drivers/media/radio/dsbr100.c - kernel/msm-4.9 - Gitiles

 /* A driver for the D-Link DSB-R100 USB radio and Gemtek USB Radio 21.
  * The device plugs into both the USB and an analog audio input, so this thing
  * only deals with initialisation and frequency setting, the
  * audio data has to be handled by a sound driver.
  *
  * Major issue: I can't find out where the device reports the signal
  * strength, and indeed the windows software appearantly just looks
  * at the stereo indicator as well.  So, scanning will only find
  * stereo stations.  Sad, but I can't help it.
  *
  * Also, the windows program sends oodles of messages over to the
  * device, and I couldn't figure out their meaning.  My suspicion
  * is that they don't have any:-)
  *
  * You might find some interesting stuff about this module at
  * http://unimut.fsk.uni-heidelberg.de/unimut/demi/dsbr
  *
  * Fully tested with the Keene USB FM Transmitter and the v4l2-compliance tool.
  *
  * Copyright (c) 2000 Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
  *
  * 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
 */

 #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 <linux/usb.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ioctl.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-event.h>

 /*
  * Version Information
  */
 MODULE_AUTHOR("Markus Demleitner <msdemlei@tucana.harvard.edu>");
 MODULE_DESCRIPTION("D-Link DSB-R100 USB FM radio driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION("1.1.0");

 #define DSB100_VENDOR 0x04b4
 #define DSB100_PRODUCT 0x1002

 /* Commands the device appears to understand */
 #define DSB100_TUNE 1
 #define DSB100_ONOFF 2

 #define TB_LEN 16

 /* 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

 #define v4l2_dev_to_radio(d) container_of(d, struct dsbr100_device, v4l2_dev)

 static int radio_nr = -1;
 module_param(radio_nr, int, 0);

 /* Data for one (physical) device */
 struct dsbr100_device {
 	struct usb_device *usbdev;
 	struct video_device videodev;
 	struct v4l2_device v4l2_dev;
 	struct v4l2_ctrl_handler hdl;

 	u8 *transfer_buffer;
 	struct mutex v4l2_lock;
 	int curfreq;
 	bool stereo;
 	bool muted;
 };

 /* Low-level device interface begins here */

 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
 static int dsbr100_setfreq(struct dsbr100_device *radio, unsigned freq)
 {
 	unsigned f = (freq / 16 * 80) / 1000 + 856;
 	int retval = 0;

 	if (!radio->muted) {
 		retval = usb_control_msg(radio->usbdev,
 				usb_rcvctrlpipe(radio->usbdev, 0),
 				DSB100_TUNE,
 				USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 				(f >> 8) & 0x00ff, f & 0xff,
 				radio->transfer_buffer, 8, 300);
 		if (retval >= 0)
 			mdelay(1);
 	}

 	if (retval >= 0) {
 		radio->curfreq = freq;
 		return 0;
 	}
 	dev_err(&radio->usbdev->dev,
 		"%s - usb_control_msg returned %i, request %i\n",
 			__func__, retval, DSB100_TUNE);
 	return retval;
 }

 /* switch on radio */
 static int dsbr100_start(struct dsbr100_device *radio)
 {
 	int retval = usb_control_msg(radio->usbdev,
 		usb_rcvctrlpipe(radio->usbdev, 0),
 		DSB100_ONOFF,
 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 		0x01, 0x00, radio->transfer_buffer, 8, 300);

 	if (retval >= 0)
 		return dsbr100_setfreq(radio, radio->curfreq);
 	dev_err(&radio->usbdev->dev,
 		"%s - usb_control_msg returned %i, request %i\n",
 			__func__, retval, DSB100_ONOFF);
 	return retval;

