drivers/media/platform/vivid/vivid-radio-rx.c - kernel/msm-4.19 - Gitiles

 /*
  * vivid-radio-rx.c - radio receiver support functions.
  *
  * Copyright 2014 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/errno.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/videodev2.h>
 #include <linux/v4l2-dv-timings.h>
 #include <linux/sched/signal.h>

 #include <media/v4l2-common.h>
 #include <media/v4l2-event.h>
 #include <media/v4l2-dv-timings.h>

 #include "vivid-core.h"
 #include "vivid-ctrls.h"
 #include "vivid-radio-common.h"
 #include "vivid-rds-gen.h"
 #include "vivid-radio-rx.h"

 ssize_t vivid_radio_rx_read(struct file *file, char __user *buf,
 			 size_t size, loff_t *offset)
 {
 	struct vivid_dev *dev = video_drvdata(file);
 	struct timespec ts;
 	struct v4l2_rds_data *data = dev->rds_gen.data;
 	bool use_alternates;
 	unsigned blk;
 	int perc;
 	int i;

 	if (dev->radio_rx_rds_controls)
 		return -EINVAL;
 	if (size < sizeof(*data))
 		return 0;
 	size = sizeof(*data) * (size / sizeof(*data));

 	if (mutex_lock_interruptible(&dev->mutex))
 		return -ERESTARTSYS;
 	if (dev->radio_rx_rds_owner &&
 	    file->private_data != dev->radio_rx_rds_owner) {
 		mutex_unlock(&dev->mutex);
 		return -EBUSY;
 	}
 	if (dev->radio_rx_rds_owner == NULL) {
 		vivid_radio_rds_init(dev);
 		dev->radio_rx_rds_owner = file->private_data;
 	}

 retry:
 	ktime_get_ts(&ts);
 	use_alternates = ts.tv_sec % 10 >= 5;
 	if (dev->radio_rx_rds_last_block == 0 ||
 	    dev->radio_rx_rds_use_alternates != use_alternates) {
 		dev->radio_rx_rds_use_alternates = use_alternates;
 		/* Re-init the RDS generator */
 		vivid_radio_rds_init(dev);
 	}
 	ts = timespec_sub(ts, dev->radio_rds_init_ts);
 	blk = ts.tv_sec * 100 + ts.tv_nsec / 10000000;
 	blk = (blk * VIVID_RDS_GEN_BLOCKS) / 500;
 	if (blk >= dev->radio_rx_rds_last_block + VIVID_RDS_GEN_BLOCKS)
 		dev->radio_rx_rds_last_block = blk - VIVID_RDS_GEN_BLOCKS + 1;

 	/*
 	 * No data is available if there hasn't been time to get new data,
 	 * or if the RDS receiver has been disabled, or if we use the data
 	 * from the RDS transmitter and that RDS transmitter has been disabled,
 	 * or if the signal quality is too weak.
 	 */
 	if (blk == dev->radio_rx_rds_last_block || !dev->radio_rx_rds_enabled ||
 	    (dev->radio_rds_loop && !(dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) ||
 	    abs(dev->radio_rx_sig_qual) > 200) {
 		mutex_unlock(&dev->mutex);
 		if (file->f_flags & O_NONBLOCK)
 			return -EWOULDBLOCK;
 		if (msleep_interruptible(20) && signal_pending(current))
 			return -EINTR;
 		if (mutex_lock_interruptible(&dev->mutex))
 			return -ERESTARTSYS;
 		goto retry;
 	}

 	/* abs(dev->radio_rx_sig_qual) <= 200, map that to a 0-50% range */
 	perc = abs(dev->radio_rx_sig_qual) / 4;

 	for (i = 0; i < size && blk > dev->radio_rx_rds_last_block;
 			dev->radio_rx_rds_last_block++) {
 		unsigned data_blk = dev->radio_rx_rds_last_block % VIVID_RDS_GEN_BLOCKS;
 		struct v4l2_rds_data rds = data[data_blk];

 		if (data_blk == 0 && dev->radio_rds_loop)
 			vivid_radio_rds_init(dev);
 		if (perc && prandom_u32_max(100) < perc) {
 			switch (prandom_u32_max(4)) {
 			case 0:
 				rds.block |= V4L2_RDS_BLOCK_CORRECTED;
 				break;
 			case 1:
 				rds.block |= V4L2_RDS_BLOCK_INVALID;
 				break;
 			case 2:
 				rds.block |= V4L2_RDS_BLOCK_ERROR;
 				rds.lsb = prandom_u32_max(256);
 				rds.msb = prandom_u32_max(256);
 				break;
 			case 3: /* Skip block altogether */
 				if (i)
 					continue;
 				/*
 				 * Must make sure at least one block is
 				 * returned, otherwise the application
 				 * might think that end-of-file occurred.
 				 */
 				break;
 			}
 		}
 		if (copy_to_user(buf + i, &rds, sizeof(rds))) {
 			i = -EFAULT;
 			break;
 		}
 		i += sizeof(rds);
 	}
 	mutex_unlock(&dev->mutex);
 	return i;
 }

