drivers/media/radio/radio-mr800.c - kernel/msm - Gitiles

 /*
  * 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.
  *
  * 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
  */

 /*
  * 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 trough 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://kerneltrap.org/mailarchive/linux-usb-devel/2007/10/11/342492
  *
  * 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 managment 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 <linux/usb.h>
 #include <linux/version.h>	/* for KERNEL_VERSION MACRO */
 #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 "0.11"
 #define RADIO_VERSION KERNEL_VERSION(0, 1, 1)

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

 #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)

 /* 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 isnt full and will be updated with implementation of new functions
  */
 #define AMRADIO_SET_FREQ	0xa4
 #define AMRADIO_SET_MUTE	0xab
 #define AMRADIO_SET_MONO	0xae

 /* Comfortable defines for amradio_set_mute */
 #define AMRADIO_START		0x00
 #define AMRADIO_STOP		0x01

 /* 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");

 static int usb_amradio_probe(struct usb_interface *intf,
 			     const struct usb_device_id *id);
 static void usb_amradio_disconnect(struct usb_interface *intf);
 static int usb_amradio_open(struct file *file);
 static int usb_amradio_close(struct file *file);
 static int usb_amradio_suspend(struct usb_interface *intf,
 				pm_message_t message);
 static int usb_amradio_resume(struct usb_interface *intf);

 /* Data for one (physical) device */
 struct amradio_device {
 	/* reference to USB and video device */
 	struct usb_device *usbdev;
 	struct video_device *videodev;
 	struct v4l2_device v4l2_dev;

 	unsigned char *buffer;
 	struct mutex lock;	/* buffer locking */
 	int curfreq;
 	int stereo;
 	int users;
 	int removed;
 	int muted;
 };

 /* USB Device ID List */
 static 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,
 	.supports_autosuspend	= 0,
 };

 /* switch on/off the radio. Send 8 bytes to device */
 static int amradio_set_mute(struct amradio_device *radio, char argument)
 {
 	int retval;
 	int size;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	mutex_lock(&radio->lock);

 	radio->buffer[0] = 0x00;
 	radio->buffer[1] = 0x55;
 	radio->buffer[2] = 0xaa;
 	radio->buffer[3] = 0x00;
 	radio->buffer[4] = AMRADIO_SET_MUTE;
 	radio->buffer[5] = argument;
 	radio->buffer[6] = 0x00;
 	radio->buffer[7] = 0x00;

 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

 	if (retval < 0 || size != BUFFER_LENGTH) {
 		mutex_unlock(&radio->lock);
 		return retval;
 	}

 	radio->muted = argument;

 	mutex_unlock(&radio->lock);

 	return retval;
 }

 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
 static int amradio_setfreq(struct amradio_device *radio, int freq)
 {
 	int retval;
 	int size;
 	unsigned short freq_send = 0x10 + (freq >> 3) / 25;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	mutex_lock(&radio->lock);

 	radio->buffer[0] = 0x00;
 	radio->buffer[1] = 0x55;
 	radio->buffer[2] = 0xaa;
 	radio->buffer[3] = 0x03;
 	radio->buffer[4] = AMRADIO_SET_FREQ;
 	radio->buffer[5] = 0x00;
 	radio->buffer[6] = 0x00;
 	radio->buffer[7] = 0x08;

 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

 	if (retval < 0 || size != BUFFER_LENGTH) {
 		mutex_unlock(&radio->lock);
 		return retval;
 	}

 	/* frequency is calculated from freq_send and placed in first 2 bytes */
 	radio->buffer[0] = (freq_send >> 8) & 0xff;
 	radio->buffer[1] = freq_send & 0xff;
 	radio->buffer[2] = 0x01;
 	radio->buffer[3] = 0x00;
 	radio->buffer[4] = 0x00;
 	/* 5 and 6 bytes of buffer already = 0x00 */
 	radio->buffer[7] = 0x00;

