Merge tag 'usb-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB updates from Greg KH:
 "Here is the big USB driver update for 3.17-rc1.

  Loads of gadget driver changes in here, including some big file
  movements to make things easier to manage over time.  There's also the
  usual xhci and uas driver updates, and a handful of other changes in
  here.  The changelog has the full details.

  All of these have been in linux-next for a while"

* tag 'usb-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (211 commits)
  USB: devio: fix issue with log flooding
  uas: Log a warning when we cannot use uas because the hcd lacks streams
  uas: Only complain about missing sg if all other checks succeed
  xhci: Add missing checks for xhci_alloc_command failure
  xhci: Rename Asrock P67 pci product-id to EJ168
  xhci: Blacklist using streams on the Etron EJ168 controller
  uas: Limit qdepth to 32 when connected over usb-2
  uwb/whci: use correct structure type name in sizeof
  usb-core bInterval quirk
  USB: serial: ftdi_sio: Add support for new Xsens devices
  USB: serial: ftdi_sio: Annotate the current Xsens PID assignments
  usb: chipidea: debug: fix sparse non static symbol warnings
  usb: ci_hdrc_imx doc: fsl,usbphy is required
  usb: ci_hdrc_imx: Return -EINVAL for missing USB PHY
  usb: core: allow zero packet flag for interrupt urbs
  usb: lvstest: Fix sparse warnings generated by kbuild test bot
  USB: core: hcd-pci: free IRQ before disabling PCI device when shutting down
  phy: miphy365x: Represent each PHY channel as a DT subnode
  phy: miphy365x: Provide support for the MiPHY356x Generic PHY
  phy: miphy365x: Add Device Tree bindings for the MiPHY365x
  ...

1 files changed, 848 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_acm.c b/drivers/usb/gadget/function/f_acm.c
new file mode 100644
index 000000000000..ab1065afbbd0
--- /dev/null
+++ b/drivers/usb/gadget/function/f_acm.c
@@ -0,0 +1,848 @@
+/*
+ * f_acm.c -- USB CDC serial (ACM) function driver
+ *
+ * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
+ * Copyright (C) 2008 by David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ * Copyright (C) 2009 by Samsung Electronics
+ * Author: Michal Nazarewicz (mina86@mina86.com)
+ *
+ * This software is distributed under the terms of the GNU General
+ * Public License ("GPL") as published by the Free Software Foundation,
+ * either version 2 of that License or (at your option) any later version.
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+
+#include "u_serial.h"
+#include "gadget_chips.h"
+
+
+/*
+ * This CDC ACM function support just wraps control functions and
+ * notifications around the generic serial-over-usb code.
+ *
+ * Because CDC ACM is standardized by the USB-IF, many host operating
+ * systems have drivers for it.  Accordingly, ACM is the preferred
+ * interop solution for serial-port type connections.  The control
+ * models are often not necessary, and in any case don't do much in
+ * this bare-bones implementation.
+ *
+ * Note that even MS-Windows has some support for ACM.  However, that
+ * support is somewhat broken because when you use ACM in a composite
+ * device, having multiple interfaces confuses the poor OS.  It doesn't
+ * seem to understand CDC Union descriptors.  The new "association"
+ * descriptors (roughly equivalent to CDC Unions) may sometimes help.
+ */
+
+struct f_acm {
+        struct gserial                  port;
+        u8                              ctrl_id, data_id;
+        u8                              port_num;
+
+        u8                              pending;
+
+        /* lock is mostly for pending and notify_req ... they get accessed
+         * by callbacks both from tty (open/close/break) under its spinlock,
+         * and notify_req.complete() which can't use that lock.
