usb: gadget: zero: Add support for interrupt EP

Interrupt endpoints behave quite similar to the bulk endpoints with the
difference that the endpoints expect data sending/reception request at
particular intervals till the whole data has not been transmitted.

The interrupt EP support is added to gadget zero. A new alternate setting (=2)
has been added. It has 2 interrupt endpoints. The default parameters are set as:
	bInterval: 1 ms for FS and 8 uFrames (implying 1 ms) for HS/SS
	wMaxPacketSize: 64 bytes for FS and 1024 bytes for HS/SS
However, the same can be overridden through the module parameter interface.

The code is tested for HS and SS on a platform having DWC3 controller.
Signed-off-by: Amit Virdi <amit.virdi@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_loopback.c

@@ -298,7 +298,8 @@ static void disable_loopback(struct f_loopback *loop)
 	struct usb_composite_dev	*cdev;
 
 	cdev = loop->function.config->cdev;
-	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
+	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL, NULL,
+			NULL);
 	VDBG(cdev, "%s disabled\n", loop->function.name);
 }
 

drivers/usb/gadget/function/f_sourcesink.c

@@ -23,6 +23,15 @@
 #include "gadget_chips.h"
 #include "u_f.h"
 
+#define USB_MS_TO_SS_INTERVAL(x) USB_MS_TO_HS_INTERVAL(x)
+
+enum eptype {
+	EP_CONTROL = 0,
+	EP_BULK,
+	EP_ISOC,
+	EP_INTERRUPT,
+};
+
 /*
  * SOURCE/SINK FUNCTION ... a primary testing vehicle for USB peripheral
  * controller drivers.
@@ -55,6 +64,8 @@ struct f_sourcesink {
 	struct usb_ep		*out_ep;
 	struct usb_ep		*iso_in_ep;
 	struct usb_ep		*iso_out_ep;
+	struct usb_ep		*int_in_ep;
+	struct usb_ep		*int_out_ep;
 	int			cur_alt;
 };
 
@@ -68,6 +79,10 @@ static unsigned isoc_interval;
 static unsigned isoc_maxpacket;
 static unsigned isoc_mult;
 static unsigned isoc_maxburst;
+static unsigned int_interval; /* In ms */
+static unsigned int_maxpacket;
+static unsigned int_mult;
+static unsigned int_maxburst;
 static unsigned buflen;
 
 /*-------------------------------------------------------------------------*/
@@ -92,6 +107,16 @@ static struct usb_interface_descriptor source_sink_intf_alt1 = {
 	/* .iInterface		= DYNAMIC */
 };
 
+static struct usb_interface_descriptor source_sink_intf_alt2 = {
+	.bLength =		USB_DT_INTERFACE_SIZE,
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	.bAlternateSetting =	2,
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
+	/* .iInterface		= DYNAMIC */
+};
+
 /* full speed support: */
 
 static struct usb_endpoint_descriptor fs_source_desc = {
@@ -130,6 +155,26 @@ static struct usb_endpoint_descriptor fs_iso_sink_desc = {
 	.bInterval =		4,
 };
 
+static struct usb_endpoint_descriptor fs_int_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(64),
+	.bInterval =		GZERO_INT_INTERVAL,
+};
+
+static struct usb_endpoint_descriptor fs_int_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(64),
+	.bInterval =		GZERO_INT_INTERVAL,
+};
+
 static struct usb_descriptor_header *fs_source_sink_descs[] = {
 	(struct usb_descriptor_header *) &source_sink_intf_alt0,
 	(struct usb_descriptor_header *) &fs_sink_desc,
@@ -140,6 +185,10 @@ static struct usb_descriptor_header *fs_source_sink_descs[] = {
 	(struct usb_descriptor_header *) &fs_source_desc,
 	(struct usb_descriptor_header *) &fs_iso_sink_desc,
 	(struct usb_descriptor_header *) &fs_iso_source_desc,
+	(struct usb_descriptor_header *) &source_sink_intf_alt2,
+#define FS_ALT_IFC_2_OFFSET	8
+	(struct usb_descriptor_header *) &fs_int_sink_desc,
+	(struct usb_descriptor_header *) &fs_int_source_desc,
 	NULL,
 };
 
