/*
 * Copyright 2013 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/usb.h>
#include <linux/hid.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>
#include <asm/unaligned.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-event.h>

/*
 * 'Thanko's Raremono' is a Japanese si4734-based AM/FM/SW USB receiver:
 *
 * http://www.raremono.jp/product/484.html/
 *
 * The USB protocol has been reversed engineered using wireshark, initially
 * by Dinesh Ram <dinesh.ram@cern.ch> and finished by Hans Verkuil
 * <hverkuil@xs4all.nl>.
 *
 * Sadly the firmware used in this product hides lots of goodies since the
 * si4734 has more features than are supported by the firmware. Oh well...
 */

/* driver and module definitions */
MODULE_AUTHOR("Hans Verkuil <hverkuil@xs4all.nl>");
MODULE_DESCRIPTION("Thanko's Raremono AM/FM/SW Receiver USB driver");
MODULE_LICENSE("GPL v2");

/*
 * The Device announces itself as Cygnal Integrated Products, Inc.
 *
 * The vendor and product IDs (and in fact all other lsusb information as
 * well) are identical to the si470x Silicon Labs USB FM Radio Reference
 * Design board, even though this card has a si4734 device. Clearly the
 * designer of this product never bothered to change the USB IDs.
 */

/* USB Device ID List */
static const struct usb_device_id usb_raremono_device_table[] = {
        {USB_DEVICE_AND_INTERFACE_INFO(0x10c4, 0x818a, USB_CLASS_HID, 0, 0) },
        { }                                             /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, usb_raremono_device_table);

#define BUFFER_LENGTH 64

/* Timeout is set to a high value, could probably be reduced. Need more tests */
#define USB_TIMEOUT 10000

/* Frequency limits in KHz */
#define FM_FREQ_RANGE_LOW       64000
#define FM_FREQ_RANGE_HIGH      108000

#define AM_FREQ_RANGE_LOW       520
#define AM_FREQ_RANGE_HIGH      1710

#define SW_FREQ_RANGE_LOW       2300
#define SW_FREQ_RANGE_HIGH      26100

enum { BAND_FM, BAND_AM, BAND_SW };

static const struct v4l2_frequency_band bands[] = {
        /* Band FM */
        {
                .type = V4L2_TUNER_RADIO,
                .index = 0,
                .capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
                              V4L2_TUNER_CAP_FREQ_BANDS,
                .rangelow   = FM_FREQ_RANGE_LOW * 16,
                .rangehigh  = FM_FREQ_RANGE_HIGH * 16,
                .modulation = V4L2_BAND_MODULATION_FM,
        },
        /* Band AM */
        {
                .type = V4L2_TUNER_RADIO,
                .index = 1,
                .capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_FREQ_BANDS,
                .rangelow   = AM_FREQ_RANGE_LOW * 16,
                .rangehigh  = AM_FREQ_RANGE_HIGH * 16,
                .modulation = V4L2_BAND_MODULATION_AM,
        },
        /* Band SW */
        {
                .type = V4L2_TUNER_RADIO,
                .index = 2,
                .capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_FREQ_BANDS,
                .rangelow   = SW_FREQ_RANGE_LOW * 16,
                .rangehigh  = SW_FREQ_RANGE_HIGH * 16,
                .modulation = V4L2_BAND_MODULATION_AM,
        },
};

struct raremono_device {
        struct usb_device *usbdev;
        struct usb_interface *intf;
        struct video_device vdev;
        struct v4l2_device v4l2_dev;
        struct mutex lock;

        u8 *buffer;
        u32 band;
        unsigned curfreq;
};

static inline struct raremono_device *to_raremono_dev(struct v4l2_device *v4l2_dev)
{
        return container_of(v4l2_dev, struct raremono_device, v4l2_dev);
}

/* Set frequency. */
static int raremono_cmd_main(struct raremono_device *radio, unsigned band, unsigned freq)
{
        unsigned band_offset;
        int ret;

        switch (band) {
        case BAND_FM:
                band_offset = 1;
                freq /= 10;
                break;
        case BAND_AM:
                band_offset = 0;
                break;
        default:
                band_offset = 2;
                break;
        }
        radio->buffer[0] = 0x04 + band_offset;
        radio->buffer[1] = freq >> 8;
        radio->buffer[2] = freq & 0xff;

        ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
                        HID_REQ_SET_REPORT,
                        USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
                        0x0300 + radio->buffer[0], 2,
                        radio->buffer, 3, USB_TIMEOUT);

        if (ret < 0) {
                dev_warn(radio->v4l2_dev.dev, "%s failed (%d)\n", __func__, ret);
                return ret;
        }
        radio->curfreq = (band == BAND_FM) ? freq * 10 : freq;
        return 0;
}

/* Handle unplugging the device.
 * We call video_unregister_device in any case.
 * The last function called in this procedure is
 * usb_raremono_device_release.
 */
static void usb_raremono_disconnect(struct usb_interface *intf)
{
        struct raremono_device *radio = to_raremono_dev(usb_get_intfdata(intf));

        dev_info(&intf->dev, "Thanko's Raremono disconnected\n");

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

/*
 * Linux Video interface
 */
static int vidioc_querycap(struct file *file, void *priv,
                                        struct v4l2_capability *v)
{
        struct raremono_device *radio = video_drvdata(file);

        strlcpy(v->driver, "radio-raremono", sizeof(v->driver));
        strlcpy(v->card, "Thanko's Raremono", sizeof(v->card));
        usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
        v->device_caps = V4L2_CAP_TUNER | V4L2_CAP_RADIO;
        v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
        return 0;
}

static int vidioc_enum_freq_bands(struct file *file, void *priv,
                struct v4l2_frequency_band *band)
{
        if (band->tuner != 0)
                return -EINVAL;

        if (band->index >= ARRAY_SIZE(bands))
                return -EINVAL;

        *band = bands[band->index];

        return 0;
}

static int vidioc_g_tuner(struct file *file, void *priv,
                struct v4l2_tuner *v)
{
        struct raremono_device *radio = video_drvdata(file);
        int ret;

        if (v->index > 0)
                return -EINVAL;

        strlcpy(v->name, "AM/FM/SW", sizeof(v->name));
        v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
                V4L2_TUNER_CAP_FREQ_BANDS;
        v->rangelow = AM_FREQ_RANGE_LOW * 16;
        v->rangehigh = FM_FREQ_RANGE_HIGH * 16;
        v->rxsubchans = V4L2_TUNER_SUB_STEREO | V4L2_TUNER_SUB_MONO;
        v->audmode = (radio->curfreq < FM_FREQ_RANGE_LOW) ?
                V4L2_TUNER_MODE_MONO : V4L2_TUNER_MODE_STEREO;
        memset(radio->buffer, 1, BUFFER_LENGTH);
        ret = usb_control_msg(radio->usbdev, usb_rcvctrlpipe(radio->usbdev, 0),
                        1, 0xa1, 0x030d, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);

        if (ret < 0) {
                dev_warn(radio->v4l2_dev.dev, "%s failed (%d)\n", __func__, ret);
                return ret;
        }
        v->signal = ((radio->buffer[1] & 0xf) << 8 | radio->buffer[2]) << 4;
        return 0;
}

static int vidioc_s_tuner(struct file *file, void *priv,
                                        const struct v4l2_tuner *v)
{
        return v->index ? -EINVAL : 0;
}

static int vidioc_s_frequency(struct file *file, void *priv,
                                const struct v4l2_frequency *f)
{
        struct raremono_device *radio = video_drvdata(file);
        u32 freq = f->frequency;
        unsigned band;

        if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
                return -EINVAL;

        if (f->frequency >= (FM_FREQ_RANGE_LOW + SW_FREQ_RANGE_HIGH) * 8)
                band = BAND_FM;
        else if (f->frequency <= (AM_FREQ_RANGE_HIGH + SW_FREQ_RANGE_LOW) * 8)
                band = BAND_AM;
        else
                band = BAND_SW;

        freq = clamp_t(u32, f->frequency, bands[band].rangelow, bands[band].rangehigh);
        return raremono_cmd_main(radio, band, freq / 16);
}

static int vidioc_g_frequency(struct file *file, void *priv,
                                struct v4l2_frequency *f)
{
        struct raremono_device *radio = video_drvdata(file);

        if (f->tuner != 0)
                return -EINVAL;
        f->type = V4L2_TUNER_RADIO;
        f->frequency = radio->curfreq * 16;
        return 0;
}