 }

 /* switch off radio */
 static int dsbr100_stop(struct dsbr100_device *radio)
 {
 	int retval = usb_control_msg(radio->usbdev,
 		usb_rcvctrlpipe(radio->usbdev, 0),
 		DSB100_ONOFF,
 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 		0x00, 0x00, radio->transfer_buffer, 8, 300);

 	if (retval >= 0)
 		return 0;
 	dev_err(&radio->usbdev->dev,
 		"%s - usb_control_msg returned %i, request %i\n",
 			__func__, retval, DSB100_ONOFF);
 	return retval;

 }

 /* return the device status.  This is, in effect, just whether it
 sees a stereo signal or not.  Pity. */
 static void dsbr100_getstat(struct dsbr100_device *radio)
 {
 	int retval = usb_control_msg(radio->usbdev,
 		usb_rcvctrlpipe(radio->usbdev, 0),
 		USB_REQ_GET_STATUS,
 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 		0x00, 0x24, radio->transfer_buffer, 8, 300);

 	if (retval < 0) {
 		radio->stereo = false;
 		dev_err(&radio->usbdev->dev,
 			"%s - usb_control_msg returned %i, request %i\n",
 				__func__, retval, USB_REQ_GET_STATUS);
 	} else {
 		radio->stereo = !(radio->transfer_buffer[0] & 0x01);
 	}
 }

 static int vidioc_querycap(struct file *file, void *priv,
 					struct v4l2_capability *v)
 {
 	struct dsbr100_device *radio = video_drvdata(file);

 	strlcpy(v->driver, "dsbr100", sizeof(v->driver));
 	strlcpy(v->card, "D-Link R-100 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;
 	v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
 	return 0;
 }

 static int vidioc_g_tuner(struct file *file, void *priv,
 				struct v4l2_tuner *v)
 {
 	struct dsbr100_device *radio = video_drvdata(file);

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

 	dsbr100_getstat(radio);
 	strcpy(v->name, "FM");
 	v->type = V4L2_TUNER_RADIO;
 	v->rangelow = FREQ_MIN * FREQ_MUL;
 	v->rangehigh = FREQ_MAX * FREQ_MUL;
 	v->rxsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO :
 		V4L2_TUNER_SUB_MONO;
 	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
 	v->audmode = V4L2_TUNER_MODE_STEREO;
 	v->signal = radio->stereo ? 0xffff : 0;     /* We can't get the signal strength */
 	return 0;
 }

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

 static int vidioc_s_frequency(struct file *file, void *priv,
 				struct v4l2_frequency *f)
 {
 	struct dsbr100_device *radio = video_drvdata(file);

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

 	return dsbr100_setfreq(radio, clamp_t(unsigned, f->frequency,
 			FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL));
 }

 static int vidioc_g_frequency(struct file *file, void *priv,
 				struct v4l2_frequency *f)
 {
 	struct dsbr100_device *radio = video_drvdata(file);

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

 static int usb_dsbr100_s_ctrl(struct v4l2_ctrl *ctrl)
 {
 	struct dsbr100_device *radio =
 		container_of(ctrl->handler, struct dsbr100_device, hdl);

 	switch (ctrl->id) {
 	case V4L2_CID_AUDIO_MUTE:
 		radio->muted = ctrl->val;
 		return radio->muted ? dsbr100_stop(radio) : dsbr100_start(radio);
 	}
 	return -EINVAL;
 }


 /* USB subsystem interface begins here */

 /*
  * Handle unplugging of the device.
  * We call video_unregister_device in any case.
  * The last function called in this procedure is
  * usb_dsbr100_video_device_release
  */
 static void usb_dsbr100_disconnect(struct usb_interface *intf)
 {
 	struct dsbr100_device *radio = usb_get_intfdata(intf);

 	mutex_lock(&radio->v4l2_lock);
 	/*
 	 * Disconnect is also called on unload, and in that case we need to
 	 * mute the device. This call will silently fail if it is called
 	 * after a physical disconnect.
 	 */
 	usb_control_msg(radio->usbdev,
 		usb_rcvctrlpipe(radio->usbdev, 0),
 		DSB100_ONOFF,
 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 		0x00, 0x00, radio->transfer_buffer, 8, 300);
 	usb_set_intfdata(intf, NULL);
 	video_unregister_device(&radio->videodev);
 	v4l2_device_disconnect(&radio->v4l2_dev);
 	mutex_unlock(&radio->v4l2_lock);
 	v4l2_device_put(&radio->v4l2_dev);
 }


