drivers/media/video/saa5246a.c - LeafOS-Devices/android_kernel_realme_mt6785 - Gitiles

 /*
  * Driver for the SAA5246A or SAA5281 Teletext (=Videotext) decoder chips from
  * Philips.
  *
  * Only capturing of Teletext pages is tested. The videotext chips also have a
  * TV output but my hardware doesn't use it. For this reason this driver does
  * not support changing any TV display settings.
  *
  * Copyright (C) 2004 Michael Geng <linux@MichaelGeng.de>
  *
  * Derived from
  *
  * saa5249 driver
  * Copyright (C) 1998 Richard Guenther
  * <richard.guenther@student.uni-tuebingen.de>
  *
  * with changes by
  * Alan Cox <Alan.Cox@linux.org>
  *
  * and
  *
  * vtx.c
  * Copyright (C) 1994-97 Martin Buck  <martin-2.buck@student.uni-ulm.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/module.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/videotext.h>
 #include <linux/videodev.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-ioctl.h>
 #include <linux/mutex.h>

 #include "saa5246a.h"

 MODULE_AUTHOR("Michael Geng <linux@MichaelGeng.de>");
 MODULE_DESCRIPTION("Philips SAA5246A, SAA5281 Teletext decoder driver");
 MODULE_LICENSE("GPL");

 struct saa5246a_device
 {
 	u8     pgbuf[NUM_DAUS][VTX_VIRTUALSIZE];
 	int    is_searching[NUM_DAUS];
 	struct i2c_client *client;
 	struct mutex lock;
 };

 static struct video_device saa_template;	/* Declared near bottom */

 /* Addresses to scan */
 static unsigned short normal_i2c[]	 = { I2C_ADDRESS, I2C_CLIENT_END };

 I2C_CLIENT_INSMOD;

 static struct i2c_client client_template;

 static int saa5246a_attach(struct i2c_adapter *adap, int addr, int kind)
 {
 	int pgbuf;
 	int err;
 	struct i2c_client *client;
 	struct video_device *vd;
 	struct saa5246a_device *t;

 	printk(KERN_INFO "saa5246a: teletext chip found.\n");
 	client=kmalloc(sizeof(*client), GFP_KERNEL);
 	if(client==NULL)
 		return -ENOMEM;
 	client_template.adapter = adap;
 	client_template.addr = addr;
 	memcpy(client, &client_template, sizeof(*client));
 	t = kzalloc(sizeof(*t), GFP_KERNEL);
 	if(t==NULL)
 	{
 		kfree(client);
 		return -ENOMEM;
 	}
 	strlcpy(client->name, IF_NAME, I2C_NAME_SIZE);
 	mutex_init(&t->lock);

 	/*
 	 *	Now create a video4linux device
 	 */

 	vd = video_device_alloc();
 	if(vd==NULL)
 	{
 		kfree(t);
 		kfree(client);
 		return -ENOMEM;
 	}
 	i2c_set_clientdata(client, vd);
 	memcpy(vd, &saa_template, sizeof(*vd));

 	for (pgbuf = 0; pgbuf < NUM_DAUS; pgbuf++)
 	{
 		memset(t->pgbuf[pgbuf], ' ', sizeof(t->pgbuf[0]));
 		t->is_searching[pgbuf] = false;
 	}
 	vd->priv=t;


 	/*
 	 *	Register it
 	 */

 	if((err=video_register_device(vd, VFL_TYPE_VTX,-1))<0)
 	{
 		kfree(t);
 		kfree(client);
 		video_device_release(vd);
 		return err;
 	}
 	t->client = client;
 	i2c_attach_client(client);
 	return 0;
 }

 /*
  *	We do most of the hard work when we become a device on the i2c.
  */
 static int saa5246a_probe(struct i2c_adapter *adap)
 {
 	if (adap->class & I2C_CLASS_TV_ANALOG)
 		return i2c_probe(adap, &addr_data, saa5246a_attach);
 	return 0;
 }

 static int saa5246a_detach(struct i2c_client *client)
 {
 	struct video_device *vd = i2c_get_clientdata(client);
 	i2c_detach_client(client);
 	video_unregister_device(vd);
 	kfree(vd->priv);
 	kfree(client);
 	return 0;
 }

 /*
  *	I2C interfaces
  */

 static struct i2c_driver i2c_driver_videotext =
 {
 	.driver = {
 		.name 	= IF_NAME,		/* name */
 	},
 	.id 		= I2C_DRIVERID_SAA5249, /* in i2c.h */
 	.attach_adapter = saa5246a_probe,
 	.detach_client  = saa5246a_detach,
 };

 static struct i2c_client client_template = {
 	.driver		= &i2c_driver_videotext,
 	.name		= "(unset)",
 };

 static int i2c_sendbuf(struct saa5246a_device *t, int reg, int count, u8 *data)
 {
 	char buf[64];

 	buf[0] = reg;
 	memcpy(buf+1, data, count);

 	if(i2c_master_send(t->client, buf, count+1)==count+1)
 		return 0;
 	return -1;
 }

