/*
   * 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 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)
  ", __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
  ");
  
  	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)
  ", __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.
  ");
  		return -ENODEV;
  	}
  
  	dev_info(&intf->dev, "Thanko's Raremono connected: (%04X:%04X)
  ",
  			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
  ");
  		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);
  	set_bit(V4L2_FL_USE_FH_PRIO, &radio->vdev.flags);
  
  	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
  ",
  				video_device_node_name(&radio->vdev));
  		return 0;
  	}
  	dev_err(&intf->dev, "could not register video device
  ");
  	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);