usb gadget serial: use composite gadget framework

This switches the serial gadget over to using the new "function"
versions of the serial port interfacing code.  The remaining code
in the main source file is quite small...

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 145 insertions, 928 deletions

diff --git a/drivers/usb/gadget/serial.c b/drivers/usb/gadget/serial.c
index 64ce7e00e98..b3699afff00 100644
--- a/drivers/usb/gadget/serial.c
+++ b/drivers/usb/gadget/serial.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
  * Copyright (C) 2008 by David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
  *
  * This software is distributed under the terms of the GNU General
  * Public License ("GPL") as published by the Free Software Foundation,
@@ -21,314 +22,79 @@
 
 /* Defines */
 
-#define GS_VERSION_STR			"v2.3"
-#define GS_VERSION_NUM			0x2300
+#define GS_VERSION_STR			"v2.4"
+#define GS_VERSION_NUM			0x2400
 
 #define GS_LONG_NAME			"Gadget Serial"
-#define GS_SHORT_NAME			"g_serial"
-
 #define GS_VERSION_NAME			GS_LONG_NAME " " GS_VERSION_STR
 
-
-/* REVISIT only one port is supported for now;
- * see gs_{send,recv}_packet() ... no multiplexing,
- * and no support for multiple ACM devices.
- */
-#define GS_NUM_PORTS			1
-
-#define GS_NUM_CONFIGS			1
-#define GS_NO_CONFIG_ID			0
-#define GS_BULK_CONFIG_ID		1
-#define GS_ACM_CONFIG_ID		2
-
-#define GS_MAX_NUM_INTERFACES		2
-#define GS_BULK_INTERFACE_ID		0
-#define GS_CONTROL_INTERFACE_ID		0
-#define GS_DATA_INTERFACE_ID		1
-
-#define GS_MAX_DESC_LEN			256
-
-#define GS_DEFAULT_USE_ACM		0
-
-
-/* maxpacket and other transfer characteristics vary by speed. */
-static inline struct usb_endpoint_descriptor *
-choose_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
-		struct usb_endpoint_descriptor *fs)
-{
-	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
-		return hs;
-	return fs;
-}
-
+/*-------------------------------------------------------------------------*/
 
 /* Thanks to NetChip Technologies for donating this product ID.
- *
- * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
- * Instead:  allocate your own, using normal USB-IF procedures.
- */
+*
+* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
+* Instead:  allocate your own, using normal USB-IF procedures.
+*/
 #define GS_VENDOR_ID			0x0525	/* NetChip */
 #define GS_PRODUCT_ID			0xa4a6	/* Linux-USB Serial Gadget */
 #define GS_CDC_PRODUCT_ID		0xa4a7	/* ... as CDC-ACM */
 
-#define GS_LOG2_NOTIFY_INTERVAL		5	/* 1 << 5 == 32 msec */
-#define GS_NOTIFY_MAXPACKET		8
+/* string IDs are assigned dynamically */
 
-/* the device structure holds info for the USB device */
-struct gs_dev {
-	struct usb_gadget	*dev_gadget;	/* gadget device pointer */
-	spinlock_t		dev_lock;	/* lock for set/reset config */
-	int			dev_config;	/* configuration number */
-	struct usb_request	*dev_ctrl_req;	/* control request */
+#define STRING_MANUFACTURER_IDX		0
+#define STRING_PRODUCT_IDX		1
+#define STRING_DESCRIPTION_IDX		2
 
-	struct gserial		gser;		/* serial/tty port */
-};
-
-
-/* Functions */
-
-/* gadget driver internals */
-static int gs_set_config(struct gs_dev *dev, unsigned config);
-static void gs_reset_config(struct gs_dev *dev);
-static int gs_build_config_buf(u8 *buf, struct usb_gadget *g,
-		u8 type, unsigned int index, int is_otg);
-
-static struct usb_request *gs_alloc_req(struct usb_ep *ep, unsigned int len,
-	gfp_t kmalloc_flags);
-static void gs_free_req(struct usb_ep *ep, struct usb_request *req);
-
-/*-------------------------------------------------------------------------*/
-
-/* USB descriptors */
-
-#define GS_MANUFACTURER_STR_ID	1
-#define GS_PRODUCT_STR_ID	2
-#define GS_SERIAL_STR_ID	3
-#define GS_BULK_CONFIG_STR_ID	4
-#define GS_ACM_CONFIG_STR_ID	5
-#define GS_CONTROL_STR_ID	6
-#define GS_DATA_STR_ID		7
-
-/* static strings, in UTF-8 */
 static char manufacturer[50];
-static struct usb_string gs_strings[] = {
-	{ GS_MANUFACTURER_STR_ID, manufacturer },
-	{ GS_PRODUCT_STR_ID, GS_VERSION_NAME },
-	{ GS_BULK_CONFIG_STR_ID, "Gadget Serial Bulk" },
-	{ GS_ACM_CONFIG_STR_ID, "Gadget Serial CDC ACM" },
-	{ GS_CONTROL_STR_ID, "Gadget Serial Control" },
-	{ GS_DATA_STR_ID, "Gadget Serial Data" },
+
+static struct usb_string strings_dev[] = {
+	[STRING_MANUFACTURER_IDX].s = manufacturer,
+	[STRING_PRODUCT_IDX].s = GS_VERSION_NAME,
+	[STRING_DESCRIPTION_IDX].s = NULL /* updated; f(use_acm) */,
 	{  } /* end of list */
 };
 
-static struct usb_gadget_strings gs_string_table = {
-	.language =		0x0409,	/* en-us */
-	.strings =		gs_strings,
+static struct usb_gadget_strings stringtab_dev = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings_dev,
 };
 