 static int i2c_senddata(struct saa5246a_device *t, ...)
 {
 	unsigned char buf[64];
 	int v;
 	int ct = 0;
 	va_list argp;
 	va_start(argp, t);

 	while ((v = va_arg(argp, int)) != -1)
 		buf[ct++] = v;

 	va_end(argp);
 	return i2c_sendbuf(t, buf[0], ct-1, buf+1);
 }

 /* Get count number of bytes from I²C-device at address adr, store them in buf.
  * Start & stop handshaking is done by this routine, ack will be sent after the
  * last byte to inhibit further sending of data. If uaccess is 'true', data is
  * written to user-space with put_user. Returns -1 if I²C-device didn't send
  * acknowledge, 0 otherwise
  */
 static int i2c_getdata(struct saa5246a_device *t, int count, u8 *buf)
 {
 	if(i2c_master_recv(t->client, buf, count)!=count)
 		return -1;
 	return 0;
 }

 /* When a page is found then the not FOUND bit in one of the status registers
  * of the SAA5264A chip is cleared. Unfortunately this bit is not set
  * automatically when a new page is requested. Instead this function must be
  * called after a page has been requested.
  *
  * Return value: 0 if successful
  */
 static int saa5246a_clear_found_bit(struct saa5246a_device *t,
 	unsigned char dau_no)
 {
 	unsigned char row_25_column_8;

 	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

 		dau_no |
 		R8_DO_NOT_CLEAR_MEMORY,

 		R9_CURSER_ROW_25,

 		R10_CURSER_COLUMN_8,

 		COMMAND_END) ||
 		i2c_getdata(t, 1, &row_25_column_8))
 	{
 		return -EIO;
 	}
 	row_25_column_8 |= ROW25_COLUMN8_PAGE_NOT_FOUND;
 	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

 		dau_no |
 		R8_DO_NOT_CLEAR_MEMORY,

 		R9_CURSER_ROW_25,

 		R10_CURSER_COLUMN_8,

 		row_25_column_8,

 		COMMAND_END))
 	{
 		return -EIO;
 	}

 	return 0;
 }

 /* Requests one videotext page as described in req. The fields of req are
  * checked and an error is returned if something is invalid.
  *
  * Return value: 0 if successful
  */
 static int saa5246a_request_page(struct saa5246a_device *t,
     vtx_pagereq_t *req)
 {
 	if (req->pagemask < 0 || req->pagemask >= PGMASK_MAX)
 		return -EINVAL;
 	if (req->pagemask & PGMASK_PAGE)
 		if (req->page < 0 || req->page > PAGE_MAX)
 			return -EINVAL;
 	if (req->pagemask & PGMASK_HOUR)
 		if (req->hour < 0 || req->hour > HOUR_MAX)
 			return -EINVAL;
 	if (req->pagemask & PGMASK_MINUTE)
 		if (req->minute < 0 || req->minute > MINUTE_MAX)
 			return -EINVAL;
 	if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
 		return -EINVAL;

 	if (i2c_senddata(t, SAA5246A_REGISTER_R2,

 		R2_IN_R3_SELECT_PAGE_HUNDREDS |
 		req->pgbuf << 4 |
 		R2_BANK_0 |
 		R2_HAMMING_CHECK_OFF,

 		HUNDREDS_OF_PAGE(req->page) |
 		R3_HOLD_PAGE |
 		(req->pagemask & PG_HUND ?
 			R3_PAGE_HUNDREDS_DO_CARE :
 			R3_PAGE_HUNDREDS_DO_NOT_CARE),

 		TENS_OF_PAGE(req->page) |
 		(req->pagemask & PG_TEN ?
 			R3_PAGE_TENS_DO_CARE :
 			R3_PAGE_TENS_DO_NOT_CARE),

 		UNITS_OF_PAGE(req->page) |
 		(req->pagemask & PG_UNIT ?
 			R3_PAGE_UNITS_DO_CARE :
 			R3_PAGE_UNITS_DO_NOT_CARE),

 		TENS_OF_HOUR(req->hour) |
 		(req->pagemask & HR_TEN ?
 			R3_HOURS_TENS_DO_CARE :
 			R3_HOURS_TENS_DO_NOT_CARE),

 		UNITS_OF_HOUR(req->hour) |
 		(req->pagemask & HR_UNIT ?
 			R3_HOURS_UNITS_DO_CARE :
 			R3_HOURS_UNITS_DO_NOT_CARE),

 		TENS_OF_MINUTE(req->minute) |
 		(req->pagemask & MIN_TEN ?
 			R3_MINUTES_TENS_DO_CARE :
 			R3_MINUTES_TENS_DO_NOT_CARE),

 		UNITS_OF_MINUTE(req->minute) |
 		(req->pagemask & MIN_UNIT ?
 			R3_MINUTES_UNITS_DO_CARE :
 			R3_MINUTES_UNITS_DO_NOT_CARE),