 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

 	if (retval < 0 || size != BUFFER_LENGTH) {
 		mutex_unlock(&radio->lock);
 		return retval;
 	}

 	mutex_unlock(&radio->lock);

 	return retval;
 }

 static int amradio_set_stereo(struct amradio_device *radio, char argument)
 {
 	int retval;
 	int size;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	mutex_lock(&radio->lock);

 	radio->buffer[0] = 0x00;
 	radio->buffer[1] = 0x55;
 	radio->buffer[2] = 0xaa;
 	radio->buffer[3] = 0x00;
 	radio->buffer[4] = AMRADIO_SET_MONO;
 	radio->buffer[5] = argument;
 	radio->buffer[6] = 0x00;
 	radio->buffer[7] = 0x00;

 	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
 		(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

 	if (retval < 0 || size != BUFFER_LENGTH) {
 		radio->stereo = -1;
 		mutex_unlock(&radio->lock);
 		return retval;
 	}

 	radio->stereo = 1;

 	mutex_unlock(&radio->lock);

 	return retval;
 }

 /* 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 = usb_get_intfdata(intf);

 	mutex_lock(&radio->lock);
 	radio->removed = 1;
 	mutex_unlock(&radio->lock);

 	usb_set_intfdata(intf, NULL);
 	video_unregister_device(radio->videodev);
 	v4l2_device_disconnect(&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->version = RADIO_VERSION;
 	v->capabilities = V4L2_CAP_TUNER;
 	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_get_drvdata(video_devdata(file));
 	int retval;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

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

 /* TODO: Add function which look is signal stereo or not
  * 	amradio_getstat(radio);
  */

 /* we call amradio_set_stereo to set radio->stereo
  * Honestly, amradio_getstat should cover this in future and
  * amradio_set_stereo shouldn't be here
  */
 	retval = amradio_set_stereo(radio, WANT_STEREO);
 	if (retval < 0)
 		amradio_dev_warn(&radio->videodev->dev,
 			"set stereo failed\n");

 	strcpy(v->name, "FM");
 	v->type = V4L2_TUNER_RADIO;
 	v->rangelow = FREQ_MIN * FREQ_MUL;
 	v->rangehigh = FREQ_MAX * FREQ_MUL;
 	v->rxsubchans = V4L2_TUNER_SUB_MONO | V4L2_TUNER_SUB_STEREO;
 	v->capability = V4L2_TUNER_CAP_LOW;
 	if (radio->stereo)
 		v->audmode = V4L2_TUNER_MODE_STEREO;
 	else
 		v->audmode = V4L2_TUNER_MODE_MONO;
 	v->signal = 0xffff;     /* Can't get the signal strength, sad.. */
 	v->afc = 0; /* Don't know what is this */
 	return 0;
 }

 /* vidioc_s_tuner - set tuner attributes */
 static int vidioc_s_tuner(struct file *file, void *priv,
 				struct v4l2_tuner *v)
 {
 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
 	int retval;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

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

 	/* mono/stereo selector */
 	switch (v->audmode) {
 	case V4L2_TUNER_MODE_MONO:
 		retval = amradio_set_stereo(radio, WANT_MONO);
 		if (retval < 0)
 			amradio_dev_warn(&radio->videodev->dev,
 				"set mono failed\n");
 		break;
 	case V4L2_TUNER_MODE_STEREO:
 		retval = amradio_set_stereo(radio, WANT_STEREO);
 		if (retval < 0)
 			amradio_dev_warn(&radio->videodev->dev,
 				"set stereo failed\n");
 		break;
 	default:
 		return -EINVAL;
 	}

 	return 0;
 }

 /* vidioc_s_frequency - set tuner radio frequency */
 static int vidioc_s_frequency(struct file *file, void *priv,
 				struct v4l2_frequency *f)
 {
 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
 	int retval;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	mutex_lock(&radio->lock);
 	radio->curfreq = f->frequency;
 	mutex_unlock(&radio->lock);

 	retval = amradio_setfreq(radio, radio->curfreq);
 	if (retval < 0)
 		amradio_dev_warn(&radio->videodev->dev,
 			"set frequency failed\n");
 	return 0;
 }

