// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for the Diolan DLN-2 USB adapter
 *
 * Copyright (c) 2014 Intel Corporation
 *
 * Derived from:
 *  i2c-diolan-u2c.c
 *  Copyright (c) 2010-2011 Ericsson AB
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/mfd/core.h>
#include <linux/mfd/dln2.h>
#include <linux/rculist.h>

struct dln2_header {
        __le16 size;
        __le16 id;
        __le16 echo;
        __le16 handle;
};

struct dln2_response {
        struct dln2_header hdr;
        __le16 result;
};

#define DLN2_GENERIC_MODULE_ID          0x00
#define DLN2_GENERIC_CMD(cmd)           DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID)
#define CMD_GET_DEVICE_VER              DLN2_GENERIC_CMD(0x30)
#define CMD_GET_DEVICE_SN               DLN2_GENERIC_CMD(0x31)

#define DLN2_HW_ID                      0x200
#define DLN2_USB_TIMEOUT                200     /* in ms */
#define DLN2_MAX_RX_SLOTS               16
#define DLN2_MAX_URBS                   16
#define DLN2_RX_BUF_SIZE                512

enum dln2_handle {
        DLN2_HANDLE_EVENT = 0,          /* don't change, hardware defined */
        DLN2_HANDLE_CTRL,
        DLN2_HANDLE_GPIO,
        DLN2_HANDLE_I2C,
        DLN2_HANDLE_SPI,
        DLN2_HANDLE_ADC,
        DLN2_HANDLES
};

/*
 * Receive context used between the receive demultiplexer and the transfer
 * routine. While sending a request the transfer routine will look for a free
 * receive context and use it to wait for a response and to receive the URB and
 * thus the response data.
 */
struct dln2_rx_context {
        /* completion used to wait for a response */
        struct completion done;

        /* if non-NULL the URB contains the response */
        struct urb *urb;

        /* if true then this context is used to wait for a response */
        bool in_use;
};

/*
 * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the
 * handle header field to identify the module in dln2_dev.mod_rx_slots and then
 * the echo header field to index the slots field and find the receive context
 * for a particular request.
 */
struct dln2_mod_rx_slots {
        /* RX slots bitmap */
        DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);

        /* used to wait for a free RX slot */
        wait_queue_head_t wq;

        /* used to wait for an RX operation to complete */
        struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS];

        /* avoid races between alloc/free_rx_slot and dln2_rx_transfer */
        spinlock_t lock;
};

struct dln2_dev {
        struct usb_device *usb_dev;
        struct usb_interface *interface;
        u8 ep_in;
        u8 ep_out;

        struct urb *rx_urb[DLN2_MAX_URBS];
        void *rx_buf[DLN2_MAX_URBS];

        struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES];

        struct list_head event_cb_list;
        spinlock_t event_cb_lock;

        bool disconnect;
        int active_transfers;
        wait_queue_head_t disconnect_wq;
        spinlock_t disconnect_lock;
};

struct dln2_event_cb_entry {
        struct list_head list;
        u16 id;
        struct platform_device *pdev;
        dln2_event_cb_t callback;
};

int dln2_register_event_cb(struct platform_device *pdev, u16 id,
                           dln2_event_cb_t event_cb)
{
        struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
        struct dln2_event_cb_entry *i, *entry;
        unsigned long flags;
        int ret = 0;

        entry = kzalloc_obj(*entry);
        if (!entry)
                return -ENOMEM;

        entry->id = id;
        entry->callback = event_cb;
        entry->pdev = pdev;

        spin_lock_irqsave(&dln2->event_cb_lock, flags);

        list_for_each_entry(i, &dln2->event_cb_list, list) {
                if (i->id == id) {
                        ret = -EBUSY;
                        break;
                }
        }

        if (!ret)
                list_add_rcu(&entry->list, &dln2->event_cb_list);

        spin_unlock_irqrestore(&dln2->event_cb_lock, flags);

        if (ret)
                kfree(entry);

        return ret;
}
EXPORT_SYMBOL(dln2_register_event_cb);

void dln2_unregister_event_cb(struct platform_device *pdev, u16 id)
{
        struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
        struct dln2_event_cb_entry *i;
        unsigned long flags;
        bool found = false;

        spin_lock_irqsave(&dln2->event_cb_lock, flags);

        list_for_each_entry(i, &dln2->event_cb_list, list) {
                if (i->id == id) {
                        list_del_rcu(&i->list);
                        found = true;
                        break;
                }
        }

        spin_unlock_irqrestore(&dln2->event_cb_lock, flags);

        if (found) {
                synchronize_rcu();
                kfree(i);
        }
}
EXPORT_SYMBOL(dln2_unregister_event_cb);

