usb: gadget: move gadget API functions to udc-core

instead of defining all functions as static inlines,
let's move them to udc-core and export them with
EXPORT_SYMBOL_GPL, that way we can make sure that
only GPL drivers will use them.

As a side effect, it'll be nicer to add tracepoints
to the gadget API.

While at that, also fix Kconfig dependencies to
avoid randconfig build failures.
Acked-By: NSebastian Reichel <sre@kernel.org>
Acked-by: NPeter Chen <peter.chen@nxp.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/phy/Kconfig

@@ -176,6 +176,7 @@ config TWL4030_USB
 	tristate "TWL4030 USB Transceiver Driver"
 	depends on TWL4030_CORE && REGULATOR_TWL4030 && USB_MUSB_OMAP2PLUS
 	depends on USB_SUPPORT
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't 'y'
 	select GENERIC_PHY
 	select USB_PHY
 	help

drivers/power/Kconfig

@@ -309,6 +309,7 @@ config BATTERY_RX51
 config CHARGER_ISP1704
 	tristate "ISP1704 USB Charger Detection"
 	depends on USB_PHY
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	help
 	  Say Y to enable support for USB Charger Detection with
 	  ISP1707/ISP1704 USB transceivers.

drivers/usb/gadget/udc/udc-core.c

@@ -59,6 +59,579 @@ static int udc_bind_to_driver(struct usb_udc *udc,
 
 /* ------------------------------------------------------------------------- */
 
+/**
+ * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
+ * @ep:the endpoint being configured
+ * @maxpacket_limit:value of maximum packet size limit
+ *
+ * This function should be used only in UDC drivers to initialize endpoint
+ * (usually in probe function).
+ */
+void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
+					      unsigned maxpacket_limit)
+{
+	ep->maxpacket_limit = maxpacket_limit;
+	ep->maxpacket = maxpacket_limit;
+}
+EXPORT_SYMBOL_GPL(usb_ep_set_maxpacket_limit);
+
+/**
+ * usb_ep_enable - configure endpoint, making it usable
+ * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
+ *	drivers discover endpoints through the ep_list of a usb_gadget.
+ *
+ * When configurations are set, or when interface settings change, the driver
+ * will enable or disable the relevant endpoints.  while it is enabled, an
+ * endpoint may be used for i/o until the driver receives a disconnect() from
+ * the host or until the endpoint is disabled.
+ *
+ * the ep0 implementation (which calls this routine) must ensure that the
+ * hardware capabilities of each endpoint match the descriptor provided
+ * for it.  for example, an endpoint named "ep2in-bulk" would be usable
+ * for interrupt transfers as well as bulk, but it likely couldn't be used
+ * for iso transfers or for endpoint 14.  some endpoints are fully
+ * configurable, with more generic names like "ep-a".  (remember that for
+ * USB, "in" means "towards the USB master".)
+ *
+ * returns zero, or a negative error code.
+ */
+int usb_ep_enable(struct usb_ep *ep)
+{
+	int ret;
+
+	if (ep->enabled)
+		return 0;
+
+	ret = ep->ops->enable(ep, ep->desc);
+	if (ret)
+		return ret;
+
+	ep->enabled = true;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_ep_enable);
+
+/**
+ * usb_ep_disable - endpoint is no longer usable
+ * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
+ *
+ * no other task may be using this endpoint when this is called.
+ * any pending and uncompleted requests will complete with status
+ * indicating disconnect (-ESHUTDOWN) before this call returns.
+ * gadget drivers must call usb_ep_enable() again before queueing
+ * requests to the endpoint.
+ *
+ * returns zero, or a negative error code.
+ */
+int usb_ep_disable(struct usb_ep *ep)
+{
+	int ret;
+
+	if (!ep->enabled)
+		return 0;
+
+	ret = ep->ops->disable(ep);
+	if (ret)
+		return ret;
+
+	ep->enabled = false;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_ep_disable);
+
+/**
+ * usb_ep_alloc_request - allocate a request object to use with this endpoint
+ * @ep:the endpoint to be used with with the request
+ * @gfp_flags:GFP_* flags to use
+ *
+ * Request objects must be allocated with this call, since they normally
+ * need controller-specific setup and may even need endpoint-specific
+ * resources such as allocation of DMA descriptors.
+ * Requests may be submitted with usb_ep_queue(), and receive a single