+         */
+        spinlock_t                      lock;
+
+        struct usb_ep                   *notify;
+        struct usb_request              *notify_req;
+
+        struct usb_cdc_line_coding      port_line_coding;       /* 8-N-1 etc */
+
+        /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
+        u16                             port_handshake_bits;
+#define ACM_CTRL_RTS    (1 << 1)        /* unused with full duplex */
+#define ACM_CTRL_DTR    (1 << 0)        /* host is ready for data r/w */
+
+        /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
+        u16                             serial_state;
+#define ACM_CTRL_OVERRUN        (1 << 6)
+#define ACM_CTRL_PARITY         (1 << 5)
+#define ACM_CTRL_FRAMING        (1 << 4)
+#define ACM_CTRL_RI             (1 << 3)
+#define ACM_CTRL_BRK            (1 << 2)
+#define ACM_CTRL_DSR            (1 << 1)
+#define ACM_CTRL_DCD            (1 << 0)
+};
+
+static inline struct f_acm *func_to_acm(struct usb_function *f)
+{
+        return container_of(f, struct f_acm, port.func);
+}
+
+static inline struct f_acm *port_to_acm(struct gserial *p)
+{
+        return container_of(p, struct f_acm, port);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* notification endpoint uses smallish and infrequent fixed-size messages */
+
+#define GS_NOTIFY_INTERVAL_MS           32
+#define GS_NOTIFY_MAXPACKET             10      /* notification + 2 bytes */
+
+/* interface and class descriptors: */
+
+static struct usb_interface_assoc_descriptor
+acm_iad_descriptor = {
+        .bLength =              sizeof acm_iad_descriptor,
+        .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
+
+        /* .bFirstInterface =   DYNAMIC, */
+        .bInterfaceCount =      2,      // control + data
+        .bFunctionClass =       USB_CLASS_COMM,
+        .bFunctionSubClass =    USB_CDC_SUBCLASS_ACM,
+        .bFunctionProtocol =    USB_CDC_ACM_PROTO_AT_V25TER,
+        /* .iFunction =         DYNAMIC */
+};
+
+
+static struct usb_interface_descriptor acm_control_interface_desc = {
+        .bLength =              USB_DT_INTERFACE_SIZE,
+        .bDescriptorType =      USB_DT_INTERFACE,
+        /* .bInterfaceNumber = DYNAMIC */
+        .bNumEndpoints =        1,
+        .bInterfaceClass =      USB_CLASS_COMM,
+        .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
+        .bInterfaceProtocol =   USB_CDC_ACM_PROTO_AT_V25TER,
+        /* .iInterface = DYNAMIC */
+};
+
+static struct usb_interface_descriptor acm_data_interface_desc = {
+        .bLength =              USB_DT_INTERFACE_SIZE,
+        .bDescriptorType =      USB_DT_INTERFACE,
+        /* .bInterfaceNumber = DYNAMIC */
+        .bNumEndpoints =        2,
+        .bInterfaceClass =      USB_CLASS_CDC_DATA,
+        .bInterfaceSubClass =   0,
+        .bInterfaceProtocol =   0,
+        /* .iInterface = DYNAMIC */
+};
+
+static struct usb_cdc_header_desc acm_header_desc = {
+        .bLength =              sizeof(acm_header_desc),
+        .bDescriptorType =      USB_DT_CS_INTERFACE,
+        .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
+        .bcdCDC =               cpu_to_le16(0x0110),
+};
+
+static struct usb_cdc_call_mgmt_descriptor
+acm_call_mgmt_descriptor = {
+        .bLength =              sizeof(acm_call_mgmt_descriptor),
+        .bDescriptorType =      USB_DT_CS_INTERFACE,
+        .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
+        .bmCapabilities =       0,
+        /* .bDataInterface = DYNAMIC */
+};
+
+static struct usb_cdc_acm_descriptor acm_descriptor = {
+        .bLength =              sizeof(acm_descriptor),
+        .bDescriptorType =      USB_DT_CS_INTERFACE,
+        .bDescriptorSubType =   USB_CDC_ACM_TYPE,
+        .bmCapabilities =       USB_CDC_CAP_LINE,
+};
+
+static struct usb_cdc_union_desc acm_union_desc = {
+        .bLength =              sizeof(acm_union_desc),
+        .bDescriptorType =      USB_DT_CS_INTERFACE,
+        .bDescriptorSubType =   USB_CDC_UNION_TYPE,
+        /* .bMasterInterface0 = DYNAMIC */
+        /* .bSlaveInterface0 =  DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor acm_fs_notify_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bEndpointAddress =     USB_DIR_IN,
+        .bmAttributes =         USB_ENDPOINT_XFER_INT,
+        .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
+        .bInterval =            GS_NOTIFY_INTERVAL_MS,
+};
+
+static struct usb_endpoint_descriptor acm_fs_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 acm_fs_out_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bEndpointAddress =     USB_DIR_OUT,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *acm_fs_function[] = {
+        (struct usb_descriptor_header *) &acm_iad_descriptor,
+        (struct usb_descriptor_header *) &acm_control_interface_desc,
