text: /*
   * A driver for the AverMedia MR 800 USB FM radio. This device plugs
   * into both the USB and an analog audio input, so this thing
   * only deals with initialization and frequency setting, the
   * audio data has to be handled by a sound driver.
   *
   * Copyright (c) 2008 Alexey Klimov <klimov.linux@gmail.com>
   *
   * 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.
   */
  
  /*
   * Big thanks to authors and contributors of dsbr100.c and radio-si470x.c
   *
   * When work was looked pretty good, i discover this:
   * http://av-usbradio.sourceforge.net/index.php
   * http://sourceforge.net/projects/av-usbradio/
   * Latest release of theirs project was in 2005.
   * Probably, this driver could be improved through using their
   * achievements (specifications given).
   * Also, Faidon Liambotis <paravoid@debian.org> wrote nice driver for this radio
   * in 2007. He allowed to use his driver to improve current mr800 radio driver.
   * http://www.spinics.net/lists/linux-usb-devel/msg10109.html
   *
   * Version 0.01:	First working version.
   *			It's required to blacklist AverMedia USB Radio
   *			in usbhid/hid-quirks.c
   * Version 0.10:	A lot of cleanups and fixes: unpluging the device,
   *			few mutex locks were added, codinstyle issues, etc.
   *			Added stereo support. Thanks to
   *			Douglas Schilling Landgraf <dougsland@gmail.com> and
   *			David Ellingsworth <david@identd.dyndns.org>
   *			for discussion, help and support.
   * Version 0.11:	Converted to v4l2_device.
   *
   * Many things to do:
   *	- Correct power management of device (suspend & resume)
   *	- Add code for scanning and smooth tuning
   *	- Add code for sensitivity value
   *	- Correct mistakes
   *	- In Japan another FREQ_MIN and FREQ_MAX
   */
  
  /* kernel includes */
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/input.h>
  #include <linux/videodev2.h>
  #include <media/v4l2-device.h>
  #include <media/v4l2-ioctl.h>
  #include <media/v4l2-ctrls.h>
  #include <media/v4l2-event.h>
  #include <linux/usb.h>
  #include <linux/mutex.h>
  
  /* driver and module definitions */
  #define DRIVER_AUTHOR "Alexey Klimov <klimov.linux@gmail.com>"
  #define DRIVER_DESC "AverMedia MR 800 USB FM radio driver"
  #define DRIVER_VERSION "0.1.2"
  
  MODULE_AUTHOR(DRIVER_AUTHOR);
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  MODULE_VERSION(DRIVER_VERSION);
  
  #define USB_AMRADIO_VENDOR 0x07ca
  #define USB_AMRADIO_PRODUCT 0xb800
  
  /* dev_warn macro with driver name */
  #define MR800_DRIVER_NAME "radio-mr800"
  #define amradio_dev_warn(dev, fmt, arg...)				\
  		dev_warn(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
  
  #define amradio_dev_err(dev, fmt, arg...) \
  		dev_err(dev, MR800_DRIVER_NAME " - " fmt, ##arg)
  
  /* Probably USB_TIMEOUT should be modified in module parameter */
  #define BUFFER_LENGTH 8
  #define USB_TIMEOUT 500
  
  /* Frequency limits in MHz -- these are European values.  For Japanese
  devices, that would be 76 and 91.  */
  #define FREQ_MIN  87.5
  #define FREQ_MAX 108.0
  #define FREQ_MUL 16000
  
  /*
   * Commands that device should understand
   * List isn't full and will be updated with implementation of new functions
   */
  #define AMRADIO_SET_FREQ	0xa4
  #define AMRADIO_GET_READY_FLAG	0xa5
  #define AMRADIO_GET_SIGNAL	0xa7
  #define AMRADIO_GET_FREQ	0xa8
  #define AMRADIO_SET_SEARCH_UP	0xa9
  #define AMRADIO_SET_SEARCH_DOWN	0xaa
  #define AMRADIO_SET_MUTE	0xab
  #define AMRADIO_SET_RIGHT_MUTE	0xac
  #define AMRADIO_SET_LEFT_MUTE	0xad
  #define AMRADIO_SET_MONO	0xae
  #define AMRADIO_SET_SEARCH_LVL	0xb0
  #define AMRADIO_STOP_SEARCH	0xb1
  
  /* Comfortable defines for amradio_set_stereo */
  #define WANT_STEREO		0x00
  #define WANT_MONO		0x01
  
