/*
 *  drivers/media/radio/si470x/radio-si470x-usb.c
 *
 *  USB driver for radios with Silicon Labs Si470x FM Radio Receivers
 *
 *  Copyright (c) 2009 Tobias Lorenz <tobias.lorenz@gmx.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


/*
 * ToDo:
 * - add firmware download/update support
 */


/* driver definitions */
#define DRIVER_AUTHOR "Tobias Lorenz <tobias.lorenz@gmx.net>"
#define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
#define DRIVER_DESC "USB radio driver for Si470x FM Radio Receivers"
#define DRIVER_VERSION "1.0.10"

/* kernel includes */
#include <linux/usb.h>
#include <linux/hid.h>
#include <linux/slab.h>

#include "radio-si470x.h"


/* USB Device ID List */
static struct usb_device_id si470x_usb_driver_id_table[] = {
        /* Silicon Labs USB FM Radio Reference Design */
        { USB_DEVICE_AND_INTERFACE_INFO(0x10c4, 0x818a, USB_CLASS_HID, 0, 0) },
        /* ADS/Tech FM Radio Receiver (formerly Instant FM Music) */
        { USB_DEVICE_AND_INTERFACE_INFO(0x06e1, 0xa155, USB_CLASS_HID, 0, 0) },
        /* KWorld USB FM Radio SnapMusic Mobile 700 (FM700) */
        { USB_DEVICE_AND_INTERFACE_INFO(0x1b80, 0xd700, USB_CLASS_HID, 0, 0) },
        /* Sanei Electric, Inc. FM USB Radio (sold as DealExtreme.com PCear) */
        { USB_DEVICE_AND_INTERFACE_INFO(0x10c5, 0x819a, USB_CLASS_HID, 0, 0) },
        /* Axentia ALERT FM USB Receiver */
        { USB_DEVICE_AND_INTERFACE_INFO(0x12cf, 0x7111, USB_CLASS_HID, 0, 0) },
        /* Terminating entry */
        { }
};
MODULE_DEVICE_TABLE(usb, si470x_usb_driver_id_table);



/**************************************************************************
 * Module Parameters
 **************************************************************************/

/* Radio Nr */
static int radio_nr = -1;
module_param(radio_nr, int, 0444);
MODULE_PARM_DESC(radio_nr, "Radio Nr");

/* USB timeout */
static unsigned int usb_timeout = 500;
module_param(usb_timeout, uint, 0644);
MODULE_PARM_DESC(usb_timeout, "USB timeout (ms): *500*");

/* RDS buffer blocks */
static unsigned int rds_buf = 100;
module_param(rds_buf, uint, 0444);
MODULE_PARM_DESC(rds_buf, "RDS buffer entries: *100*");

/* RDS maximum block errors */
static unsigned short max_rds_errors = 1;
/* 0 means   0  errors requiring correction */
/* 1 means 1-2  errors requiring correction (used by original USBRadio.exe) */
/* 2 means 3-5  errors requiring correction */
/* 3 means   6+ errors or errors in checkword, correction not possible */
module_param(max_rds_errors, ushort, 0644);
MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");



/**************************************************************************
 * USB HID Reports
 **************************************************************************/

/* Reports 1-16 give direct read/write access to the 16 Si470x registers */
/* with the (REPORT_ID - 1) corresponding to the register address across USB */
/* endpoint 0 using GET_REPORT and SET_REPORT */
#define REGISTER_REPORT_SIZE    (RADIO_REGISTER_SIZE + 1)
#define REGISTER_REPORT(reg)    ((reg) + 1)

/* Report 17 gives direct read/write access to the entire Si470x register */
/* map across endpoint 0 using GET_REPORT and SET_REPORT */
#define ENTIRE_REPORT_SIZE      (RADIO_REGISTER_NUM * RADIO_REGISTER_SIZE + 1)
#define ENTIRE_REPORT           17

