#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/hid.h>
+#include <linux/idr.h>
 #include <linux/cdev.h>
 #include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/usb/g_hid.h>
 
 #include "u_f.h"
+#include "u_hid.h"
+
+#define HIDG_MINORS    4
 
 static int major, minors;
 static struct class *hidg_class;
+#ifndef USBF_HID_INCLUDED
+static DEFINE_IDA(hidg_ida);
+static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */
+#endif
 
 /*-------------------------------------------------------------------------*/
 /*                            HID gadget struct                            */
        NULL,
 };
 
+/*-------------------------------------------------------------------------*/
+/*                                 Strings                                 */
+
+#define CT_FUNC_HID_IDX        0
+
+static struct usb_string ct_func_string_defs[] = {
+       [CT_FUNC_HID_IDX].s     = "HID Interface",
+       {},                     /* end of list */
+};
+
+static struct usb_gadget_strings ct_func_string_table = {
+       .language       = 0x0409,       /* en-US */
+       .strings        = ct_func_string_defs,
+};
+
+static struct usb_gadget_strings *ct_func_strings[] = {
+       &ct_func_string_table,
+       NULL,
+};
+
 /*-------------------------------------------------------------------------*/
 /*                              Char Device                                */
 
        .llseek         = noop_llseek,
 };
 
-static int __init hidg_bind(struct usb_configuration *c, struct usb_function *f)
+static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
 {
        struct usb_ep           *ep;
        struct f_hidg           *hidg = func_to_hidg(f);
        int                     status;
        dev_t                   dev;
 
+       /* maybe allocate device-global string IDs, and patch descriptors */
+       if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
+               status = usb_string_id(c->cdev);
+               if (status < 0)
+                       return status;
+               ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
+               hidg_interface_desc.iInterface = status;
+       }
+
        /* allocate instance-specific interface IDs, and patch descriptors */
        status = usb_interface_id(c, f);
        if (status < 0)
        return status;
 }
 
+#ifdef USBF_HID_INCLUDED
 static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
 {
        struct f_hidg *hidg = func_to_hidg(f);
        kfree(hidg);
 }
 
-/*-------------------------------------------------------------------------*/
-/*                                 Strings                                 */
-
-#define CT_FUNC_HID_IDX        0
-
-static struct usb_string ct_func_string_defs[] = {
-       [CT_FUNC_HID_IDX].s     = "HID Interface",
-       {},                     /* end of list */
-};
-
-static struct usb_gadget_strings ct_func_string_table = {
-       .language       = 0x0409,       /* en-US */
-       .strings        = ct_func_string_defs,
-};
-
-static struct usb_gadget_strings *ct_func_strings[] = {
-       &ct_func_string_table,
-       NULL,
-};
-
 /*-------------------------------------------------------------------------*/
 /*                             usb_configuration                           */
-
 int __init hidg_bind_config(struct usb_configuration *c,
                            struct hidg_func_descriptor *fdesc, int index)
 {
        if (index >= minors)
                return -ENOENT;
 
-       /* maybe allocate device-global string IDs, and patch descriptors */
-       if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
-               status = usb_string_id(c->cdev);
-               if (status < 0)
-                       return status;
-               ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
-               hidg_interface_desc.iInterface = status;
-       }
-
        /* allocate and initialize one new instance */
        hidg = kzalloc(sizeof *hidg, GFP_KERNEL);
        if (!hidg)
        return status;
 }
 
