538 lines
18 KiB
Rust
538 lines
18 KiB
Rust
#![no_std]
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#![feature(generic_associated_types)]
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#![feature(type_alias_impl_trait)]
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//! Implements HID functionality for a usb-device device.
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// This mod MUST go first, so that the others see its macros.
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pub(crate) mod fmt;
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use core::mem::MaybeUninit;
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use core::ops::Range;
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use core::sync::atomic::{AtomicUsize, Ordering};
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use embassy::time::Duration;
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use embassy_usb::driver::EndpointOut;
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use embassy_usb::{
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control::{ControlHandler, InResponse, OutResponse, Request, RequestType},
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driver::{Driver, Endpoint, EndpointError, EndpointIn},
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UsbDeviceBuilder,
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};
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#[cfg(feature = "usbd-hid")]
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use ssmarshal::serialize;
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#[cfg(feature = "usbd-hid")]
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use usbd_hid::descriptor::AsInputReport;
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const USB_CLASS_HID: u8 = 0x03;
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const USB_SUBCLASS_NONE: u8 = 0x00;
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const USB_PROTOCOL_NONE: u8 = 0x00;
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// HID
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const HID_DESC_DESCTYPE_HID: u8 = 0x21;
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const HID_DESC_DESCTYPE_HID_REPORT: u8 = 0x22;
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const HID_DESC_SPEC_1_10: [u8; 2] = [0x10, 0x01];
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const HID_DESC_COUNTRY_UNSPEC: u8 = 0x00;
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const HID_REQ_SET_IDLE: u8 = 0x0a;
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const HID_REQ_GET_IDLE: u8 = 0x02;
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const HID_REQ_GET_REPORT: u8 = 0x01;
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const HID_REQ_SET_REPORT: u8 = 0x09;
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const HID_REQ_GET_PROTOCOL: u8 = 0x03;
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const HID_REQ_SET_PROTOCOL: u8 = 0x0b;
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pub struct Config<'d> {
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/// HID report descriptor.
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pub report_descriptor: &'d [u8],
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/// Handler for control requests.
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pub request_handler: Option<&'d dyn RequestHandler>,
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/// Configures how frequently the host should poll for reading/writing HID reports.
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///
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/// A lower value means better throughput & latency, at the expense
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/// of CPU on the device & bandwidth on the bus. A value of 10 is reasonable for
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/// high performance uses, and a value of 255 is good for best-effort usecases.
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pub poll_ms: u8,
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/// Max packet size for both the IN and OUT endpoints.
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pub max_packet_size: u16,
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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pub enum ReportId {
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In(u8),
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Out(u8),
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Feature(u8),
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}
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impl ReportId {
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fn try_from(value: u16) -> Result<Self, ()> {
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match value >> 8 {
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1 => Ok(ReportId::In(value as u8)),
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2 => Ok(ReportId::Out(value as u8)),
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3 => Ok(ReportId::Feature(value as u8)),
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_ => Err(()),
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}
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}
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}
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pub struct State<'d> {
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control: MaybeUninit<Control<'d>>,
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out_report_offset: AtomicUsize,
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}
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impl<'d> State<'d> {
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pub fn new() -> Self {
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State {
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control: MaybeUninit::uninit(),
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out_report_offset: AtomicUsize::new(0),
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}
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}
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}
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pub struct HidReaderWriter<'d, D: Driver<'d>, const READ_N: usize, const WRITE_N: usize> {
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reader: HidReader<'d, D, READ_N>,
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writer: HidWriter<'d, D, WRITE_N>,
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}
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fn build<'d, D: Driver<'d>>(
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builder: &mut UsbDeviceBuilder<'d, D>,
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state: &'d mut State<'d>,
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config: Config<'d>,
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with_out_endpoint: bool,
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) -> (Option<D::EndpointOut>, D::EndpointIn, &'d AtomicUsize) {
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let control = state.control.write(Control::new(
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config.report_descriptor,
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config.request_handler,
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&state.out_report_offset,
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));
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let len = config.report_descriptor.len();
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let if_num = builder.alloc_interface_with_handler(control);
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let ep_in = builder.alloc_interrupt_endpoint_in(config.max_packet_size, config.poll_ms);
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let ep_out = if with_out_endpoint {
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Some(builder.alloc_interrupt_endpoint_out(config.max_packet_size, config.poll_ms))
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} else {
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None
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};
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builder.config_descriptor.interface(
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if_num,
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USB_CLASS_HID,
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USB_SUBCLASS_NONE,
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USB_PROTOCOL_NONE,
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);
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// HID descriptor
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builder.config_descriptor.write(
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HID_DESC_DESCTYPE_HID,
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&[
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// HID Class spec version
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HID_DESC_SPEC_1_10[0],
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HID_DESC_SPEC_1_10[1],
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// Country code not supported
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HID_DESC_COUNTRY_UNSPEC,
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// Number of following descriptors
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1,
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// We have a HID report descriptor the host should read
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HID_DESC_DESCTYPE_HID_REPORT,
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// HID report descriptor size,
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(len & 0xFF) as u8,
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(len >> 8 & 0xFF) as u8,
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],
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);
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builder.config_descriptor.endpoint(ep_in.info());
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if let Some(ep_out) = &ep_out {
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builder.config_descriptor.endpoint(ep_out.info());
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}
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(ep_out, ep_in, &state.out_report_offset)
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}
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impl<'d, D: Driver<'d>, const READ_N: usize, const WRITE_N: usize>
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HidReaderWriter<'d, D, READ_N, WRITE_N>
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{
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/// Creates a new HidReaderWriter.