@@ -179,6 +228,24 @@ static struct usb_endpoint_descriptor hs_iso_sink_desc = {
 	.bInterval =		4,
 };
 
+static struct usb_endpoint_descriptor hs_int_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+	.bInterval =		USB_MS_TO_HS_INTERVAL(GZERO_INT_INTERVAL),
+};
+
+static struct usb_endpoint_descriptor hs_int_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+	.bInterval =		USB_MS_TO_HS_INTERVAL(GZERO_INT_INTERVAL),
+};
+
 static struct usb_descriptor_header *hs_source_sink_descs[] = {
 	(struct usb_descriptor_header *) &source_sink_intf_alt0,
 	(struct usb_descriptor_header *) &hs_source_desc,
@@ -189,6 +256,10 @@ static struct usb_descriptor_header *hs_source_sink_descs[] = {
 	(struct usb_descriptor_header *) &hs_sink_desc,
 	(struct usb_descriptor_header *) &hs_iso_source_desc,
 	(struct usb_descriptor_header *) &hs_iso_sink_desc,
+	(struct usb_descriptor_header *) &source_sink_intf_alt2,
+#define HS_ALT_IFC_2_OFFSET	8
+	(struct usb_descriptor_header *) &hs_int_source_desc,
+	(struct usb_descriptor_header *) &hs_int_sink_desc,
 	NULL,
 };
 
@@ -264,6 +335,42 @@ static struct usb_ss_ep_comp_descriptor ss_iso_sink_comp_desc = {
 	.wBytesPerInterval =	cpu_to_le16(1024),
 };
 
+static struct usb_endpoint_descriptor ss_int_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+	.bInterval =		USB_MS_TO_SS_INTERVAL(GZERO_INT_INTERVAL),
+};
+
+struct usb_ss_ep_comp_descriptor ss_int_source_comp_desc = {
+	.bLength =		USB_DT_SS_EP_COMP_SIZE,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+
+	.bMaxBurst =		0,
+	.bmAttributes =		0,
+	.wBytesPerInterval =	cpu_to_le16(1024),
+};
+
+static struct usb_endpoint_descriptor ss_int_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+	.bInterval =		USB_MS_TO_SS_INTERVAL(GZERO_INT_INTERVAL),
+};
+
+struct usb_ss_ep_comp_descriptor ss_int_sink_comp_desc = {
+	.bLength =		USB_DT_SS_EP_COMP_SIZE,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+
+	.bMaxBurst =		0,
+	.bmAttributes =		0,
+	.wBytesPerInterval =	cpu_to_le16(1024),
+};
+
 static struct usb_descriptor_header *ss_source_sink_descs[] = {
 	(struct usb_descriptor_header *) &source_sink_intf_alt0,
 	(struct usb_descriptor_header *) &ss_source_desc,
@@ -280,6 +387,12 @@ static struct usb_descriptor_header *ss_source_sink_descs[] = {
 	(struct usb_descriptor_header *) &ss_iso_source_comp_desc,
 	(struct usb_descriptor_header *) &ss_iso_sink_desc,
 	(struct usb_descriptor_header *) &ss_iso_sink_comp_desc,
+	(struct usb_descriptor_header *) &source_sink_intf_alt2,
+#define SS_ALT_IFC_2_OFFSET	14
+	(struct usb_descriptor_header *) &ss_int_source_desc,
+	(struct usb_descriptor_header *) &ss_int_source_comp_desc,
+	(struct usb_descriptor_header *) &ss_int_sink_desc,
+	(struct usb_descriptor_header *) &ss_int_sink_comp_desc,
 	NULL,
 };
 
@@ -301,6 +414,21 @@ static struct usb_gadget_strings *sourcesink_strings[] = {
 };
 