/* Report 18 is used to send the lowest 6 Si470x registers up the HID */
/* interrupt endpoint 1 to Windows every 20 milliseconds for status */
#define RDS_REPORT_SIZE         (RDS_REGISTER_NUM * RADIO_REGISTER_SIZE + 1)
#define RDS_REPORT              18

/* Report 19: LED state */
#define LED_REPORT_SIZE         3
#define LED_REPORT              19

/* Report 19: stream */
#define STREAM_REPORT_SIZE      3
#define STREAM_REPORT           19

/* Report 20: scratch */
#define SCRATCH_PAGE_SIZE       63
#define SCRATCH_REPORT_SIZE     (SCRATCH_PAGE_SIZE + 1)
#define SCRATCH_REPORT          20

/* Reports 19-22: flash upgrade of the C8051F321 */
#define WRITE_REPORT_SIZE       4
#define WRITE_REPORT            19
#define FLASH_REPORT_SIZE       64
#define FLASH_REPORT            20
#define CRC_REPORT_SIZE         3
#define CRC_REPORT              21
#define RESPONSE_REPORT_SIZE    2
#define RESPONSE_REPORT         22

/* Report 23: currently unused, but can accept 60 byte reports on the HID */
/* interrupt out endpoint 2 every 1 millisecond */
#define UNUSED_REPORT           23



/**************************************************************************
 * Software/Hardware Versions from Scratch Page
 **************************************************************************/
#define RADIO_SW_VERSION_NOT_BOOTLOADABLE       6
#define RADIO_SW_VERSION                        1
#define RADIO_HW_VERSION                        1



/**************************************************************************
 * LED State Definitions
 **************************************************************************/
#define LED_COMMAND             0x35

#define NO_CHANGE_LED           0x00
#define ALL_COLOR_LED           0x01    /* streaming state */
#define BLINK_GREEN_LED         0x02    /* connect state */
#define BLINK_RED_LED           0x04
#define BLINK_ORANGE_LED        0x10    /* disconnect state */
#define SOLID_GREEN_LED         0x20    /* tuning/seeking state */
#define SOLID_RED_LED           0x40    /* bootload state */
#define SOLID_ORANGE_LED        0x80



/**************************************************************************
 * Stream State Definitions
 **************************************************************************/
#define STREAM_COMMAND  0x36
#define STREAM_VIDPID   0x00
#define STREAM_AUDIO    0xff



/**************************************************************************
 * Bootloader / Flash Commands
 **************************************************************************/

/* unique id sent to bootloader and required to put into a bootload state */
#define UNIQUE_BL_ID            0x34

/* mask for the flash data */
#define FLASH_DATA_MASK         0x55

/* bootloader commands */
#define GET_SW_VERSION_COMMAND  0x00
#define SET_PAGE_COMMAND        0x01
#define ERASE_PAGE_COMMAND      0x02
#define WRITE_PAGE_COMMAND      0x03
#define CRC_ON_PAGE_COMMAND     0x04
#define READ_FLASH_BYTE_COMMAND 0x05
#define RESET_DEVICE_COMMAND    0x06
#define GET_HW_VERSION_COMMAND  0x07
#define BLANK                   0xff

/* bootloader command responses */
#define COMMAND_OK              0x01
#define COMMAND_FAILED          0x02
#define COMMAND_PENDING         0x03



/**************************************************************************
 * General Driver Functions - REGISTER_REPORTs
 **************************************************************************/

/*
 * si470x_get_report - receive a HID report
 */
static int si470x_get_report(struct si470x_device *radio, void *buf, int size)
{
        unsigned char *report = (unsigned char *) buf;
        int retval;

        retval = usb_control_msg(radio->usbdev,
                usb_rcvctrlpipe(radio->usbdev, 0),
                HID_REQ_GET_REPORT,
                USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
                report[0], 2,
                buf, size, usb_timeout);

        if (retval < 0)
                dev_warn(&radio->intf->dev,
                        "si470x_get_report: usb_control_msg returned %d\n",
                        retval);
        return retval;
}