/*
 * Returns true if a valid transfer slot is found. In this case the URB must not
 * be resubmitted immediately in dln2_rx as we need the data when dln2_transfer
 * is woke up. It will be resubmitted there.
 */
static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
                                   u16 handle, u16 rx_slot)
{
        struct device *dev = &dln2->interface->dev;
        struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
        struct dln2_rx_context *rxc;
        unsigned long flags;
        bool valid_slot = false;

        if (rx_slot >= DLN2_MAX_RX_SLOTS)
                goto out;

        rxc = &rxs->slots[rx_slot];

        spin_lock_irqsave(&rxs->lock, flags);
        if (rxc->in_use && !rxc->urb) {
                rxc->urb = urb;
                complete(&rxc->done);
                valid_slot = true;
        }
        spin_unlock_irqrestore(&rxs->lock, flags);

out:
        if (!valid_slot)
                dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);

        return valid_slot;
}

static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
                                     void *data, int len)
{
        struct dln2_event_cb_entry *i;

        rcu_read_lock();

        list_for_each_entry_rcu(i, &dln2->event_cb_list, list) {
                if (i->id == id) {
                        i->callback(i->pdev, echo, data, len);
                        break;
                }
        }

        rcu_read_unlock();
}

static void dln2_rx(struct urb *urb)
{
        struct dln2_dev *dln2 = urb->context;
        struct dln2_header *hdr = urb->transfer_buffer;
        struct device *dev = &dln2->interface->dev;
        u16 id, echo, handle, size;
        u8 *data;
        int len;
        int err;

        switch (urb->status) {
        case 0:
                /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
        case -EPIPE:
                /* this urb is terminated, clean up */
                dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
                return;
        default:
                dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
                goto out;
        }

        if (urb->actual_length < sizeof(struct dln2_header)) {
                dev_err(dev, "short response: %d\n", urb->actual_length);
                goto out;
        }

        handle = le16_to_cpu(hdr->handle);
        id = le16_to_cpu(hdr->id);
        echo = le16_to_cpu(hdr->echo);
        size = le16_to_cpu(hdr->size);

        if (size != urb->actual_length) {
                dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
                        handle, id, echo, size, urb->actual_length);
                goto out;
        }

        if (handle >= DLN2_HANDLES) {
                dev_warn(dev, "invalid handle %d\n", handle);
                goto out;
        }

        data = urb->transfer_buffer + sizeof(struct dln2_header);
        len = urb->actual_length - sizeof(struct dln2_header);

        if (handle == DLN2_HANDLE_EVENT) {
                unsigned long flags;

                spin_lock_irqsave(&dln2->event_cb_lock, flags);
                dln2_run_event_callbacks(dln2, id, echo, data, len);
                spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
        } else {
                /* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
                if (dln2_transfer_complete(dln2, urb, handle, echo))
                        return;
        }

out:
        err = usb_submit_urb(urb, GFP_ATOMIC);
        if (err < 0)
                dev_err(dev, "failed to resubmit RX URB: %d\n", err);
}

static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf,
                           int *obuf_len, gfp_t gfp)
{
        int len;
        void *buf;
        struct dln2_header *hdr;

        len = *obuf_len + sizeof(*hdr);
        buf = kmalloc(len, gfp);
        if (!buf)
                return NULL;

        hdr = (struct dln2_header *)buf;
        hdr->id = cpu_to_le16(cmd);
        hdr->size = cpu_to_le16(len);
        hdr->echo = cpu_to_le16(echo);
        hdr->handle = cpu_to_le16(handle);

        memcpy(buf + sizeof(*hdr), obuf, *obuf_len);

        *obuf_len = len;

        return buf;
}

static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo,
                          const void *obuf, int obuf_len)
{
        int ret = 0;
        int len = obuf_len;
        void *buf;
        int actual;

        buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = usb_bulk_msg(dln2->usb_dev,
                           usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out),
                           buf, len, &actual, DLN2_USB_TIMEOUT);

        kfree(buf);

        return ret;
}

static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot)
{
        struct dln2_mod_rx_slots *rxs;
        unsigned long flags;

        if (dln2->disconnect) {
                *slot = -ENODEV;
                return true;
        }

        rxs = &dln2->mod_rx_slots[handle];

        spin_lock_irqsave(&rxs->lock, flags);

        *slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS);

        if (*slot < DLN2_MAX_RX_SLOTS) {
                struct dln2_rx_context *rxc = &rxs->slots[*slot];

                set_bit(*slot, rxs->bmap);
                rxc->in_use = true;
        }

        spin_unlock_irqrestore(&rxs->lock, flags);

        return *slot < DLN2_MAX_RX_SLOTS;
}

static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle)
{
        int ret;
        int slot;