 /*-------------------------------------------------------------------------*/
+static const char *get_ep_string(enum eptype ep_type)
+{
+	switch (ep_type) {
+	case EP_ISOC:
+		return "ISOC-";
+	case EP_INTERRUPT:
+		return "INTERRUPT-";
+	case EP_CONTROL:
+		return "CTRL-";
+	case EP_BULK:
+		return "BULK-";
+	default:
+		return "UNKNOWN-";
+	}
+}
 
 static inline struct usb_request *ss_alloc_ep_req(struct usb_ep *ep, int len)
 {
@@ -328,7 +456,8 @@ static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
 
 void disable_endpoints(struct usb_composite_dev *cdev,
 		struct usb_ep *in, struct usb_ep *out,
-		struct usb_ep *iso_in, struct usb_ep *iso_out)
+		struct usb_ep *iso_in, struct usb_ep *iso_out,
+		struct usb_ep *int_in, struct usb_ep *int_out)
 {
 	disable_ep(cdev, in);
 	disable_ep(cdev, out);
@@ -336,6 +465,10 @@ void disable_endpoints(struct usb_composite_dev *cdev,
 		disable_ep(cdev, iso_in);
 	if (iso_out)
 		disable_ep(cdev, iso_out);
+	if (int_in)
+		disable_ep(cdev, int_in);
+	if (int_out)
+		disable_ep(cdev, int_out);
 }
 
 static int
@@ -352,6 +485,7 @@ sourcesink_bind(struct usb_configuration *c, struct usb_function *f)
 		return id;
 	source_sink_intf_alt0.bInterfaceNumber = id;
 	source_sink_intf_alt1.bInterfaceNumber = id;
+	source_sink_intf_alt2.bInterfaceNumber = id;
 
 	/* allocate bulk endpoints */
 	ss->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_source_desc);
@@ -412,14 +546,55 @@ sourcesink_bind(struct usb_configuration *c, struct usb_function *f)
 	if (isoc_maxpacket > 1024)
 		isoc_maxpacket = 1024;
 
+	/* sanity check the interrupt module parameters */
+	if (int_interval < 1)
+		int_interval = 1;
+	if (int_interval > 4096)
+		int_interval = 4096;
+	if (int_mult > 2)
+		int_mult = 2;
+	if (int_maxburst > 15)
+		int_maxburst = 15;
+
+	/* fill in the FS interrupt descriptors from the module parameters */
+	fs_int_source_desc.wMaxPacketSize = int_maxpacket > 64 ?
+						64 : int_maxpacket;
+	fs_int_source_desc.bInterval = int_interval > 255 ?
+						255 : int_interval;
+	fs_int_sink_desc.wMaxPacketSize = int_maxpacket > 64 ?
+						64 : int_maxpacket;
+	fs_int_sink_desc.bInterval = int_interval > 255 ?
+						255 : int_interval;
+
+	/* allocate int endpoints */
+	ss->int_in_ep = usb_ep_autoconfig(cdev->gadget, &fs_int_source_desc);
+	if (!ss->int_in_ep)
+		goto no_int;
+	ss->int_in_ep->driver_data = cdev;	/* claim */
+
+	ss->int_out_ep = usb_ep_autoconfig(cdev->gadget, &fs_int_sink_desc);
+	if (ss->int_out_ep) {
+		ss->int_out_ep->driver_data = cdev;	/* claim */
+	} else {
+		ss->int_in_ep->driver_data = NULL;
+		ss->int_in_ep = NULL;
+no_int:
+		fs_source_sink_descs[FS_ALT_IFC_2_OFFSET] = NULL;
+		hs_source_sink_descs[HS_ALT_IFC_2_OFFSET] = NULL;
+		ss_source_sink_descs[SS_ALT_IFC_2_OFFSET] = NULL;
+	}
+
+	if (int_maxpacket > 1024)
+		int_maxpacket = 1024;
+
 	/* support high speed hardware */
 	hs_source_desc.bEndpointAddress = fs_source_desc.bEndpointAddress;
 	hs_sink_desc.bEndpointAddress = fs_sink_desc.bEndpointAddress;
 