  /* module parameter */
  static int radio_nr = -1;
  module_param(radio_nr, int, 0);
  MODULE_PARM_DESC(radio_nr, "Radio Nr");
  
  /* Data for one (physical) device */
  struct amradio_device {
  	/* reference to USB and video device */
  	struct usb_device *usbdev;
  	struct usb_interface *intf;
  	struct video_device vdev;
  	struct v4l2_device v4l2_dev;
  	struct v4l2_ctrl_handler hdl;
  
  	u8 *buffer;
  	struct mutex lock;	/* buffer locking */
  	int curfreq;
  	int stereo;
  	int muted;
  };
  
  static inline struct amradio_device *to_amradio_dev(struct v4l2_device *v4l2_dev)
  {
  	return container_of(v4l2_dev, struct amradio_device, v4l2_dev);
  }
  
  static int amradio_send_cmd(struct amradio_device *radio, u8 cmd, u8 arg,
  		u8 *extra, u8 extralen, bool reply)
  {
  	int retval;
  	int size;
  
  	radio->buffer[0] = 0x00;
  	radio->buffer[1] = 0x55;
  	radio->buffer[2] = 0xaa;
  	radio->buffer[3] = extralen;
  	radio->buffer[4] = cmd;
  	radio->buffer[5] = arg;
  	radio->buffer[6] = 0x00;
  	radio->buffer[7] = extra || reply ? 8 : 0;
  
  	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
  		radio->buffer, BUFFER_LENGTH, &size, USB_TIMEOUT);
  
  	if (retval < 0 || size != BUFFER_LENGTH) {
  		if (video_is_registered(&radio->vdev))
  			amradio_dev_warn(&radio->vdev.dev,
  					"cmd %02x failed\n", cmd);
  		return retval ? retval : -EIO;
  	}
  	if (!extra && !reply)
  		return 0;
  
  	if (extra) {
  		memcpy(radio->buffer, extra, extralen);
  		memset(radio->buffer + extralen, 0, 8 - extralen);
  		retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
  			radio->buffer, BUFFER_LENGTH, &size, USB_TIMEOUT);
  	} else {
  		memset(radio->buffer, 0, 8);
  		retval = usb_bulk_msg(radio->usbdev, usb_rcvbulkpipe(radio->usbdev, 0x81),
  			radio->buffer, BUFFER_LENGTH, &size, USB_TIMEOUT);
  	}
  	if (retval == 0 && size == BUFFER_LENGTH)
  		return 0;
  	if (video_is_registered(&radio->vdev) && cmd != AMRADIO_GET_READY_FLAG)
  		amradio_dev_warn(&radio->vdev.dev, "follow-up to cmd %02x failed\n", cmd);
  	return retval ? retval : -EIO;
  }
  
  /* switch on/off the radio. Send 8 bytes to device */
  static int amradio_set_mute(struct amradio_device *radio, bool mute)
  {
  	int ret = amradio_send_cmd(radio,
  			AMRADIO_SET_MUTE, mute, NULL, 0, false);
  
  	if (!ret)
  		radio->muted = mute;
  	return ret;
  }
  
  /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
  static int amradio_set_freq(struct amradio_device *radio, int freq)
  {
  	unsigned short freq_send;
  	u8 buf[3];
  	int retval;
  
  	/* we need to be sure that frequency isn't out of range */
  	freq = clamp_t(unsigned, freq, FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL);
  	freq_send = 0x10 + (freq >> 3) / 25;
  
  	/* frequency is calculated from freq_send and placed in first 2 bytes */
  	buf[0] = (freq_send >> 8) & 0xff;
  	buf[1] = freq_send & 0xff;
  	buf[2] = 0x01;
  
  	retval = amradio_send_cmd(radio, AMRADIO_SET_FREQ, 0, buf, 3, false);
  	if (retval)
  		return retval;
  	radio->curfreq = freq;
  	msleep(40);
  	return 0;
  }
  
  static int amradio_set_stereo(struct amradio_device *radio, bool stereo)
  {
  	int ret = amradio_send_cmd(radio,
  			AMRADIO_SET_MONO, !stereo, NULL, 0, false);
  
  	if (!ret)
  		radio->stereo = stereo;
  	return ret;
  }
  
  static int amradio_get_stat(struct amradio_device *radio, bool *is_stereo, u32 *signal)
  {
  	int ret = amradio_send_cmd(radio,
  			AMRADIO_GET_SIGNAL, 0, NULL, 0, true);
  
  	if (ret)
  		return ret;
  	*is_stereo = radio->buffer[2] >> 7;
  	*signal = (radio->buffer[3] & 0xf0) << 8;
  	return 0;
  }
  