-static struct usb_device_descriptor gs_device_desc = {
+static struct usb_gadget_strings *dev_strings[] = {
+	&stringtab_dev,
+	NULL,
+};
+
+static struct usb_device_descriptor device_desc = {
 	.bLength =		USB_DT_DEVICE_SIZE,
 	.bDescriptorType =	USB_DT_DEVICE,
 	.bcdUSB =		__constant_cpu_to_le16(0x0200),
+	/* .bDeviceClass = f(use_acm) */
 	.bDeviceSubClass =	0,
 	.bDeviceProtocol =	0,
+	/* .bMaxPacketSize0 = f(hardware) */
 	.idVendor =		__constant_cpu_to_le16(GS_VENDOR_ID),
-	.idProduct =		__constant_cpu_to_le16(GS_PRODUCT_ID),
-	.iManufacturer =	GS_MANUFACTURER_STR_ID,
-	.iProduct =		GS_PRODUCT_STR_ID,
-	.bNumConfigurations =	GS_NUM_CONFIGS,
+	/* .idProduct =	f(use_acm) */
+	/* .bcdDevice = f(hardware) */
+	/* .iManufacturer = DYNAMIC */
+	/* .iProduct = DYNAMIC */
+	.bNumConfigurations =	1,
 };
 
-static struct usb_otg_descriptor gs_otg_descriptor = {
-	.bLength =		sizeof(gs_otg_descriptor),
+static struct usb_otg_descriptor otg_descriptor = {
+	.bLength =		sizeof otg_descriptor,
 	.bDescriptorType =	USB_DT_OTG,
-	.bmAttributes =		USB_OTG_SRP,
-};
 