+ * completion callback.  Free requests with usb_ep_free_request(), when
+ * they are no longer needed.
+ *
+ * Returns the request, or null if one could not be allocated.
+ */
+struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
+						       gfp_t gfp_flags)
+{
+	return ep->ops->alloc_request(ep, gfp_flags);
+}
+EXPORT_SYMBOL_GPL(usb_ep_alloc_request);
+
+/**
+ * usb_ep_free_request - frees a request object
+ * @ep:the endpoint associated with the request
+ * @req:the request being freed
+ *
+ * Reverses the effect of usb_ep_alloc_request().
+ * Caller guarantees the request is not queued, and that it will
+ * no longer be requeued (or otherwise used).
+ */
+void usb_ep_free_request(struct usb_ep *ep,
+				       struct usb_request *req)
+{
+	ep->ops->free_request(ep, req);
+}
+EXPORT_SYMBOL_GPL(usb_ep_free_request);
+
+/**
+ * usb_ep_queue - queues (submits) an I/O request to an endpoint.
+ * @ep:the endpoint associated with the request
+ * @req:the request being submitted
+ * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
+ *	pre-allocate all necessary memory with the request.
+ *
+ * This tells the device controller to perform the specified request through
+ * that endpoint (reading or writing a buffer).  When the request completes,
+ * including being canceled by usb_ep_dequeue(), the request's completion
+ * routine is called to return the request to the driver.  Any endpoint
+ * (except control endpoints like ep0) may have more than one transfer
+ * request queued; they complete in FIFO order.  Once a gadget driver
+ * submits a request, that request may not be examined or modified until it
+ * is given back to that driver through the completion callback.
+ *
+ * Each request is turned into one or more packets.  The controller driver
+ * never merges adjacent requests into the same packet.  OUT transfers
+ * will sometimes use data that's already buffered in the hardware.
+ * Drivers can rely on the fact that the first byte of the request's buffer
+ * always corresponds to the first byte of some USB packet, for both
+ * IN and OUT transfers.
+ *
+ * Bulk endpoints can queue any amount of data; the transfer is packetized
+ * automatically.  The last packet will be short if the request doesn't fill it
+ * out completely.  Zero length packets (ZLPs) should be avoided in portable
+ * protocols since not all usb hardware can successfully handle zero length
+ * packets.  (ZLPs may be explicitly written, and may be implicitly written if
+ * the request 'zero' flag is set.)  Bulk endpoints may also be used
+ * for interrupt transfers; but the reverse is not true, and some endpoints
+ * won't support every interrupt transfer.  (Such as 768 byte packets.)
+ *
+ * Interrupt-only endpoints are less functional than bulk endpoints, for
+ * example by not supporting queueing or not handling buffers that are
+ * larger than the endpoint's maxpacket size.  They may also treat data
+ * toggle differently.
+ *
+ * Control endpoints ... after getting a setup() callback, the driver queues
+ * one response (even if it would be zero length).  That enables the
+ * status ack, after transferring data as specified in the response.  Setup
+ * functions may return negative error codes to generate protocol stalls.
+ * (Note that some USB device controllers disallow protocol stall responses
+ * in some cases.)  When control responses are deferred (the response is
+ * written after the setup callback returns), then usb_ep_set_halt() may be
+ * used on ep0 to trigger protocol stalls.  Depending on the controller,
+ * it may not be possible to trigger a status-stage protocol stall when the
+ * data stage is over, that is, from within the response's completion
+ * routine.
+ *
+ * For periodic endpoints, like interrupt or isochronous ones, the usb host
+ * arranges to poll once per interval, and the gadget driver usually will
+ * have queued some data to transfer at that time.
+ *
+ * Returns zero, or a negative error code.  Endpoints that are not enabled
+ * report errors; errors will also be
+ * reported when the usb peripheral is disconnected.
+ */
+int usb_ep_queue(struct usb_ep *ep,
+			       struct usb_request *req, gfp_t gfp_flags)
+{
+	if (WARN_ON_ONCE(!ep->enabled && ep->address))
+		return -ESHUTDOWN;
