }
 
@@ -756,16 +750,12 @@ impl<'d, D: Driver<'d>> Inner<'d, D> {
                     };
 
                     if let Some(s) = s {
-                        if buf.len() < 2 {
+                        assert!(buf.len() >= 2, "control buffer too small");
-                            panic!("control buffer too small");
-                        }
 
                         buf[1] = descriptor_type::STRING;
                         let mut pos = 2;
                         for c in s.encode_utf16() {
-                            if pos + 2 >= buf.len() {
+                            assert!(pos + 2 < buf.len(), "control buffer too small");
-                                panic!("control buffer too small");
-                            }
 
                             buf[pos..pos + 2].copy_from_slice(&c.to_le_bytes());
                             pos += 2;

embassy-usb/src/msos.rs

@@ -6,7 +6,7 @@
 
 use core::mem::size_of;
 
-use super::{capability_type, BosWriter};
+use crate::descriptor::{capability_type, BosWriter};
 use crate::types::InterfaceNumber;
 
 /// A serialized Microsoft OS 2.0 Descriptor set.

embassy-usb/src/types.rs

@@ -7,7 +7,7 @@
 pub struct InterfaceNumber(pub u8);
 
 impl InterfaceNumber {
-    pub(crate) fn new(index: u8) -> InterfaceNumber {
+    pub(crate) const fn new(index: u8) -> InterfaceNumber {
         InterfaceNumber(index)
     }
 }
@@ -25,7 +25,7 @@ impl From<InterfaceNumber> for u8 {
 pub struct StringIndex(pub u8);
 
 impl StringIndex {
-    pub(crate) fn new(index: u8) -> StringIndex {
+    pub(crate) const fn new(index: u8) -> StringIndex {
         StringIndex(index)
     }
 }