 /* Suspend device - stop device. */
 static int usb_dsbr100_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct dsbr100_device *radio = usb_get_intfdata(intf);

 	mutex_lock(&radio->v4l2_lock);
 	if (!radio->muted && dsbr100_stop(radio) < 0)
 		dev_warn(&intf->dev, "dsbr100_stop failed\n");
 	mutex_unlock(&radio->v4l2_lock);

 	dev_info(&intf->dev, "going into suspend..\n");
 	return 0;
 }

 /* Resume device - start device. */
 static int usb_dsbr100_resume(struct usb_interface *intf)
 {
 	struct dsbr100_device *radio = usb_get_intfdata(intf);

 	mutex_lock(&radio->v4l2_lock);
 	if (!radio->muted && dsbr100_start(radio) < 0)
 		dev_warn(&intf->dev, "dsbr100_start failed\n");
 	mutex_unlock(&radio->v4l2_lock);

 	dev_info(&intf->dev, "coming out of suspend..\n");
 	return 0;
 }

 /* free data structures */
 static void usb_dsbr100_release(struct v4l2_device *v4l2_dev)
 {
 	struct dsbr100_device *radio = v4l2_dev_to_radio(v4l2_dev);

 	v4l2_ctrl_handler_free(&radio->hdl);
 	v4l2_device_unregister(&radio->v4l2_dev);
 	kfree(radio->transfer_buffer);
 	kfree(radio);
 }

 static const struct v4l2_ctrl_ops usb_dsbr100_ctrl_ops = {
 	.s_ctrl = usb_dsbr100_s_ctrl,
 };

 /* File system interface */
 static const struct v4l2_file_operations usb_dsbr100_fops = {
 	.owner		= THIS_MODULE,
 	.unlocked_ioctl	= video_ioctl2,
 	.open           = v4l2_fh_open,
 	.release        = v4l2_fh_release,
 	.poll		= v4l2_ctrl_poll,
 };

 static const struct v4l2_ioctl_ops usb_dsbr100_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_log_status  = v4l2_ctrl_log_status,
 	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
 };

 /* check if the device is present and register with v4l and usb if it is */
 static int usb_dsbr100_probe(struct usb_interface *intf,
 				const struct usb_device_id *id)
 {
 	struct dsbr100_device *radio;
 	struct v4l2_device *v4l2_dev;
 	int retval;

 	radio = kzalloc(sizeof(struct dsbr100_device), GFP_KERNEL);

 	if (!radio)
 		return -ENOMEM;

 	radio->transfer_buffer = kmalloc(TB_LEN, GFP_KERNEL);

 	if (!(radio->transfer_buffer)) {
 		kfree(radio);
 		return -ENOMEM;
 	}

 	v4l2_dev = &radio->v4l2_dev;
 	v4l2_dev->release = usb_dsbr100_release;

 	retval = v4l2_device_register(&intf->dev, v4l2_dev);
 	if (retval < 0) {
 		v4l2_err(v4l2_dev, "couldn't register v4l2_device\n");
 		goto err_reg_dev;
 	}