  /* Handle unplugging the device.
   * We call video_unregister_device in any case.
   * The last function called in this procedure is
   * usb_amradio_device_release.
   */
  static void usb_amradio_disconnect(struct usb_interface *intf)
  {
  	struct amradio_device *radio = to_amradio_dev(usb_get_intfdata(intf));
  
  	mutex_lock(&radio->lock);
  	video_unregister_device(&radio->vdev);
  	amradio_set_mute(radio, true);
  	usb_set_intfdata(intf, NULL);
  	v4l2_device_disconnect(&radio->v4l2_dev);
  	mutex_unlock(&radio->lock);
  	v4l2_device_put(&radio->v4l2_dev);
  }
  
  /* vidioc_querycap - query device capabilities */
  static int vidioc_querycap(struct file *file, void *priv,
  					struct v4l2_capability *v)
  {
  	struct amradio_device *radio = video_drvdata(file);
  
  	strlcpy(v->driver, "radio-mr800", sizeof(v->driver));
  	strlcpy(v->card, "AverMedia MR 800 USB FM Radio", sizeof(v->card));
  	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
  	v->device_caps = V4L2_CAP_RADIO | V4L2_CAP_TUNER |
  					V4L2_CAP_HW_FREQ_SEEK;
  	v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
  	return 0;
  }
  
  /* vidioc_g_tuner - get tuner attributes */
  static int vidioc_g_tuner(struct file *file, void *priv,
  				struct v4l2_tuner *v)
  {
  	struct amradio_device *radio = video_drvdata(file);
  	bool is_stereo = false;
  	int retval;
  
  	if (v->index > 0)
  		return -EINVAL;
  
  	v->signal = 0;
  	retval = amradio_get_stat(radio, &is_stereo, &v->signal);
  	if (retval)
  		return retval;
  
  	strcpy(v->name, "FM");
  	v->type = V4L2_TUNER_RADIO;
  	v->rangelow = FREQ_MIN * FREQ_MUL;
  	v->rangehigh = FREQ_MAX * FREQ_MUL;
  	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
  		V4L2_TUNER_CAP_HWSEEK_WRAP;
  	v->rxsubchans = is_stereo ? V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
  	v->audmode = radio->stereo ?
  		V4L2_TUNER_MODE_STEREO : V4L2_TUNER_MODE_MONO;
  	return 0;
  }
  
  /* vidioc_s_tuner - set tuner attributes */
  static int vidioc_s_tuner(struct file *file, void *priv,
  				const struct v4l2_tuner *v)
  {
  	struct amradio_device *radio = video_drvdata(file);
  
  	if (v->index > 0)
  		return -EINVAL;
  
  	/* mono/stereo selector */
  	switch (v->audmode) {
  	case V4L2_TUNER_MODE_MONO:
  		return amradio_set_stereo(radio, WANT_MONO);
  	default:
  		return amradio_set_stereo(radio, WANT_STEREO);
  	}
  }
  
  /* vidioc_s_frequency - set tuner radio frequency */
  static int vidioc_s_frequency(struct file *file, void *priv,
  				const struct v4l2_frequency *f)
  {
  	struct amradio_device *radio = video_drvdata(file);
  
  	if (f->tuner != 0)
  		return -EINVAL;
  	return amradio_set_freq(radio, f->frequency);
  }
  
  /* vidioc_g_frequency - get tuner radio frequency */
  static int vidioc_g_frequency(struct file *file, void *priv,
  				struct v4l2_frequency *f)
  {
  	struct amradio_device *radio = video_drvdata(file);
  