/*
 * si470x_set_report - send a HID report
 */
static int si470x_set_report(struct si470x_device *radio, void *buf, int size)
{
        unsigned char *report = (unsigned char *) buf;
        int retval;

        retval = usb_control_msg(radio->usbdev,
                usb_sndctrlpipe(radio->usbdev, 0),
                HID_REQ_SET_REPORT,
                USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
                report[0], 2,
                buf, size, usb_timeout);

        if (retval < 0)
                dev_warn(&radio->intf->dev,
                        "si470x_set_report: usb_control_msg returned %d\n",
                        retval);
        return retval;
}


/*
 * si470x_get_register - read register
 */
int si470x_get_register(struct si470x_device *radio, int regnr)
{
        unsigned char buf[REGISTER_REPORT_SIZE];
        int retval;

        buf[0] = REGISTER_REPORT(regnr);

        retval = si470x_get_report(radio, (void *) &buf, sizeof(buf));

        if (retval >= 0)
                radio->registers[regnr] = get_unaligned_be16(&buf[1]);

        return (retval < 0) ? -EINVAL : 0;
}


/*
 * si470x_set_register - write register
 */
int si470x_set_register(struct si470x_device *radio, int regnr)
{
        unsigned char buf[REGISTER_REPORT_SIZE];
        int retval;

        buf[0] = REGISTER_REPORT(regnr);
        put_unaligned_be16(radio->registers[regnr], &buf[1]);

        retval = si470x_set_report(radio, (void *) &buf, sizeof(buf));

        return (retval < 0) ? -EINVAL : 0;
}



/**************************************************************************
 * General Driver Functions - ENTIRE_REPORT
 **************************************************************************/

/*
 * si470x_get_all_registers - read entire registers
 */
static int si470x_get_all_registers(struct si470x_device *radio)
{
        unsigned char buf[ENTIRE_REPORT_SIZE];
        int retval;
        unsigned char regnr;

        buf[0] = ENTIRE_REPORT;

        retval = si470x_get_report(radio, (void *) &buf, sizeof(buf));

        if (retval >= 0)
                for (regnr = 0; regnr < RADIO_REGISTER_NUM; regnr++)
                        radio->registers[regnr] = get_unaligned_be16(
                                &buf[regnr * RADIO_REGISTER_SIZE + 1]);

        return (retval < 0) ? -EINVAL : 0;
}



/**************************************************************************
 * General Driver Functions - LED_REPORT
 **************************************************************************/

/*
 * si470x_set_led_state - sets the led state
 */
static int si470x_set_led_state(struct si470x_device *radio,
                unsigned char led_state)
{
        unsigned char buf[LED_REPORT_SIZE];
        int retval;

        buf[0] = LED_REPORT;
        buf[1] = LED_COMMAND;
        buf[2] = led_state;

        retval = si470x_set_report(radio, (void *) &buf, sizeof(buf));

        return (retval < 0) ? -EINVAL : 0;
}



/**************************************************************************
 * General Driver Functions - SCRATCH_REPORT
 **************************************************************************/

/*
 * si470x_get_scratch_versions - gets the scratch page and version infos
 */
static int si470x_get_scratch_page_versions(struct si470x_device *radio)
{
        unsigned char buf[SCRATCH_REPORT_SIZE];
        int retval;

        buf[0] = SCRATCH_REPORT;

        retval = si470x_get_report(radio, (void *) &buf, sizeof(buf));

        if (retval < 0)
                dev_warn(&radio->intf->dev, "si470x_get_scratch: "
                        "si470x_get_report returned %d\n", retval);
        else {
                radio->software_version = buf[1];
                radio->hardware_version = buf[2];
        }

        return (retval < 0) ? -EINVAL : 0;
}



/**************************************************************************
 * RDS Driver Functions
 **************************************************************************/