-static struct usb_config_descriptor gs_bulk_config_desc = {
-	.bLength =		USB_DT_CONFIG_SIZE,
-	.bDescriptorType =	USB_DT_CONFIG,
-	/* .wTotalLength computed dynamically */
-	.bNumInterfaces =	1,
-	.bConfigurationValue =	GS_BULK_CONFIG_ID,
-	.iConfiguration =	GS_BULK_CONFIG_STR_ID,
-	.bmAttributes =		USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
-	.bMaxPower =		1,
-};
-
-static struct usb_config_descriptor gs_acm_config_desc = {
-	.bLength =		USB_DT_CONFIG_SIZE,
-	.bDescriptorType =	USB_DT_CONFIG,
-	/* .wTotalLength computed dynamically */
-	.bNumInterfaces =	2,
-	.bConfigurationValue =	GS_ACM_CONFIG_ID,
-	.iConfiguration =	GS_ACM_CONFIG_STR_ID,
-	.bmAttributes =		USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
-	.bMaxPower =		1,
-};
-
-static const struct usb_interface_descriptor gs_bulk_interface_desc = {
-	.bLength =		USB_DT_INTERFACE_SIZE,
-	.bDescriptorType =	USB_DT_INTERFACE,
-	.bInterfaceNumber =	GS_BULK_INTERFACE_ID,
-	.bNumEndpoints =	2,
-	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
-	.bInterfaceSubClass =	0,
-	.bInterfaceProtocol =	0,
-	.iInterface =		GS_DATA_STR_ID,
-};
-
-static const struct usb_interface_descriptor gs_control_interface_desc = {
-	.bLength =		USB_DT_INTERFACE_SIZE,
-	.bDescriptorType =	USB_DT_INTERFACE,
-	.bInterfaceNumber =	GS_CONTROL_INTERFACE_ID,
-	.bNumEndpoints =	1,
-	.bInterfaceClass =	USB_CLASS_COMM,
-	.bInterfaceSubClass =	USB_CDC_SUBCLASS_ACM,
-	.bInterfaceProtocol =	USB_CDC_ACM_PROTO_AT_V25TER,
-	.iInterface =		GS_CONTROL_STR_ID,
-};
-
-static const struct usb_interface_descriptor gs_data_interface_desc = {
-	.bLength =		USB_DT_INTERFACE_SIZE,
-	.bDescriptorType =	USB_DT_INTERFACE,
-	.bInterfaceNumber =	GS_DATA_INTERFACE_ID,
-	.bNumEndpoints =	2,
-	.bInterfaceClass =	USB_CLASS_CDC_DATA,
-	.bInterfaceSubClass =	0,
-	.bInterfaceProtocol =	0,
-	.iInterface =		GS_DATA_STR_ID,
-};
-
-static const struct usb_cdc_header_desc gs_header_desc = {
-	.bLength =		sizeof(gs_header_desc),
-	.bDescriptorType =	USB_DT_CS_INTERFACE,
-	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
-	.bcdCDC =		__constant_cpu_to_le16(0x0110),
-};
-
-static const struct usb_cdc_call_mgmt_descriptor gs_call_mgmt_descriptor = {
-	.bLength =		sizeof(gs_call_mgmt_descriptor),
-	.bDescriptorType =	USB_DT_CS_INTERFACE,
-	.bDescriptorSubType =	USB_CDC_CALL_MANAGEMENT_TYPE,
-	.bmCapabilities =	0,
-	.bDataInterface =	1,	/* index of data interface */
-};
-
-static struct usb_cdc_acm_descriptor gs_acm_descriptor = {
-	.bLength =		sizeof(gs_acm_descriptor),
-	.bDescriptorType =	USB_DT_CS_INTERFACE,
-	.bDescriptorSubType =	USB_CDC_ACM_TYPE,
-	.bmCapabilities =	(1 << 1),
-};
-
-static const struct usb_cdc_union_desc gs_union_desc = {
-	.bLength =		sizeof(gs_union_desc),
-	.bDescriptorType =	USB_DT_CS_INTERFACE,
-	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
-	.bMasterInterface0 =	0,	/* index of control interface */
-	.bSlaveInterface0 =	1,	/* index of data interface */
-};
-
-static struct usb_endpoint_descriptor gs_fullspeed_notify_desc = {
-	.bLength =		USB_DT_ENDPOINT_SIZE,
-	.bDescriptorType =	USB_DT_ENDPOINT,
-	.bEndpointAddress =	USB_DIR_IN,
-	.bmAttributes =		USB_ENDPOINT_XFER_INT,
-	.wMaxPacketSize =	__constant_cpu_to_le16(GS_NOTIFY_MAXPACKET),
-	.bInterval =		1 << GS_LOG2_NOTIFY_INTERVAL,
-};
-
-static struct usb_endpoint_descriptor gs_fullspeed_in_desc = {
-	.bLength =		USB_DT_ENDPOINT_SIZE,
-	.bDescriptorType =	USB_DT_ENDPOINT,
-	.bEndpointAddress =	USB_DIR_IN,
-	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
-};
-
-static struct usb_endpoint_descriptor gs_fullspeed_out_desc = {
-	.bLength =		USB_DT_ENDPOINT_SIZE,
-	.bDescriptorType =	USB_DT_ENDPOINT,
-	.bEndpointAddress =	USB_DIR_OUT,
-	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
-};
-
-static const struct usb_descriptor_header *gs_bulk_fullspeed_function[] = {
-	(struct usb_descriptor_header *) &gs_otg_descriptor,
-	(struct usb_descriptor_header *) &gs_bulk_interface_desc,
-	(struct usb_descriptor_header *) &gs_fullspeed_in_desc,
-	(struct usb_descriptor_header *) &gs_fullspeed_out_desc,
-	NULL,
-};
-
-static const struct usb_descriptor_header *gs_acm_fullspeed_function[] = {
-	(struct usb_descriptor_header *) &gs_otg_descriptor,
-	(struct usb_descriptor_header *) &gs_control_interface_desc,
-	(struct usb_descriptor_header *) &gs_header_desc,
-	(struct usb_descriptor_header *) &gs_call_mgmt_descriptor,
-	(struct usb_descriptor_header *) &gs_acm_descriptor,
-	(struct usb_descriptor_header *) &gs_union_desc,
-	(struct usb_descriptor_header *) &gs_fullspeed_notify_desc,
-	(struct usb_descriptor_header *) &gs_data_interface_desc,
-	(struct usb_descriptor_header *) &gs_fullspeed_in_desc,
-	(struct usb_descriptor_header *) &gs_fullspeed_out_desc,
-	NULL,
-};
-
-static struct usb_endpoint_descriptor gs_highspeed_notify_desc = {
-	.bLength =		USB_DT_ENDPOINT_SIZE,
-	.bDescriptorType =	USB_DT_ENDPOINT,
-	.bEndpointAddress =	USB_DIR_IN,
-	.bmAttributes =		USB_ENDPOINT_XFER_INT,
-	.wMaxPacketSize =	__constant_cpu_to_le16(GS_NOTIFY_MAXPACKET),
-	.bInterval =		GS_LOG2_NOTIFY_INTERVAL+4,
-};
-
-static struct usb_endpoint_descriptor gs_highspeed_in_desc = {
-	.bLength =		USB_DT_ENDPOINT_SIZE,
-	.bDescriptorType =	USB_DT_ENDPOINT,
-	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
-	.wMaxPacketSize =	__constant_cpu_to_le16(512),
-};
-
-static struct usb_endpoint_descriptor gs_highspeed_out_desc = {
-	.bLength =		USB_DT_ENDPOINT_SIZE,
-	.bDescriptorType =	USB_DT_ENDPOINT,
-	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
-	.wMaxPacketSize =	__constant_cpu_to_le16(512),
-};
-
-static struct usb_qualifier_descriptor gs_qualifier_desc = {
-	.bLength =		sizeof(struct usb_qualifier_descriptor),
-	.bDescriptorType =	USB_DT_DEVICE_QUALIFIER,
-	.bcdUSB =		__constant_cpu_to_le16 (0x0200),
-	/* assumes ep0 uses the same value for both speeds ... */
-	.bNumConfigurations =	GS_NUM_CONFIGS,
-};
-
-static const struct usb_descriptor_header *gs_bulk_highspeed_function[] = {
-	(struct usb_descriptor_header *) &gs_otg_descriptor,
-	(struct usb_descriptor_header *) &gs_bulk_interface_desc,
-	(struct usb_descriptor_header *) &gs_highspeed_in_desc,
-	(struct usb_descriptor_header *) &gs_highspeed_out_desc,
-	NULL,
+	/* REVISIT SRP-only hardware is possible, although
+	 * it would not be called "OTG" ...
+	 */
+	.bmAttributes =		USB_OTG_SRP | USB_OTG_HNP,
 };
 
-static const struct usb_descriptor_header *gs_acm_highspeed_function[] = {
-	(struct usb_descriptor_header *) &gs_otg_descriptor,
-	(struct usb_descriptor_header *) &gs_control_interface_desc,
-	(struct usb_descriptor_header *) &gs_header_desc,
-	(struct usb_descriptor_header *) &gs_call_mgmt_descriptor,
-	(struct usb_descriptor_header *) &gs_acm_descriptor,
-	(struct usb_descriptor_header *) &gs_union_desc,
-	(struct usb_descriptor_header *) &gs_highspeed_notify_desc,
-	(struct usb_descriptor_header *) &gs_data_interface_desc,
-	(struct usb_descriptor_header *) &gs_highspeed_in_desc,
-	(struct usb_descriptor_header *) &gs_highspeed_out_desc,
+static const struct usb_descriptor_header *otg_desc[] = {
+	(struct usb_descriptor_header *) &otg_descriptor,
 	NULL,
 };
 