 		COMMAND_END) || i2c_senddata(t, SAA5246A_REGISTER_R2,

 		R2_IN_R3_SELECT_PAGE_HUNDREDS |
 		req->pgbuf << 4 |
 		R2_BANK_0 |
 		R2_HAMMING_CHECK_OFF,

 		HUNDREDS_OF_PAGE(req->page) |
 		R3_UPDATE_PAGE |
 		(req->pagemask & PG_HUND ?
 			R3_PAGE_HUNDREDS_DO_CARE :
 			R3_PAGE_HUNDREDS_DO_NOT_CARE),

 		COMMAND_END))
 	{
 		return -EIO;
 	}

 	t->is_searching[req->pgbuf] = true;
 	return 0;
 }

 /* This routine decodes the page number from the infobits contained in line 25.
  *
  * Parameters:
  * infobits: must be bits 0 to 9 of column 25
  *
  * Return value: page number coded in hexadecimal, i. e. page 123 is coded 0x123
  */
 static inline int saa5246a_extract_pagenum_from_infobits(
     unsigned char infobits[10])
 {
 	int page_hundreds, page_tens, page_units;

 	page_units    = infobits[0] & ROW25_COLUMN0_PAGE_UNITS;
 	page_tens     = infobits[1] & ROW25_COLUMN1_PAGE_TENS;
 	page_hundreds = infobits[8] & ROW25_COLUMN8_PAGE_HUNDREDS;

 	/* page 0x.. means page 8.. */
 	if (page_hundreds == 0)
 		page_hundreds = 8;

 	return((page_hundreds << 8) | (page_tens << 4) | page_units);
 }

 /* Decodes the hour from the infobits contained in line 25.
  *
  * Parameters:
  * infobits: must be bits 0 to 9 of column 25
  *
  * Return: hour coded in hexadecimal, i. e. 12h is coded 0x12
  */
 static inline int saa5246a_extract_hour_from_infobits(
     unsigned char infobits[10])
 {
 	int hour_tens, hour_units;

 	hour_units = infobits[4] & ROW25_COLUMN4_HOUR_UNITS;
 	hour_tens  = infobits[5] & ROW25_COLUMN5_HOUR_TENS;

 	return((hour_tens << 4) | hour_units);
 }

 /* Decodes the minutes from the infobits contained in line 25.
  *
  * Parameters:
  * infobits: must be bits 0 to 9 of column 25
  *
  * Return: minutes coded in hexadecimal, i. e. 10min is coded 0x10
  */
 static inline int saa5246a_extract_minutes_from_infobits(
     unsigned char infobits[10])
 {
 	int minutes_tens, minutes_units;

 	minutes_units = infobits[2] & ROW25_COLUMN2_MINUTES_UNITS;
 	minutes_tens  = infobits[3] & ROW25_COLUMN3_MINUTES_TENS;

 	return((minutes_tens << 4) | minutes_units);
 }

 /* Reads the status bits contained in the first 10 columns of the first line
  * and extracts the information into info.
  *
  * Return value: 0 if successful
  */
 static inline int saa5246a_get_status(struct saa5246a_device *t,
     vtx_pageinfo_t *info, unsigned char dau_no)
 {
 	unsigned char infobits[10];
 	int column;

 	if (dau_no >= NUM_DAUS)
 		return -EINVAL;

 	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

 		dau_no |
 		R8_DO_NOT_CLEAR_MEMORY,

 		R9_CURSER_ROW_25,

 		R10_CURSER_COLUMN_0,

 		COMMAND_END) ||
 		i2c_getdata(t, 10, infobits))
 	{
 		return -EIO;
 	}

 	info->pagenum = saa5246a_extract_pagenum_from_infobits(infobits);
 	info->hour    = saa5246a_extract_hour_from_infobits(infobits);
 	info->minute  = saa5246a_extract_minutes_from_infobits(infobits);
 	info->charset = ((infobits[7] & ROW25_COLUMN7_CHARACTER_SET) >> 1);
 	info->delete = !!(infobits[3] & ROW25_COLUMN3_DELETE_PAGE);
 	info->headline = !!(infobits[5] & ROW25_COLUMN5_INSERT_HEADLINE);
 	info->subtitle = !!(infobits[5] & ROW25_COLUMN5_INSERT_SUBTITLE);
 	info->supp_header = !!(infobits[6] & ROW25_COLUMN6_SUPPRESS_HEADER);
 	info->update = !!(infobits[6] & ROW25_COLUMN6_UPDATE_PAGE);
 	info->inter_seq = !!(infobits[6] & ROW25_COLUMN6_INTERRUPTED_SEQUENCE);
 	info->dis_disp = !!(infobits[6] & ROW25_COLUMN6_SUPPRESS_DISPLAY);
 	info->serial = !!(infobits[7] & ROW25_COLUMN7_SERIAL_MODE);
 	info->notfound = !!(infobits[8] & ROW25_COLUMN8_PAGE_NOT_FOUND);
 	info->pblf = !!(infobits[9] & ROW25_COLUMN9_PAGE_BEING_LOOKED_FOR);
 	info->hamming = 0;
 	for (column = 0; column <= 7; column++) {
 		if (infobits[column] & ROW25_COLUMN0_TO_7_HAMMING_ERROR) {
 			info->hamming = 1;
 			break;
 		}
 	}
 	if (!info->hamming && !info->notfound)
 		t->is_searching[dau_no] = false;
 	return 0;
 }