+
+	return ep->ops->queue(ep, req, gfp_flags);
+}
+EXPORT_SYMBOL_GPL(usb_ep_queue);
+
+/**
+ * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
+ * @ep:the endpoint associated with the request
+ * @req:the request being canceled
+ *
+ * If the request is still active on the endpoint, it is dequeued and its
+ * completion routine is called (with status -ECONNRESET); else a negative
+ * error code is returned. This is guaranteed to happen before the call to
+ * usb_ep_dequeue() returns.
+ *
+ * Note that some hardware can't clear out write fifos (to unlink the request
+ * at the head of the queue) except as part of disconnecting from usb. Such
+ * restrictions prevent drivers from supporting configuration changes,
+ * even to configuration zero (a "chapter 9" requirement).
+ */
+int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
+{
+	return ep->ops->dequeue(ep, req);
+}
+EXPORT_SYMBOL_GPL(usb_ep_dequeue);
+
+/**
+ * usb_ep_set_halt - sets the endpoint halt feature.
+ * @ep: the non-isochronous endpoint being stalled
+ *
+ * Use this to stall an endpoint, perhaps as an error report.
+ * Except for control endpoints,
+ * the endpoint stays halted (will not stream any data) until the host
+ * clears this feature; drivers may need to empty the endpoint's request
+ * queue first, to make sure no inappropriate transfers happen.
+ *
+ * Note that while an endpoint CLEAR_FEATURE will be invisible to the
+ * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
+ * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
+ * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
+ *
+ * Returns zero, or a negative error code.  On success, this call sets
+ * underlying hardware state that blocks data transfers.
+ * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
+ * transfer requests are still queued, or if the controller hardware
+ * (usually a FIFO) still holds bytes that the host hasn't collected.
+ */
+int usb_ep_set_halt(struct usb_ep *ep)
+{
+	return ep->ops->set_halt(ep, 1);
+}
+EXPORT_SYMBOL_GPL(usb_ep_set_halt);
+
+/**
+ * usb_ep_clear_halt - clears endpoint halt, and resets toggle
+ * @ep:the bulk or interrupt endpoint being reset
+ *
+ * Use this when responding to the standard usb "set interface" request,
+ * for endpoints that aren't reconfigured, after clearing any other state
+ * in the endpoint's i/o queue.
+ *
+ * Returns zero, or a negative error code.  On success, this call clears
+ * the underlying hardware state reflecting endpoint halt and data toggle.
+ * Note that some hardware can't support this request (like pxa2xx_udc),
+ * and accordingly can't correctly implement interface altsettings.
+ */
+int usb_ep_clear_halt(struct usb_ep *ep)
+{
+	return ep->ops->set_halt(ep, 0);
+}
+EXPORT_SYMBOL_GPL(usb_ep_clear_halt);
+
+/**
+ * usb_ep_set_wedge - sets the halt feature and ignores clear requests
+ * @ep: the endpoint being wedged
+ *
+ * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
+ * requests. If the gadget driver clears the halt status, it will
+ * automatically unwedge the endpoint.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_ep_set_wedge(struct usb_ep *ep)
+{
+	if (ep->ops->set_wedge)
+		return ep->ops->set_wedge(ep);
+	else
+		return ep->ops->set_halt(ep, 1);
+}
+EXPORT_SYMBOL_GPL(usb_ep_set_wedge);
+
+/**
+ * usb_ep_fifo_status - returns number of bytes in fifo, or error
+ * @ep: the endpoint whose fifo status is being checked.
+ *
+ * FIFO endpoints may have "unclaimed data" in them in certain cases,
+ * such as after aborted transfers.  Hosts may not have collected all
+ * the IN data written by the gadget driver (and reported by a request
+ * completion).  The gadget driver may not have collected all the data
+ * written OUT to it by the host.  Drivers that need precise handling for
+ * fault reporting or recovery may need to use this call.
+ *
+ * This returns the number of such bytes in the fifo, or a negative
+ * errno if the endpoint doesn't use a FIFO or doesn't support such
+ * precise handling.
+ */
+int usb_ep_fifo_status(struct usb_ep *ep)
+{
+	if (ep->ops->fifo_status)
+		return ep->ops->fifo_status(ep);
+	else
+		return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(usb_ep_fifo_status);
+
+/**