+        (struct usb_descriptor_header *) &acm_header_desc,
+        (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
+        (struct usb_descriptor_header *) &acm_descriptor,
+        (struct usb_descriptor_header *) &acm_union_desc,
+        (struct usb_descriptor_header *) &acm_fs_notify_desc,
+        (struct usb_descriptor_header *) &acm_data_interface_desc,
+        (struct usb_descriptor_header *) &acm_fs_in_desc,
+        (struct usb_descriptor_header *) &acm_fs_out_desc,
+        NULL,
+};
+
+/* high speed support: */
+static struct usb_endpoint_descriptor acm_hs_notify_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bEndpointAddress =     USB_DIR_IN,
+        .bmAttributes =         USB_ENDPOINT_XFER_INT,
+        .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
+        .bInterval =            USB_MS_TO_HS_INTERVAL(GS_NOTIFY_INTERVAL_MS),
+};
+
+static struct usb_endpoint_descriptor acm_hs_in_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor acm_hs_out_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *acm_hs_function[] = {
+        (struct usb_descriptor_header *) &acm_iad_descriptor,
+        (struct usb_descriptor_header *) &acm_control_interface_desc,
+        (struct usb_descriptor_header *) &acm_header_desc,
+        (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
+        (struct usb_descriptor_header *) &acm_descriptor,
+        (struct usb_descriptor_header *) &acm_union_desc,
+        (struct usb_descriptor_header *) &acm_hs_notify_desc,
+        (struct usb_descriptor_header *) &acm_data_interface_desc,
+        (struct usb_descriptor_header *) &acm_hs_in_desc,
+        (struct usb_descriptor_header *) &acm_hs_out_desc,
+        NULL,
+};
+
+static struct usb_endpoint_descriptor acm_ss_in_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(1024),
+};
+
+static struct usb_endpoint_descriptor acm_ss_out_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor acm_ss_bulk_comp_desc = {
+        .bLength =              sizeof acm_ss_bulk_comp_desc,
+        .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
+};
+
+static struct usb_descriptor_header *acm_ss_function[] = {
+        (struct usb_descriptor_header *) &acm_iad_descriptor,
+        (struct usb_descriptor_header *) &acm_control_interface_desc,
+        (struct usb_descriptor_header *) &acm_header_desc,
+        (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
+        (struct usb_descriptor_header *) &acm_descriptor,
+        (struct usb_descriptor_header *) &acm_union_desc,
+        (struct usb_descriptor_header *) &acm_hs_notify_desc,
+        (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
+        (struct usb_descriptor_header *) &acm_data_interface_desc,
+        (struct usb_descriptor_header *) &acm_ss_in_desc,
+        (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
+        (struct usb_descriptor_header *) &acm_ss_out_desc,
+        (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
+        NULL,
+};
+
+/* string descriptors: */
+
+#define ACM_CTRL_IDX    0
+#define ACM_DATA_IDX    1
+#define ACM_IAD_IDX     2
+
+/* static strings, in UTF-8 */
+static struct usb_string acm_string_defs[] = {
+        [ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
+        [ACM_DATA_IDX].s = "CDC ACM Data",
+        [ACM_IAD_IDX ].s = "CDC Serial",
+        {  } /* end of list */
+};
+
+static struct usb_gadget_strings acm_string_table = {
+        .language =             0x0409, /* en-us */
+        .strings =              acm_string_defs,
+};
+
+static struct usb_gadget_strings *acm_strings[] = {
+        &acm_string_table,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* ACM control ... data handling is delegated to tty library code.
+ * The main task of this function is to activate and deactivate
+ * that code based on device state; track parameters like line
+ * speed, handshake state, and so on; and issue notifications.
+ */
+
+static void acm_complete_set_line_coding(struct usb_ep *ep,
+                struct usb_request *req)
+{
+        struct f_acm    *acm = ep->driver_data;
+        struct usb_composite_dev *cdev = acm->port.func.config->cdev;
+
+        if (req->status != 0) {
+                DBG(cdev, "acm ttyGS%d completion, err %d\n",
+                                acm->port_num, req->status);
+                return;
+        }
+
+        /* normal completion */
+        if (req->actual != sizeof(acm->port_line_coding)) {
+                DBG(cdev, "acm ttyGS%d short resp, len %d\n",
+                                acm->port_num, req->actual);
+                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,
+                 * (c) worry about locking.  This is information on
+                 * the order of 9600-8-N-1 ... most of which means
+                 * nothing unless we control a real RS232 line.
