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>

1 files changed, 491 insertions, 20 deletions

diff --git a/drivers/usb/gadget/function/f_sourcesink.c b/drivers/usb/gadget/function/f_sourcesink.c
index d3cd52db78fe..7c091a328228 100644
--- a/drivers/usb/gadget/function/f_sourcesink.c
+++ b/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 @@ no_iso:
         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 @@ no_iso:
         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 @@ no_iso:
                 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 @@ no_iso:
                 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 @@ fail:
                 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 @@ fail2:
                         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 @@ fail3:
                         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);