-
 /*-------------------------------------------------------------------------*/
 
 /* Module */
@@ -337,699 +103,150 @@ MODULE_AUTHOR("Al Borchers");
 MODULE_AUTHOR("David Brownell");
 MODULE_LICENSE("GPL");
 
-static unsigned int use_acm = GS_DEFAULT_USE_ACM;
-module_param(use_acm, uint, S_IRUGO);
-MODULE_PARM_DESC(use_acm, "Use CDC ACM, 0=no, 1=yes, default=no");
+static int use_acm = true;
+module_param(use_acm, bool, 0);
+MODULE_PARM_DESC(use_acm, "Use CDC ACM, default=yes");
 
-/*-------------------------------------------------------------------------*/
+static unsigned n_ports = 1;
+module_param(n_ports, uint, 0);
+MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");
 
-/* Gadget Driver */
+/*-------------------------------------------------------------------------*/
 
-/*
- * gs_unbind
- *
- * Called on module unload.  Frees the control request and device
- * structure.
- */
-static void __exit gs_unbind(struct usb_gadget *gadget)
+static int __init serial_bind_config(struct usb_configuration *c)
 {
-	struct gs_dev *dev = get_gadget_data(gadget);
+	unsigned i;
+	int status = 0;
 
-	/* read/write requests already freed, only control request remains */
-	if (dev != NULL) {
-		if (dev->dev_ctrl_req != NULL) {
-			gs_free_req(gadget->ep0, dev->dev_ctrl_req);
-			dev->dev_ctrl_req = NULL;
-		}
-		gs_reset_config(dev);
-		kfree(dev);
-		set_gadget_data(gadget, NULL);
+	for (i = 0; i < n_ports && status == 0; i++) {
+		if (use_acm)
+			status = acm_bind_config(c, i);
+		else
+			status = gser_bind_config(c, i);
 	}
-
-	pr_info("gs_unbind: %s unbound\n", GS_VERSION_NAME);
-
-	gserial_cleanup();
+	return status;
 }
 
-/*
- * gs_bind
- *
- * Called on module load.  Allocates and initializes the device
- * structure and a control request.
- */
-static int __init gs_bind(struct usb_gadget *gadget)
+static struct usb_configuration serial_config_driver = {
+	/* .label = f(use_acm) */
+	.bind		= serial_bind_config,
+	/* .bConfigurationValue = f(use_acm) */
+	/* .iConfiguration = DYNAMIC */
+	.bmAttributes	= USB_CONFIG_ATT_SELFPOWER,
+	.bMaxPower	= 1,	/* 2 mA, minimal */
+};
+
+static int __init gs_bind(struct usb_composite_dev *cdev)
 {
-	int ret;
-	struct usb_ep *ep;
-	struct gs_dev *dev;
-	int gcnum;
+	int			gcnum;
+	struct usb_gadget	*gadget = cdev->gadget;
+	int			status;
 
-	ret = gserial_setup(gadget, GS_NUM_PORTS);
-	if (ret < 0)
-		return ret;
+	status = gserial_setup(cdev->gadget, n_ports);
+	if (status < 0)
+		return status;
 
-	/* Some controllers can't support CDC ACM:
-	 * - sh doesn't support multiple interfaces or configs;
-	 * - sa1100 doesn't have a third interrupt endpoint
+	/* Allocate string descriptor numbers ... note that string
+	 * contents can be overridden by the composite_dev glue.
 	 */
-	if (gadget_is_sh(gadget) || gadget_is_sa1100(gadget))
-		use_acm = 0;
-
-	gcnum = usb_gadget_controller_number(gadget);
-	if (gcnum >= 0)
-		gs_device_desc.bcdDevice =
-				cpu_to_le16(GS_VERSION_NUM | gcnum);
-	else {
-		pr_warning("gs_bind: controller '%s' not recognized\n",
-			gadget->name);
-		/* unrecognized, but safe unless bulk is REALLY quirky */
-		gs_device_desc.bcdDevice =
-			__constant_cpu_to_le16(GS_VERSION_NUM|0x0099);
-	}
-
-	dev = kzalloc(sizeof(struct gs_dev), GFP_KERNEL);
-	if (dev == NULL) {
-		ret = -ENOMEM;
-		goto autoconf_fail;
-	}
-
-	usb_ep_autoconfig_reset(gadget);
-	ret = -ENXIO;
-
-	ep = usb_ep_autoconfig(gadget, &gs_fullspeed_in_desc);
-	if (!ep)
-		goto autoconf_fail;
-	dev->gser.in = ep;
-	ep->driver_data = dev;	/* claim the endpoint */
-
-	ep = usb_ep_autoconfig(gadget, &gs_fullspeed_out_desc);
-	if (!ep)
-		goto autoconf_fail;
-	dev->gser.out = ep;
-	ep->driver_data = dev;	/* claim the endpoint */
-
-	if (use_acm) {
-		ep = usb_ep_autoconfig(gadget, &gs_fullspeed_notify_desc);
-		if (!ep) {
-			pr_err("gs_bind: cannot run ACM on %s\n", gadget->name);
-			goto autoconf_fail;
-		}
-		gs_device_desc.idProduct = __constant_cpu_to_le16(
-						GS_CDC_PRODUCT_ID),
-		dev->gser.notify = ep;
-		ep->driver_data = dev;	/* claim the endpoint */
-	}
-
-	gs_device_desc.bDeviceClass = use_acm
-		? USB_CLASS_COMM : USB_CLASS_VENDOR_SPEC;
-	gs_device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
-
-	if (gadget_is_dualspeed(gadget)) {
-		gs_qualifier_desc.bDeviceClass = use_acm
-			? USB_CLASS_COMM : USB_CLASS_VENDOR_SPEC;
-		/* assume ep0 uses the same packet size for both speeds */
-		gs_qualifier_desc.bMaxPacketSize0 =
-			gs_device_desc.bMaxPacketSize0;
-		/* assume endpoints are dual-speed */
-		gs_highspeed_notify_desc.bEndpointAddress =
-			gs_fullspeed_notify_desc.bEndpointAddress;
-		gs_highspeed_in_desc.bEndpointAddress =
-			gs_fullspeed_in_desc.bEndpointAddress;
-		gs_highspeed_out_desc.bEndpointAddress =
-			gs_fullspeed_out_desc.bEndpointAddress;
-	}
-
-	usb_gadget_set_selfpowered(gadget);
-
-	if (gadget_is_otg(gadget)) {
-		gs_otg_descriptor.bmAttributes |= USB_OTG_HNP,
-		gs_bulk_config_desc.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
-		gs_acm_config_desc.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
-	}
 
