usb: gadget: add 'quirk_altset_not_supp' to usb_gadget

Due to some UDC controllers may not support altsettings, usb gadget layer
needs to provide a generic way to inform gadget functions about non-standard
hardware limitations.

This patch adds 'quirk_altset_not_supp' field to struct usb_gadget and helper
function gadget_is_altset_supported(). It also sets 'quirk_altset_not_supp'
to 1 in pxa25x_udc and pxa27x_udc drivers, which have such limitation.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc/pxa25x_udc.c

@@ -1176,6 +1176,7 @@ static void udc_reinit(struct pxa25x_udc *dev)
 	INIT_LIST_HEAD (&dev->gadget.ep_list);
 	INIT_LIST_HEAD (&dev->gadget.ep0->ep_list);
 	dev->ep0state = EP0_IDLE;
+	dev->gadget.quirk_altset_not_supp = 1;
 
 	/* basic endpoint records init */
 	for (i = 0; i < PXA_UDC_NUM_ENDPOINTS; i++) {

drivers/usb/gadget/udc/pxa27x_udc.c

@@ -1710,6 +1710,7 @@ static void udc_init_data(struct pxa_udc *dev)
 	INIT_LIST_HEAD(&dev->gadget.ep_list);
 	INIT_LIST_HEAD(&dev->gadget.ep0->ep_list);
 	dev->udc_usb_ep[0].pxa_ep = &dev->pxa_ep[0];
+	dev->gadget.quirk_altset_not_supp = 1;
 	ep0_idle(dev);
 
 	/* PXA endpoints init */

include/linux/usb/gadget.h

@@ -572,6 +572,7 @@ struct usb_gadget {
 	unsigned			a_hnp_support:1;
 	unsigned			a_alt_hnp_support:1;
 	unsigned			quirk_ep_out_aligned_size:1;
+	unsigned			quirk_altset_not_supp:1;
 	unsigned			is_selfpowered:1;
 	unsigned			deactivated:1;
 	unsigned			connected:1;
@@ -609,6 +610,16 @@ usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
 			round_up(len, (size_t)ep->desc->wMaxPacketSize);
 }
 
+/**
+ * gadget_is_altset_supported - return true iff the hardware supports
+ *	altsettings
+ * @g: controller to check for quirk
+ */
+static inline int gadget_is_altset_supported(struct usb_gadget *g)
+{
+	return !g->quirk_altset_not_supp;
+}
+
 /**
  * gadget_is_dualspeed - return true iff the hardware handles high speed
  * @g: controller that might support both high and full speeds