 /* Reads 1 videotext page buffer of the SAA5246A.
  *
  * req is used both as input and as output. It contains information which part
  * must be read. The videotext page is copied into req->buffer.
  *
  * Return value: 0 if successful
  */
 static inline int saa5246a_get_page(struct saa5246a_device *t,
 	vtx_pagereq_t *req)
 {
 	int start, end, size;
 	char *buf;
 	int err;

 	if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS ||
 	    req->start < 0 || req->start > req->end || req->end >= VTX_PAGESIZE)
 		return -EINVAL;

 	buf = kmalloc(VTX_PAGESIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	/* Read "normal" part of page */
 	err = -EIO;

 	end = min(req->end, VTX_PAGESIZE - 1);
 	if (i2c_senddata(t, SAA5246A_REGISTER_R8,
 			req->pgbuf | R8_DO_NOT_CLEAR_MEMORY,
 			ROW(req->start), COLUMN(req->start), COMMAND_END))
 		goto out;
 	if (i2c_getdata(t, end - req->start + 1, buf))
 		goto out;
 	err = -EFAULT;
 	if (copy_to_user(req->buffer, buf, end - req->start + 1))
 		goto out;

 	/* Always get the time from buffer 4, since this stupid SAA5246A only
 	 * updates the currently displayed buffer...
 	 */
 	if (REQ_CONTAINS_TIME(req)) {
 		start = max(req->start, POS_TIME_START);
 		end   = min(req->end,   POS_TIME_END);
 		size = end - start + 1;
 		err = -EINVAL;
 		if (size < 0)
 			goto out;
 		err = -EIO;
 		if (i2c_senddata(t, SAA5246A_REGISTER_R8,
 				R8_ACTIVE_CHAPTER_4 | R8_DO_NOT_CLEAR_MEMORY,
 				R9_CURSER_ROW_0, start, COMMAND_END))
 			goto out;
 		if (i2c_getdata(t, size, buf))
 			goto out;
 		err = -EFAULT;
 		if (copy_to_user(req->buffer + start - req->start, buf, size))
 			goto out;
 	}
 	/* Insert the header from buffer 4 only, if acquisition circuit is still searching for a page */
 	if (REQ_CONTAINS_HEADER(req) && t->is_searching[req->pgbuf]) {
 		start = max(req->start, POS_HEADER_START);
 		end   = min(req->end,   POS_HEADER_END);
 		size = end - start + 1;
 		err = -EINVAL;
 		if (size < 0)
 			goto out;
 		err = -EIO;
 		if (i2c_senddata(t, SAA5246A_REGISTER_R8,
 				R8_ACTIVE_CHAPTER_4 | R8_DO_NOT_CLEAR_MEMORY,
 				R9_CURSER_ROW_0, start, COMMAND_END))
 			goto out;
 		if (i2c_getdata(t, end - start + 1, buf))
 			goto out;
 		err = -EFAULT;
 		if (copy_to_user(req->buffer + start - req->start, buf, size))
 			goto out;
 	}
 	err = 0;
 out:
 	kfree(buf);
 	return err;
 }

 /* Stops the acquisition circuit given in dau_no. The page buffer associated
  * with this acquisition circuit will no more be updated. The other daus are
  * not affected.
  *
  * Return value: 0 if successful
  */
 static inline int saa5246a_stop_dau(struct saa5246a_device *t,
     unsigned char dau_no)
 {
 	if (dau_no >= NUM_DAUS)
 		return -EINVAL;
 	if (i2c_senddata(t, SAA5246A_REGISTER_R2,

 		R2_IN_R3_SELECT_PAGE_HUNDREDS |
 		dau_no << 4 |
 		R2_BANK_0 |
 		R2_HAMMING_CHECK_OFF,

 		R3_PAGE_HUNDREDS_0 |
 		R3_HOLD_PAGE |
 		R3_PAGE_HUNDREDS_DO_NOT_CARE,

 		COMMAND_END))
 	{
 		return -EIO;
 	}
 	t->is_searching[dau_no] = false;
 	return 0;
 }

 /*  Handles ioctls defined in videotext.h
  *
  *  Returns 0 if successful
  */
 static int do_saa5246a_ioctl(struct inode *inode, struct file *file,
 			    unsigned int cmd, void *arg)
 {
 	struct video_device *vd = video_devdata(file);
 	struct saa5246a_device *t=vd->priv;
 	switch(cmd)
 	{
 		case VTXIOCGETINFO:
 		{
 			vtx_info_t *info = arg;

 			info->version_major = MAJOR_VERSION;
 			info->version_minor = MINOR_VERSION;
 			info->numpages = NUM_DAUS;
 			return 0;
 		}

 		case VTXIOCCLRPAGE:
 		{
 			vtx_pagereq_t *req = arg;

 			if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
 				return -EINVAL;
 			memset(t->pgbuf[req->pgbuf], ' ', sizeof(t->pgbuf[0]));
 			return 0;
 		}

 		case VTXIOCCLRFOUND:
 		{
 			vtx_pagereq_t *req = arg;