  	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
  		return -EINVAL;
  	f->type = V4L2_TUNER_RADIO;
  	f->frequency = radio->curfreq;
  
  	return 0;
  }
  
  static int vidioc_s_hw_freq_seek(struct file *file, void *priv,
  		const struct v4l2_hw_freq_seek *seek)
  {
  	static u8 buf[8] = {
  		0x3d, 0x32, 0x0f, 0x08, 0x3d, 0x32, 0x0f, 0x08
  	};
  	struct amradio_device *radio = video_drvdata(file);
  	unsigned long timeout;
  	int retval;
  
  	if (seek->tuner != 0 || !seek->wrap_around)
  		return -EINVAL;
  
  	if (file->f_flags & O_NONBLOCK)
  		return -EWOULDBLOCK;
  
  	retval = amradio_send_cmd(radio,
  			AMRADIO_SET_SEARCH_LVL, 0, buf, 8, false);
  	if (retval)
  		return retval;
  	amradio_set_freq(radio, radio->curfreq);
  	retval = amradio_send_cmd(radio,
  		seek->seek_upward ? AMRADIO_SET_SEARCH_UP : AMRADIO_SET_SEARCH_DOWN,
  		0, NULL, 0, false);
  	if (retval)
  		return retval;
  	timeout = jiffies + msecs_to_jiffies(30000);
  	for (;;) {
  		if (time_after(jiffies, timeout)) {
  			retval = -ENODATA;
  			break;
  		}
  		if (schedule_timeout_interruptible(msecs_to_jiffies(10))) {
  			retval = -ERESTARTSYS;
  			break;
  		}
  		retval = amradio_send_cmd(radio, AMRADIO_GET_READY_FLAG,
  				0, NULL, 0, true);
  		if (retval)
  			continue;
  		amradio_send_cmd(radio, AMRADIO_GET_FREQ, 0, NULL, 0, true);
  		if (radio->buffer[1] || radio->buffer[2]) {
  			/* To check: sometimes radio->curfreq is set to out of range value */
  			radio->curfreq = (radio->buffer[1] << 8) | radio->buffer[2];
  			radio->curfreq = (radio->curfreq - 0x10) * 200;
  			amradio_send_cmd(radio, AMRADIO_STOP_SEARCH,
  					0, NULL, 0, false);
  			amradio_set_freq(radio, radio->curfreq);
  			retval = 0;
  			break;
  		}
  	}
  	amradio_send_cmd(radio, AMRADIO_STOP_SEARCH, 0, NULL, 0, false);
  	amradio_set_freq(radio, radio->curfreq);
  	return retval;
  }
  
  static int usb_amradio_s_ctrl(struct v4l2_ctrl *ctrl)
  {
  	struct amradio_device *radio =
  		container_of(ctrl->handler, struct amradio_device, hdl);
  
  	switch (ctrl->id) {
  	case V4L2_CID_AUDIO_MUTE:
  		return amradio_set_mute(radio, ctrl->val);
  	}
  
  	return -EINVAL;
  }
  
  static int usb_amradio_init(struct amradio_device *radio)
  {
  	int retval;
  
  	retval = amradio_set_mute(radio, true);
  	if (retval)
  		goto out_err;
  	retval = amradio_set_stereo(radio, true);
  	if (retval)
  		goto out_err;
  	retval = amradio_set_freq(radio, radio->curfreq);
  	if (retval)
  		goto out_err;
  	return 0;
  
  out_err:
  	amradio_dev_err(&radio->vdev.dev, "initialization failed\n");
  	return retval;
  }
  
  /* Suspend device - stop device. Need to be checked and fixed */
  static int usb_amradio_suspend(struct usb_interface *intf, pm_message_t message)
  {
  	struct amradio_device *radio = to_amradio_dev(usb_get_intfdata(intf));
  
  	mutex_lock(&radio->lock);
  	if (!radio->muted) {
  		amradio_set_mute(radio, true);
  		radio->muted = false;
  	}
  	mutex_unlock(&radio->lock);
  
  	dev_info(&intf->dev, "going into suspend..\n");
  	return 0;
  }
  
  /* Resume device - start device. Need to be checked and fixed */
  static int usb_amradio_resume(struct usb_interface *intf)
  {
  	struct amradio_device *radio = to_amradio_dev(usb_get_intfdata(intf));
  
  	mutex_lock(&radio->lock);
  	amradio_set_stereo(radio, radio->stereo);
  	amradio_set_freq(radio, radio->curfreq);
  
  	if (!radio->muted)
  		amradio_set_mute(radio, false);
  
  	mutex_unlock(&radio->lock);
  
  	dev_info(&intf->dev, "coming out of suspend..\n");
  	return 0;
  }
  
  static const struct v4l2_ctrl_ops usb_amradio_ctrl_ops = {
  	.s_ctrl = usb_amradio_s_ctrl,
  };
  
