machine: add USBDevice.Attach and USBDevice.Detach

src/machine/machine_atsamd21_usb.go

@@ -68,6 +68,20 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	dev.initcomplete = true
 }
 
+// Attach connects the device to the USB bus, allowing the host to detect and
+// enumerate it. It can be used together with Detach to delay enumeration
+// until the USB configuration (device identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	sam.USB_DEVICE.CTRLB.ClearBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
+// Detach disconnects the device from the USB bus. To the host this appears
+// as if the device was unplugged. A subsequent Attach makes the host
+// enumerate the device again.
+func (dev *USBDevice) Detach() {
+	sam.USB_DEVICE.CTRLB.SetBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
 func handlePadCalibration() {
 	// Load Pad Calibration data from non-volatile memory
 	// This requires registers that are not included in the SVD file.

src/machine/machine_atsamd51_usb.go

@@ -71,6 +71,20 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	dev.initcomplete = true
 }
 
+// Attach connects the device to the USB bus, allowing the host to detect and
+// enumerate it. It can be used together with Detach to delay enumeration
+// until the USB configuration (device identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	sam.USB_DEVICE.CTRLB.ClearBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
+// Detach disconnects the device from the USB bus. To the host this appears
+// as if the device was unplugged. A subsequent Attach makes the host
+// enumerate the device again.
+func (dev *USBDevice) Detach() {
+	sam.USB_DEVICE.CTRLB.SetBits(sam.USB_DEVICE_CTRLB_DETACH)
+}
+
 func handlePadCalibration() {
 	// Load Pad Calibration data from non-volatile memory
 	// This requires registers that are not included in the SVD file.

src/machine/machine_nrf52840_usb.go

@@ -89,6 +89,21 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	dev.initcomplete = true
 }
 
+// Attach connects the device to the USB bus by enabling the DP pull-up,
+// allowing the host to detect and enumerate it. It can be used together with
+// Detach to delay enumeration until the USB configuration (device
+// identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	nrf.USBD.USBPULLUP.Set(1)
+}
+
+// Detach disconnects the device from the USB bus by disabling the DP pull-up.
+// To the host this appears as if the device was unplugged. A subsequent
+// Attach makes the host enumerate the device again.
+func (dev *USBDevice) Detach() {
+	nrf.USBD.USBPULLUP.Set(0)
+}
+
 func handleUSBIRQ(interrupt.Interrupt) {
 	if nrf.USBD.EVENTS_SOF.Get() == 1 {
 		nrf.USBD.EVENTS_SOF.Set(0)

src/machine/machine_rp2040_usb.go

@@ -46,6 +46,21 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	rp.USBCTRL_REGS.SIE_CTRL.SetBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
 }
 
+// Attach connects the device to the USB bus by enabling the DP pull-up,
+// allowing the host to detect and enumerate it. It can be used together with
+// Detach to delay enumeration until the USB configuration (device
+// identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	rp.USBCTRL_REGS.SIE_CTRL.SetBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
+}
+
+// Detach disconnects the device from the USB bus by disabling the DP pull-up.
+// To the host this appears as if the device was unplugged. A subsequent
+// Attach makes the host enumerate the device again.
+func (dev *USBDevice) Detach() {
+	rp.USBCTRL_REGS.SIE_CTRL.ClearBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
+}
+
 func handleUSBIRQ(intr interrupt.Interrupt) {
 	status := rp.USBCTRL_REGS.INTS.Get()
 

src/machine/machine_rp2350_usb.go

@@ -49,6 +49,21 @@ func (dev *USBDevice) Configure(config UARTConfig) {
 	rp.USB.SetMAIN_CTRL_PHY_ISO(0x0)
 }
 
+// Attach connects the device to the USB bus by enabling the DP pull-up,
+// allowing the host to detect and enumerate it. It can be used together with
+// Detach to delay enumeration until the USB configuration (device
+// identifiers, classes, ...) is complete.
+func (dev *USBDevice) Attach() {
+	rp.USB.SIE_CTRL.SetBits(rp.USB_SIE_CTRL_PULLUP_EN)
+}
+
+// Detach disconnects the device from the USB bus by disabling the DP pull-up.
+// To the host this appears as if the device was unplugged. A subsequent
+// Attach makes the host enumerate the device again.
+func (dev *USBDevice) Detach() {
+	rp.USB.SIE_CTRL.ClearBits(rp.USB_SIE_CTRL_PULLUP_EN)
+}
+
 func handleUSBIRQ(intr interrupt.Interrupt) {
 	status := rp.USB.INTS.Get()