+                 */
+                acm->port_line_coding = *value;
+        }
+}
+
+static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+        struct f_acm            *acm = func_to_acm(f);
+        struct usb_composite_dev *cdev = f->config->cdev;
+        struct usb_request      *req = cdev->req;
+        int                     value = -EOPNOTSUPP;
+        u16                     w_index = le16_to_cpu(ctrl->wIndex);
+        u16                     w_value = le16_to_cpu(ctrl->wValue);
+        u16                     w_length = le16_to_cpu(ctrl->wLength);
+
+        /* composite driver infrastructure handles everything except
+         * CDC class messages; interface activation uses set_alt().
+         *
+         * Note CDC spec table 4 lists the ACM request profile.  It requires
+         * encapsulated command support ... we don't handle any, and respond
+         * to them by stalling.  Options include get/set/clear comm features
+         * (not that useful) and SEND_BREAK.
+         */
+        switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
+
+        /* SET_LINE_CODING ... just read and save what the host sends */
+        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
+                        | USB_CDC_REQ_SET_LINE_CODING:
+                if (w_length != sizeof(struct usb_cdc_line_coding)
+                                || w_index != acm->ctrl_id)
+                        goto invalid;
+
+                value = w_length;
+                cdev->gadget->ep0->driver_data = acm;
+                req->complete = acm_complete_set_line_coding;
+                break;
+
+        /* GET_LINE_CODING ... return what host sent, or initial value */
+        case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
+                        | USB_CDC_REQ_GET_LINE_CODING:
+                if (w_index != acm->ctrl_id)
+                        goto invalid;
+
+                value = min_t(unsigned, w_length,
+                                sizeof(struct usb_cdc_line_coding));
+                memcpy(req->buf, &acm->port_line_coding, value);
+                break;
+
+        /* SET_CONTROL_LINE_STATE ... save what the host sent */
+        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
+                        | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
+                if (w_index != acm->ctrl_id)
+                        goto invalid;
+
+                value = 0;
+
+                /* FIXME we should not allow data to flow until the
+                 * host sets the ACM_CTRL_DTR bit; and when it clears
+                 * that bit, we should return to that no-flow state.
+                 */
+                acm->port_handshake_bits = w_value;
+                break;
+
+        default:
+invalid:
+                VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
+                        ctrl->bRequestType, ctrl->bRequest,
+                        w_value, w_index, w_length);
+        }
+
+        /* respond with data transfer or status phase? */
+        if (value >= 0) {
+                DBG(cdev, "acm ttyGS%d req%02x.%02x v%04x i%04x l%d\n",
+                        acm->port_num, ctrl->bRequestType, ctrl->bRequest,
+                        w_value, w_index, w_length);
+                req->zero = 0;
+                req->length = value;
+                value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+                if (value < 0)
+                        ERROR(cdev, "acm response on ttyGS%d, err %d\n",
+                                        acm->port_num, value);
+        }
+
+        /* device either stalls (value < 0) or reports success */
+        return value;
+}
+
+static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+        struct f_acm            *acm = func_to_acm(f);
+        struct usb_composite_dev *cdev = f->config->cdev;
+
+        /* we know alt == 0, so this is an activation or a reset */
+
+        if (intf == acm->ctrl_id) {
+                if (acm->notify->driver_data) {
+                        VDBG(cdev, "reset acm control interface %d\n", intf);
+                        usb_ep_disable(acm->notify);
+                } else {
+                        VDBG(cdev, "init acm ctrl interface %d\n", intf);
+                        if (config_ep_by_speed(cdev->gadget, f, acm->notify))
+                                return -EINVAL;
+                }
+                usb_ep_enable(acm->notify);
+                acm->notify->driver_data = acm;
+
+        } else if (intf == acm->data_id) {
+                if (acm->port.in->driver_data) {
+                        DBG(cdev, "reset acm ttyGS%d\n", acm->port_num);
+                        gserial_disconnect(&acm->port);
+                }
+                if (!acm->port.in->desc || !acm->port.out->desc) {
+                        DBG(cdev, "activate acm ttyGS%d\n", acm->port_num);
+                        if (config_ep_by_speed(cdev->gadget, f,
+                                               acm->port.in) ||
+                            config_ep_by_speed(cdev->gadget, f,
+                                               acm->port.out)) {
+                                acm->port.in->desc = NULL;
+                                acm->port.out->desc = NULL;
+                                return -EINVAL;
+                        }
+                }
+                gserial_connect(&acm->port, acm->port_num);
+
+        } else
+                return -EINVAL;
+
+        return 0;
+}
+
+static void acm_disable(struct usb_function *f)
+{
+        struct f_acm    *acm = func_to_acm(f);
+        struct usb_composite_dev *cdev = f->config->cdev;
+
+        DBG(cdev, "acm ttyGS%d deactivated\n", acm->port_num);
+        gserial_disconnect(&acm->port);
+        usb_ep_disable(acm->notify);
+        acm->notify->driver_data = NULL;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/**
+ * acm_cdc_notify - issue CDC notification to host
+ * @acm: wraps host to be notified
+ * @type: notification type
+ * @value: Refer to cdc specs, wValue field.