 	v4l2_ctrl_handler_init(&radio->hdl, 1);
 	v4l2_ctrl_new_std(&radio->hdl, &usb_dsbr100_ctrl_ops,
 			  V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
 	if (radio->hdl.error) {
 		retval = radio->hdl.error;
 		v4l2_err(v4l2_dev, "couldn't register control\n");
 		goto err_reg_ctrl;
 	}
 	mutex_init(&radio->v4l2_lock);
 	strlcpy(radio->videodev.name, v4l2_dev->name, sizeof(radio->videodev.name));
 	radio->videodev.v4l2_dev = v4l2_dev;
 	radio->videodev.fops = &usb_dsbr100_fops;
 	radio->videodev.ioctl_ops = &usb_dsbr100_ioctl_ops;
 	radio->videodev.release = video_device_release_empty;
 	radio->videodev.lock = &radio->v4l2_lock;
 	radio->videodev.ctrl_handler = &radio->hdl;
 	set_bit(V4L2_FL_USE_FH_PRIO, &radio->videodev.flags);

 	radio->usbdev = interface_to_usbdev(intf);
 	radio->curfreq = FREQ_MIN * FREQ_MUL;
 	radio->muted = true;

 	video_set_drvdata(&radio->videodev, radio);
 	usb_set_intfdata(intf, radio);

 	retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO, radio_nr);
 	if (retval == 0)
 		return 0;
 	v4l2_err(v4l2_dev, "couldn't register video device\n");

 err_reg_ctrl:
 	v4l2_ctrl_handler_free(&radio->hdl);
 	v4l2_device_unregister(v4l2_dev);
 err_reg_dev:
 	kfree(radio->transfer_buffer);
 	kfree(radio);
 	return retval;
 }

 static struct usb_device_id usb_dsbr100_device_table[] = {
 	{ USB_DEVICE(DSB100_VENDOR, DSB100_PRODUCT) },
 	{ }						/* Terminating entry */
 };

 MODULE_DEVICE_TABLE(usb, usb_dsbr100_device_table);

 /* USB subsystem interface */
 static struct usb_driver usb_dsbr100_driver = {
 	.name			= "dsbr100",
 	.probe			= usb_dsbr100_probe,
 	.disconnect		= usb_dsbr100_disconnect,
 	.id_table		= usb_dsbr100_device_table,
 	.suspend		= usb_dsbr100_suspend,
 	.resume			= usb_dsbr100_resume,
 	.reset_resume		= usb_dsbr100_resume,
 };

 module_usb_driver(usb_dsbr100_driver);
	/* A driver for the D-Link DSB-R100 USB radio and Gemtek USB Radio 21.
	* The device plugs into both the USB and an analog audio input, so this thing
	* only deals with initialisation and frequency setting, the
	* audio data has to be handled by a sound driver.
	*
	* Major issue: I can't find out where the device reports the signal
	* strength, and indeed the windows software appearantly just looks
	* at the stereo indicator as well. So, scanning will only find
	* stereo stations. Sad, but I can't help it.
	*
	* Also, the windows program sends oodles of messages over to the
	* device, and I couldn't figure out their meaning. My suspicion
	* is that they don't have any:-)
	*
	* You might find some interesting stuff about this module at
	* http://unimut.fsk.uni-heidelberg.de/unimut/demi/dsbr
	*
	* Fully tested with the Keene USB FM Transmitter and the v4l2-compliance tool.
	*
	* Copyright (c) 2000 Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
	*
	* 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
	*/

	#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 <linux/usb.h>
	#include <media/v4l2-device.h>
	#include <media/v4l2-ioctl.h>
	#include <media/v4l2-ctrls.h>
	#include <media/v4l2-event.h>

	/*
	* Version Information
	*/
	MODULE_AUTHOR("Markus Demleitner <msdemlei@tucana.harvard.edu>");
	MODULE_DESCRIPTION("D-Link DSB-R100 USB FM radio driver");
	MODULE_LICENSE("GPL");
	MODULE_VERSION("1.1.0");

	#define DSB100_VENDOR 0x04b4
	#define DSB100_PRODUCT 0x1002

	/* Commands the device appears to understand */
	#define DSB100_TUNE 1
	#define DSB100_ONOFF 2

	#define TB_LEN 16

	/* 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

	#define v4l2_dev_to_radio(d) container_of(d, struct dsbr100_device, v4l2_dev)

	static int radio_nr = -1;
	module_param(radio_nr, int, 0);