/*
 * si470x_int_in_callback - rds callback and processing function
 *
 * TODO: do we need to use mutex locks in some sections?
 */
static void si470x_int_in_callback(struct urb *urb)
{
        struct si470x_device *radio = urb->context;
        int retval;
        unsigned char regnr;
        unsigned char blocknum;
        unsigned short bler; /* rds block errors */
        unsigned short rds;
        unsigned char tmpbuf[3];

        if (urb->status) {
                if (urb->status == -ENOENT ||
                                urb->status == -ECONNRESET ||
                                urb->status == -ESHUTDOWN) {
                        return;
                } else {
                        dev_warn(&radio->intf->dev,
                         "non-zero urb status (%d)\n", urb->status);
                        goto resubmit; /* Maybe we can recover. */
                }
        }

        /* Sometimes the device returns len 0 packets */
        if (urb->actual_length != RDS_REPORT_SIZE)
                goto resubmit;

        radio->registers[STATUSRSSI] =
                get_unaligned_be16(&radio->int_in_buffer[1]);

        if (radio->registers[STATUSRSSI] & STATUSRSSI_STC)
                complete(&radio->completion);

        if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS)) {
                /* Update RDS registers with URB data */
                for (regnr = 1; regnr < RDS_REGISTER_NUM; regnr++)
                        radio->registers[STATUSRSSI + regnr] =
                            get_unaligned_be16(&radio->int_in_buffer[
                                regnr * RADIO_REGISTER_SIZE + 1]);
                /* get rds blocks */
                if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0) {
                        /* No RDS group ready, better luck next time */
                        goto resubmit;
                }
                if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSS) == 0) {
                        /* RDS decoder not synchronized */
                        goto resubmit;
                }
                for (blocknum = 0; blocknum < 4; blocknum++) {
                        switch (blocknum) {
                        default:
                                bler = (radio->registers[STATUSRSSI] &
                                                STATUSRSSI_BLERA) >> 9;
                                rds = radio->registers[RDSA];
                                break;
                        case 1:
                                bler = (radio->registers[READCHAN] &
                                                READCHAN_BLERB) >> 14;
                                rds = radio->registers[RDSB];
                                break;
                        case 2:
                                bler = (radio->registers[READCHAN] &
                                                READCHAN_BLERC) >> 12;
                                rds = radio->registers[RDSC];
                                break;
                        case 3:
                                bler = (radio->registers[READCHAN] &
                                                READCHAN_BLERD) >> 10;
                                rds = radio->registers[RDSD];
                                break;
                        }

                        /* Fill the V4L2 RDS buffer */
                        put_unaligned_le16(rds, &tmpbuf);
                        tmpbuf[2] = blocknum;           /* offset name */
                        tmpbuf[2] |= blocknum << 3;     /* received offset */
                        if (bler > max_rds_errors)
                                tmpbuf[2] |= 0x80; /* uncorrectable errors */
                        else if (bler > 0)
                                tmpbuf[2] |= 0x40; /* corrected error(s) */

                        /* copy RDS block to internal buffer */
                        memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
                        radio->wr_index += 3;

                        /* wrap write pointer */
                        if (radio->wr_index >= radio->buf_size)
                                radio->wr_index = 0;

                        /* check for overflow */
                        if (radio->wr_index == radio->rd_index) {
                                /* increment and wrap read pointer */
                                radio->rd_index += 3;
                                if (radio->rd_index >= radio->buf_size)
                                        radio->rd_index = 0;
                        }
                }
                if (radio->wr_index != radio->rd_index)
                        wake_up_interruptible(&radio->read_queue);
        }

resubmit:
        /* Resubmit if we're still running. */
        if (radio->int_in_running && radio->usbdev) {
                retval = usb_submit_urb(radio->int_in_urb, GFP_ATOMIC);
                if (retval) {
                        dev_warn(&radio->intf->dev,
                               "resubmitting urb failed (%d)", retval);
                        radio->int_in_running = 0;
                }
        }
        radio->status_rssi_auto_update = radio->int_in_running;
}