 /* 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_get_drvdata(video_devdata(file));

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	f->type = V4L2_TUNER_RADIO;
 	f->frequency = radio->curfreq;
 	return 0;
 }

 /* vidioc_queryctrl - enumerate control items */
 static int vidioc_queryctrl(struct file *file, void *priv,
 				struct v4l2_queryctrl *qc)
 {
 	switch (qc->id) {
 	case V4L2_CID_AUDIO_MUTE:
 		return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
 	}

 	return -EINVAL;
 }

 /* vidioc_g_ctrl - get the value of a control */
 static int vidioc_g_ctrl(struct file *file, void *priv,
 				struct v4l2_control *ctrl)
 {
 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	switch (ctrl->id) {
 	case V4L2_CID_AUDIO_MUTE:
 		ctrl->value = radio->muted;
 		return 0;
 	}
 	return -EINVAL;
 }

 /* vidioc_s_ctrl - set the value of a control */
 static int vidioc_s_ctrl(struct file *file, void *priv,
 				struct v4l2_control *ctrl)
 {
 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
 	int retval;

 	/* safety check */
 	if (radio->removed)
 		return -EIO;

 	switch (ctrl->id) {
 	case V4L2_CID_AUDIO_MUTE:
 		if (ctrl->value) {
 			retval = amradio_set_mute(radio, AMRADIO_STOP);
 			if (retval < 0) {
 				amradio_dev_warn(&radio->videodev->dev,
 					"amradio_stop failed\n");
 				return -1;
 			}
 		} else {
 			retval = amradio_set_mute(radio, AMRADIO_START);
 			if (retval < 0) {
 				amradio_dev_warn(&radio->videodev->dev,
 					"amradio_start failed\n");
 				return -1;
 			}
 		}
 		return 0;
 	}
 	return -EINVAL;
 }

 /* vidioc_g_audio - get audio attributes */
 static int vidioc_g_audio(struct file *file, void *priv,
 				struct v4l2_audio *a)
 {
 	if (a->index > 1)
 		return -EINVAL;

 	strcpy(a->name, "Radio");
 	a->capability = V4L2_AUDCAP_STEREO;
 	return 0;
 }

 /* vidioc_s_audio - set audio attributes  */
 static int vidioc_s_audio(struct file *file, void *priv,
 					struct v4l2_audio *a)
 {
 	if (a->index != 0)
 		return -EINVAL;
 	return 0;
 }

 /* vidioc_g_input - get input */
 static int vidioc_g_input(struct file *filp, void *priv, unsigned int *i)
 {
 	*i = 0;
 	return 0;
 }

 /* vidioc_s_input - set input */
 static int vidioc_s_input(struct file *filp, void *priv, unsigned int i)
 {
 	if (i != 0)
 		return -EINVAL;
 	return 0;
 }

 /* open device - amradio_start() and amradio_setfreq() */
 static int usb_amradio_open(struct file *file)
 {
 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
 	int retval;

 	lock_kernel();

 	radio->users = 1;
 	radio->muted = 1;

 	retval = amradio_set_mute(radio, AMRADIO_START);
 	if (retval < 0) {
 		amradio_dev_warn(&radio->videodev->dev,
 			"radio did not start up properly\n");
 		radio->users = 0;
 		unlock_kernel();
 		return -EIO;
 	}

 	retval = amradio_set_stereo(radio, WANT_STEREO);
 	if (retval < 0)
 		amradio_dev_warn(&radio->videodev->dev,
 			"set stereo failed\n");

 	retval = amradio_setfreq(radio, radio->curfreq);
 	if (retval < 0)
 		amradio_dev_warn(&radio->videodev->dev,
 			"set frequency failed\n");

 	unlock_kernel();
 	return 0;
 }

 /*close device */
 static int usb_amradio_close(struct file *file)
 {
 	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
 	int retval;

 	if (!radio)
 		return -ENODEV;

 	mutex_lock(&radio->lock);
 	radio->users = 0;
 	mutex_unlock(&radio->lock);

 	if (!radio->removed) {
 		retval = amradio_set_mute(radio, AMRADIO_STOP);
 		if (retval < 0)
 			amradio_dev_warn(&radio->videodev->dev,
 				"amradio_stop failed\n");
 	}

 	return 0;
 }

 /* 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 = usb_get_intfdata(intf);
 	int retval;

 	retval = amradio_set_mute(radio, AMRADIO_STOP);
 	if (retval < 0)
 		dev_warn(&intf->dev, "amradio_stop failed\n");