 	/*
-	 * Fill in the HS isoc descriptors from the module parameters.
-	 * We assume that the user knows what they are doing and won't
-	 * give parameters that their UDC doesn't support.
+	 * Fill in the HS isoc and interrupt descriptors from the module
+	 * parameters. We assume that the user knows what they are doing and
+	 * won't give parameters that their UDC doesn't support.
 	 */
 	hs_iso_source_desc.wMaxPacketSize = isoc_maxpacket;
 	hs_iso_source_desc.wMaxPacketSize |= isoc_mult << 11;
@@ -432,6 +607,17 @@ sourcesink_bind(struct usb_configuration *c, struct usb_function *f)
 	hs_iso_sink_desc.bInterval = isoc_interval;
 	hs_iso_sink_desc.bEndpointAddress = fs_iso_sink_desc.bEndpointAddress;
 
+	hs_int_source_desc.wMaxPacketSize = int_maxpacket;
+	hs_int_source_desc.wMaxPacketSize |= int_mult << 11;
+	hs_int_source_desc.bInterval = USB_MS_TO_HS_INTERVAL(int_interval);
+	hs_int_source_desc.bEndpointAddress =
+		fs_int_source_desc.bEndpointAddress;
+
+	hs_int_sink_desc.wMaxPacketSize = int_maxpacket;
+	hs_int_sink_desc.wMaxPacketSize |= int_mult << 11;
+	hs_int_sink_desc.bInterval = USB_MS_TO_HS_INTERVAL(int_interval);
+	hs_int_sink_desc.bEndpointAddress = fs_int_sink_desc.bEndpointAddress;
+
 	/* support super speed hardware */
 	ss_source_desc.bEndpointAddress =
 		fs_source_desc.bEndpointAddress;
@@ -439,9 +625,9 @@ sourcesink_bind(struct usb_configuration *c, struct usb_function *f)
 		fs_sink_desc.bEndpointAddress;
 
 	/*
-	 * Fill in the SS isoc descriptors from the module parameters.
-	 * We assume that the user knows what they are doing and won't
-	 * give parameters that their UDC doesn't support.
+	 * Fill in the SS isoc and interrupt descriptors from the module
+	 * parameters. We assume that the user knows what they are doing and
+	 * won't give parameters that their UDC doesn't support.
 	 */
 	ss_iso_source_desc.wMaxPacketSize = isoc_maxpacket;
 	ss_iso_source_desc.bInterval = isoc_interval;
@@ -460,17 +646,37 @@ sourcesink_bind(struct usb_configuration *c, struct usb_function *f)
 		isoc_maxpacket * (isoc_mult + 1) * (isoc_maxburst + 1);
 	ss_iso_sink_desc.bEndpointAddress = fs_iso_sink_desc.bEndpointAddress;
 
+	ss_int_source_desc.wMaxPacketSize = int_maxpacket;
+	ss_int_source_desc.bInterval = USB_MS_TO_SS_INTERVAL(int_interval);
+	ss_int_source_comp_desc.bmAttributes = int_mult;
+	ss_int_source_comp_desc.bMaxBurst = int_maxburst;
+	ss_int_source_comp_desc.wBytesPerInterval =
+		int_maxpacket * (int_mult + 1) * (int_maxburst + 1);
+	ss_int_source_desc.bEndpointAddress =
+		fs_int_source_desc.bEndpointAddress;
+
+	ss_int_sink_desc.wMaxPacketSize = int_maxpacket;
+	ss_int_sink_desc.bInterval = USB_MS_TO_SS_INTERVAL(int_interval);
+	ss_int_sink_comp_desc.bmAttributes = int_mult;
+	ss_int_sink_comp_desc.bMaxBurst = int_maxburst;
+	ss_int_sink_comp_desc.wBytesPerInterval =
+		int_maxpacket * (int_mult + 1) * (int_maxburst + 1);
+	ss_int_sink_desc.bEndpointAddress = fs_int_sink_desc.bEndpointAddress;
+
 	ret = usb_assign_descriptors(f, fs_source_sink_descs,
 			hs_source_sink_descs, ss_source_sink_descs);
 	if (ret)
 		return ret;
 