+ * @data: data to be sent
+ * @length: size of data
+ * Context: irqs blocked, acm->lock held, acm_notify_req non-null
+ *
+ * Returns zero on success or a negative errno.
+ *
+ * See section 6.3.5 of the CDC 1.1 specification for information
+ * about the only notification we issue:  SerialState change.
+ */
+static int acm_cdc_notify(struct f_acm *acm, u8 type, u16 value,
+                void *data, unsigned length)
+{
+        struct usb_ep                   *ep = acm->notify;
+        struct usb_request              *req;
+        struct usb_cdc_notification     *notify;
+        const unsigned                  len = sizeof(*notify) + length;
+        void                            *buf;
+        int                             status;
+
+        req = acm->notify_req;
+        acm->notify_req = NULL;
+        acm->pending = false;
+
+        req->length = len;
+        notify = req->buf;
+        buf = notify + 1;
+
+        notify->bmRequestType = USB_DIR_IN | USB_TYPE_CLASS
+                        | USB_RECIP_INTERFACE;
+        notify->bNotificationType = type;
+        notify->wValue = cpu_to_le16(value);
+        notify->wIndex = cpu_to_le16(acm->ctrl_id);
+        notify->wLength = cpu_to_le16(length);
+        memcpy(buf, data, length);
+
+        /* ep_queue() can complete immediately if it fills the fifo... */
+        spin_unlock(&acm->lock);
+        status = usb_ep_queue(ep, req, GFP_ATOMIC);
+        spin_lock(&acm->lock);
+
+        if (status < 0) {
+                ERROR(acm->port.func.config->cdev,
+                                "acm ttyGS%d can't notify serial state, %d\n",
+                                acm->port_num, status);
+                acm->notify_req = req;
+        }
+
+        return status;
+}
+
+static int acm_notify_serial_state(struct f_acm *acm)
+{
+        struct usb_composite_dev *cdev = acm->port.func.config->cdev;
+        int                     status;
+
+        spin_lock(&acm->lock);
+        if (acm->notify_req) {
+                DBG(cdev, "acm ttyGS%d serial state %04x\n",
+                                acm->port_num, acm->serial_state);
+                status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
+                                0, &acm->serial_state, sizeof(acm->serial_state));
+        } else {
+                acm->pending = true;
+                status = 0;
+        }
+        spin_unlock(&acm->lock);
+        return status;
+}
+
+static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
+{
+        struct f_acm            *acm = req->context;
+        u8                      doit = false;
+
+        /* on this call path we do NOT hold the port spinlock,
+         * which is why ACM needs its own spinlock
+         */
+        spin_lock(&acm->lock);
+        if (req->status != -ESHUTDOWN)
+                doit = acm->pending;
+        acm->notify_req = req;
+        spin_unlock(&acm->lock);
+
+        if (doit)
+                acm_notify_serial_state(acm);
+}
+
+/* connect == the TTY link is open */
+
+static void acm_connect(struct gserial *port)
+{
+        struct f_acm            *acm = port_to_acm(port);
+
+        acm->serial_state |= ACM_CTRL_DSR | ACM_CTRL_DCD;
+        acm_notify_serial_state(acm);
+}
+
+static void acm_disconnect(struct gserial *port)
+{
+        struct f_acm            *acm = port_to_acm(port);
+
+        acm->serial_state &= ~(ACM_CTRL_DSR | ACM_CTRL_DCD);
+        acm_notify_serial_state(acm);
+}
+
+static int acm_send_break(struct gserial *port, int duration)
+{
+        struct f_acm            *acm = port_to_acm(port);
+        u16                     state;
+
+        state = acm->serial_state;
+        state &= ~ACM_CTRL_BRK;
+        if (duration)
+                state |= ACM_CTRL_BRK;
+
+        acm->serial_state = state;
+        return acm_notify_serial_state(acm);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* ACM function driver setup/binding */
+static int
+acm_bind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct usb_composite_dev *cdev = c->cdev;
+        struct f_acm            *acm = func_to_acm(f);
+        struct usb_string       *us;
+        int                     status;
+        struct usb_ep           *ep;
+
+        /* REVISIT might want instance-specific strings to help
+         * distinguish instances ...