 	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 = usb_get_intfdata(intf);
 	int retval;

 	retval = amradio_set_mute(radio, AMRADIO_START);
 	if (retval < 0)
 		dev_warn(&intf->dev, "amradio_start failed\n");

 	dev_info(&intf->dev, "coming out of suspend..\n");

 	return 0;
 }

 /* File system interface */
 static const struct v4l2_file_operations usb_amradio_fops = {
 	.owner		= THIS_MODULE,
 	.open		= usb_amradio_open,
 	.release	= usb_amradio_close,
 	.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_queryctrl   = vidioc_queryctrl,
 	.vidioc_g_ctrl      = vidioc_g_ctrl,
 	.vidioc_s_ctrl      = vidioc_s_ctrl,
 	.vidioc_g_audio     = vidioc_g_audio,
 	.vidioc_s_audio     = vidioc_s_audio,
 	.vidioc_g_input     = vidioc_g_input,
 	.vidioc_s_input     = vidioc_s_input,
 };

 static void usb_amradio_video_device_release(struct video_device *videodev)
 {
 	struct amradio_device *radio = video_get_drvdata(videodev);

 	/* we call v4l to free radio->videodev */
 	video_device_release(videodev);

 	v4l2_device_unregister(&radio->v4l2_dev);

 	/* free rest memory */
 	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;
 	struct v4l2_device *v4l2_dev;
 	int retval;

 	radio = kzalloc(sizeof(struct amradio_device), GFP_KERNEL);

 	if (!radio) {
 		dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
 		return -ENOMEM;
 	}

 	radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);

 	if (!radio->buffer) {
 		dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
 		kfree(radio);
 		return -ENOMEM;
 	}

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

 	radio->videodev = video_device_alloc();

 	if (!radio->videodev) {
 		dev_err(&intf->dev, "video_device_alloc failed\n");
 		kfree(radio->buffer);
 		kfree(radio);
 		return -ENOMEM;
 	}

 	strlcpy(radio->videodev->name, v4l2_dev->name, sizeof(radio->videodev->name));
 	radio->videodev->v4l2_dev = v4l2_dev;
 	radio->videodev->fops = &usb_amradio_fops;
 	radio->videodev->ioctl_ops = &usb_amradio_ioctl_ops;
 	radio->videodev->release = usb_amradio_video_device_release;

 	radio->removed = 0;
 	radio->users = 0;
 	radio->usbdev = interface_to_usbdev(intf);
 	radio->curfreq = 95.16 * FREQ_MUL;
 	radio->stereo = -1;

 	mutex_init(&radio->lock);

 	video_set_drvdata(radio->videodev, radio);

 	retval = video_register_device(radio->videodev,	VFL_TYPE_RADIO,	radio_nr);
 	if (retval < 0) {
 		dev_err(&intf->dev, "could not register video device\n");
 		video_device_release(radio->videodev);
 		v4l2_device_unregister(v4l2_dev);
 		kfree(radio->buffer);
 		kfree(radio);
 		return -EIO;
 	}

 	usb_set_intfdata(intf, radio);
 	return 0;
 }

 static int __init amradio_init(void)
 {
 	int retval = usb_register(&usb_amradio_driver);

 	pr_info(KBUILD_MODNAME
 		": version " DRIVER_VERSION " " DRIVER_DESC "\n");

 	if (retval)
 		pr_err(KBUILD_MODNAME
 			": usb_register failed. Error number %d\n", retval);

 	return retval;
 }

 static void __exit amradio_exit(void)
 {
 	usb_deregister(&usb_amradio_driver);
 }

 module_init(amradio_init);
 module_exit(amradio_exit);
	/*
	* 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.
	*
	* 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
	*/