/* File system interface */
static const struct v4l2_file_operations usb_raremono_fops = {
        .owner          = THIS_MODULE,
        .open           = v4l2_fh_open,
        .release        = v4l2_fh_release,
        .unlocked_ioctl = video_ioctl2,
};

static const struct v4l2_ioctl_ops usb_raremono_ioctl_ops = {
        .vidioc_querycap = vidioc_querycap,
        .vidioc_g_tuner = vidioc_g_tuner,
        .vidioc_s_tuner = vidioc_s_tuner,
        .vidioc_g_frequency = vidioc_g_frequency,
        .vidioc_s_frequency = vidioc_s_frequency,
        .vidioc_enum_freq_bands = vidioc_enum_freq_bands,
};

/* check if the device is present and register with v4l and usb if it is */
static int usb_raremono_probe(struct usb_interface *intf,
                                const struct usb_device_id *id)
{
        struct raremono_device *radio;
        int retval = 0;

        radio = devm_kzalloc(&intf->dev, sizeof(struct raremono_device), GFP_KERNEL);
        if (radio)
                radio->buffer = devm_kmalloc(&intf->dev, BUFFER_LENGTH, GFP_KERNEL);

        if (!radio || !radio->buffer)
                return -ENOMEM;

        radio->usbdev = interface_to_usbdev(intf);
        radio->intf = intf;

        /*
         * This device uses the same USB IDs as the si470x SiLabs reference
         * design. So do an additional check: attempt to read the device ID
         * from the si470x: the lower 12 bits are 0x0242 for the si470x. The
         * Raremono always returns 0x0800 (the meaning of that is unknown, but
         * at least it works).
         *
         * We use this check to determine which device we are dealing with.
         */
        msleep(20);
        retval = usb_control_msg(radio->usbdev,
                usb_rcvctrlpipe(radio->usbdev, 0),
                HID_REQ_GET_REPORT,
                USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
                1, 2,
                radio->buffer, 3, 500);
        if (retval != 3 ||
            (get_unaligned_be16(&radio->buffer[1]) & 0xfff) == 0x0242) {
                dev_info(&intf->dev, "this is not Thanko's Raremono.\n");
                return -ENODEV;
        }

        dev_info(&intf->dev, "Thanko's Raremono connected: (%04X:%04X)\n",
                        id->idVendor, id->idProduct);

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

        mutex_init(&radio->lock);

        strlcpy(radio->vdev.name, radio->v4l2_dev.name,
                sizeof(radio->vdev.name));
        radio->vdev.v4l2_dev = &radio->v4l2_dev;
        radio->vdev.fops = &usb_raremono_fops;
        radio->vdev.ioctl_ops = &usb_raremono_ioctl_ops;
        radio->vdev.lock = &radio->lock;
        radio->vdev.release = video_device_release_empty;

        usb_set_intfdata(intf, &radio->v4l2_dev);

        video_set_drvdata(&radio->vdev, radio);

        raremono_cmd_main(radio, BAND_FM, 95160);

        retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
        if (retval == 0) {
                dev_info(&intf->dev, "V4L2 device registered as %s\n",
                                video_device_node_name(&radio->vdev));
                return 0;
        }
        dev_err(&intf->dev, "could not register video device\n");
        v4l2_device_unregister(&radio->v4l2_dev);
        return retval;
}

/* USB subsystem interface */
static struct usb_driver usb_raremono_driver = {
        .name                   = "radio-raremono",
        .probe                  = usb_raremono_probe,
        .disconnect             = usb_raremono_disconnect,
        .id_table               = usb_raremono_device_table,
};

module_usb_driver(usb_raremono_driver);