        /*
         * No need to timeout here, the wait is bounded by the timeout in
         * _dln2_transfer.
         */
        ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq,
                                       find_free_slot(dln2, handle, &slot));
        if (ret < 0)
                return ret;

        return slot;
}

static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot)
{
        struct dln2_mod_rx_slots *rxs;
        struct urb *urb = NULL;
        unsigned long flags;
        struct dln2_rx_context *rxc;

        rxs = &dln2->mod_rx_slots[handle];

        spin_lock_irqsave(&rxs->lock, flags);

        clear_bit(slot, rxs->bmap);

        rxc = &rxs->slots[slot];
        rxc->in_use = false;
        urb = rxc->urb;
        rxc->urb = NULL;
        reinit_completion(&rxc->done);

        spin_unlock_irqrestore(&rxs->lock, flags);

        if (urb) {
                int err;
                struct device *dev = &dln2->interface->dev;

                err = usb_submit_urb(urb, GFP_KERNEL);
                if (err < 0)
                        dev_err(dev, "failed to resubmit RX URB: %d\n", err);
        }

        wake_up_interruptible(&rxs->wq);
}

static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
                          const void *obuf, unsigned obuf_len,
                          void *ibuf, unsigned *ibuf_len)
{
        int ret = 0;
        int rx_slot;
        struct dln2_response *rsp;
        struct dln2_rx_context *rxc;
        struct device *dev = &dln2->interface->dev;
        const unsigned long timeout = msecs_to_jiffies(DLN2_USB_TIMEOUT);
        struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
        int size;

        spin_lock(&dln2->disconnect_lock);
        if (!dln2->disconnect)
                dln2->active_transfers++;
        else
                ret = -ENODEV;
        spin_unlock(&dln2->disconnect_lock);

        if (ret)
                return ret;

        rx_slot = alloc_rx_slot(dln2, handle);
        if (rx_slot < 0) {
                ret = rx_slot;
                goto out_decr;
        }

        ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len);
        if (ret < 0) {
                dev_err(dev, "USB write failed: %d\n", ret);
                goto out_free_rx_slot;
        }

        rxc = &rxs->slots[rx_slot];

        ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
        if (ret <= 0) {
                if (!ret)
                        ret = -ETIMEDOUT;
                goto out_free_rx_slot;
        } else {
                ret = 0;
        }

        if (dln2->disconnect) {
                ret = -ENODEV;
                goto out_free_rx_slot;
        }

        /* if we got here we know that the response header has been checked */
        rsp = rxc->urb->transfer_buffer;
        size = le16_to_cpu(rsp->hdr.size);

        if (size < sizeof(*rsp)) {
                ret = -EPROTO;
                goto out_free_rx_slot;
        }

        if (le16_to_cpu(rsp->result) > 0x80) {
                dev_dbg(dev, "%d received response with error %d\n",
                        handle, le16_to_cpu(rsp->result));
                ret = -EREMOTEIO;
                goto out_free_rx_slot;
        }

        if (!ibuf)
                goto out_free_rx_slot;

        if (*ibuf_len > size - sizeof(*rsp))
                *ibuf_len = size - sizeof(*rsp);

        memcpy(ibuf, rsp + 1, *ibuf_len);

out_free_rx_slot:
        free_rx_slot(dln2, handle, rx_slot);
out_decr:
        spin_lock(&dln2->disconnect_lock);
        dln2->active_transfers--;
        spin_unlock(&dln2->disconnect_lock);
        if (dln2->disconnect)
                wake_up(&dln2->disconnect_wq);

        return ret;
}

int dln2_transfer(struct platform_device *pdev, u16 cmd,
                  const void *obuf, unsigned obuf_len,
                  void *ibuf, unsigned *ibuf_len)
{
        struct dln2_platform_data *dln2_pdata;
        struct dln2_dev *dln2;
        u16 handle;

        dln2 = dev_get_drvdata(pdev->dev.parent);
        dln2_pdata = dev_get_platdata(&pdev->dev);
        handle = dln2_pdata->handle;

        return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf,
                              ibuf_len);
}
EXPORT_SYMBOL(dln2_transfer);

static int dln2_check_hw(struct dln2_dev *dln2)
{
        int ret;
        __le32 hw_type;
        int len = sizeof(hw_type);

        ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER,
                             NULL, 0, &hw_type, &len);
        if (ret < 0)
                return ret;
        if (len < sizeof(hw_type))
                return -EREMOTEIO;

        if (le32_to_cpu(hw_type) != DLN2_HW_ID) {
                dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n",
                        le32_to_cpu(hw_type));
                return -ENODEV;
        }

        return 0;
}

static int dln2_print_serialno(struct dln2_dev *dln2)
{
        int ret;
        __le32 serial_no;
        int len = sizeof(serial_no);
        struct device *dev = &dln2->interface->dev;

        ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
                             &serial_no, &len);
        if (ret < 0)
                return ret;
        if (len < sizeof(serial_no))
                return -EREMOTEIO;

        dev_info(dev, "Diolan DLN2 serial %u\n", le32_to_cpu(serial_no));

        return 0;
}

static int dln2_hw_init(struct dln2_dev *dln2)
{
        int ret;

        ret = dln2_check_hw(dln2);
        if (ret < 0)
                return ret;

        return dln2_print_serialno(dln2);
}

static void dln2_free_rx_urbs(struct dln2_dev *dln2)
{
        int i;

        for (i = 0; i < DLN2_MAX_URBS; i++) {
                usb_free_urb(dln2->rx_urb[i]);
                kfree(dln2->rx_buf[i]);
        }
}

static void dln2_stop_rx_urbs(struct dln2_dev *dln2)
{
        int i;

        for (i = 0; i < DLN2_MAX_URBS; i++)
                usb_kill_urb(dln2->rx_urb[i]);
}

static void dln2_free(struct dln2_dev *dln2)
{
        dln2_free_rx_urbs(dln2);
        usb_put_dev(dln2->usb_dev);
        kfree(dln2);
}

static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
                              struct usb_host_interface *hostif)
{
        int i;
        const int rx_max_size = DLN2_RX_BUF_SIZE;

        for (i = 0; i < DLN2_MAX_URBS; i++) {
                dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
                if (!dln2->rx_buf[i])
                        return -ENOMEM;

                dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
                if (!dln2->rx_urb[i])
                        return -ENOMEM;

                usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
                                  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
                                  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
        }

        return 0;
}

static int dln2_start_rx_urbs(struct dln2_dev *dln2, gfp_t gfp)
{
        struct device *dev = &dln2->interface->dev;
        int ret;
        int i;

        for (i = 0; i < DLN2_MAX_URBS; i++) {
                ret = usb_submit_urb(dln2->rx_urb[i], gfp);
                if (ret < 0) {
                        dev_err(dev, "failed to submit RX URB: %d\n", ret);
                        return ret;
                }
        }

        return 0;
}

enum {
        DLN2_ACPI_MATCH_GPIO    = 0,
        DLN2_ACPI_MATCH_I2C     = 1,
        DLN2_ACPI_MATCH_SPI     = 2,
        DLN2_ACPI_MATCH_ADC     = 3,
};

static struct dln2_platform_data dln2_pdata_gpio = {
        .handle = DLN2_HANDLE_GPIO,
};

static struct mfd_cell_acpi_match dln2_acpi_match_gpio = {
        .adr = DLN2_ACPI_MATCH_GPIO,
};

/* Only one I2C port seems to be supported on current hardware */
static struct dln2_platform_data dln2_pdata_i2c = {
        .handle = DLN2_HANDLE_I2C,
        .port = 0,
};

static struct mfd_cell_acpi_match dln2_acpi_match_i2c = {
        .adr = DLN2_ACPI_MATCH_I2C,
};

/* Only one SPI port supported */
static struct dln2_platform_data dln2_pdata_spi = {
        .handle = DLN2_HANDLE_SPI,
        .port = 0,
};

static struct mfd_cell_acpi_match dln2_acpi_match_spi = {
        .adr = DLN2_ACPI_MATCH_SPI,
};

/* Only one ADC port supported */
static struct dln2_platform_data dln2_pdata_adc = {
        .handle = DLN2_HANDLE_ADC,
        .port = 0,
};

static struct mfd_cell_acpi_match dln2_acpi_match_adc = {
        .adr = DLN2_ACPI_MATCH_ADC,
};

static const struct mfd_cell dln2_devs[] = {
        {
                .name = "dln2-gpio",
                .acpi_match = &dln2_acpi_match_gpio,
                .platform_data = &dln2_pdata_gpio,
                .pdata_size = sizeof(struct dln2_platform_data),
        },
        {
                .name = "dln2-i2c",
                .acpi_match = &dln2_acpi_match_i2c,
                .platform_data = &dln2_pdata_i2c,
                .pdata_size = sizeof(struct dln2_platform_data),
        },
        {
                .name = "dln2-spi",
                .acpi_match = &dln2_acpi_match_spi,
                .platform_data = &dln2_pdata_spi,
                .pdata_size = sizeof(struct dln2_platform_data),
        },
        {
                .name = "dln2-adc",
                .acpi_match = &dln2_acpi_match_adc,
                .platform_data = &dln2_pdata_adc,
                .pdata_size = sizeof(struct dln2_platform_data),
        },
};

static void dln2_stop(struct dln2_dev *dln2)
{
        int i, j;