-	snprintf(manufacturer, sizeof(manufacturer), "%s %s with %s",
+	/* device description: manufacturer, product */
+	snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
 		init_utsname()->sysname, init_utsname()->release,
 		gadget->name);
+	status = usb_string_id(cdev);
+	if (status < 0)
+		goto fail;
+	strings_dev[STRING_MANUFACTURER_IDX].id = status;
 
-	dev->dev_gadget = gadget;
-	spin_lock_init(&dev->dev_lock);
-	set_gadget_data(gadget, dev);
-
-	/* preallocate control response and buffer */
-	dev->dev_ctrl_req = gs_alloc_req(gadget->ep0, GS_MAX_DESC_LEN,
-		GFP_KERNEL);
-	if (dev->dev_ctrl_req == NULL) {
-		ret = -ENOMEM;
-		goto autoconf_fail;
-	}
-	gadget->ep0->driver_data = dev;
-
-	pr_info("gs_bind: %s bound\n", GS_VERSION_NAME);
-
-	return 0;
-
-autoconf_fail:
-	kfree(dev);
-	gserial_cleanup();
-	pr_err("gs_bind: to %s, err %d\n", gadget->name, ret);
-	return ret;
-}
-
-static int gs_setup_standard(struct usb_gadget *gadget,
-	const struct usb_ctrlrequest *ctrl)
-{
-	int ret = -EOPNOTSUPP;
-	struct gs_dev *dev = get_gadget_data(gadget);
-	struct usb_request *req = dev->dev_ctrl_req;
-	u16 wIndex = le16_to_cpu(ctrl->wIndex);
-	u16 wValue = le16_to_cpu(ctrl->wValue);
-	u16 wLength = le16_to_cpu(ctrl->wLength);
-
-	switch (ctrl->bRequest) {
-	case USB_REQ_GET_DESCRIPTOR:
-		if (ctrl->bRequestType != USB_DIR_IN)
-			break;
-
-		switch (wValue >> 8) {
-		case USB_DT_DEVICE:
-			ret = min(wLength,
-				(u16)sizeof(struct usb_device_descriptor));
-			memcpy(req->buf, &gs_device_desc, ret);
-			break;
-
-		case USB_DT_DEVICE_QUALIFIER:
-			if (!gadget_is_dualspeed(gadget))
-				break;
-			ret = min(wLength,
-				(u16)sizeof(struct usb_qualifier_descriptor));
-			memcpy(req->buf, &gs_qualifier_desc, ret);
-			break;
-
-		case USB_DT_OTHER_SPEED_CONFIG:
-			if (!gadget_is_dualspeed(gadget))
-				break;
-			/* fall through */
-		case USB_DT_CONFIG:
-			ret = gs_build_config_buf(req->buf, gadget,
-				wValue >> 8, wValue & 0xff,
-				gadget_is_otg(gadget));
-			if (ret >= 0)
-				ret = min(wLength, (u16)ret);
-			break;
-
-		case USB_DT_STRING:
-			/* wIndex == language code. */
-			ret = usb_gadget_get_string(&gs_string_table,
-				wValue & 0xff, req->buf);
-			if (ret >= 0)
-				ret = min(wLength, (u16)ret);
-			break;
-		}
-		break;
+	device_desc.iManufacturer = status;
 
-	case USB_REQ_SET_CONFIGURATION:
-		if (ctrl->bRequestType != 0)
-			break;
-		spin_lock(&dev->dev_lock);
-		ret = gs_set_config(dev, wValue);
-		spin_unlock(&dev->dev_lock);
-		break;
+	status = usb_string_id(cdev);
+	if (status < 0)
+		goto fail;
+	strings_dev[STRING_PRODUCT_IDX].id = status;
 
-	case USB_REQ_GET_CONFIGURATION:
-		if (ctrl->bRequestType != USB_DIR_IN)
-			break;
-		*(u8 *)req->buf = dev->dev_config;
-		ret = min(wLength, (u16)1);
-		break;
+	device_desc.iProduct = status;
 