  /* File system interface */
  static const struct v4l2_file_operations usb_amradio_fops = {
  	.owner		= THIS_MODULE,
  	.open		= v4l2_fh_open,
  	.release	= v4l2_fh_release,
  	.poll		= v4l2_ctrl_poll,
  	.unlocked_ioctl	= video_ioctl2,
  };
  
  static const struct v4l2_ioctl_ops usb_amradio_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_s_hw_freq_seek = vidioc_s_hw_freq_seek,
  	.vidioc_log_status  = v4l2_ctrl_log_status,
  	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
  	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
  };
  
  static void usb_amradio_release(struct v4l2_device *v4l2_dev)
  {
  	struct amradio_device *radio = to_amradio_dev(v4l2_dev);
  
  	/* free rest memory */
  	v4l2_ctrl_handler_free(&radio->hdl);
  	v4l2_device_unregister(&radio->v4l2_dev);
  	kfree(radio->buffer);
  	kfree(radio);
  }
  
  /* check if the device is present and register with v4l and usb if it is */
  static int usb_amradio_probe(struct usb_interface *intf,
  				const struct usb_device_id *id)
  {
  	struct amradio_device *radio;
  	int retval;
  
  	radio = kzalloc(sizeof(struct amradio_device), GFP_KERNEL);
  
  	if (!radio) {
  		dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
  		retval = -ENOMEM;
  		goto err;
  	}
  
  	radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
  
  	if (!radio->buffer) {
  		dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
  		retval = -ENOMEM;
  		goto err_nobuf;
  	}
  
  	retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
  	if (retval < 0) {
  		dev_err(&intf->dev, "couldn't register v4l2_device\n");
  		goto err_v4l2;
  	}
  
  	v4l2_ctrl_handler_init(&radio->hdl, 1);
  	v4l2_ctrl_new_std(&radio->hdl, &usb_amradio_ctrl_ops,
  			  V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
  	if (radio->hdl.error) {
  		retval = radio->hdl.error;
  		dev_err(&intf->dev, "couldn't register control\n");
  		goto err_ctrl;
  	}
  	mutex_init(&radio->lock);
  
  	radio->v4l2_dev.ctrl_handler = &radio->hdl;
  	radio->v4l2_dev.release = usb_amradio_release;
  	strlcpy(radio->vdev.name, radio->v4l2_dev.name,
  		sizeof(radio->vdev.name));
  	radio->vdev.v4l2_dev = &radio->v4l2_dev;
  	radio->vdev.fops = &usb_amradio_fops;
  	radio->vdev.ioctl_ops = &usb_amradio_ioctl_ops;
  	radio->vdev.release = video_device_release_empty;
  	radio->vdev.lock = &radio->lock;
  
  	radio->usbdev = interface_to_usbdev(intf);
  	radio->intf = intf;
  	usb_set_intfdata(intf, &radio->v4l2_dev);
  	radio->curfreq = 95.16 * FREQ_MUL;
  
  	video_set_drvdata(&radio->vdev, radio);
  	retval = usb_amradio_init(radio);
  	if (retval)
  		goto err_vdev;
  
  	retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO,
  					radio_nr);
  	if (retval < 0) {
  		dev_err(&intf->dev, "could not register video device\n");
  		goto err_vdev;
  	}
  
  	return 0;
  
  err_vdev:
  	v4l2_ctrl_handler_free(&radio->hdl);
  err_ctrl:
  	v4l2_device_unregister(&radio->v4l2_dev);
  err_v4l2:
  	kfree(radio->buffer);
  err_nobuf:
  	kfree(radio);
  err:
  	return retval;
  }
  
  /* USB Device ID List */
  static const struct usb_device_id usb_amradio_device_table[] = {
  	{ USB_DEVICE_AND_INTERFACE_INFO(USB_AMRADIO_VENDOR, USB_AMRADIO_PRODUCT,
  							USB_CLASS_HID, 0, 0) },
  	{ }						/* Terminating entry */
  };
  
  MODULE_DEVICE_TABLE(usb, usb_amradio_device_table);
  
  /* USB subsystem interface */
  static struct usb_driver usb_amradio_driver = {
  	.name			= MR800_DRIVER_NAME,
  	.probe			= usb_amradio_probe,
  	.disconnect		= usb_amradio_disconnect,
  	.suspend		= usb_amradio_suspend,
  	.resume			= usb_amradio_resume,
  	.reset_resume		= usb_amradio_resume,
  	.id_table		= usb_amradio_device_table,
  };
  
  module_usb_driver(usb_amradio_driver);
  