+         */
+
+        /* maybe allocate device-global string IDs, and patch descriptors */
+        us = usb_gstrings_attach(cdev, acm_strings,
+                        ARRAY_SIZE(acm_string_defs));
+        if (IS_ERR(us))
+                return PTR_ERR(us);
+        acm_control_interface_desc.iInterface = us[ACM_CTRL_IDX].id;
+        acm_data_interface_desc.iInterface = us[ACM_DATA_IDX].id;
+        acm_iad_descriptor.iFunction = us[ACM_IAD_IDX].id;
+
+        /* allocate instance-specific interface IDs, and patch descriptors */
+        status = usb_interface_id(c, f);
+        if (status < 0)
+                goto fail;
+        acm->ctrl_id = status;
+        acm_iad_descriptor.bFirstInterface = status;
+
+        acm_control_interface_desc.bInterfaceNumber = status;
+        acm_union_desc .bMasterInterface0 = status;
+
+        status = usb_interface_id(c, f);
+        if (status < 0)
+                goto fail;
+        acm->data_id = status;
+
+        acm_data_interface_desc.bInterfaceNumber = status;
+        acm_union_desc.bSlaveInterface0 = status;
+        acm_call_mgmt_descriptor.bDataInterface = status;
+
+        status = -ENODEV;
+
+        /* allocate instance-specific endpoints */
+        ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
+        if (!ep)
+                goto fail;
+        acm->port.in = ep;
+        ep->driver_data = cdev; /* claim */
+
+        ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
+        if (!ep)
+                goto fail;
+        acm->port.out = ep;
+        ep->driver_data = cdev; /* claim */
+
+        ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
+        if (!ep)
+                goto fail;
+        acm->notify = ep;
+        ep->driver_data = cdev; /* claim */
+
+        /* allocate notification */
+        acm->notify_req = gs_alloc_req(ep,
+                        sizeof(struct usb_cdc_notification) + 2,
+                        GFP_KERNEL);
+        if (!acm->notify_req)
+                goto fail;
+
+        acm->notify_req->complete = acm_cdc_notify_complete;
+        acm->notify_req->context = acm;
+
+        /* support all relevant hardware speeds... we expect that when
+         * hardware is dual speed, all bulk-capable endpoints work at
+         * both speeds
+         */
+        acm_hs_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
+        acm_hs_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
+        acm_hs_notify_desc.bEndpointAddress =
+                acm_fs_notify_desc.bEndpointAddress;
+
+        acm_ss_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
+        acm_ss_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
+
+        status = usb_assign_descriptors(f, acm_fs_function, acm_hs_function,
+                        acm_ss_function);
+        if (status)
+                goto fail;
+
+        DBG(cdev, "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n",
+                        acm->port_num,
+                        gadget_is_superspeed(c->cdev->gadget) ? "super" :
+                        gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+                        acm->port.in->name, acm->port.out->name,
+                        acm->notify->name);
+        return 0;
+
+fail:
+        if (acm->notify_req)
+                gs_free_req(acm->notify, acm->notify_req);
+
+        /* we might as well release our claims on endpoints */
+        if (acm->notify)
+                acm->notify->driver_data = NULL;
+        if (acm->port.out)
+                acm->port.out->driver_data = NULL;
+        if (acm->port.in)
+                acm->port.in->driver_data = NULL;
+
+        ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
+
+        return status;
+}
+
+static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct f_acm            *acm = func_to_acm(f);