+ * usb_ep_fifo_flush - flushes contents of a fifo
+ * @ep: the endpoint whose fifo is being flushed.
+ *
+ * This call may be used to flush the "unclaimed data" that may exist in
+ * an endpoint fifo after abnormal transaction terminations.  The call
+ * must never be used except when endpoint is not being used for any
+ * protocol translation.
+ */
+void usb_ep_fifo_flush(struct usb_ep *ep)
+{
+	if (ep->ops->fifo_flush)
+		ep->ops->fifo_flush(ep);
+}
+EXPORT_SYMBOL_GPL(usb_ep_fifo_flush);
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * usb_gadget_frame_number - returns the current frame number
+ * @gadget: controller that reports the frame number
+ *
+ * Returns the usb frame number, normally eleven bits from a SOF packet,
+ * or negative errno if this device doesn't support this capability.
+ */
+int usb_gadget_frame_number(struct usb_gadget *gadget)
+{
+	return gadget->ops->get_frame(gadget);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_frame_number);
+
+/**
+ * usb_gadget_wakeup - tries to wake up the host connected to this gadget
+ * @gadget: controller used to wake up the host
+ *
+ * Returns zero on success, else negative error code if the hardware
+ * doesn't support such attempts, or its support has not been enabled
+ * by the usb host.  Drivers must return device descriptors that report
+ * their ability to support this, or hosts won't enable it.
+ *
+ * This may also try to use SRP to wake the host and start enumeration,
+ * even if OTG isn't otherwise in use.  OTG devices may also start
+ * remote wakeup even when hosts don't explicitly enable it.
+ */
+int usb_gadget_wakeup(struct usb_gadget *gadget)
+{
+	if (!gadget->ops->wakeup)
+		return -EOPNOTSUPP;
+	return gadget->ops->wakeup(gadget);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_wakeup);
+
+/**
+ * usb_gadget_set_selfpowered - sets the device selfpowered feature.
+ * @gadget:the device being declared as self-powered
+ *
+ * this affects the device status reported by the hardware driver
+ * to reflect that it now has a local power supply.
+ *
+ * returns zero on success, else negative errno.
+ */
+int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
+{
+	if (!gadget->ops->set_selfpowered)
+		return -EOPNOTSUPP;
+	return gadget->ops->set_selfpowered(gadget, 1);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_set_selfpowered);
+
+/**
+ * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
+ * @gadget:the device being declared as bus-powered
+ *
+ * this affects the device status reported by the hardware driver.
+ * some hardware may not support bus-powered operation, in which
+ * case this feature's value can never change.
+ *
+ * returns zero on success, else negative errno.
+ */
+int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
+{
+	if (!gadget->ops->set_selfpowered)
+		return -EOPNOTSUPP;
+	return gadget->ops->set_selfpowered(gadget, 0);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_clear_selfpowered);
+
+/**
+ * usb_gadget_vbus_connect - Notify controller that VBUS is powered
+ * @gadget:The device which now has VBUS power.
+ * Context: can sleep
+ *
+ * This call is used by a driver for an external transceiver (or GPIO)
+ * that detects a VBUS power session starting.  Common responses include
+ * resuming the controller, activating the D+ (or D-) pullup to let the
+ * host detect that a USB device is attached, and starting to draw power
+ * (8mA or possibly more, especially after SET_CONFIGURATION).
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_vbus_connect(struct usb_gadget *gadget)
+{
+	if (!gadget->ops->vbus_session)
+		return -EOPNOTSUPP;
+	return gadget->ops->vbus_session(gadget, 1);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_vbus_connect);
+
+/**
+ * usb_gadget_vbus_draw - constrain controller's VBUS power usage
+ * @gadget:The device whose VBUS usage is being described
+ * @mA:How much current to draw, in milliAmperes.  This should be twice
+ *	the value listed in the configuration descriptor bMaxPower field.
+ *
+ * This call is used by gadget drivers during SET_CONFIGURATION calls,
+ * reporting how much power the device may consume.  For example, this
+ * could affect how quickly batteries are recharged.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