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///
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/// This will allocate one IN and one OUT endpoints. If you only need writing (sending)
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/// HID reports, consider using [`HidWriter::new`] instead, which allocates an IN endpoint only.
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///
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pub fn new(
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builder: &mut UsbDeviceBuilder<'d, D>,
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state: &'d mut State<'d>,
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config: Config<'d>,
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) -> Self {
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let (ep_out, ep_in, offset) = build(builder, state, config, true);
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Self {
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reader: HidReader {
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ep_out: ep_out.unwrap(),
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offset,
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},
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writer: HidWriter { ep_in },
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}
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}
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/// Splits into seperate readers/writers for input and output reports.
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pub fn split(self) -> (HidReader<'d, D, READ_N>, HidWriter<'d, D, WRITE_N>) {
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(self.reader, self.writer)
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}
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/// Waits for both IN and OUT endpoints to be enabled.
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pub async fn ready(&mut self) -> () {
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self.reader.ready().await;
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self.writer.ready().await;
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}
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/// Writes an input report by serializing the given report structure.
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#[cfg(feature = "usbd-hid")]
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pub async fn write_serialize<IR: AsInputReport>(
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&mut self,
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r: &IR,
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) -> Result<(), EndpointError> {
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self.writer.write_serialize(r).await
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}
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/// Writes `report` to its interrupt endpoint.
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pub async fn write(&mut self, report: &[u8]) -> Result<(), EndpointError> {
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self.writer.write(report).await
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}
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/// Reads an output report from the Interrupt Out pipe.
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///
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/// See [`HidReader::read`].
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pub async fn read(&mut self, buf: &mut [u8]) -> Result<usize, ReadError> {
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self.reader.read(buf).await
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}
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}
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pub struct HidWriter<'d, D: Driver<'d>, const N: usize> {
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ep_in: D::EndpointIn,
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}
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pub struct HidReader<'d, D: Driver<'d>, const N: usize> {
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ep_out: D::EndpointOut,
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offset: &'d AtomicUsize,
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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pub enum ReadError {
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BufferOverflow,
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Disabled,
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Sync(Range<usize>),
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}
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impl From<embassy_usb::driver::EndpointError> for ReadError {
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fn from(val: embassy_usb::driver::EndpointError) -> Self {
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use embassy_usb::driver::EndpointError::*;
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match val {
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BufferOverflow => ReadError::BufferOverflow,
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Disabled => ReadError::Disabled,
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}
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}
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}
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impl<'d, D: Driver<'d>, const N: usize> HidWriter<'d, D, N> {
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/// Creates a new HidWriter.
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///
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/// This will allocate one IN endpoint only, so the host won't be able to send
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/// reports to us. If you need that, consider using [`HidReaderWriter::new`] instead.
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///
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/// poll_ms configures how frequently the host should poll for reading/writing
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/// HID reports. A lower value means better throughput & latency, at the expense
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/// of CPU on the device & bandwidth on the bus. A value of 10 is reasonable for
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/// high performance uses, and a value of 255 is good for best-effort usecases.
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pub fn new(
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builder: &mut UsbDeviceBuilder<'d, D>,
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state: &'d mut State<'d>,
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config: Config<'d>,
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) -> Self {
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let (ep_out, ep_in, _offset) = build(builder, state, config, false);
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assert!(ep_out.is_none());
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Self { ep_in }
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}
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/// Waits for the interrupt in endpoint to be enabled.
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pub async fn ready(&mut self) -> () {
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self.ep_in.wait_enabled().await
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}
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/// Writes an input report by serializing the given report structure.
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#[cfg(feature = "usbd-hid")]
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pub async fn write_serialize<IR: AsInputReport>(
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&mut self,
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r: &IR,
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) -> Result<(), EndpointError> {
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let mut buf: [u8; N] = [0; N];
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let size = match serialize(&mut buf, r) {
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Ok(size) => size,
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Err(_) => return Err(EndpointError::BufferOverflow),
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};
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self.write(&buf[0..size]).await
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}
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/// Writes `report` to its interrupt endpoint.