-	case USB_REQ_SET_INTERFACE:
-		if (ctrl->bRequestType != USB_RECIP_INTERFACE
-				|| !dev->dev_config
-				|| wIndex >= GS_MAX_NUM_INTERFACES)
-			break;
-		if (dev->dev_config == GS_BULK_CONFIG_ID
-				&& wIndex != GS_BULK_INTERFACE_ID)
-			break;
-		/* no alternate interface settings */
-		if (wValue != 0)
-			break;
-		spin_lock(&dev->dev_lock);
-		/* PXA hardware partially handles SET_INTERFACE;
-		 * we need to kluge around that interference.  */
-		if (gadget_is_pxa(gadget)) {
-			ret = gs_set_config(dev, use_acm ?
-				GS_ACM_CONFIG_ID : GS_BULK_CONFIG_ID);
-			goto set_interface_done;
-		}
-		if (dev->dev_config != GS_BULK_CONFIG_ID
-				&& wIndex == GS_CONTROL_INTERFACE_ID) {
-			if (dev->gser.notify) {
-				usb_ep_disable(dev->gser.notify);
-				usb_ep_enable(dev->gser.notify,
-						dev->gser.notify_desc);
-			}
-		} else {
-			gserial_connect(&dev->gser, 0);
-			gserial_disconnect(&dev->gser);
-		}
-		ret = 0;
-set_interface_done:
-		spin_unlock(&dev->dev_lock);
-		break;
+	/* config description */
+	status = usb_string_id(cdev);
+	if (status < 0)
+		goto fail;
+	strings_dev[STRING_DESCRIPTION_IDX].id = status;
 
-	case USB_REQ_GET_INTERFACE:
-		if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE)
-		|| dev->dev_config == GS_NO_CONFIG_ID)
-			break;
-		if (wIndex >= GS_MAX_NUM_INTERFACES
-				|| (dev->dev_config == GS_BULK_CONFIG_ID
-				&& wIndex != GS_BULK_INTERFACE_ID)) {
-			ret = -EDOM;
-			break;
-		}
-		/* no alternate interface settings */
-		*(u8 *)req->buf = 0;
-		ret = min(wLength, (u16)1);
-		break;
+	serial_config_driver.iConfiguration = status;
 
-	default:
-		pr_err("gs_setup: unknown standard request, type=%02x, "
-			"request=%02x, value=%04x, index=%04x, length=%d\n",
-			ctrl->bRequestType, ctrl->bRequest,
-			wValue, wIndex, wLength);
-		break;
-	}
-
-	return ret;
-}
-
-static void gs_setup_complete_set_line_coding(struct usb_ep *ep,
-		struct usb_request *req)
-{
-	struct gs_dev *dev = ep->driver_data;
-
-	switch (req->status) {
-	case 0:
-		/* normal completion */
-		if (req->actual != sizeof(dev->gser.port_line_coding))
-			usb_ep_set_halt(ep);
-		else {
-			struct usb_cdc_line_coding	*value = req->buf;
-
-			/* REVISIT:  we currently just remember this data.
-			 * If we change that, (a) validate it first, then
-			 * (b) update whatever hardware needs updating.
-			 */
-			spin_lock(&dev->dev_lock);
-			dev->gser.port_line_coding = *value;
-			spin_unlock(&dev->dev_lock);
-		}
-		break;
-
-	case -ESHUTDOWN:
-		/* disconnect */
-		gs_free_req(ep, req);
-		break;
-
-	default:
-		/* unexpected */
-		break;
-	}
-	return;
-}
-
-static int gs_setup_class(struct usb_gadget *gadget,
-	const struct usb_ctrlrequest *ctrl)
-{
-	int ret = -EOPNOTSUPP;
-	struct gs_dev *dev = get_gadget_data(gadget);
-	struct usb_request *req = dev->dev_ctrl_req;
-	u16 wIndex = le16_to_cpu(ctrl->wIndex);
-	u16 wValue = le16_to_cpu(ctrl->wValue);
-	u16 wLength = le16_to_cpu(ctrl->wLength);
-
-	switch (ctrl->bRequest) {
-	case USB_CDC_REQ_SET_LINE_CODING:
-		if (wLength != sizeof(struct usb_cdc_line_coding))
-			break;
-		ret = wLength;
-		req->complete = gs_setup_complete_set_line_coding;
-		break;
-
-	case USB_CDC_REQ_GET_LINE_CODING:
-		ret = min_t(int, wLength, sizeof(struct usb_cdc_line_coding));
-		spin_lock(&dev->dev_lock);
-		memcpy(req->buf, &dev->gser.port_line_coding, ret);
-		spin_unlock(&dev->dev_lock);
-		break;
-
-	case USB_CDC_REQ_SET_CONTROL_LINE_STATE:
-		if (wLength != 0)
-			break;
-		ret = 0;
-		/* REVISIT:  we currently just remember this data.
-		 * If we change that, update whatever hardware needs
-		 * updating.
-		 */
-		spin_lock(&dev->dev_lock);
-		dev->gser.port_handshake_bits = wValue;
-		spin_unlock(&dev->dev_lock);
-		break;
-
-	default:
-		/* NOTE:  strictly speaking, we should accept AT-commands
-		 * using SEND_ENCPSULATED_COMMAND/GET_ENCAPSULATED_RESPONSE.
-		 * But our call management descriptor says we don't handle
-		 * call management, so we should be able to get by without
-		 * handling those "required" commands (except by stalling).
+	/* set up other descriptors */
+	gcnum = usb_gadget_controller_number(gadget);
+	if (gcnum >= 0)
+		device_desc.bcdDevice = cpu_to_le16(GS_VERSION_NUM | gcnum);
+	else {
+		/* this is so simple (for now, no altsettings) that it
+		 * SHOULD NOT have problems with bulk-capable hardware.
+		 * so warn about unrcognized controllers -- don't panic.
+		 *
+		 * things like configuration and altsetting numbering
+		 * can need hardware-specific attention though.
 		 */
-		pr_err("gs_setup: unknown class request, "
-				"type=%02x, request=%02x, value=%04x, "
-				"index=%04x, length=%d\n",
-			ctrl->bRequestType, ctrl->bRequest,
-			wValue, wIndex, wLength);
-		break;
-	}
-
-	return ret;
-}
-
-/*
- * gs_setup_complete
- */
-static void gs_setup_complete(struct usb_ep *ep, struct usb_request *req)
-{
-	if (req->status || req->actual != req->length) {
-		pr_err("gs_setup_complete: status error, status=%d, "
-			"actual=%d, length=%d\n",
-			req->status, req->actual, req->length);
-	}
-}
-
-/*
- * gs_setup
- *
- * Implements all the control endpoint functionality that's not
- * handled in hardware or the hardware driver.
- *
- * Returns the size of the data sent to the host, or a negative
- * error number.
- */
-static int gs_setup(struct usb_gadget *gadget,
-	const struct usb_ctrlrequest *ctrl)
-{
-	int		ret = -EOPNOTSUPP;
-	struct gs_dev	*dev = get_gadget_data(gadget);
-	struct usb_request *req = dev->dev_ctrl_req;
-	u16		wIndex = le16_to_cpu(ctrl->wIndex);
-	u16		wValue = le16_to_cpu(ctrl->wValue);
-	u16		wLength = le16_to_cpu(ctrl->wLength);
-
-	req->complete = gs_setup_complete;
-
-	switch (ctrl->bRequestType & USB_TYPE_MASK) {
-	case USB_TYPE_STANDARD:
-		ret = gs_setup_standard(gadget, ctrl);
-		break;
-
-	case USB_TYPE_CLASS:
-		ret = gs_setup_class(gadget, ctrl);
-		break;
-
-	default:
-		pr_err("gs_setup: unknown request, type=%02x, request=%02x, "
-			"value=%04x, index=%04x, length=%d\n",
-			ctrl->bRequestType, ctrl->bRequest,
-			wValue, wIndex, wLength);
-		break;
+		pr_warning("gs_bind: controller '%s' not recognized\n",
+			gadget->name);
+		device_desc.bcdDevice =
+			__constant_cpu_to_le16(GS_VERSION_NUM | 0x0099);
 	}
 