	/* Data for one (physical) device */
	struct dsbr100_device {
	struct usb_device *usbdev;
	struct video_device videodev;
	struct v4l2_device v4l2_dev;
	struct v4l2_ctrl_handler hdl;

	u8 *transfer_buffer;
	struct mutex v4l2_lock;
	int curfreq;
	bool stereo;
	bool muted;
	};

	/* Low-level device interface begins here */

	/* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
	static int dsbr100_setfreq(struct dsbr100_device *radio, unsigned freq)
	{
	unsigned f = (freq / 16 * 80) / 1000 + 856;
	int retval = 0;

	if (!radio->muted) {
	retval = usb_control_msg(radio->usbdev,
	usb_rcvctrlpipe(radio->usbdev, 0),
	DSB100_TUNE,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	(f >> 8) & 0x00ff, f & 0xff,
	radio->transfer_buffer, 8, 300);
	if (retval >= 0)
	mdelay(1);
	}

	if (retval >= 0) {
	radio->curfreq = freq;
	return 0;
	}
	dev_err(&radio->usbdev->dev,
	"%s - usb_control_msg returned %i, request %i\n",
	__func__, retval, DSB100_TUNE);
	return retval;
	}

	/* switch on radio */
	static int dsbr100_start(struct dsbr100_device *radio)
	{
	int retval = usb_control_msg(radio->usbdev,
	usb_rcvctrlpipe(radio->usbdev, 0),
	DSB100_ONOFF,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	0x01, 0x00, radio->transfer_buffer, 8, 300);

	if (retval >= 0)
	return dsbr100_setfreq(radio, radio->curfreq);
	dev_err(&radio->usbdev->dev,
	"%s - usb_control_msg returned %i, request %i\n",
	__func__, retval, DSB100_ONOFF);
	return retval;

	}

	/* switch off radio */
	static int dsbr100_stop(struct dsbr100_device *radio)
	{
	int retval = usb_control_msg(radio->usbdev,
	usb_rcvctrlpipe(radio->usbdev, 0),
	DSB100_ONOFF,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	0x00, 0x00, radio->transfer_buffer, 8, 300);

	if (retval >= 0)
	return 0;
	dev_err(&radio->usbdev->dev,
	"%s - usb_control_msg returned %i, request %i\n",
	__func__, retval, DSB100_ONOFF);
	return retval;

	}

	/* return the device status. This is, in effect, just whether it
	sees a stereo signal or not. Pity. */
	static void dsbr100_getstat(struct dsbr100_device *radio)
	{
	int retval = usb_control_msg(radio->usbdev,
	usb_rcvctrlpipe(radio->usbdev, 0),
	USB_REQ_GET_STATUS,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	0x00, 0x24, radio->transfer_buffer, 8, 300);

	if (retval < 0) {
	radio->stereo = false;
	dev_err(&radio->usbdev->dev,
	"%s - usb_control_msg returned %i, request %i\n",
	__func__, retval, USB_REQ_GET_STATUS);
	} else {
	radio->stereo = !(radio->transfer_buffer[0] & 0x01);
	}
	}

	static int vidioc_querycap(struct file file, void priv,
	struct v4l2_capability *v)
	{
	struct dsbr100_device *radio = video_drvdata(file);

	strlcpy(v->driver, "dsbr100", sizeof(v->driver));
	strlcpy(v->card, "D-Link R-100 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;
	v->capabilities = v->device_caps \| V4L2_CAP_DEVICE_CAPS;
	return 0;
	}

	static int vidioc_g_tuner(struct file file, void priv,
	struct v4l2_tuner *v)
	{
	struct dsbr100_device *radio = video_drvdata(file);