	/*
	* 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 trough 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://kerneltrap.org/mailarchive/linux-usb-devel/2007/10/11/342492
	*
	* 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 managment 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 <linux/usb.h>
	#include <linux/version.h> /* for KERNEL_VERSION MACRO */
	#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 "0.11"
	#define RADIO_VERSION KERNEL_VERSION(0, 1, 1)

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

	#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)

	/* 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 isnt full and will be updated with implementation of new functions
	*/
	#define AMRADIO_SET_FREQ 0xa4
	#define AMRADIO_SET_MUTE 0xab
	#define AMRADIO_SET_MONO 0xae

	/* Comfortable defines for amradio_set_mute */
	#define AMRADIO_START 0x00
	#define AMRADIO_STOP 0x01

	/* 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");

	static int usb_amradio_probe(struct usb_interface *intf,
	const struct usb_device_id *id);
	static void usb_amradio_disconnect(struct usb_interface *intf);
	static int usb_amradio_open(struct file *file);
	static int usb_amradio_close(struct file *file);
	static int usb_amradio_suspend(struct usb_interface *intf,
	pm_message_t message);
	static int usb_amradio_resume(struct usb_interface *intf);

	/* Data for one (physical) device */
	struct amradio_device {
	/* reference to USB and video device */
	struct usb_device *usbdev;
	struct video_device *videodev;
	struct v4l2_device v4l2_dev;

	unsigned char *buffer;
	struct mutex lock; /* buffer locking */
	int curfreq;
	int stereo;
	int users;
	int removed;
	int muted;
	};

	/* USB Device ID List */
	static 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,
	.supports_autosuspend = 0,
	};

	/* switch on/off the radio. Send 8 bytes to device */
	static int amradio_set_mute(struct amradio_device *radio, char argument)
	{
	int retval;
	int size;

	/* safety check */
	if (radio->removed)
	return -EIO;

	mutex_lock(&radio->lock);

	radio->buffer[0] = 0x00;
	radio->buffer[1] = 0x55;
	radio->buffer[2] = 0xaa;
	radio->buffer[3] = 0x00;
	radio->buffer[4] = AMRADIO_SET_MUTE;
	radio->buffer[5] = argument;
	radio->buffer[6] = 0x00;
	radio->buffer[7] = 0x00;

	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
	(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

	if (retval < 0 \|\| size != BUFFER_LENGTH) {
	mutex_unlock(&radio->lock);
	return retval;
	}

	radio->muted = argument;

	mutex_unlock(&radio->lock);

	return retval;
	}

	/* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
	static int amradio_setfreq(struct amradio_device *radio, int freq)
	{
	int retval;
	int size;
	unsigned short freq_send = 0x10 + (freq >> 3) / 25;

	/* safety check */
	if (radio->removed)
	return -EIO;

	mutex_lock(&radio->lock);

	radio->buffer[0] = 0x00;
	radio->buffer[1] = 0x55;
	radio->buffer[2] = 0xaa;
	radio->buffer[3] = 0x03;
	radio->buffer[4] = AMRADIO_SET_FREQ;
	radio->buffer[5] = 0x00;
	radio->buffer[6] = 0x00;
	radio->buffer[7] = 0x08;

	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
	(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

	if (retval < 0 \|\| size != BUFFER_LENGTH) {
	mutex_unlock(&radio->lock);
	return retval;
	}

	/* frequency is calculated from freq_send and placed in first 2 bytes */
	radio->buffer[0] = (freq_send >> 8) & 0xff;
	radio->buffer[1] = freq_send & 0xff;
	radio->buffer[2] = 0x01;
	radio->buffer[3] = 0x00;
	radio->buffer[4] = 0x00;
	/* 5 and 6 bytes of buffer already = 0x00 */
	radio->buffer[7] = 0x00;