+{
+	if (!gadget->ops->vbus_draw)
+		return -EOPNOTSUPP;
+	return gadget->ops->vbus_draw(gadget, mA);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_vbus_draw);
+
+/**
+ * usb_gadget_vbus_disconnect - notify controller about VBUS session end
+ * @gadget:the device whose VBUS supply is being described
+ * Context: can sleep
+ *
+ * This call is used by a driver for an external transceiver (or GPIO)
+ * that detects a VBUS power session ending.  Common responses include
+ * reversing everything done in usb_gadget_vbus_connect().
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
+{
+	if (!gadget->ops->vbus_session)
+		return -EOPNOTSUPP;
+	return gadget->ops->vbus_session(gadget, 0);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_vbus_disconnect);
+
+/**
+ * usb_gadget_connect - software-controlled connect to USB host
+ * @gadget:the peripheral being connected
+ *
+ * Enables the D+ (or potentially D-) pullup.  The host will start
+ * enumerating this gadget when the pullup is active and a VBUS session
+ * is active (the link is powered).  This pullup is always enabled unless
+ * usb_gadget_disconnect() has been used to disable it.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_connect(struct usb_gadget *gadget)
+{
+	int ret;
+
+	if (!gadget->ops->pullup)
+		return -EOPNOTSUPP;
+
+	if (gadget->deactivated) {
+		/*
+		 * If gadget is deactivated we only save new state.
+		 * Gadget will be connected automatically after activation.
+		 */
+		gadget->connected = true;
+		return 0;
+	}
+
+	ret = gadget->ops->pullup(gadget, 1);
+	if (!ret)
+		gadget->connected = 1;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_connect);
+
+/**
+ * usb_gadget_disconnect - software-controlled disconnect from USB host
+ * @gadget:the peripheral being disconnected
+ *
+ * Disables the D+ (or potentially D-) pullup, which the host may see
+ * as a disconnect (when a VBUS session is active).  Not all systems
+ * support software pullup controls.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_disconnect(struct usb_gadget *gadget)
+{
+	int ret;
+
+	if (!gadget->ops->pullup)
+		return -EOPNOTSUPP;
+
+	if (gadget->deactivated) {
+		/*
+		 * If gadget is deactivated we only save new state.
+		 * Gadget will stay disconnected after activation.
+		 */
+		gadget->connected = false;
+		return 0;
+	}
+
+	ret = gadget->ops->pullup(gadget, 0);
+	if (!ret)
+		gadget->connected = 0;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_disconnect);
+
+/**
+ * usb_gadget_deactivate - deactivate function which is not ready to work
+ * @gadget: the peripheral being deactivated
+ *
+ * This routine may be used during the gadget driver bind() call to prevent
+ * the peripheral from ever being visible to the USB host, unless later
+ * usb_gadget_activate() is called.  For example, user mode components may
+ * need to be activated before the system can talk to hosts.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_deactivate(struct usb_gadget *gadget)
+{
+	int ret;
+
+	if (gadget->deactivated)
+		return 0;
+
+	if (gadget->connected) {
+		ret = usb_gadget_disconnect(gadget);
+		if (ret)
+			return ret;
+		/*
+		 * If gadget was being connected before deactivation, we want
+		 * to reconnect it in usb_gadget_activate().
+		 */
+		gadget->connected = true;
+	}
+	gadget->deactivated = true;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_deactivate);
+
+/**
+ * usb_gadget_activate - activate function which is not ready to work
+ * @gadget: the peripheral being activated
+ *
+ * This routine activates gadget which was previously deactivated with
+ * usb_gadget_deactivate() call. It calls usb_gadget_connect() if needed.
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_activate(struct usb_gadget *gadget)
+{
+	if (!gadget->deactivated)
+		return 0;
+
+	gadget->deactivated = false;
+
+	/*
+	 * If gadget has been connected before deactivation, or became connected
+	 * while it was being deactivated, we call usb_gadget_connect().
+	 */
+	if (gadget->connected)
+		return usb_gadget_connect(gadget);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_activate);
+
+/* ------------------------------------------------------------------------- */
+
 #ifdef	CONFIG_HAS_DMA
 