int si470x_fops_open(struct file *file)
{
        return v4l2_fh_open(file);
}

int si470x_fops_release(struct file *file)
{
        return v4l2_fh_release(file);
}

static void si470x_usb_release(struct v4l2_device *v4l2_dev)
{
        struct si470x_device *radio =
                container_of(v4l2_dev, struct si470x_device, v4l2_dev);

        usb_free_urb(radio->int_in_urb);
        v4l2_ctrl_handler_free(&radio->hdl);
        v4l2_device_unregister(&radio->v4l2_dev);
        kfree(radio->int_in_buffer);
        kfree(radio->buffer);
        kfree(radio);
}


/**************************************************************************
 * Video4Linux Interface
 **************************************************************************/

/*
 * si470x_vidioc_querycap - query device capabilities
 */
int si470x_vidioc_querycap(struct file *file, void *priv,
                struct v4l2_capability *capability)
{
        struct si470x_device *radio = video_drvdata(file);

        strlcpy(capability->driver, DRIVER_NAME, sizeof(capability->driver));
        strlcpy(capability->card, DRIVER_CARD, sizeof(capability->card));
        usb_make_path(radio->usbdev, capability->bus_info,
                        sizeof(capability->bus_info));
        capability->device_caps = V4L2_CAP_HW_FREQ_SEEK | V4L2_CAP_READWRITE |
                V4L2_CAP_TUNER | V4L2_CAP_RADIO | V4L2_CAP_RDS_CAPTURE;
        capability->capabilities = capability->device_caps | V4L2_CAP_DEVICE_CAPS;
        return 0;
}


static int si470x_start_usb(struct si470x_device *radio)
{
        int retval;

        /* initialize interrupt urb */
        usb_fill_int_urb(radio->int_in_urb, radio->usbdev,
                        usb_rcvintpipe(radio->usbdev,
                                radio->int_in_endpoint->bEndpointAddress),
                        radio->int_in_buffer,
                        le16_to_cpu(radio->int_in_endpoint->wMaxPacketSize),
                        si470x_int_in_callback,
                        radio,
                        radio->int_in_endpoint->bInterval);

        radio->int_in_running = 1;
        mb();

        retval = usb_submit_urb(radio->int_in_urb, GFP_KERNEL);
        if (retval) {
                dev_info(&radio->intf->dev,
                                "submitting int urb failed (%d)\n", retval);
                radio->int_in_running = 0;
        }
        radio->status_rssi_auto_update = radio->int_in_running;

        /* start radio */
        retval = si470x_start(radio);
        if (retval < 0)
                return retval;

        v4l2_ctrl_handler_setup(&radio->hdl);

        return retval;
}

/**************************************************************************
 * USB Interface
 **************************************************************************/

/*
 * si470x_usb_driver_probe - probe for the device
 */
static int si470x_usb_driver_probe(struct usb_interface *intf,
                const struct usb_device_id *id)
{
        struct si470x_device *radio;
        struct usb_host_interface *iface_desc;
        struct usb_endpoint_descriptor *endpoint;
        int i, int_end_size, retval = 0;
        unsigned char version_warning = 0;

        /* private data allocation and initialization */
        radio = kzalloc(sizeof(struct si470x_device), GFP_KERNEL);
        if (!radio) {
                retval = -ENOMEM;
                goto err_initial;
        }
        radio->usbdev = interface_to_usbdev(intf);
        radio->intf = intf;
        radio->band = 1; /* Default to 76 - 108 MHz */
        mutex_init(&radio->lock);
        init_completion(&radio->completion);

        iface_desc = intf->cur_altsetting;