+
+        acm_string_defs[0].id = 0;
+        usb_free_all_descriptors(f);
+        if (acm->notify_req)
+                gs_free_req(acm->notify, acm->notify_req);
+}
+
+static void acm_free_func(struct usb_function *f)
+{
+        struct f_acm            *acm = func_to_acm(f);
+
+        kfree(acm);
+}
+
+static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
+{
+        struct f_serial_opts *opts;
+        struct f_acm *acm;
+
+        acm = kzalloc(sizeof(*acm), GFP_KERNEL);
+        if (!acm)
+                return ERR_PTR(-ENOMEM);
+
+        spin_lock_init(&acm->lock);
+
+        acm->port.connect = acm_connect;
+        acm->port.disconnect = acm_disconnect;
+        acm->port.send_break = acm_send_break;
+
+        acm->port.func.name = "acm";
+        acm->port.func.strings = acm_strings;
+        /* descriptors are per-instance copies */
+        acm->port.func.bind = acm_bind;
+        acm->port.func.set_alt = acm_set_alt;
+        acm->port.func.setup = acm_setup;
+        acm->port.func.disable = acm_disable;
+
+        opts = container_of(fi, struct f_serial_opts, func_inst);
+        acm->port_num = opts->port_num;
+        acm->port.func.unbind = acm_unbind;
+        acm->port.func.free_func = acm_free_func;
+
+        return &acm->port.func;
+}
+
+static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
+{
+        return container_of(to_config_group(item), struct f_serial_opts,
+                        func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_serial_opts);
+static ssize_t f_acm_attr_show(struct config_item *item,
+                                 struct configfs_attribute *attr,
+                                 char *page)
+{
+        struct f_serial_opts *opts = to_f_serial_opts(item);
+        struct f_serial_opts_attribute *f_serial_opts_attr =
+                container_of(attr, struct f_serial_opts_attribute, attr);
+        ssize_t ret = 0;
+
+        if (f_serial_opts_attr->show)
+                ret = f_serial_opts_attr->show(opts, page);
+        return ret;
+}
+
+static void acm_attr_release(struct config_item *item)
+{
+        struct f_serial_opts *opts = to_f_serial_opts(item);
+
+        usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations acm_item_ops = {
+        .release                = acm_attr_release,
+        .show_attribute         = f_acm_attr_show,
+};
+
+static ssize_t f_acm_port_num_show(struct f_serial_opts *opts, char *page)
+{
+        return sprintf(page, "%u\n", opts->port_num);
+}
+
+static struct f_serial_opts_attribute f_acm_port_num =
+        __CONFIGFS_ATTR_RO(port_num, f_acm_port_num_show);
+
+
+static struct configfs_attribute *acm_attrs[] = {
+        &f_acm_port_num.attr,
+        NULL,
+};
+
+static struct config_item_type acm_func_type = {
+        .ct_item_ops    = &acm_item_ops,
+        .ct_attrs       = acm_attrs,
+        .ct_owner       = THIS_MODULE,
+};
+
+static void acm_free_instance(struct usb_function_instance *fi)
+{
+        struct f_serial_opts *opts;
+
+        opts = container_of(fi, struct f_serial_opts, func_inst);
+        gserial_free_line(opts->port_num);
+        kfree(opts);
+}
+
+static struct usb_function_instance *acm_alloc_instance(void)
+{
+        struct f_serial_opts *opts;
+        int ret;
+
+        opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+        if (!opts)
+                return ERR_PTR(-ENOMEM);
+        opts->func_inst.free_func_inst = acm_free_instance;
+        ret = gserial_alloc_line(&opts->port_num);
+        if (ret) {
+                kfree(opts);
+                return ERR_PTR(ret);
+        }
+        config_group_init_type_name(&opts->func_inst.group, "",
+                        &acm_func_type);
+        return &opts->func_inst;
+}
+DECLARE_USB_FUNCTION_INIT(acm, acm_alloc_instance, acm_alloc_func);
+MODULE_LICENSE("GPL");