 			if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
 				return -EINVAL;
 			return(saa5246a_clear_found_bit(t, req->pgbuf));
 		}

 		case VTXIOCPAGEREQ:
 		{
 			vtx_pagereq_t *req = arg;

 			return(saa5246a_request_page(t, req));
 		}

 		case VTXIOCGETSTAT:
 		{
 			vtx_pagereq_t *req = arg;
 			vtx_pageinfo_t info;
 			int rval;

 			if ((rval = saa5246a_get_status(t, &info, req->pgbuf)))
 				return rval;
 			if(copy_to_user(req->buffer, &info,
 				sizeof(vtx_pageinfo_t)))
 				return -EFAULT;
 			return 0;
 		}

 		case VTXIOCGETPAGE:
 		{
 			vtx_pagereq_t *req = arg;

 			return(saa5246a_get_page(t, req));
 		}

 		case VTXIOCSTOPDAU:
 		{
 			vtx_pagereq_t *req = arg;

 			return(saa5246a_stop_dau(t, req->pgbuf));
 		}

 		case VTXIOCPUTPAGE:
 		case VTXIOCSETDISP:
 		case VTXIOCPUTSTAT:
 			return 0;

 		case VTXIOCCLRCACHE:
 		{
 			return 0;
 		}

 		case VTXIOCSETVIRT:
 		{
 			/* I do not know what "virtual mode" means */
 			return 0;
 		}
 	}
 	return -EINVAL;
 }

 /*
  * Translates old vtx IOCTLs to new ones
  *
  * This keeps new kernel versions compatible with old userspace programs.
  */
 static inline unsigned int vtx_fix_command(unsigned int cmd)
 {
 	switch (cmd) {
 	case VTXIOCGETINFO_OLD:
 		cmd = VTXIOCGETINFO;
 		break;
 	case VTXIOCCLRPAGE_OLD:
 		cmd = VTXIOCCLRPAGE;
 		break;
 	case VTXIOCCLRFOUND_OLD:
 		cmd = VTXIOCCLRFOUND;
 		break;
 	case VTXIOCPAGEREQ_OLD:
 		cmd = VTXIOCPAGEREQ;
 		break;
 	case VTXIOCGETSTAT_OLD:
 		cmd = VTXIOCGETSTAT;
 		break;
 	case VTXIOCGETPAGE_OLD:
 		cmd = VTXIOCGETPAGE;
 		break;
 	case VTXIOCSTOPDAU_OLD:
 		cmd = VTXIOCSTOPDAU;
 		break;
 	case VTXIOCPUTPAGE_OLD:
 		cmd = VTXIOCPUTPAGE;
 		break;
 	case VTXIOCSETDISP_OLD:
 		cmd = VTXIOCSETDISP;
 		break;
 	case VTXIOCPUTSTAT_OLD:
 		cmd = VTXIOCPUTSTAT;
 		break;
 	case VTXIOCCLRCACHE_OLD:
 		cmd = VTXIOCCLRCACHE;
 		break;
 	case VTXIOCSETVIRT_OLD:
 		cmd = VTXIOCSETVIRT;
 		break;
 	}
 	return cmd;
 }

 /*
  *	Handle the locking
  */
 static int saa5246a_ioctl(struct inode *inode, struct file *file,
 			 unsigned int cmd, unsigned long arg)
 {
 	struct video_device *vd = video_devdata(file);
 	struct saa5246a_device *t = vd->priv;
 	int err;

 	cmd = vtx_fix_command(cmd);
 	mutex_lock(&t->lock);
 	err = video_usercopy(inode, file, cmd, arg, do_saa5246a_ioctl);
 	mutex_unlock(&t->lock);
 	return err;
 }

 static int saa5246a_open(struct inode *inode, struct file *file)
 {
 	struct video_device *vd = video_devdata(file);
 	struct saa5246a_device *t = vd->priv;
 	int err;

 	err = video_exclusive_open(inode,file);
 	if (err < 0)
 		return err;

 	if (t->client==NULL) {
 		err = -ENODEV;
 		goto fail;
 	}

 	if (i2c_senddata(t, SAA5246A_REGISTER_R0,

 		R0_SELECT_R11 |
 		R0_PLL_TIME_CONSTANT_LONG |
 		R0_ENABLE_nODD_EVEN_OUTPUT |
 		R0_ENABLE_HDR_POLL |
 		R0_DO_NOT_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED |
 		R0_NO_FREE_RUN_PLL |
 		R0_NO_AUTOMATIC_FASTEXT_PROMPT,

 		R1_NON_INTERLACED_312_312_LINES |
 		R1_DEW |
 		R1_EXTENDED_PACKET_DISABLE |
 		R1_DAUS_ALL_ON |
 		R1_8_BITS_NO_PARITY |
 		R1_VCS_TO_SCS,

 		COMMAND_END) ||
 		i2c_senddata(t, SAA5246A_REGISTER_R4,

 		/* We do not care much for the TV display but nevertheless we
 		 * need the currently displayed page later because only on that
 		 * page the time is updated. */
 		R4_DISPLAY_PAGE_4,