        /* don't allow starting new transfers */
        spin_lock(&dln2->disconnect_lock);
        dln2->disconnect = true;
        spin_unlock(&dln2->disconnect_lock);

        /* cancel in progress transfers */
        for (i = 0; i < DLN2_HANDLES; i++) {
                struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i];
                unsigned long flags;

                spin_lock_irqsave(&rxs->lock, flags);

                /* cancel all response waiters */
                for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) {
                        struct dln2_rx_context *rxc = &rxs->slots[j];

                        if (rxc->in_use)
                                complete(&rxc->done);
                }

                spin_unlock_irqrestore(&rxs->lock, flags);
        }

        /* wait for transfers to end */
        wait_event(dln2->disconnect_wq, !dln2->active_transfers);

        dln2_stop_rx_urbs(dln2);
}

static void dln2_disconnect(struct usb_interface *interface)
{
        struct dln2_dev *dln2 = usb_get_intfdata(interface);

        dln2_stop(dln2);

        mfd_remove_devices(&interface->dev);

        dln2_free(dln2);
}

static int dln2_probe(struct usb_interface *interface,
                      const struct usb_device_id *usb_id)
{
        struct usb_host_interface *hostif = interface->cur_altsetting;
        struct usb_endpoint_descriptor *epin;
        struct usb_endpoint_descriptor *epout;
        struct device *dev = &interface->dev;
        struct dln2_dev *dln2;
        int ret;
        int i, j;

        if (hostif->desc.bInterfaceNumber != 0)
                return -ENODEV;

        ret = usb_find_common_endpoints(hostif, &epin, &epout, NULL, NULL);
        if (ret)
                return ret;

        dln2 = kzalloc_obj(*dln2);
        if (!dln2)
                return -ENOMEM;

        dln2->ep_out = epout->bEndpointAddress;
        dln2->ep_in = epin->bEndpointAddress;
        dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
        dln2->interface = interface;
        usb_set_intfdata(interface, dln2);
        init_waitqueue_head(&dln2->disconnect_wq);

        for (i = 0; i < DLN2_HANDLES; i++) {
                init_waitqueue_head(&dln2->mod_rx_slots[i].wq);
                spin_lock_init(&dln2->mod_rx_slots[i].lock);
                for (j = 0; j < DLN2_MAX_RX_SLOTS; j++)
                        init_completion(&dln2->mod_rx_slots[i].slots[j].done);
        }

        spin_lock_init(&dln2->event_cb_lock);
        spin_lock_init(&dln2->disconnect_lock);
        INIT_LIST_HEAD(&dln2->event_cb_list);

        ret = dln2_setup_rx_urbs(dln2, hostif);
        if (ret)
                goto out_free;

        ret = dln2_start_rx_urbs(dln2, GFP_KERNEL);
        if (ret)
                goto out_stop_rx;

        ret = dln2_hw_init(dln2);
        if (ret < 0) {
                dev_err(dev, "failed to initialize hardware\n");
                goto out_stop_rx;
        }

        ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs));
        if (ret != 0) {
                dev_err(dev, "failed to add mfd devices to core\n");
                goto out_stop_rx;
        }

        return 0;

out_stop_rx:
        dln2_stop_rx_urbs(dln2);

out_free:
        dln2_free(dln2);

        return ret;
}

static int dln2_suspend(struct usb_interface *iface, pm_message_t message)
{
        struct dln2_dev *dln2 = usb_get_intfdata(iface);

        dln2_stop(dln2);

        return 0;
}

static int dln2_resume(struct usb_interface *iface)
{
        struct dln2_dev *dln2 = usb_get_intfdata(iface);

        dln2->disconnect = false;

        return dln2_start_rx_urbs(dln2, GFP_NOIO);
}

static const struct usb_device_id dln2_table[] = {
        { USB_DEVICE(0xa257, 0x2013) },
        { }
};

MODULE_DEVICE_TABLE(usb, dln2_table);

static struct usb_driver dln2_driver = {
        .name = "dln2",
        .probe = dln2_probe,
        .disconnect = dln2_disconnect,
        .id_table = dln2_table,
        .suspend = dln2_suspend,
        .resume = dln2_resume,
};

module_usb_driver(dln2_driver);

MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter");
MODULE_LICENSE("GPL v2");