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

	dsbr100_getstat(radio);
	strcpy(v->name, "FM");
	v->type = V4L2_TUNER_RADIO;
	v->rangelow = FREQ_MIN * FREQ_MUL;
	v->rangehigh = FREQ_MAX * FREQ_MUL;
	v->rxsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO :
	V4L2_TUNER_SUB_MONO;
	v->capability = V4L2_TUNER_CAP_LOW \| V4L2_TUNER_CAP_STEREO;
	v->audmode = V4L2_TUNER_MODE_STEREO;
	v->signal = radio->stereo ? 0xffff : 0; /* We can't get the signal strength */
	return 0;
	}

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

	static int vidioc_s_frequency(struct file file, void priv,
	struct v4l2_frequency *f)
	{
	struct dsbr100_device *radio = video_drvdata(file);

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

	return dsbr100_setfreq(radio, clamp_t(unsigned, f->frequency,
	FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL));
	}

	static int vidioc_g_frequency(struct file file, void priv,
	struct v4l2_frequency *f)
	{
	struct dsbr100_device *radio = video_drvdata(file);

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

	static int usb_dsbr100_s_ctrl(struct v4l2_ctrl *ctrl)
	{
	struct dsbr100_device *radio =
	container_of(ctrl->handler, struct dsbr100_device, hdl);

	switch (ctrl->id) {
	case V4L2_CID_AUDIO_MUTE:
	radio->muted = ctrl->val;
	return radio->muted ? dsbr100_stop(radio) : dsbr100_start(radio);
	}
	return -EINVAL;
	}


	/* USB subsystem interface begins here */

	/*
	* Handle unplugging of the device.
	* We call video_unregister_device in any case.
	* The last function called in this procedure is
	* usb_dsbr100_video_device_release
	*/
	static void usb_dsbr100_disconnect(struct usb_interface *intf)
	{
	struct dsbr100_device *radio = usb_get_intfdata(intf);

	mutex_lock(&radio->v4l2_lock);
	/*
	* Disconnect is also called on unload, and in that case we need to
	* mute the device. This call will silently fail if it is called
	* after a physical disconnect.
	*/
	usb_control_msg(radio->usbdev,
	usb_rcvctrlpipe(radio->usbdev, 0),
	DSB100_ONOFF,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	0x00, 0x00, radio->transfer_buffer, 8, 300);
	usb_set_intfdata(intf, NULL);
	video_unregister_device(&radio->videodev);
	v4l2_device_disconnect(&radio->v4l2_dev);
	mutex_unlock(&radio->v4l2_lock);
	v4l2_device_put(&radio->v4l2_dev);
	}


	/* Suspend device - stop device. */
	static int usb_dsbr100_suspend(struct usb_interface *intf, pm_message_t message)
	{
	struct dsbr100_device *radio = usb_get_intfdata(intf);

	mutex_lock(&radio->v4l2_lock);
	if (!radio->muted && dsbr100_stop(radio) < 0)
	dev_warn(&intf->dev, "dsbr100_stop failed\n");
	mutex_unlock(&radio->v4l2_lock);

	dev_info(&intf->dev, "going into suspend..\n");
	return 0;
	}

	/* Resume device - start device. */
	static int usb_dsbr100_resume(struct usb_interface *intf)
	{
	struct dsbr100_device *radio = usb_get_intfdata(intf);

	mutex_lock(&radio->v4l2_lock);
	if (!radio->muted && dsbr100_start(radio) < 0)
	dev_warn(&intf->dev, "dsbr100_start failed\n");
	mutex_unlock(&radio->v4l2_lock);

	dev_info(&intf->dev, "coming out of suspend..\n");
	return 0;
	}

	/* free data structures */
	static void usb_dsbr100_release(struct v4l2_device *v4l2_dev)
	{
	struct dsbr100_device *radio = v4l2_dev_to_radio(v4l2_dev);

	v4l2_ctrl_handler_free(&radio->hdl);
	v4l2_device_unregister(&radio->v4l2_dev);
	kfree(radio->transfer_buffer);
	kfree(radio);
	}

	static const struct v4l2_ctrl_ops usb_dsbr100_ctrl_ops = {
	.s_ctrl = usb_dsbr100_s_ctrl,
	};

