Update stm32 usb_raw example to use MSOS descriptors for WinUSB

examples/stm32f4/Cargo.toml

@@ -10,7 +10,7 @@ embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["
 embassy-sync = { version = "0.4.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.3.1", path = "../../embassy-executor", features = ["nightly", "arch-cortex-m", "executor-thread", "executor-interrupt", "defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.5", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "unstable-traits", "tick-hz-32_768"] }
-embassy-usb = { version = "0.1.0", path = "../../embassy-usb", features = ["defmt"] }
+embassy-usb = { version = "0.1.0", path = "../../embassy-usb", features = ["defmt", "msos-descriptor"] }
 embassy-net = { version = "0.2.0", path = "../../embassy-net", features = ["defmt", "tcp", "dhcpv4", "medium-ethernet", "nightly"] }
 
 defmt = "0.3"

examples/stm32f4/src/bin/usb_ethernet.rs

@@ -94,6 +94,7 @@ async fn main(spawner: Spawner) {
         &mut make_static!([0; 256])[..],
         &mut make_static!([0; 256])[..],
         &mut make_static!([0; 256])[..],
+        &mut [],
         &mut make_static!([0; 128])[..],
     );
 

examples/stm32f4/src/bin/usb_raw.rs

@@ -56,10 +56,16 @@ use embassy_stm32::time::Hertz;
 use embassy_stm32::usb_otg::Driver;
 use embassy_stm32::{bind_interrupts, peripherals, usb_otg, Config};
 use embassy_usb::control::{InResponse, OutResponse, Recipient, Request, RequestType};
+use embassy_usb::msos::{self, windows_version};
 use embassy_usb::types::InterfaceNumber;
 use embassy_usb::{Builder, Handler};
 use {defmt_rtt as _, panic_probe as _};
 
+// Randomly generated UUID because Windows requires you provide one to use WinUSB.
+// In principle WinUSB-using software could find this device (or a specific interface
+// on it) by its GUID instead of using the VID/PID, but in practice that seems unhelpful.
+const DEVICE_INTERFACE_GUIDS: &[&str] = &["{DAC2087C-63FA-458D-A55D-827C0762DEC7}"];
+
 bind_interrupts!(struct Irqs {
     OTG_FS => usb_otg::InterruptHandler<peripherals::USB_OTG_FS>;
 });
@@ -114,6 +120,7 @@ async fn main(_spawner: Spawner) {
     let mut device_descriptor = [0; 256];
     let mut config_descriptor = [0; 256];
     let mut bos_descriptor = [0; 256];
+    let mut msos_descriptor = [0; 256];
     let mut control_buf = [0; 64];
 
     let mut handler = ControlHandler {
@@ -126,9 +133,23 @@ async fn main(_spawner: Spawner) {
         &mut device_descriptor,
         &mut config_descriptor,
         &mut bos_descriptor,
+        &mut msos_descriptor,
         &mut control_buf,
     );
 
+    // Add the Microsoft OS Descriptor (MSOS/MOD) descriptor.
+    // We tell Windows that this entire device is compatible with the "WINUSB" feature,
+    // which causes it to use the built-in WinUSB driver automatically, which in turn
+    // can be used by libusb/rusb software without needing a custom driver or INF file.
+    // In principle you might want to call msos_feature() just on a specific function,
+    // if your device also has other functions that still use standard class drivers.
+    builder.msos_descriptor(windows_version::WIN8_1, 0);
+    builder.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
+    builder.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
+        "DeviceInterfaceGUIDs",
+        msos::PropertyData::RegMultiSz(DEVICE_INTERFACE_GUIDS),
+    ));
+
     // Add a vendor-specific function (class 0xFF), and corresponding interface,
     // that uses our custom handler.
     let mut function = builder.function(0xFF, 0, 0);

examples/stm32f4/src/bin/usb_serial.rs

@@ -77,6 +77,7 @@ async fn main(_spawner: Spawner) {
         &mut device_descriptor,
         &mut config_descriptor,
         &mut bos_descriptor,
+        &mut [],
         &mut control_buf,
     );