 int usb_gadget_map_request_by_dev(struct device *dev,

drivers/usb/host/Kconfig

@@ -180,7 +180,7 @@ config USB_EHCI_MXC
 config USB_EHCI_HCD_OMAP
 	tristate "EHCI support for OMAP3 and later chips"
 	depends on ARCH_OMAP
-	select NOP_USB_XCEIV
+	depends on NOP_USB_XCEIV
 	default y
 	---help---
 	  Enables support for the on-chip EHCI controller on

drivers/usb/phy/Kconfig

@@ -21,6 +21,7 @@ config AB8500_USB
 config FSL_USB2_OTG
 	bool "Freescale USB OTG Transceiver Driver"
 	depends on USB_EHCI_FSL && USB_FSL_USB2 && USB_OTG_FSM && PM
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	select USB_PHY
 	help
 	  Enable this to support Freescale USB OTG transceiver.
@@ -29,6 +30,7 @@ config ISP1301_OMAP
 	tristate "Philips ISP1301 with OMAP OTG"
 	depends on I2C && ARCH_OMAP_OTG
 	depends on USB
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	select USB_PHY
 	help
 	  If you say yes here you get support for the Philips ISP1301
@@ -43,7 +45,7 @@ config ISP1301_OMAP
 config KEYSTONE_USB_PHY
 	tristate "Keystone USB PHY Driver"
 	depends on ARCH_KEYSTONE || COMPILE_TEST
-	select NOP_USB_XCEIV
+	depends on NOP_USB_XCEIV
 	help
 	  Enable this to support Keystone USB phy. This driver provides
 	  interface to interact with USB 2.0 and USB 3.0 PHY that is part
@@ -51,6 +53,7 @@ config KEYSTONE_USB_PHY
 
 config NOP_USB_XCEIV
 	tristate "NOP USB Transceiver Driver"
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, NOP can't be built-in
 	select USB_PHY
 	help
 	  This driver is to be used by all the usb transceiver which are either
@@ -63,9 +66,9 @@ config AM335X_CONTROL_USB
 config AM335X_PHY_USB
 	tristate "AM335x USB PHY Driver"
 	depends on ARM || COMPILE_TEST
+	depends on NOP_USB_XCEIV
 	select USB_PHY
 	select AM335X_CONTROL_USB
-	select NOP_USB_XCEIV
 	select USB_COMMON
 	help
 	  This driver provides PHY support for that phy which part for the
@@ -92,6 +95,7 @@ config TWL6030_USB
 config USB_GPIO_VBUS
 	tristate "GPIO based peripheral-only VBUS sensing 'transceiver'"
 	depends on GPIOLIB || COMPILE_TEST
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	select USB_PHY
 	help
 	  Provides simple GPIO VBUS sensing for controllers with an
@@ -112,6 +116,7 @@ config OMAP_OTG
 config TAHVO_USB
 	tristate "Tahvo USB transceiver driver"
 	depends on MFD_RETU && EXTCON
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	select USB_PHY
 	help
 	  Enable this to support USB transceiver on Tahvo. This is used
@@ -140,6 +145,7 @@ config USB_ISP1301
 config USB_MSM_OTG
 	tristate "Qualcomm on-chip USB OTG controller support"
 	depends on (USB || USB_GADGET) && (ARCH_QCOM || COMPILE_TEST)
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	depends on RESET_CONTROLLER
 	depends on EXTCON
 	select USB_PHY
@@ -169,6 +175,7 @@ config USB_QCOM_8X16_PHY
 config USB_MV_OTG
 	tristate "Marvell USB OTG support"
 	depends on USB_EHCI_MV && USB_MV_UDC && PM && USB_OTG
+	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
 	select USB_PHY
 	help
 	  Say Y here if you want to build Marvell USB OTG transciever