	/* File system interface */
	static const struct v4l2_file_operations usb_dsbr100_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = video_ioctl2,
	.open = v4l2_fh_open,
	.release = v4l2_fh_release,
	.poll = v4l2_ctrl_poll,
	};

	static const struct v4l2_ioctl_ops usb_dsbr100_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_log_status = v4l2_ctrl_log_status,
	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
	};

	/* check if the device is present and register with v4l and usb if it is */
	static int usb_dsbr100_probe(struct usb_interface *intf,
	const struct usb_device_id *id)
	{
	struct dsbr100_device *radio;
	struct v4l2_device *v4l2_dev;
	int retval;

	radio = kzalloc(sizeof(struct dsbr100_device), GFP_KERNEL);

	if (!radio)
	return -ENOMEM;

	radio->transfer_buffer = kmalloc(TB_LEN, GFP_KERNEL);

	if (!(radio->transfer_buffer)) {
	kfree(radio);
	return -ENOMEM;
	}

	v4l2_dev = &radio->v4l2_dev;
	v4l2_dev->release = usb_dsbr100_release;

	retval = v4l2_device_register(&intf->dev, v4l2_dev);
	if (retval < 0) {
	v4l2_err(v4l2_dev, "couldn't register v4l2_device\n");
	goto err_reg_dev;
	}

	v4l2_ctrl_handler_init(&radio->hdl, 1);
	v4l2_ctrl_new_std(&radio->hdl, &usb_dsbr100_ctrl_ops,
	V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
	if (radio->hdl.error) {
	retval = radio->hdl.error;
	v4l2_err(v4l2_dev, "couldn't register control\n");
	goto err_reg_ctrl;
	}
	mutex_init(&radio->v4l2_lock);
	strlcpy(radio->videodev.name, v4l2_dev->name, sizeof(radio->videodev.name));
	radio->videodev.v4l2_dev = v4l2_dev;
	radio->videodev.fops = &usb_dsbr100_fops;
	radio->videodev.ioctl_ops = &usb_dsbr100_ioctl_ops;
	radio->videodev.release = video_device_release_empty;
	radio->videodev.lock = &radio->v4l2_lock;
	radio->videodev.ctrl_handler = &radio->hdl;
	set_bit(V4L2_FL_USE_FH_PRIO, &radio->videodev.flags);

	radio->usbdev = interface_to_usbdev(intf);
	radio->curfreq = FREQ_MIN * FREQ_MUL;
	radio->muted = true;

	video_set_drvdata(&radio->videodev, radio);
	usb_set_intfdata(intf, radio);

	retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO, radio_nr);
	if (retval == 0)
	return 0;
	v4l2_err(v4l2_dev, "couldn't register video device\n");

	err_reg_ctrl:
	v4l2_ctrl_handler_free(&radio->hdl);
	v4l2_device_unregister(v4l2_dev);
	err_reg_dev:
	kfree(radio->transfer_buffer);
	kfree(radio);
	return retval;
	}

	static struct usb_device_id usb_dsbr100_device_table[] = {
	{ USB_DEVICE(DSB100_VENDOR, DSB100_PRODUCT) },
	{ } /* Terminating entry */
	};

	MODULE_DEVICE_TABLE(usb, usb_dsbr100_device_table);

	/* USB subsystem interface */
	static struct usb_driver usb_dsbr100_driver = {
	.name = "dsbr100",
	.probe = usb_dsbr100_probe,
	.disconnect = usb_dsbr100_disconnect,
	.id_table = usb_dsbr100_device_table,
	.suspend = usb_dsbr100_suspend,
	.resume = usb_dsbr100_resume,
	.reset_resume = usb_dsbr100_resume,
	};

	module_usb_driver(usb_dsbr100_driver);