-int __init ghid_setup(struct usb_gadget *g, int count)
+#else
+
+static inline int hidg_get_minor(void)
+{
+       int ret;
+
+       ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
+
+       return ret;
+}
+
+static inline void hidg_put_minor(int minor)
+{
+       ida_simple_remove(&hidg_ida, minor);
+}
+
+static void hidg_free_inst(struct usb_function_instance *f)
+{
+       struct f_hid_opts *opts;
+
+       opts = container_of(f, struct f_hid_opts, func_inst);
+
+       mutex_lock(&hidg_ida_lock);
+
+       hidg_put_minor(opts->minor);
+       if (idr_is_empty(&hidg_ida.idr))
+               ghid_cleanup();
+
+       mutex_unlock(&hidg_ida_lock);
+
+       if (opts->report_desc_alloc)
+               kfree(opts->report_desc);
+
+       kfree(opts);
+}
+
+static struct usb_function_instance *hidg_alloc_inst(void)
+{
+       struct f_hid_opts *opts;
+       struct usb_function_instance *ret;
+       int status = 0;
+
+       opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+       if (!opts)
+               return ERR_PTR(-ENOMEM);
+
+       opts->func_inst.free_func_inst = hidg_free_inst;
+       ret = &opts->func_inst;
+
+       mutex_lock(&hidg_ida_lock);
+
+       if (idr_is_empty(&hidg_ida.idr)) {
+               status = ghid_setup(NULL, HIDG_MINORS);
+               if (status)  {
+                       ret = ERR_PTR(status);
+                       kfree(opts);
+                       goto unlock;
+               }
+       }
+
+       opts->minor = hidg_get_minor();
+       if (opts->minor < 0) {
+               ret = ERR_PTR(opts->minor);
+               kfree(opts);
+               if (idr_is_empty(&hidg_ida.idr))
+                       ghid_cleanup();
+       }
+
+unlock:
+       mutex_unlock(&hidg_ida_lock);
+       return ret;
+}
+
+static void hidg_free(struct usb_function *f)
+{
+       struct f_hidg *hidg;
+
+       hidg = func_to_hidg(f);
+       kfree(hidg->report_desc);
+       kfree(hidg);
+}
+
+static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+       struct f_hidg *hidg = func_to_hidg(f);
+
+       device_destroy(hidg_class, MKDEV(major, hidg->minor));
+       cdev_del(&hidg->cdev);
+
+       /* disable/free request and end point */
+       usb_ep_disable(hidg->in_ep);
+       usb_ep_dequeue(hidg->in_ep, hidg->req);
+       kfree(hidg->req->buf);
+       usb_ep_free_request(hidg->in_ep, hidg->req);
+
+       usb_free_all_descriptors(f);
+}
+
+struct usb_function *hidg_alloc(struct usb_function_instance *fi)
+{
+       struct f_hidg *hidg;
+       struct f_hid_opts *opts;
+
+       /* allocate and initialize one new instance */
+       hidg = kzalloc(sizeof(*hidg), GFP_KERNEL);
+       if (!hidg)
+               return ERR_PTR(-ENOMEM);
+
+       opts = container_of(fi, struct f_hid_opts, func_inst);
+
+       hidg->minor = opts->minor;
+       hidg->bInterfaceSubClass = opts->subclass;
+       hidg->bInterfaceProtocol = opts->protocol;
+       hidg->report_length = opts->report_length;
+       hidg->report_desc_length = opts->report_desc_length;
+       if (opts->report_desc) {
+               hidg->report_desc = kmemdup(opts->report_desc,
+                                           opts->report_desc_length,
+                                           GFP_KERNEL);
+               if (!hidg->report_desc) {
+                       kfree(hidg);
+                       return ERR_PTR(-ENOMEM);
+               }
+       }
+
+       hidg->func.name    = "hid";
+       hidg->func.strings = ct_func_strings;
+       hidg->func.bind    = hidg_bind;
+       hidg->func.unbind  = hidg_unbind;
+       hidg->func.set_alt = hidg_set_alt;
+       hidg->func.disable = hidg_disable;
+       hidg->func.setup   = hidg_setup;
+       hidg->func.free_func = hidg_free;
+
+       /* this could me made configurable at some point */
+       hidg->qlen         = 4;
+
+       return &hidg->func;
+}
+
+DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Fabien Chouteau");
+
+#endif
+
+int ghid_setup(struct usb_gadget *g, int count)
 {
        int status;
        dev_t dev;