[PATCH v3 4/5] rust: usb: add a vendor-and-interface-info device id constructor

[Mike Lothian]

`USB_VENDOR_AND_INTERFACE_INFO` is the C macro a driver uses to bind to
a function rather than to a list of product IDs: one vendor, plus an
interface class, subclass and protocol, matching every product that
exposes it.

The existing constructors cover `USB_DEVICE_INFO` and
`USB_INTERFACE_INFO`, which between them can express "any device of this
class" or "any interface of this class from any vendor", but not the
combination -- and the combination is what a vendor-specific function
needs, because class `0xff` means nothing without the vendor beside it.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Mike Lothian <mike@xxxxxxxxxxxxxx>
---
 rust/kernel/usb.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index 782bae53584d..b2a0fb104ddf 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -307,6 +307,29 @@ pub const fn from_interface_info(class: u8, subclass: u8, protocol: u8) -> Self
         })
     }
 
+    /// Equivalent to C's `USB_VENDOR_AND_INTERFACE_INFO` macro.
+    ///
+    /// Matches every device from one vendor that exposes an interface of the given class,
+    /// subclass and protocol, whatever its product ID. This is how a driver binds to a *function*
+    /// rather than to a list of the products someone happened to test.
+    pub const fn from_vendor_and_interface_info(
+        vendor: u16,
+        class: u8,
+        subclass: u8,
+        protocol: u8,
+    ) -> Self {
+        Self(bindings::usb_device_id {
+            match_flags: (bindings::USB_DEVICE_ID_MATCH_VENDOR
+                | bindings::USB_DEVICE_ID_MATCH_INT_INFO) as u16,
+            idVendor: vendor,
+            bInterfaceClass: class,
+            bInterfaceSubClass: subclass,
+            bInterfaceProtocol: protocol,
+            // SAFETY: It is safe to use all zeroes for the other fields of `usb_device_id`.
+            ..unsafe { MaybeUninit::zeroed().assume_init() }
+        })
+    }
+
     /// Equivalent to C's `USB_DEVICE_INTERFACE_CLASS` macro.
     pub const fn from_device_interface_class(vendor: u16, product: u16, class: u8) -> Self {
         Self(bindings::usb_device_id {