	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
	(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

	if (retval < 0 \|\| size != BUFFER_LENGTH) {
	mutex_unlock(&radio->lock);
	return retval;
	}

	mutex_unlock(&radio->lock);

	return retval;
	}

	static int amradio_set_stereo(struct amradio_device *radio, char argument)
	{
	int retval;
	int size;

	/* safety check */
	if (radio->removed)
	return -EIO;

	mutex_lock(&radio->lock);

	radio->buffer[0] = 0x00;
	radio->buffer[1] = 0x55;
	radio->buffer[2] = 0xaa;
	radio->buffer[3] = 0x00;
	radio->buffer[4] = AMRADIO_SET_MONO;
	radio->buffer[5] = argument;
	radio->buffer[6] = 0x00;
	radio->buffer[7] = 0x00;

	retval = usb_bulk_msg(radio->usbdev, usb_sndintpipe(radio->usbdev, 2),
	(void *) (radio->buffer), BUFFER_LENGTH, &size, USB_TIMEOUT);

	if (retval < 0 \|\| size != BUFFER_LENGTH) {
	radio->stereo = -1;
	mutex_unlock(&radio->lock);
	return retval;
	}

	radio->stereo = 1;

	mutex_unlock(&radio->lock);

	return retval;
	}

	/* 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 = usb_get_intfdata(intf);

	mutex_lock(&radio->lock);
	radio->removed = 1;
	mutex_unlock(&radio->lock);

	usb_set_intfdata(intf, NULL);
	video_unregister_device(radio->videodev);
	v4l2_device_disconnect(&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->version = RADIO_VERSION;
	v->capabilities = V4L2_CAP_TUNER;
	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_get_drvdata(video_devdata(file));
	int retval;

	/* safety check */
	if (radio->removed)
	return -EIO;

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

	/* TODO: Add function which look is signal stereo or not
	* amradio_getstat(radio);
	*/

	/* we call amradio_set_stereo to set radio->stereo
	* Honestly, amradio_getstat should cover this in future and
	* amradio_set_stereo shouldn't be here
	*/
	retval = amradio_set_stereo(radio, WANT_STEREO);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"set stereo failed\n");

	strcpy(v->name, "FM");
	v->type = V4L2_TUNER_RADIO;
	v->rangelow = FREQ_MIN * FREQ_MUL;
	v->rangehigh = FREQ_MAX * FREQ_MUL;
	v->rxsubchans = V4L2_TUNER_SUB_MONO \| V4L2_TUNER_SUB_STEREO;
	v->capability = V4L2_TUNER_CAP_LOW;
	if (radio->stereo)
	v->audmode = V4L2_TUNER_MODE_STEREO;
	else
	v->audmode = V4L2_TUNER_MODE_MONO;
	v->signal = 0xffff; /* Can't get the signal strength, sad.. */
	v->afc = 0; /* Don't know what is this */
	return 0;
	}

	/* vidioc_s_tuner - set tuner attributes */
	static int vidioc_s_tuner(struct file file, void priv,
	struct v4l2_tuner *v)
	{
	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
	int retval;

	/* safety check */
	if (radio->removed)
	return -EIO;

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

	/* mono/stereo selector */
	switch (v->audmode) {
	case V4L2_TUNER_MODE_MONO:
	retval = amradio_set_stereo(radio, WANT_MONO);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"set mono failed\n");
	break;
	case V4L2_TUNER_MODE_STEREO:
	retval = amradio_set_stereo(radio, WANT_STEREO);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"set stereo failed\n");
	break;
	default:
	return -EINVAL;
	}

	return 0;
	}

	/* vidioc_s_frequency - set tuner radio frequency */
	static int vidioc_s_frequency(struct file file, void priv,
	struct v4l2_frequency *f)
	{
	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
	int retval;

