From 5fe0ad185b111371d09d87052cdd40b86fb43ad1 Mon Sep 17 00:00:00 2001
From: Erik Henriksson <henriksson@google.com>
Date: Tue, 2 Feb 2021 23:20:03 +0100
Subject: [PATCH] Support enabling SOF interrupt in USB peripheral

---
 hal/src/samd21/usb/bus.rs | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/hal/src/samd21/usb/bus.rs b/hal/src/samd21/usb/bus.rs
index b2640ed3b59..8944e5069c1 100644
--- a/hal/src/samd21/usb/bus.rs
+++ b/hal/src/samd21/usb/bus.rs
@@ -716,6 +716,14 @@ impl Inner {
         usb.ctrlb.modify(|_, w| w.detach().clear_bit());
     }
 
+    fn sof_interrupt(&self, enable: bool) {
+        if enable {
+            self.usb().intenset.write(|w| w.sof().set_bit());
+        } else {
+            self.usb().intenset.write(|w| w.sof().clear_bit());
+        }
+    }
+
     /// Configures all endpoints based on prior calls to alloc_ep().
     fn flush_eps(&self, mode: FlushConfigMode) {
         for idx in 0..8 {
@@ -860,6 +868,10 @@ impl Inner {
 
         let intbits = self.usb().epintsmry.read().bits();
         if intbits == 0 {
+            if intflags.sof().bit() {
+                // clear start of frame interrupt
+                self.usb().intflag.write(|w| w.sof().set_bit());
+            }
             return PollResult::None;
         }
 
@@ -1003,6 +1015,16 @@ impl Inner {
     }
 }
 
+impl UsbBus {
+    fn enable_sof_interrupt(&self) {
+        disable_interrupts(|cs| self.inner.borrow(cs).borrow().sof_interrupt(true))
+    }
+
+    fn disable_sof_interrupt(&self) {
+        disable_interrupts(|cs| self.inner.borrow(cs).borrow().sof_interrupt(false))
+    }
+}
+
 impl usb_device::bus::UsbBus for UsbBus {
     fn enable(&mut self) {
         disable_interrupts(|cs| self.inner.borrow(cs).borrow_mut().enable())