-	DBG(cdev, "%s speed %s: IN/%s, OUT/%s, ISO-IN/%s, ISO-OUT/%s\n",
+	DBG(cdev, "%s speed %s: IN/%s, OUT/%s, ISO-IN/%s, ISO-OUT/%s, "
+			"INT-IN/%s, INT-OUT/%s\n",
 	    (gadget_is_superspeed(c->cdev->gadget) ? "super" :
 	     (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
 			f->name, ss->in_ep->name, ss->out_ep->name,
 			ss->iso_in_ep ? ss->iso_in_ep->name : "<none>",
-			ss->iso_out_ep ? ss->iso_out_ep->name : "<none>");
+			ss->iso_out_ep ? ss->iso_out_ep->name : "<none>",
+			ss->int_in_ep ? ss->int_in_ep->name : "<none>",
+			ss->int_out_ep ? ss->int_out_ep->name : "<none>");
 	return 0;
 }
 
@@ -601,14 +807,15 @@ static void source_sink_complete(struct usb_ep *ep, struct usb_request *req)
 }
 
 static int source_sink_start_ep(struct f_sourcesink *ss, bool is_in,
-		bool is_iso, int speed)
+		enum eptype ep_type, int speed)
 {
 	struct usb_ep		*ep;
 	struct usb_request	*req;
 	int			i, size, status;
 
 	for (i = 0; i < 8; i++) {
-		if (is_iso) {
+		switch (ep_type) {
+		case EP_ISOC:
 			switch (speed) {
 			case USB_SPEED_SUPER:
 				size = isoc_maxpacket * (isoc_mult + 1) *
@@ -624,9 +831,28 @@ static int source_sink_start_ep(struct f_sourcesink *ss, bool is_in,
 			}
 			ep = is_in ? ss->iso_in_ep : ss->iso_out_ep;
 			req = ss_alloc_ep_req(ep, size);
-		} else {
+			break;
+		case EP_INTERRUPT:
+			switch (speed) {
+			case USB_SPEED_SUPER:
+				size = int_maxpacket * (int_mult + 1) *
+						(int_maxburst + 1);
+				break;
+			case USB_SPEED_HIGH:
+				size = int_maxpacket * (int_mult + 1);
+				break;
+			default:
+				size = int_maxpacket > 1023 ?
+						1023 : int_maxpacket;
+				break;
+			}
+			ep = is_in ? ss->int_in_ep : ss->int_out_ep;
+			req = ss_alloc_ep_req(ep, size);
+			break;
+		default:
 			ep = is_in ? ss->in_ep : ss->out_ep;
 			req = ss_alloc_ep_req(ep, 0);
+			break;
 		}
 
 		if (!req)
@@ -644,12 +870,12 @@ static int source_sink_start_ep(struct f_sourcesink *ss, bool is_in,
 
 			cdev = ss->function.config->cdev;
 			ERROR(cdev, "start %s%s %s --> %d\n",
-			      is_iso ? "ISO-" : "", is_in ? "IN" : "OUT",
-			      ep->name, status);
+				get_ep_string(ep_type), is_in ? "IN" : "OUT",
+				ep->name, status);
 			free_ep_req(ep, req);
 		}
 
-		if (!is_iso)
+		if (!(ep_type == EP_ISOC))
 			break;
 	}
 
@@ -662,7 +888,7 @@ static void disable_source_sink(struct f_sourcesink *ss)
 
 	cdev = ss->function.config->cdev;
 	disable_endpoints(cdev, ss->in_ep, ss->out_ep, ss->iso_in_ep,
-			ss->iso_out_ep);
+			ss->iso_out_ep, ss->int_in_ep, ss->int_out_ep);
 	VDBG(cdev, "%s disabled\n", ss->function.name);
 }
 
@@ -674,6 +900,62 @@ enable_source_sink(struct usb_composite_dev *cdev, struct f_sourcesink *ss,
 	int					speed = cdev->gadget->speed;
 	struct usb_ep				*ep;
 