        /* Set up interrupt endpoint information. */
        for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
                endpoint = &iface_desc->endpoint[i].desc;
                if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) ==
                 USB_DIR_IN) && ((endpoint->bmAttributes &
                 USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT))
                        radio->int_in_endpoint = endpoint;
        }
        if (!radio->int_in_endpoint) {
                dev_info(&intf->dev, "could not find interrupt in endpoint\n");
                retval = -EIO;
                goto err_radio;
        }

        int_end_size = le16_to_cpu(radio->int_in_endpoint->wMaxPacketSize);

        radio->int_in_buffer = kmalloc(int_end_size, GFP_KERNEL);
        if (!radio->int_in_buffer) {
                dev_info(&intf->dev, "could not allocate int_in_buffer");
                retval = -ENOMEM;
                goto err_radio;
        }

        radio->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!radio->int_in_urb) {
                dev_info(&intf->dev, "could not allocate int_in_urb");
                retval = -ENOMEM;
                goto err_intbuffer;
        }

        radio->v4l2_dev.release = si470x_usb_release;
        retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
        if (retval < 0) {
                dev_err(&intf->dev, "couldn't register v4l2_device\n");
                goto err_urb;
        }

        v4l2_ctrl_handler_init(&radio->hdl, 2);
        v4l2_ctrl_new_std(&radio->hdl, &si470x_ctrl_ops,
                          V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
        v4l2_ctrl_new_std(&radio->hdl, &si470x_ctrl_ops,
                          V4L2_CID_AUDIO_VOLUME, 0, 15, 1, 15);
        if (radio->hdl.error) {
                retval = radio->hdl.error;
                dev_err(&intf->dev, "couldn't register control\n");
                goto err_dev;
        }
        radio->videodev = si470x_viddev_template;
        radio->videodev.ctrl_handler = &radio->hdl;
        radio->videodev.lock = &radio->lock;
        radio->videodev.v4l2_dev = &radio->v4l2_dev;
        radio->videodev.release = video_device_release_empty;
        set_bit(V4L2_FL_USE_FH_PRIO, &radio->videodev.flags);
        video_set_drvdata(&radio->videodev, radio);

        /* get device and chip versions */
        if (si470x_get_all_registers(radio) < 0) {
                retval = -EIO;
                goto err_ctrl;
        }
        dev_info(&intf->dev, "DeviceID=0x%4.4hx ChipID=0x%4.4hx\n",
                        radio->registers[DEVICEID], radio->registers[CHIPID]);
        if ((radio->registers[CHIPID] & CHIPID_FIRMWARE) < RADIO_FW_VERSION) {
                dev_warn(&intf->dev,
                        "This driver is known to work with "
                        "firmware version %hu,\n", RADIO_FW_VERSION);
                dev_warn(&intf->dev,
                        "but the device has firmware version %hu.\n",
                        radio->registers[CHIPID] & CHIPID_FIRMWARE);
                version_warning = 1;
        }

        /* get software and hardware versions */
        if (si470x_get_scratch_page_versions(radio) < 0) {
                retval = -EIO;
                goto err_ctrl;
        }
        dev_info(&intf->dev, "software version %d, hardware version %d\n",
                        radio->software_version, radio->hardware_version);
        if (radio->software_version < RADIO_SW_VERSION) {
                dev_warn(&intf->dev,
                        "This driver is known to work with "
                        "software version %hu,\n", RADIO_SW_VERSION);
                dev_warn(&intf->dev,
                        "but the device has software version %hu.\n",
                        radio->software_version);
                version_warning = 1;
        }
        if (radio->hardware_version < RADIO_HW_VERSION) {
                dev_warn(&intf->dev,
                        "This driver is known to work with "
                        "hardware version %hu,\n", RADIO_HW_VERSION);
                dev_warn(&intf->dev,
                        "but the device has hardware version %hu.\n",
                        radio->hardware_version);
                version_warning = 1;
        }