 __poll_t vivid_radio_rx_poll(struct file *file, struct poll_table_struct *wait)
 {
 	return POLLIN | POLLRDNORM | v4l2_ctrl_poll(file, wait);
 }

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

 	if (band->index >= TOT_BANDS)
 		return -EINVAL;

 	*band = vivid_radio_bands[band->index];
 	return 0;
 }

 int vivid_radio_rx_s_hw_freq_seek(struct file *file, void *fh, const struct v4l2_hw_freq_seek *a)
 {
 	struct vivid_dev *dev = video_drvdata(file);
 	unsigned low, high;
 	unsigned freq;
 	unsigned spacing;
 	unsigned band;

 	if (a->tuner)
 		return -EINVAL;
 	if (a->wrap_around && dev->radio_rx_hw_seek_mode == VIVID_HW_SEEK_BOUNDED)
 		return -EINVAL;

 	if (!a->wrap_around && dev->radio_rx_hw_seek_mode == VIVID_HW_SEEK_WRAP)
 		return -EINVAL;
 	if (!a->rangelow ^ !a->rangehigh)
 		return -EINVAL;

 	if (file->f_flags & O_NONBLOCK)
 		return -EWOULDBLOCK;

 	if (a->rangelow) {
 		for (band = 0; band < TOT_BANDS; band++)
 			if (a->rangelow >= vivid_radio_bands[band].rangelow &&
 			    a->rangehigh <= vivid_radio_bands[band].rangehigh)
 				break;
 		if (band == TOT_BANDS)
 			return -EINVAL;
 		if (!dev->radio_rx_hw_seek_prog_lim &&
 		    (a->rangelow != vivid_radio_bands[band].rangelow ||
 		     a->rangehigh != vivid_radio_bands[band].rangehigh))
 			return -EINVAL;
 		low = a->rangelow;
 		high = a->rangehigh;
 	} else {
 		for (band = 0; band < TOT_BANDS; band++)
 			if (dev->radio_rx_freq >= vivid_radio_bands[band].rangelow &&
 			    dev->radio_rx_freq <= vivid_radio_bands[band].rangehigh)
 				break;
 		if (band == TOT_BANDS)
 			return -EINVAL;
 		low = vivid_radio_bands[band].rangelow;
 		high = vivid_radio_bands[band].rangehigh;
 	}
 	spacing = band == BAND_AM ? 1600 : 16000;
 	freq = clamp(dev->radio_rx_freq, low, high);

 	if (a->seek_upward) {
 		freq = spacing * (freq / spacing) + spacing;
 		if (freq > high) {
 			if (!a->wrap_around)
 				return -ENODATA;
 			freq = spacing * (low / spacing) + spacing;
 			if (freq >= dev->radio_rx_freq)
 				return -ENODATA;
 		}
 	} else {
 		freq = spacing * ((freq + spacing - 1) / spacing) - spacing;
 		if (freq < low) {
 			if (!a->wrap_around)
 				return -ENODATA;
 			freq = spacing * ((high + spacing - 1) / spacing) - spacing;
 			if (freq <= dev->radio_rx_freq)
 				return -ENODATA;
 		}
 	}
 	return 0;
 }

 int vivid_radio_rx_g_tuner(struct file *file, void *fh, struct v4l2_tuner *vt)
 {
 	struct vivid_dev *dev = video_drvdata(file);
 	int delta = 800;
 	int sig_qual;