+	if (alt == 2) {
+		/* Configure for periodic interrupt endpoint */
+		ep = ss->int_in_ep;
+		if (ep) {
+			result = config_ep_by_speed(cdev->gadget,
+					&(ss->function), ep);
+			if (result)
+				return result;
+
+			result = usb_ep_enable(ep);
+			if (result < 0)
+				return result;
+
+			ep->driver_data = ss;
+			result = source_sink_start_ep(ss, true, EP_INTERRUPT,
+					speed);
+			if (result < 0) {
+fail1:
+				ep = ss->int_in_ep;
+				if (ep) {
+					usb_ep_disable(ep);
+					ep->driver_data = NULL;
+				}
+				return result;
+			}
+		}
+
+		/*
+		 * one interrupt endpoint reads (sinks) anything OUT (from the
+		 * host)
+		 */
+		ep = ss->int_out_ep;
+		if (ep) {
+			result = config_ep_by_speed(cdev->gadget,
+					&(ss->function), ep);
+			if (result)
+				goto fail1;
+
+			result = usb_ep_enable(ep);
+			if (result < 0)
+				goto fail1;
+
+			ep->driver_data = ss;
+			result = source_sink_start_ep(ss, false, EP_INTERRUPT,
+					speed);
+			if (result < 0) {
+				ep = ss->int_out_ep;
+				usb_ep_disable(ep);
+				ep->driver_data = NULL;
+				goto fail1;
+			}
+		}
+
+		goto out;
+	}
+
 	/* one bulk endpoint writes (sources) zeroes IN (to the host) */
 	ep = ss->in_ep;
 	result = config_ep_by_speed(cdev->gadget, &(ss->function), ep);
@@ -684,7 +966,7 @@ enable_source_sink(struct usb_composite_dev *cdev, struct f_sourcesink *ss,
 		return result;
 	ep->driver_data = ss;
 
-	result = source_sink_start_ep(ss, true, false, speed);
+	result = source_sink_start_ep(ss, true, EP_BULK, speed);
 	if (result < 0) {
 fail:
 		ep = ss->in_ep;
@@ -703,7 +985,7 @@ enable_source_sink(struct usb_composite_dev *cdev, struct f_sourcesink *ss,
 		goto fail;
 	ep->driver_data = ss;
 
-	result = source_sink_start_ep(ss, false, false, speed);
+	result = source_sink_start_ep(ss, false, EP_BULK, speed);
 	if (result < 0) {
 fail2:
 		ep = ss->out_ep;
@@ -726,7 +1008,7 @@ enable_source_sink(struct usb_composite_dev *cdev, struct f_sourcesink *ss,
 			goto fail2;
 		ep->driver_data = ss;
 
-		result = source_sink_start_ep(ss, true, true, speed);
+		result = source_sink_start_ep(ss, true, EP_ISOC, speed);
 		if (result < 0) {
 fail3:
 			ep = ss->iso_in_ep;
@@ -749,13 +1031,14 @@ enable_source_sink(struct usb_composite_dev *cdev, struct f_sourcesink *ss,
 			goto fail3;
 		ep->driver_data = ss;
 
-		result = source_sink_start_ep(ss, false, true, speed);
+		result = source_sink_start_ep(ss, false, EP_ISOC, speed);
 		if (result < 0) {
 			usb_ep_disable(ep);
 			ep->driver_data = NULL;
 			goto fail3;
 		}
 	}
+
 out:
 	ss->cur_alt = alt;
 
@@ -771,6 +1054,8 @@ static int sourcesink_set_alt(struct usb_function *f,
 
 	if (ss->in_ep->driver_data)
 		disable_source_sink(ss);
+	else if (alt == 2 && ss->int_in_ep->driver_data)
+		disable_source_sink(ss);
 	return enable_source_sink(cdev, ss, alt);
 }
 
@@ -883,6 +1168,10 @@ static struct usb_function *source_sink_alloc_func(
 	isoc_maxpacket = ss_opts->isoc_maxpacket;
 	isoc_mult = ss_opts->isoc_mult;
 	isoc_maxburst = ss_opts->isoc_maxburst;
+	int_interval = ss_opts->int_interval;
+	int_maxpacket = ss_opts->int_maxpacket;
+	int_mult = ss_opts->int_mult;
+	int_maxburst = ss_opts->int_maxburst;
 	buflen = ss_opts->bulk_buflen;
 
 	ss->function.name = "source/sink";
@@ -1179,6 +1468,182 @@ static struct f_ss_opts_attribute f_ss_opts_bulk_buflen =
 			f_ss_opts_bulk_buflen_show,
 			f_ss_opts_bulk_buflen_store);
 