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pub async fn write(&mut self, report: &[u8]) -> Result<(), EndpointError> {
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assert!(report.len() <= N);
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let max_packet_size = usize::from(self.ep_in.info().max_packet_size);
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let zlp_needed = report.len() < N && (report.len() % max_packet_size == 0);
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for chunk in report.chunks(max_packet_size) {
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self.ep_in.write(chunk).await?;
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}
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if zlp_needed {
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self.ep_in.write(&[]).await?;
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}
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Ok(())
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}
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}
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impl<'d, D: Driver<'d>, const N: usize> HidReader<'d, D, N> {
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/// Waits for the interrupt out endpoint to be enabled.
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pub async fn ready(&mut self) -> () {
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self.ep_out.wait_enabled().await
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}
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/// Delivers output reports from the Interrupt Out pipe to `handler`.
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///
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/// If `use_report_ids` is true, the first byte of the report will be used as
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/// the `ReportId` value. Otherwise the `ReportId` value will be 0.
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pub async fn run<T: RequestHandler>(mut self, use_report_ids: bool, handler: &T) -> ! {
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let offset = self.offset.load(Ordering::Acquire);
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assert!(offset == 0);
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let mut buf = [0; N];
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loop {
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match self.read(&mut buf).await {
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Ok(len) => {
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let id = if use_report_ids { buf[0] } else { 0 };
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handler.set_report(ReportId::Out(id), &buf[..len]); }
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Err(ReadError::BufferOverflow) => warn!("Host sent output report larger than the configured maximum output report length ({})", N),
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Err(ReadError::Disabled) => self.ep_out.wait_enabled().await,
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Err(ReadError::Sync(_)) => unreachable!(),
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}
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}
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}
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/// Reads an output report from the Interrupt Out pipe.
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///
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/// **Note:** Any reports sent from the host over the control pipe will be
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/// passed to [`RequestHandler::set_report()`] for handling. The application
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/// is responsible for ensuring output reports from both pipes are handled
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/// correctly.
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///
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/// **Note:** If `N` > the maximum packet size of the endpoint (i.e. output
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/// reports may be split across multiple packets) and this method's future
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/// is dropped after some packets have been read, the next call to `read()`
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/// will return a [`ReadError::SyncError()`]. The range in the sync error
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/// indicates the portion `buf` that was filled by the current call to
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/// `read()`. If the dropped future used the same `buf`, then `buf` will
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/// contain the full report.
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pub async fn read(&mut self, buf: &mut [u8]) -> Result<usize, ReadError> {
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assert!(N != 0);
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assert!(buf.len() >= N);
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// Read packets from the endpoint
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let max_packet_size = usize::from(self.ep_out.info().max_packet_size);
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let starting_offset = self.offset.load(Ordering::Acquire);
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let mut total = starting_offset;
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loop {
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for chunk in buf[starting_offset..N].chunks_mut(max_packet_size) {
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match self.ep_out.read(chunk).await {
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Ok(size) => {
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total += size;
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if size < max_packet_size || total == N {
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self.offset.store(0, Ordering::Release);
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break;
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} else {
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self.offset.store(total, Ordering::Release);
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}
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}
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Err(err) => {
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self.offset.store(0, Ordering::Release);
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return Err(err.into());
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}
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}
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}
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// Some hosts may send ZLPs even when not required by the HID spec, so we'll loop as long as total == 0.
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if total > 0 {
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break;
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}
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}
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if starting_offset > 0 {
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Err(ReadError::Sync(starting_offset..total))
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} else {
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Ok(total)
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}
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}
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}
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pub trait RequestHandler {
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/// Reads the value of report `id` into `buf` returning the size.
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///
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/// Returns `None` if `id` is invalid or no data is available.
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fn get_report(&self, id: ReportId, buf: &mut [u8]) -> Option<usize> {
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let _ = (id, buf);
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None
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}
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/// Sets the value of report `id` to `data`.
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fn set_report(&self, id: ReportId, data: &[u8]) -> OutResponse {
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let _ = (id, data);
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OutResponse::Rejected
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}
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/// Get the idle rate for `id`.
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///
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/// If `id` is `None`, get the idle rate for all reports. Returning `None`
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/// will reject the control request. Any duration at or above 1.024 seconds
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/// or below 4ms will be returned as an indefinite idle rate.
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fn get_idle(&self, id: Option<ReportId>) -> Option<Duration> {
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let _ = id;
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None
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}
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/// Set the idle rate for `id` to `dur`.