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

 	strlcpy(vt->name, "AM/FM/SW Receiver", sizeof(vt->name));
 	vt->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
 			 V4L2_TUNER_CAP_FREQ_BANDS | V4L2_TUNER_CAP_RDS |
 			 (dev->radio_rx_rds_controls ?
 				V4L2_TUNER_CAP_RDS_CONTROLS :
 				V4L2_TUNER_CAP_RDS_BLOCK_IO) |
 			 (dev->radio_rx_hw_seek_prog_lim ?
 				V4L2_TUNER_CAP_HWSEEK_PROG_LIM : 0);
 	switch (dev->radio_rx_hw_seek_mode) {
 	case VIVID_HW_SEEK_BOUNDED:
 		vt->capability |= V4L2_TUNER_CAP_HWSEEK_BOUNDED;
 		break;
 	case VIVID_HW_SEEK_WRAP:
 		vt->capability |= V4L2_TUNER_CAP_HWSEEK_WRAP;
 		break;
 	case VIVID_HW_SEEK_BOTH:
 		vt->capability |= V4L2_TUNER_CAP_HWSEEK_WRAP |
 				  V4L2_TUNER_CAP_HWSEEK_BOUNDED;
 		break;
 	}
 	vt->rangelow = AM_FREQ_RANGE_LOW;
 	vt->rangehigh = FM_FREQ_RANGE_HIGH;
 	sig_qual = dev->radio_rx_sig_qual;
 	vt->signal = abs(sig_qual) > delta ? 0 :
 		     0xffff - (abs(sig_qual) * 0xffff) / delta;
 	vt->afc = sig_qual > delta ? 0 : sig_qual;
 	if (abs(sig_qual) > delta)
 		vt->rxsubchans = 0;
 	else if (dev->radio_rx_freq < FM_FREQ_RANGE_LOW || vt->signal < 0x8000)
 		vt->rxsubchans = V4L2_TUNER_SUB_MONO;
 	else if (dev->radio_rds_loop && !(dev->radio_tx_subchans & V4L2_TUNER_SUB_STEREO))
 		vt->rxsubchans = V4L2_TUNER_SUB_MONO;
 	else
 		vt->rxsubchans = V4L2_TUNER_SUB_STEREO;
 	if (dev->radio_rx_rds_enabled &&
 	    (!dev->radio_rds_loop || (dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) &&
 	    dev->radio_rx_freq >= FM_FREQ_RANGE_LOW && vt->signal >= 0xc000)
 		vt->rxsubchans |= V4L2_TUNER_SUB_RDS;
 	if (dev->radio_rx_rds_controls)
 		vivid_radio_rds_init(dev);
 	vt->audmode = dev->radio_rx_audmode;
 	return 0;
 }

 int vivid_radio_rx_s_tuner(struct file *file, void *fh, const struct v4l2_tuner *vt)
 {
 	struct vivid_dev *dev = video_drvdata(file);

 	if (vt->index)
 		return -EINVAL;
 	dev->radio_rx_audmode = vt->audmode >= V4L2_TUNER_MODE_STEREO;
 	return 0;
 }
	/*
	* vivid-radio-rx.c - radio receiver support functions.
	*
	* Copyright 2014 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/errno.h>
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/videodev2.h>
	#include <linux/v4l2-dv-timings.h>
	#include <linux/sched/signal.h>

	#include <media/v4l2-common.h>
	#include <media/v4l2-event.h>
	#include <media/v4l2-dv-timings.h>

	#include "vivid-core.h"
	#include "vivid-ctrls.h"
	#include "vivid-radio-common.h"
	#include "vivid-rds-gen.h"
	#include "vivid-radio-rx.h"

	ssize_t vivid_radio_rx_read(struct file file, char __user buf,
	size_t size, loff_t *offset)
	{
	struct vivid_dev *dev = video_drvdata(file);
	struct timespec ts;
	struct v4l2_rds_data *data = dev->rds_gen.data;
	bool use_alternates;
	unsigned blk;
	int perc;
	int i;

	if (dev->radio_rx_rds_controls)
	return -EINVAL;
	if (size < sizeof(*data))
	return 0;
	size = sizeof(data) (size / sizeof(*data));

	if (mutex_lock_interruptible(&dev->mutex))
	return -ERESTARTSYS;
	if (dev->radio_rx_rds_owner &&
	file->private_data != dev->radio_rx_rds_owner) {
	mutex_unlock(&dev->mutex);
	return -EBUSY;
	}
	if (dev->radio_rx_rds_owner == NULL) {
	vivid_radio_rds_init(dev);
	dev->radio_rx_rds_owner = file->private_data;
	}

	retry:
	ktime_get_ts(&ts);
	use_alternates = ts.tv_sec % 10 >= 5;
	if (dev->radio_rx_rds_last_block == 0 \|\|
	dev->radio_rx_rds_use_alternates != use_alternates) {
	dev->radio_rx_rds_use_alternates = use_alternates;
	/* Re-init the RDS generator */
	vivid_radio_rds_init(dev);
	}
	ts = timespec_sub(ts, dev->radio_rds_init_ts);
	blk = ts.tv_sec * 100 + ts.tv_nsec / 10000000;
	blk = (blk * VIVID_RDS_GEN_BLOCKS) / 500;
	if (blk >= dev->radio_rx_rds_last_block + VIVID_RDS_GEN_BLOCKS)
	dev->radio_rx_rds_last_block = blk - VIVID_RDS_GEN_BLOCKS + 1;