+static ssize_t f_ss_opts_int_interval_show(struct f_ss_opts *opts, char *page)
+{
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d", opts->int_interval);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_ss_opts_int_interval_store(struct f_ss_opts *opts,
+				       const char *page, size_t len)
+{
+	int ret;
+	u8 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		goto end;
+
+	if (num > 4096) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	opts->int_interval = num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+static struct f_ss_opts_attribute f_ss_opts_int_interval =
+	__CONFIGFS_ATTR(int_interval, S_IRUGO | S_IWUSR,
+			f_ss_opts_int_interval_show,
+			f_ss_opts_int_interval_store);
+
+static ssize_t f_ss_opts_int_maxpacket_show(struct f_ss_opts *opts, char *page)
+{
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d", opts->int_maxpacket);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_ss_opts_int_maxpacket_store(struct f_ss_opts *opts,
+				       const char *page, size_t len)
+{
+	int ret;
+	u16 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou16(page, 0, &num);
+	if (ret)
+		goto end;
+
+	if (num > 1024) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	opts->int_maxpacket = num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+static struct f_ss_opts_attribute f_ss_opts_int_maxpacket =
+	__CONFIGFS_ATTR(int_maxpacket, S_IRUGO | S_IWUSR,
+			f_ss_opts_int_maxpacket_show,
+			f_ss_opts_int_maxpacket_store);
+
+static ssize_t f_ss_opts_int_mult_show(struct f_ss_opts *opts, char *page)
+{
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d", opts->int_mult);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_ss_opts_int_mult_store(struct f_ss_opts *opts,
+				       const char *page, size_t len)
+{
+	int ret;
+	u8 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		goto end;
+
+	if (num > 2) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	opts->int_mult = num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+static struct f_ss_opts_attribute f_ss_opts_int_mult =
+	__CONFIGFS_ATTR(int_mult, S_IRUGO | S_IWUSR,
+			f_ss_opts_int_mult_show,
+			f_ss_opts_int_mult_store);
+
+static ssize_t f_ss_opts_int_maxburst_show(struct f_ss_opts *opts, char *page)
+{
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d", opts->int_maxburst);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_ss_opts_int_maxburst_store(struct f_ss_opts *opts,
+				       const char *page, size_t len)
+{
+	int ret;
+	u8 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou8(page, 0, &num);
+	if (ret)
+		goto end;
+
+	if (num > 15) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	opts->int_maxburst = num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+static struct f_ss_opts_attribute f_ss_opts_int_maxburst =
+	__CONFIGFS_ATTR(int_maxburst, S_IRUGO | S_IWUSR,
+			f_ss_opts_int_maxburst_show,
+			f_ss_opts_int_maxburst_store);
+
 static struct configfs_attribute *ss_attrs[] = {
 	&f_ss_opts_pattern.attr,
 	&f_ss_opts_isoc_interval.attr,
@@ -1186,6 +1651,10 @@ static struct configfs_attribute *ss_attrs[] = {
 	&f_ss_opts_isoc_mult.attr,
 	&f_ss_opts_isoc_maxburst.attr,
 	&f_ss_opts_bulk_buflen.attr,
+	&f_ss_opts_int_interval.attr,
+	&f_ss_opts_int_maxpacket.attr,
+	&f_ss_opts_int_mult.attr,
+	&f_ss_opts_int_maxburst.attr,
 	NULL,
 };
 