-	/* respond with data transfer before status phase? */
-	if (ret >= 0) {
-		req->length = ret;
-		req->zero = ret < wLength
-				&& (ret % gadget->ep0->maxpacket) == 0;
-		ret = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
-		if (ret < 0) {
-			pr_err("gs_setup: cannot queue response, ret=%d\n",
-				ret);
-			req->status = 0;
-			gs_setup_complete(gadget->ep0, req);
-		}
+	if (gadget_is_otg(cdev->gadget)) {
+		serial_config_driver.descriptors = otg_desc;
+		serial_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 	}
 
-	/* device either stalls (ret < 0) or reports success */
-	return ret;
-}
+	/* register our configuration */
+	status = usb_add_config(cdev, &serial_config_driver);
+	if (status < 0)
+		goto fail;
 
-/*
- * gs_disconnect
- *
- * Called when the device is disconnected.  Frees the closed
- * ports and disconnects open ports.  Open ports will be freed
- * on close.  Then reallocates the ports for the next connection.
- */
-static void gs_disconnect(struct usb_gadget *gadget)
-{
-	unsigned long flags;
-	struct gs_dev *dev = get_gadget_data(gadget);
+	INFO(cdev, "%s\n", GS_VERSION_NAME);
 
-	spin_lock_irqsave(&dev->dev_lock, flags);
-	gs_reset_config(dev);
-	spin_unlock_irqrestore(&dev->dev_lock, flags);
+	return 0;
 
-	pr_info("gs_disconnect: %s disconnected\n", GS_LONG_NAME);
+fail:
+	gserial_cleanup();
+	return status;
 }
 
-static struct usb_gadget_driver gs_gadget_driver = {
-#ifdef CONFIG_USB_GADGET_DUALSPEED
-	.speed =		USB_SPEED_HIGH,
-#else
-	.speed =		USB_SPEED_FULL,
-#endif /* CONFIG_USB_GADGET_DUALSPEED */
-	.function =		GS_LONG_NAME,
-	.bind =			gs_bind,
-	.unbind =		gs_unbind,
-	.setup =		gs_setup,
-	.disconnect =		gs_disconnect,
-	.driver = {
-		.name =		GS_SHORT_NAME,
-		.owner =	THIS_MODULE,
-	},
+static struct usb_composite_driver gserial_driver = {
+	.name		= "g_serial",
+	.dev		= &device_desc,
+	.strings	= dev_strings,
+	.bind		= gs_bind,
 };
 