	/*
	* No data is available if there hasn't been time to get new data,
	* or if the RDS receiver has been disabled, or if we use the data
	* from the RDS transmitter and that RDS transmitter has been disabled,
	* or if the signal quality is too weak.
	*/
	if (blk == dev->radio_rx_rds_last_block \|\| !dev->radio_rx_rds_enabled \|\|
	(dev->radio_rds_loop && !(dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) \|\|
	abs(dev->radio_rx_sig_qual) > 200) {
	mutex_unlock(&dev->mutex);
	if (file->f_flags & O_NONBLOCK)
	return -EWOULDBLOCK;
	if (msleep_interruptible(20) && signal_pending(current))
	return -EINTR;
	if (mutex_lock_interruptible(&dev->mutex))
	return -ERESTARTSYS;
	goto retry;
	}

	/* abs(dev->radio_rx_sig_qual) <= 200, map that to a 0-50% range */
	perc = abs(dev->radio_rx_sig_qual) / 4;

	for (i = 0; i < size && blk > dev->radio_rx_rds_last_block;
	dev->radio_rx_rds_last_block++) {
	unsigned data_blk = dev->radio_rx_rds_last_block % VIVID_RDS_GEN_BLOCKS;
	struct v4l2_rds_data rds = data[data_blk];

	if (data_blk == 0 && dev->radio_rds_loop)
	vivid_radio_rds_init(dev);
	if (perc && prandom_u32_max(100) < perc) {
	switch (prandom_u32_max(4)) {
	case 0:
	rds.block \|= V4L2_RDS_BLOCK_CORRECTED;
	break;
	case 1:
	rds.block \|= V4L2_RDS_BLOCK_INVALID;
	break;
	case 2:
	rds.block \|= V4L2_RDS_BLOCK_ERROR;
	rds.lsb = prandom_u32_max(256);
	rds.msb = prandom_u32_max(256);
	break;
	case 3: /* Skip block altogether */
	if (i)
	continue;
	/*
	* Must make sure at least one block is
	* returned, otherwise the application
	* might think that end-of-file occurred.
	*/
	break;
	}
	}
	if (copy_to_user(buf + i, &rds, sizeof(rds))) {
	i = -EFAULT;
	break;
	}
	i += sizeof(rds);
	}
	mutex_unlock(&dev->mutex);
	return i;
	}

	__poll_t vivid_radio_rx_poll(struct file file, struct poll_table_struct wait)
	{
	return POLLIN \| POLLRDNORM \| v4l2_ctrl_poll(file, wait);
	}

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

	if (band->index >= TOT_BANDS)
	return -EINVAL;

	*band = vivid_radio_bands[band->index];
	return 0;
	}

	int vivid_radio_rx_s_hw_freq_seek(struct file file, void fh, const struct v4l2_hw_freq_seek *a)
	{
	struct vivid_dev *dev = video_drvdata(file);
	unsigned low, high;
	unsigned freq;
	unsigned spacing;
	unsigned band;

	if (a->tuner)
	return -EINVAL;
	if (a->wrap_around && dev->radio_rx_hw_seek_mode == VIVID_HW_SEEK_BOUNDED)
	return -EINVAL;

	if (!a->wrap_around && dev->radio_rx_hw_seek_mode == VIVID_HW_SEEK_WRAP)
	return -EINVAL;
	if (!a->rangelow ^ !a->rangehigh)
	return -EINVAL;

	if (file->f_flags & O_NONBLOCK)
	return -EWOULDBLOCK;

	if (a->rangelow) {
	for (band = 0; band < TOT_BANDS; band++)
	if (a->rangelow >= vivid_radio_bands[band].rangelow &&
	a->rangehigh <= vivid_radio_bands[band].rangehigh)
	break;
	if (band == TOT_BANDS)
	return -EINVAL;
	if (!dev->radio_rx_hw_seek_prog_lim &&
	(a->rangelow != vivid_radio_bands[band].rangelow \|\|
	a->rangehigh != vivid_radio_bands[band].rangehigh))
	return -EINVAL;
	low = a->rangelow;
	high = a->rangehigh;
	} else {
	for (band = 0; band < TOT_BANDS; band++)
	if (dev->radio_rx_freq >= vivid_radio_bands[band].rangelow &&
	dev->radio_rx_freq <= vivid_radio_bands[band].rangehigh)
	break;
	if (band == TOT_BANDS)
	return -EINVAL;
	low = vivid_radio_bands[band].rangelow;
	high = vivid_radio_bands[band].rangehigh;
	}
	spacing = band == BAND_AM ? 1600 : 16000;
	freq = clamp(dev->radio_rx_freq, low, high);