 		COMMAND_END))
 	{
 		err = -EIO;
 		goto fail;
 	}

 	return 0;

 fail:
 	video_exclusive_release(inode,file);
 	return err;
 }

 static int saa5246a_release(struct inode *inode, struct file *file)
 {
 	struct video_device *vd = video_devdata(file);
 	struct saa5246a_device *t = vd->priv;

 	/* Stop all acquisition circuits. */
 	i2c_senddata(t, SAA5246A_REGISTER_R1,

 		R1_INTERLACED_312_AND_HALF_312_AND_HALF_LINES |
 		R1_DEW |
 		R1_EXTENDED_PACKET_DISABLE |
 		R1_DAUS_ALL_OFF |
 		R1_8_BITS_NO_PARITY |
 		R1_VCS_TO_SCS,

 		COMMAND_END);
 	video_exclusive_release(inode,file);
 	return 0;
 }

 static int __init init_saa_5246a (void)
 {
 	printk(KERN_INFO
 		"SAA5246A (or compatible) Teletext decoder driver version %d.%d\n",
 		MAJOR_VERSION, MINOR_VERSION);
 	return i2c_add_driver(&i2c_driver_videotext);
 }

 static void __exit cleanup_saa_5246a (void)
 {
 	i2c_del_driver(&i2c_driver_videotext);
 }

 module_init(init_saa_5246a);
 module_exit(cleanup_saa_5246a);

 static const struct file_operations saa_fops = {
 	.owner	 = THIS_MODULE,
 	.open	 = saa5246a_open,
 	.release = saa5246a_release,
 	.ioctl	 = saa5246a_ioctl,
 	.llseek	 = no_llseek,
 };

 static struct video_device saa_template =
 {
 	.name	  = IF_NAME,
 	.fops	  = &saa_fops,
 	.release  = video_device_release,
 	.minor    = -1,
 };
	/*
	* Driver for the SAA5246A or SAA5281 Teletext (=Videotext) decoder chips from
	* Philips.
	*
	* Only capturing of Teletext pages is tested. The videotext chips also have a
	* TV output but my hardware doesn't use it. For this reason this driver does
	* not support changing any TV display settings.
	*
	* Copyright (C) 2004 Michael Geng <linux@MichaelGeng.de>
	*
	* Derived from
	*
	* saa5249 driver
	* Copyright (C) 1998 Richard Guenther
	* <richard.guenther@student.uni-tuebingen.de>
	*
	* with changes by
	* Alan Cox <Alan.Cox@linux.org>
	*
	* and
	*
	* vtx.c
	* Copyright (C) 1994-97 Martin Buck <martin-2.buck@student.uni-ulm.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/module.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/init.h>
	#include <linux/i2c.h>
	#include <linux/videotext.h>
	#include <linux/videodev.h>
	#include <media/v4l2-common.h>
	#include <media/v4l2-ioctl.h>
	#include <linux/mutex.h>

	#include "saa5246a.h"

	MODULE_AUTHOR("Michael Geng <linux@MichaelGeng.de>");
	MODULE_DESCRIPTION("Philips SAA5246A, SAA5281 Teletext decoder driver");
	MODULE_LICENSE("GPL");

	struct saa5246a_device
	{
	u8 pgbuf[NUM_DAUS][VTX_VIRTUALSIZE];
	int is_searching[NUM_DAUS];
	struct i2c_client *client;
	struct mutex lock;
	};

	static struct video_device saa_template; /* Declared near bottom */

	/* Addresses to scan */
	static unsigned short normal_i2c[] = { I2C_ADDRESS, I2C_CLIENT_END };

	I2C_CLIENT_INSMOD;

	static struct i2c_client client_template;

	static int saa5246a_attach(struct i2c_adapter *adap, int addr, int kind)
	{
	int pgbuf;
	int err;
	struct i2c_client *client;
	struct video_device *vd;
	struct saa5246a_device *t;

	printk(KERN_INFO "saa5246a: teletext chip found.\n");
	client=kmalloc(sizeof(*client), GFP_KERNEL);
	if(client==NULL)
	return -ENOMEM;
	client_template.adapter = adap;
	client_template.addr = addr;
	memcpy(client, &client_template, sizeof(*client));
	t = kzalloc(sizeof(*t), GFP_KERNEL);
	if(t==NULL)
	{
	kfree(client);
	return -ENOMEM;
	}
	strlcpy(client->name, IF_NAME, I2C_NAME_SIZE);
	mutex_init(&t->lock);

	/*
	* Now create a video4linux device
	*/

	vd = video_device_alloc();
	if(vd==NULL)
	{
	kfree(t);
	kfree(client);
	return -ENOMEM;
	}
	i2c_set_clientdata(client, vd);
	memcpy(vd, &saa_template, sizeof(*vd));

	for (pgbuf = 0; pgbuf < NUM_DAUS; pgbuf++)
	{
	memset(t->pgbuf[pgbuf], ' ', sizeof(t->pgbuf[0]));
	t->is_searching[pgbuf] = false;
	}
	vd->priv=t;