	/* safety check */
	if (radio->removed)
	return -EIO;

	mutex_lock(&radio->lock);
	radio->curfreq = f->frequency;
	mutex_unlock(&radio->lock);

	retval = amradio_setfreq(radio, radio->curfreq);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"set frequency failed\n");
	return 0;
	}

	/* 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_get_drvdata(video_devdata(file));

	/* safety check */
	if (radio->removed)
	return -EIO;

	f->type = V4L2_TUNER_RADIO;
	f->frequency = radio->curfreq;
	return 0;
	}

	/* vidioc_queryctrl - enumerate control items */
	static int vidioc_queryctrl(struct file file, void priv,
	struct v4l2_queryctrl *qc)
	{
	switch (qc->id) {
	case V4L2_CID_AUDIO_MUTE:
	return v4l2_ctrl_query_fill(qc, 0, 1, 1, 1);
	}

	return -EINVAL;
	}

	/* vidioc_g_ctrl - get the value of a control */
	static int vidioc_g_ctrl(struct file file, void priv,
	struct v4l2_control *ctrl)
	{
	struct amradio_device *radio = video_get_drvdata(video_devdata(file));

	/* safety check */
	if (radio->removed)
	return -EIO;

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
	ctrl->value = radio->muted;
	return 0;
	}
	return -EINVAL;
	}

	/* vidioc_s_ctrl - set the value of a control */
	static int vidioc_s_ctrl(struct file file, void priv,
	struct v4l2_control *ctrl)
	{
	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
	int retval;

	/* safety check */
	if (radio->removed)
	return -EIO;

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
	if (ctrl->value) {
	retval = amradio_set_mute(radio, AMRADIO_STOP);
	if (retval < 0) {
	amradio_dev_warn(&radio->videodev->dev,
	"amradio_stop failed\n");
	return -1;
	}
	} else {
	retval = amradio_set_mute(radio, AMRADIO_START);
	if (retval < 0) {
	amradio_dev_warn(&radio->videodev->dev,
	"amradio_start failed\n");
	return -1;
	}
	}
	return 0;
	}
	return -EINVAL;
	}

	/* vidioc_g_audio - get audio attributes */
	static int vidioc_g_audio(struct file file, void priv,
	struct v4l2_audio *a)
	{
	if (a->index > 1)
	return -EINVAL;

	strcpy(a->name, "Radio");
	a->capability = V4L2_AUDCAP_STEREO;
	return 0;
	}

	/* vidioc_s_audio - set audio attributes */
	static int vidioc_s_audio(struct file file, void priv,
	struct v4l2_audio *a)
	{
	if (a->index != 0)
	return -EINVAL;
	return 0;
	}

	/* vidioc_g_input - get input */
	static int vidioc_g_input(struct file filp, void priv, unsigned int *i)
	{
	*i = 0;
	return 0;
	}

	/* vidioc_s_input - set input */
	static int vidioc_s_input(struct file filp, void priv, unsigned int i)
	{
	if (i != 0)
	return -EINVAL;
	return 0;
	}

	/* open device - amradio_start() and amradio_setfreq() */
	static int usb_amradio_open(struct file *file)
	{
	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
	int retval;

	lock_kernel();

	radio->users = 1;
	radio->muted = 1;

	retval = amradio_set_mute(radio, AMRADIO_START);
	if (retval < 0) {
	amradio_dev_warn(&radio->videodev->dev,
	"radio did not start up properly\n");
	radio->users = 0;
	unlock_kernel();
	return -EIO;
	}

	retval = amradio_set_stereo(radio, WANT_STEREO);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"set stereo failed\n");

	retval = amradio_setfreq(radio, radio->curfreq);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"set frequency failed\n");

	unlock_kernel();
	return 0;
	}

	/close device /
	static int usb_amradio_close(struct file *file)
	{
	struct amradio_device *radio = video_get_drvdata(video_devdata(file));
	int retval;

	if (!radio)
	return -ENODEV;

	mutex_lock(&radio->lock);
	radio->users = 0;
	mutex_unlock(&radio->lock);

	if (!radio->removed) {
	retval = amradio_set_mute(radio, AMRADIO_STOP);
	if (retval < 0)
	amradio_dev_warn(&radio->videodev->dev,
	"amradio_stop failed\n");
	}

	return 0;
	}

	/* 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 = usb_get_intfdata(intf);
	int retval;

	retval = amradio_set_mute(radio, AMRADIO_STOP);
	if (retval < 0)
	dev_warn(&intf->dev, "amradio_stop failed\n");