	if (a->seek_upward) {
	freq = spacing * (freq / spacing) + spacing;
	if (freq > high) {
	if (!a->wrap_around)
	return -ENODATA;
	freq = spacing * (low / spacing) + spacing;
	if (freq >= dev->radio_rx_freq)
	return -ENODATA;
	}
	} else {
	freq = spacing * ((freq + spacing - 1) / spacing) - spacing;
	if (freq < low) {
	if (!a->wrap_around)
	return -ENODATA;
	freq = spacing * ((high + spacing - 1) / spacing) - spacing;
	if (freq <= dev->radio_rx_freq)
	return -ENODATA;
	}
	}
	return 0;
	}

	int vivid_radio_rx_g_tuner(struct file file, void fh, struct v4l2_tuner *vt)
	{
	struct vivid_dev *dev = video_drvdata(file);
	int delta = 800;
	int sig_qual;

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

	strlcpy(vt->name, "AM/FM/SW Receiver", sizeof(vt->name));
	vt->capability = V4L2_TUNER_CAP_LOW \| V4L2_TUNER_CAP_STEREO \|
	V4L2_TUNER_CAP_FREQ_BANDS \| V4L2_TUNER_CAP_RDS \|
	(dev->radio_rx_rds_controls ?
	V4L2_TUNER_CAP_RDS_CONTROLS :
	V4L2_TUNER_CAP_RDS_BLOCK_IO) \|
	(dev->radio_rx_hw_seek_prog_lim ?
	V4L2_TUNER_CAP_HWSEEK_PROG_LIM : 0);
	switch (dev->radio_rx_hw_seek_mode) {
	case VIVID_HW_SEEK_BOUNDED:
	vt->capability \|= V4L2_TUNER_CAP_HWSEEK_BOUNDED;
	break;
	case VIVID_HW_SEEK_WRAP:
	vt->capability \|= V4L2_TUNER_CAP_HWSEEK_WRAP;
	break;
	case VIVID_HW_SEEK_BOTH:
	vt->capability \|= V4L2_TUNER_CAP_HWSEEK_WRAP \|
	V4L2_TUNER_CAP_HWSEEK_BOUNDED;
	break;
	}
	vt->rangelow = AM_FREQ_RANGE_LOW;
	vt->rangehigh = FM_FREQ_RANGE_HIGH;
	sig_qual = dev->radio_rx_sig_qual;
	vt->signal = abs(sig_qual) > delta ? 0 :
	0xffff - (abs(sig_qual) * 0xffff) / delta;
	vt->afc = sig_qual > delta ? 0 : sig_qual;
	if (abs(sig_qual) > delta)
	vt->rxsubchans = 0;
	else if (dev->radio_rx_freq < FM_FREQ_RANGE_LOW \|\| vt->signal < 0x8000)
	vt->rxsubchans = V4L2_TUNER_SUB_MONO;
	else if (dev->radio_rds_loop && !(dev->radio_tx_subchans & V4L2_TUNER_SUB_STEREO))
	vt->rxsubchans = V4L2_TUNER_SUB_MONO;
	else
	vt->rxsubchans = V4L2_TUNER_SUB_STEREO;
	if (dev->radio_rx_rds_enabled &&
	(!dev->radio_rds_loop \|\| (dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) &&
	dev->radio_rx_freq >= FM_FREQ_RANGE_LOW && vt->signal >= 0xc000)
	vt->rxsubchans \|= V4L2_TUNER_SUB_RDS;
	if (dev->radio_rx_rds_controls)
	vivid_radio_rds_init(dev);
	vt->audmode = dev->radio_rx_audmode;
	return 0;
	}

	int vivid_radio_rx_s_tuner(struct file file, void fh, const struct v4l2_tuner *vt)
	{
	struct vivid_dev *dev = video_drvdata(file);

	if (vt->index)
	return -EINVAL;
	dev->radio_rx_audmode = vt->audmode >= V4L2_TUNER_MODE_STEREO;
	return 0;
	}