-/*
- * gs_set_config
- *
- * Configures the device by enabling device specific
- * optimizations, setting up the endpoints, allocating
- * read and write requests and queuing read requests.
- *
- * The device lock must be held when calling this function.
- */
-static int gs_set_config(struct gs_dev *dev, unsigned config)
+static int __init init(void)
 {
-	int ret = 0;
-	struct usb_gadget *gadget = dev->dev_gadget;
-
-	if (config == dev->dev_config)
-		return 0;
-
-	gs_reset_config(dev);
-
-	switch (config) {
-	case GS_NO_CONFIG_ID:
-		return 0;
-	case GS_BULK_CONFIG_ID:
-		if (use_acm)
-			return -EINVAL;
-		break;
-	case GS_ACM_CONFIG_ID:
-		if (!use_acm)
-			return -EINVAL;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	dev->gser.in_desc = choose_ep_desc(gadget,
-			&gs_highspeed_in_desc,
-			&gs_fullspeed_in_desc);
-	dev->gser.out_desc = choose_ep_desc(gadget,
-			&gs_highspeed_out_desc,
-			&gs_fullspeed_out_desc);
-	dev->gser.notify_desc = dev->gser.notify
-		? choose_ep_desc(gadget,
-				&gs_highspeed_notify_desc,
-				&gs_fullspeed_notify_desc)
-		: NULL;
-
-	/* only support one "serial" port for now */
-	if (dev->gser.notify) {
-		ret = usb_ep_enable(dev->gser.notify, dev->gser.notify_desc);
-		if (ret < 0)
-			return ret;
-		dev->gser.notify->driver_data = dev;
-	}
-
-	ret = gserial_connect(&dev->gser, 0);
-	if (ret < 0) {
-		if (dev->gser.notify) {
-			usb_ep_disable(dev->gser.notify);
-			dev->gser.notify->driver_data = NULL;
-		}
-		return ret;
-	}
-
-	dev->dev_config = config;
-
-	/* REVISIT the ACM mode should be able to actually *issue* some
-	 * notifications, for at least serial state change events if
-	 * not also for network connection; say so in bmCapabilities.
+	/* We *could* export two configs; that'd be much cleaner...
+	 * but neither of these product IDs was defined that way.
 	 */
-
-	pr_info("gs_set_config: %s configured, %s speed %s config\n",
-		GS_LONG_NAME,
-		gadget->speed == USB_SPEED_HIGH ? "high" : "full",
-		config == GS_BULK_CONFIG_ID ? "BULK" : "CDC-ACM");
-
-	return 0;
-}
-
-/*
- * gs_reset_config
- *
- * Mark the device as not configured, disable all endpoints,
- * which forces completion of pending I/O and frees queued
- * requests, and free the remaining write requests on the
- * free list.
- *
- * The device lock must be held when calling this function.
- */
-static void gs_reset_config(struct gs_dev *dev)
-{
-	if (dev->dev_config == GS_NO_CONFIG_ID)
-		return;
-
-	dev->dev_config = GS_NO_CONFIG_ID;
-
-	gserial_disconnect(&dev->gser);
-	if (dev->gser.notify) {
-		usb_ep_disable(dev->gser.notify);
-		dev->gser.notify->driver_data = NULL;
-	}
-}
-
-/*
- * gs_build_config_buf
- *
- * Builds the config descriptors in the given buffer and returns the
- * length, or a negative error number.
- */
-static int gs_build_config_buf(u8 *buf, struct usb_gadget *g,
-	u8 type, unsigned int index, int is_otg)
-{
-	int len;
-	int high_speed = 0;
-	const struct usb_config_descriptor *config_desc;
-	const struct usb_descriptor_header **function;
-
-	if (index >= gs_device_desc.bNumConfigurations)
-		return -EINVAL;
-
-	/* other speed switches high and full speed */
-	if (gadget_is_dualspeed(g)) {
-		high_speed = (g->speed == USB_SPEED_HIGH);
-		if (type == USB_DT_OTHER_SPEED_CONFIG)
-			high_speed = !high_speed;
-	}
-
 	if (use_acm) {
-		config_desc = &gs_acm_config_desc;
-		function = high_speed
-			? gs_acm_highspeed_function
-			: gs_acm_fullspeed_function;
+		serial_config_driver.label = "CDC ACM config";
+		serial_config_driver.bConfigurationValue = 2;
+		device_desc.bDeviceClass = USB_CLASS_COMM;
+		device_desc.idProduct =
+				__constant_cpu_to_le16(GS_CDC_PRODUCT_ID);
 	} else {
-		config_desc = &gs_bulk_config_desc;
-		function = high_speed
-			? gs_bulk_highspeed_function
-			: gs_bulk_fullspeed_function;
-	}
-
-	/* for now, don't advertise srp-only devices */
-	if (!is_otg)
-		function++;
-
-	len = usb_gadget_config_buf(config_desc, buf, GS_MAX_DESC_LEN, function);
-	if (len < 0)
-		return len;
-
-	((struct usb_config_descriptor *)buf)->bDescriptorType = type;
-
-	return len;
-}
-
-/*
- * gs_alloc_req
- *
- * Allocate a usb_request and its buffer.  Returns a pointer to the
- * usb_request or NULL if there is an error.
- */
-static struct usb_request *
-gs_alloc_req(struct usb_ep *ep, unsigned int len, gfp_t kmalloc_flags)
-{
-	struct usb_request *req;
-
-	if (ep == NULL)
-		return NULL;
-
-	req = usb_ep_alloc_request(ep, kmalloc_flags);
-
-	if (req != NULL) {
-		req->length = len;
-		req->buf = kmalloc(len, kmalloc_flags);
-		if (req->buf == NULL) {
-			usb_ep_free_request(ep, req);
-			return NULL;
-		}
-	}
-
-	return req;
-}
-
-/*
- * gs_free_req
- *
- * Free a usb_request and its buffer.
- */
-static void gs_free_req(struct usb_ep *ep, struct usb_request *req)
-{
-	if (ep != NULL && req != NULL) {
-		kfree(req->buf);
-		usb_ep_free_request(ep, req);
+		serial_config_driver.label = "Generic Serial config";
+		serial_config_driver.bConfigurationValue = 1;
+		device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
+		device_desc.idProduct =
+				__constant_cpu_to_le16(GS_PRODUCT_ID);
 	}
-}
-
-/*-------------------------------------------------------------------------*/
+	strings_dev[STRING_DESCRIPTION_IDX].s = serial_config_driver.label;
 
-/*
- *  gs_module_init
- *
- *  Register as a USB gadget driver and a tty driver.
- */
-static int __init gs_module_init(void)
-{
-	return usb_gadget_register_driver(&gs_gadget_driver);
+	return usb_composite_register(&gserial_driver);
 }
-module_init(gs_module_init);
+module_init(init);
 
-/*
- * gs_module_exit
- *
- * Unregister as a tty driver and a USB gadget driver.
- */
-static void __exit gs_module_exit(void)
+static void __exit cleanup(void)
 {
-	usb_gadget_unregister_driver(&gs_gadget_driver);
+	usb_composite_unregister(&gserial_driver);
+	gserial_cleanup();
 }
-module_exit(gs_module_exit);
+module_exit(cleanup);