	/*
	* Register it
	*/

	if((err=video_register_device(vd, VFL_TYPE_VTX,-1))<0)
	{
	kfree(t);
	kfree(client);
	video_device_release(vd);
	return err;
	}
	t->client = client;
	i2c_attach_client(client);
	return 0;
	}

	/*
	* We do most of the hard work when we become a device on the i2c.
	*/
	static int saa5246a_probe(struct i2c_adapter *adap)
	{
	if (adap->class & I2C_CLASS_TV_ANALOG)
	return i2c_probe(adap, &addr_data, saa5246a_attach);
	return 0;
	}

	static int saa5246a_detach(struct i2c_client *client)
	{
	struct video_device *vd = i2c_get_clientdata(client);
	i2c_detach_client(client);
	video_unregister_device(vd);
	kfree(vd->priv);
	kfree(client);
	return 0;
	}

	/*
	* I2C interfaces
	*/

	static struct i2c_driver i2c_driver_videotext =
	{
	.driver = {
	.name = IF_NAME, /* name */
	},
	.id = I2C_DRIVERID_SAA5249, /* in i2c.h */
	.attach_adapter = saa5246a_probe,
	.detach_client = saa5246a_detach,
	};

	static struct i2c_client client_template = {
	.driver = &i2c_driver_videotext,
	.name = "(unset)",
	};

	static int i2c_sendbuf(struct saa5246a_device t, int reg, int count, u8 data)
	{
	char buf[64];

	buf[0] = reg;
	memcpy(buf+1, data, count);

	if(i2c_master_send(t->client, buf, count+1)==count+1)
	return 0;
	return -1;
	}

	static int i2c_senddata(struct saa5246a_device *t, ...)
	{
	unsigned char buf[64];
	int v;
	int ct = 0;
	va_list argp;
	va_start(argp, t);

	while ((v = va_arg(argp, int)) != -1)
	buf[ct++] = v;

	va_end(argp);
	return i2c_sendbuf(t, buf[0], ct-1, buf+1);
	}

	/* Get count number of bytes from I²C-device at address adr, store them in buf.
	* Start & stop handshaking is done by this routine, ack will be sent after the
	* last byte to inhibit further sending of data. If uaccess is 'true', data is
	* written to user-space with put_user. Returns -1 if I²C-device didn't send
	* acknowledge, 0 otherwise
	*/
	static int i2c_getdata(struct saa5246a_device t, int count, u8 buf)
	{
	if(i2c_master_recv(t->client, buf, count)!=count)
	return -1;
	return 0;
	}

	/* When a page is found then the not FOUND bit in one of the status registers
	* of the SAA5264A chip is cleared. Unfortunately this bit is not set
	* automatically when a new page is requested. Instead this function must be
	* called after a page has been requested.
	*
	* Return value: 0 if successful
	*/
	static int saa5246a_clear_found_bit(struct saa5246a_device *t,
	unsigned char dau_no)
	{
	unsigned char row_25_column_8;

	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

	dau_no \|
	R8_DO_NOT_CLEAR_MEMORY,

	R9_CURSER_ROW_25,

	R10_CURSER_COLUMN_8,

	COMMAND_END) \|\|
	i2c_getdata(t, 1, &row_25_column_8))
	{
	return -EIO;
	}
	row_25_column_8 \|= ROW25_COLUMN8_PAGE_NOT_FOUND;
	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

	dau_no \|
	R8_DO_NOT_CLEAR_MEMORY,

	R9_CURSER_ROW_25,

	R10_CURSER_COLUMN_8,

	row_25_column_8,

	COMMAND_END))
	{
	return -EIO;
	}

	return 0;
	}

	/* Requests one videotext page as described in req. The fields of req are
	* checked and an error is returned if something is invalid.
	*
	* Return value: 0 if successful
	*/
	static int saa5246a_request_page(struct saa5246a_device *t,
	vtx_pagereq_t *req)
	{
	if (req->pagemask < 0 \|\| req->pagemask >= PGMASK_MAX)
	return -EINVAL;
	if (req->pagemask & PGMASK_PAGE)
	if (req->page < 0 \|\| req->page > PAGE_MAX)
	return -EINVAL;
	if (req->pagemask & PGMASK_HOUR)
	if (req->hour < 0 \|\| req->hour > HOUR_MAX)
	return -EINVAL;
	if (req->pagemask & PGMASK_MINUTE)
	if (req->minute < 0 \|\| req->minute > MINUTE_MAX)
	return -EINVAL;
	if (req->pgbuf < 0 \|\| req->pgbuf >= NUM_DAUS)
	return -EINVAL;

	if (i2c_senddata(t, SAA5246A_REGISTER_R2,

	R2_IN_R3_SELECT_PAGE_HUNDREDS \|
	req->pgbuf << 4 \|
	R2_BANK_0 \|
	R2_HAMMING_CHECK_OFF,

	HUNDREDS_OF_PAGE(req->page) \|
	R3_HOLD_PAGE \|
	(req->pagemask & PG_HUND ?
	R3_PAGE_HUNDREDS_DO_CARE :
	R3_PAGE_HUNDREDS_DO_NOT_CARE),