	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 = usb_get_intfdata(intf);
	int retval;

	retval = amradio_set_mute(radio, AMRADIO_START);
	if (retval < 0)
	dev_warn(&intf->dev, "amradio_start failed\n");

	dev_info(&intf->dev, "coming out of suspend..\n");

	return 0;
	}

	/* File system interface */
	static const struct v4l2_file_operations usb_amradio_fops = {
	.owner = THIS_MODULE,
	.open = usb_amradio_open,
	.release = usb_amradio_close,
	.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_queryctrl = vidioc_queryctrl,
	.vidioc_g_ctrl = vidioc_g_ctrl,
	.vidioc_s_ctrl = vidioc_s_ctrl,
	.vidioc_g_audio = vidioc_g_audio,
	.vidioc_s_audio = vidioc_s_audio,
	.vidioc_g_input = vidioc_g_input,
	.vidioc_s_input = vidioc_s_input,
	};

	static void usb_amradio_video_device_release(struct video_device *videodev)
	{
	struct amradio_device *radio = video_get_drvdata(videodev);

	/* we call v4l to free radio->videodev */
	video_device_release(videodev);

	v4l2_device_unregister(&radio->v4l2_dev);

	/* free rest memory */
	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;
	struct v4l2_device *v4l2_dev;
	int retval;

	radio = kzalloc(sizeof(struct amradio_device), GFP_KERNEL);

	if (!radio) {
	dev_err(&intf->dev, "kmalloc for amradio_device failed\n");
	return -ENOMEM;
	}

	radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);

	if (!radio->buffer) {
	dev_err(&intf->dev, "kmalloc for radio->buffer failed\n");
	kfree(radio);
	return -ENOMEM;
	}

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

	radio->videodev = video_device_alloc();

	if (!radio->videodev) {
	dev_err(&intf->dev, "video_device_alloc failed\n");
	kfree(radio->buffer);
	kfree(radio);
	return -ENOMEM;
	}

	strlcpy(radio->videodev->name, v4l2_dev->name, sizeof(radio->videodev->name));
	radio->videodev->v4l2_dev = v4l2_dev;
	radio->videodev->fops = &usb_amradio_fops;
	radio->videodev->ioctl_ops = &usb_amradio_ioctl_ops;
	radio->videodev->release = usb_amradio_video_device_release;

	radio->removed = 0;
	radio->users = 0;
	radio->usbdev = interface_to_usbdev(intf);
	radio->curfreq = 95.16 * FREQ_MUL;
	radio->stereo = -1;

	mutex_init(&radio->lock);

	video_set_drvdata(radio->videodev, radio);

	retval = video_register_device(radio->videodev, VFL_TYPE_RADIO, radio_nr);
	if (retval < 0) {
	dev_err(&intf->dev, "could not register video device\n");
	video_device_release(radio->videodev);
	v4l2_device_unregister(v4l2_dev);
	kfree(radio->buffer);
	kfree(radio);
	return -EIO;
	}

	usb_set_intfdata(intf, radio);
	return 0;
	}

	static int __init amradio_init(void)
	{
	int retval = usb_register(&usb_amradio_driver);

	pr_info(KBUILD_MODNAME
	": version " DRIVER_VERSION " " DRIVER_DESC "\n");

	if (retval)
	pr_err(KBUILD_MODNAME
	": usb_register failed. Error number %d\n", retval);

	return retval;
	}

	static void __exit amradio_exit(void)
	{
	usb_deregister(&usb_amradio_driver);
	}

	module_init(amradio_init);
	module_exit(amradio_exit);