        /* give out version warning */
        if (version_warning == 1) {
                dev_warn(&intf->dev,
                        "If you have some trouble using this driver,\n");
                dev_warn(&intf->dev,
                        "please report to V4L ML at "
                        "linux-media@vger.kernel.org\n");
        }

        /* set led to connect state */
        si470x_set_led_state(radio, BLINK_GREEN_LED);

        /* rds buffer allocation */
        radio->buf_size = rds_buf * 3;
        radio->buffer = kmalloc(radio->buf_size, GFP_KERNEL);
        if (!radio->buffer) {
                retval = -EIO;
                goto err_ctrl;
        }

        /* rds buffer configuration */
        radio->wr_index = 0;
        radio->rd_index = 0;
        init_waitqueue_head(&radio->read_queue);
        usb_set_intfdata(intf, radio);

        /* start radio */
        retval = si470x_start_usb(radio);
        if (retval < 0)
                goto err_all;

        /* set initial frequency */
        si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */

        /* register video device */
        retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO,
                        radio_nr);
        if (retval) {
                dev_err(&intf->dev, "Could not register video device\n");
                goto err_all;
        }

        return 0;
err_all:
        kfree(radio->buffer);
err_ctrl:
        v4l2_ctrl_handler_free(&radio->hdl);
err_dev:
        v4l2_device_unregister(&radio->v4l2_dev);
err_urb:
        usb_free_urb(radio->int_in_urb);
err_intbuffer:
        kfree(radio->int_in_buffer);
err_radio:
        kfree(radio);
err_initial:
        return retval;
}


/*
 * si470x_usb_driver_suspend - suspend the device
 */
static int si470x_usb_driver_suspend(struct usb_interface *intf,
                pm_message_t message)
{
        struct si470x_device *radio = usb_get_intfdata(intf);

        dev_info(&intf->dev, "suspending now...\n");

        /* shutdown interrupt handler */
        if (radio->int_in_running) {
                radio->int_in_running = 0;
                if (radio->int_in_urb)
                        usb_kill_urb(radio->int_in_urb);
        }

        /* cancel read processes */
        wake_up_interruptible(&radio->read_queue);

        /* stop radio */
        si470x_stop(radio);
        return 0;
}


/*
 * si470x_usb_driver_resume - resume the device
 */
static int si470x_usb_driver_resume(struct usb_interface *intf)
{
        struct si470x_device *radio = usb_get_intfdata(intf);
        int ret;

        dev_info(&intf->dev, "resuming now...\n");

        /* start radio */
        ret = si470x_start_usb(radio);
        if (ret == 0)
                v4l2_ctrl_handler_setup(&radio->hdl);

        return ret;
}


/*
 * si470x_usb_driver_disconnect - disconnect the device
 */
static void si470x_usb_driver_disconnect(struct usb_interface *intf)
{
        struct si470x_device *radio = usb_get_intfdata(intf);

        mutex_lock(&radio->lock);
        v4l2_device_disconnect(&radio->v4l2_dev);
        video_unregister_device(&radio->videodev);
        usb_set_intfdata(intf, NULL);
        mutex_unlock(&radio->lock);
        v4l2_device_put(&radio->v4l2_dev);
}


/*
 * si470x_usb_driver - usb driver interface
 *
 * A note on suspend/resume: this driver had only empty suspend/resume
 * functions, and when I tried to test suspend/resume it always disconnected
 * instead of resuming (using my ADS InstantFM stick). So I've decided to
 * remove these callbacks until someone else with better hardware can
 * implement and test this.
 */
static struct usb_driver si470x_usb_driver = {
        .name                   = DRIVER_NAME,
        .probe                  = si470x_usb_driver_probe,
        .disconnect             = si470x_usb_driver_disconnect,
        .suspend                = si470x_usb_driver_suspend,
        .resume                 = si470x_usb_driver_resume,
        .reset_resume           = si470x_usb_driver_resume,
        .id_table               = si470x_usb_driver_id_table,
};

module_usb_driver(si470x_usb_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);