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///
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/// If `id` is `None`, set the idle rate of all input reports to `dur`. If
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/// an indefinite duration is requested, `dur` will be set to `Duration::MAX`.
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fn set_idle(&self, id: Option<ReportId>, dur: Duration) {
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let _ = (id, dur);
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}
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}
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struct Control<'d> {
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report_descriptor: &'d [u8],
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request_handler: Option<&'d dyn RequestHandler>,
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out_report_offset: &'d AtomicUsize,
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hid_descriptor: [u8; 9],
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}
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impl<'d> Control<'d> {
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fn new(
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report_descriptor: &'d [u8],
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request_handler: Option<&'d dyn RequestHandler>,
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out_report_offset: &'d AtomicUsize,
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) -> Self {
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Control {
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report_descriptor,
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request_handler,
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out_report_offset,
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hid_descriptor: [
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// Length of buf inclusive of size prefix
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9,
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// Descriptor type
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HID_DESC_DESCTYPE_HID,
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// HID Class spec version
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HID_DESC_SPEC_1_10[0],
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HID_DESC_SPEC_1_10[1],
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// Country code not supported
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HID_DESC_COUNTRY_UNSPEC,
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// Number of following descriptors
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1,
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// We have a HID report descriptor the host should read
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HID_DESC_DESCTYPE_HID_REPORT,
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// HID report descriptor size,
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(report_descriptor.len() & 0xFF) as u8,
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(report_descriptor.len() >> 8 & 0xFF) as u8,
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],
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}
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}
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}
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impl<'d> ControlHandler for Control<'d> {
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fn reset(&mut self) {
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self.out_report_offset.store(0, Ordering::Release);
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}
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fn control_out(&mut self, req: embassy_usb::control::Request, data: &[u8]) -> OutResponse {
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trace!("HID control_out {:?} {=[u8]:x}", req, data);
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if let RequestType::Class = req.request_type {
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match req.request {
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HID_REQ_SET_IDLE => {
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if let Some(handler) = self.request_handler {
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let id = req.value as u8;
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let id = (id != 0).then(|| ReportId::In(id));
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let dur = u64::from(req.value >> 8);
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let dur = if dur == 0 {
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Duration::MAX
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} else {
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Duration::from_millis(4 * dur)
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};
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handler.set_idle(id, dur);
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}
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OutResponse::Accepted
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}
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HID_REQ_SET_REPORT => match (ReportId::try_from(req.value), self.request_handler) {
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(Ok(id), Some(handler)) => handler.set_report(id, data),
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_ => OutResponse::Rejected,
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},
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HID_REQ_SET_PROTOCOL => {
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if req.value == 1 {
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OutResponse::Accepted
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} else {
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warn!("HID Boot Protocol is unsupported.");
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OutResponse::Rejected // UNSUPPORTED: Boot Protocol
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}
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}
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_ => OutResponse::Rejected,
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}
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} else {
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OutResponse::Rejected // UNSUPPORTED: SET_DESCRIPTOR
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}
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}
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fn control_in<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
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trace!("HID control_in {:?}", req);
|
|
match (req.request_type, req.request) {
|
|
(RequestType::Standard, Request::GET_DESCRIPTOR) => match (req.value >> 8) as u8 {
|
|
HID_DESC_DESCTYPE_HID_REPORT => InResponse::Accepted(self.report_descriptor),
|
|
HID_DESC_DESCTYPE_HID => InResponse::Accepted(&self.hid_descriptor),
|
|
_ => InResponse::Rejected,
|
|
},
|
|
(RequestType::Class, HID_REQ_GET_REPORT) => {
|
|
let size = match ReportId::try_from(req.value) {
|
|
Ok(id) => self.request_handler.and_then(|x| x.get_report(id, buf)),
|
|
Err(_) => None,
|
|
};
|
|
|
|
if let Some(size) = size {
|
|
InResponse::Accepted(&buf[0..size])
|
|
} else {
|
|
InResponse::Rejected
|
|
}
|
|
}
|
|
(RequestType::Class, 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));
|
|
if let Some(dur) = handler.get_idle(id) {
|
|
let dur = u8::try_from(dur.as_millis() / 4).unwrap_or(0);
|
|
buf[0] = dur;
|
|
InResponse::Accepted(&buf[0..1])
|
|
} else {
|
|
InResponse::Rejected
|
|
}
|
|
} else {
|
|
InResponse::Rejected
|
|
}
|
|
}
|
|
(RequestType::Class, HID_REQ_GET_PROTOCOL) => {
|
|
// UNSUPPORTED: Boot Protocol
|
|
buf[0] = 1;
|
|
InResponse::Accepted(&buf[0..1])
|
|
}
|
|
_ => InResponse::Rejected,
|
|
}
|
|
}
|
|
}
|