@@ -1215,6 +1684,8 @@ static struct usb_function_instance *source_sink_alloc_inst(void)
 	ss_opts->isoc_interval = GZERO_ISOC_INTERVAL;
 	ss_opts->isoc_maxpacket = GZERO_ISOC_MAXPACKET;
 	ss_opts->bulk_buflen = GZERO_BULK_BUFLEN;
+	ss_opts->int_interval = GZERO_INT_INTERVAL;
+	ss_opts->int_maxpacket = GZERO_INT_MAXPACKET;
 
 	config_group_init_type_name(&ss_opts->func_inst.group, "",
 				    &ss_func_type);

drivers/usb/gadget/function/g_zero.h

@@ -10,6 +10,8 @@
 #define GZERO_QLEN		32
 #define GZERO_ISOC_INTERVAL	4
 #define GZERO_ISOC_MAXPACKET	1024
+#define GZERO_INT_INTERVAL	1 /* Default interrupt interval = 1 ms */
+#define GZERO_INT_MAXPACKET	1024
 
 struct usb_zero_options {
 	unsigned pattern;
@@ -17,6 +19,10 @@ struct usb_zero_options {
 	unsigned isoc_maxpacket;
 	unsigned isoc_mult;
 	unsigned isoc_maxburst;
+	unsigned int_interval; /* In ms */
+	unsigned int_maxpacket;
+	unsigned int_mult;
+	unsigned int_maxburst;
 	unsigned bulk_buflen;
 	unsigned qlen;
 };
@@ -28,6 +34,10 @@ struct f_ss_opts {
 	unsigned isoc_maxpacket;
 	unsigned isoc_mult;
 	unsigned isoc_maxburst;
+	unsigned int_interval; /* In ms */
+	unsigned int_maxpacket;
+	unsigned int_mult;
+	unsigned int_maxburst;
 	unsigned bulk_buflen;
 
 	/*
@@ -62,6 +72,7 @@ int lb_modinit(void);
 void free_ep_req(struct usb_ep *ep, struct usb_request *req);
 void disable_endpoints(struct usb_composite_dev *cdev,
 		struct usb_ep *in, struct usb_ep *out,
-		struct usb_ep *iso_in, struct usb_ep *iso_out);
+		struct usb_ep *iso_in, struct usb_ep *iso_out,
+		struct usb_ep *int_in, struct usb_ep *int_out);
 
 #endif /* __G_ZERO_H */

drivers/usb/gadget/legacy/zero.c

@@ -68,6 +68,8 @@ static struct usb_zero_options gzero_options = {
 	.isoc_maxpacket = GZERO_ISOC_MAXPACKET,
 	.bulk_buflen = GZERO_BULK_BUFLEN,
 	.qlen = GZERO_QLEN,
+	.int_interval = GZERO_INT_INTERVAL,
+	.int_maxpacket = GZERO_INT_MAXPACKET,
 };
 
 /*-------------------------------------------------------------------------*/
@@ -266,6 +268,21 @@ module_param_named(isoc_maxburst, gzero_options.isoc_maxburst, uint,
 		S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(isoc_maxburst, "0 - 15 (ss only)");
 
+module_param_named(int_interval, gzero_options.int_interval, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_interval, "1 - 16");
+
+module_param_named(int_maxpacket, gzero_options.int_maxpacket, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_maxpacket, "0 - 1023 (fs), 0 - 1024 (hs/ss)");
+
+module_param_named(int_mult, gzero_options.int_mult, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_mult, "0 - 2 (hs/ss only)");
+
+module_param_named(int_maxburst, gzero_options.int_maxburst, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(int_maxburst, "0 - 15 (ss only)");
+
 static struct usb_function *func_lb;
 static struct usb_function_instance *func_inst_lb;
 
@@ -301,6 +318,10 @@ static int __init zero_bind(struct usb_composite_dev *cdev)
 	ss_opts->isoc_maxpacket = gzero_options.isoc_maxpacket;
 	ss_opts->isoc_mult = gzero_options.isoc_mult;
 	ss_opts->isoc_maxburst = gzero_options.isoc_maxburst;
+	ss_opts->int_interval = gzero_options.int_interval;
+	ss_opts->int_maxpacket = gzero_options.int_maxpacket;
+	ss_opts->int_mult = gzero_options.int_mult;
+	ss_opts->int_maxburst = gzero_options.int_maxburst;
 	ss_opts->bulk_buflen = gzero_options.bulk_buflen;
 
 	func_ss = usb_get_function(func_inst_ss);