	TENS_OF_PAGE(req->page) \|
	(req->pagemask & PG_TEN ?
	R3_PAGE_TENS_DO_CARE :
	R3_PAGE_TENS_DO_NOT_CARE),

	UNITS_OF_PAGE(req->page) \|
	(req->pagemask & PG_UNIT ?
	R3_PAGE_UNITS_DO_CARE :
	R3_PAGE_UNITS_DO_NOT_CARE),

	TENS_OF_HOUR(req->hour) \|
	(req->pagemask & HR_TEN ?
	R3_HOURS_TENS_DO_CARE :
	R3_HOURS_TENS_DO_NOT_CARE),

	UNITS_OF_HOUR(req->hour) \|
	(req->pagemask & HR_UNIT ?
	R3_HOURS_UNITS_DO_CARE :
	R3_HOURS_UNITS_DO_NOT_CARE),

	TENS_OF_MINUTE(req->minute) \|
	(req->pagemask & MIN_TEN ?
	R3_MINUTES_TENS_DO_CARE :
	R3_MINUTES_TENS_DO_NOT_CARE),

	UNITS_OF_MINUTE(req->minute) \|
	(req->pagemask & MIN_UNIT ?
	R3_MINUTES_UNITS_DO_CARE :
	R3_MINUTES_UNITS_DO_NOT_CARE),

	COMMAND_END) \|\| i2c_senddata(t, SAA5246A_REGISTER_R2,

	R2_IN_R3_SELECT_PAGE_HUNDREDS \|
	req->pgbuf << 4 \|
	R2_BANK_0 \|
	R2_HAMMING_CHECK_OFF,

	HUNDREDS_OF_PAGE(req->page) \|
	R3_UPDATE_PAGE \|
	(req->pagemask & PG_HUND ?
	R3_PAGE_HUNDREDS_DO_CARE :
	R3_PAGE_HUNDREDS_DO_NOT_CARE),

	COMMAND_END))
	{
	return -EIO;
	}

	t->is_searching[req->pgbuf] = true;
	return 0;
	}

	/* This routine decodes the page number from the infobits contained in line 25.
	*
	* Parameters:
	* infobits: must be bits 0 to 9 of column 25
	*
	* Return value: page number coded in hexadecimal, i. e. page 123 is coded 0x123
	*/
	static inline int saa5246a_extract_pagenum_from_infobits(
	unsigned char infobits[10])
	{
	int page_hundreds, page_tens, page_units;

	page_units = infobits[0] & ROW25_COLUMN0_PAGE_UNITS;
	page_tens = infobits[1] & ROW25_COLUMN1_PAGE_TENS;
	page_hundreds = infobits[8] & ROW25_COLUMN8_PAGE_HUNDREDS;

	/* page 0x.. means page 8.. */
	if (page_hundreds == 0)
	page_hundreds = 8;

	return((page_hundreds << 8) \| (page_tens << 4) \| page_units);
	}

	/* Decodes the hour from the infobits contained in line 25.
	*
	* Parameters:
	* infobits: must be bits 0 to 9 of column 25
	*
	* Return: hour coded in hexadecimal, i. e. 12h is coded 0x12
	*/
	static inline int saa5246a_extract_hour_from_infobits(
	unsigned char infobits[10])
	{
	int hour_tens, hour_units;

	hour_units = infobits[4] & ROW25_COLUMN4_HOUR_UNITS;
	hour_tens = infobits[5] & ROW25_COLUMN5_HOUR_TENS;

	return((hour_tens << 4) \| hour_units);
	}

	/* Decodes the minutes from the infobits contained in line 25.
	*
	* Parameters:
	* infobits: must be bits 0 to 9 of column 25
	*
	* Return: minutes coded in hexadecimal, i. e. 10min is coded 0x10
	*/
	static inline int saa5246a_extract_minutes_from_infobits(
	unsigned char infobits[10])
	{
	int minutes_tens, minutes_units;

	minutes_units = infobits[2] & ROW25_COLUMN2_MINUTES_UNITS;
	minutes_tens = infobits[3] & ROW25_COLUMN3_MINUTES_TENS;

	return((minutes_tens << 4) \| minutes_units);
	}

	/* Reads the status bits contained in the first 10 columns of the first line
	* and extracts the information into info.
	*
	* Return value: 0 if successful
	*/
	static inline int saa5246a_get_status(struct saa5246a_device *t,
	vtx_pageinfo_t *info, unsigned char dau_no)
	{
	unsigned char infobits[10];
	int column;

	if (dau_no >= NUM_DAUS)
	return -EINVAL;

	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

	dau_no \|
	R8_DO_NOT_CLEAR_MEMORY,

	R9_CURSER_ROW_25,

	R10_CURSER_COLUMN_0,

	COMMAND_END) \|\|
	i2c_getdata(t, 10, infobits))
	{
	return -EIO;
	}

	info->pagenum = saa5246a_extract_pagenum_from_infobits(infobits);
	info->hour = saa5246a_extract_hour_from_infobits(infobits);
	info->minute = saa5246a_extract_minutes_from_infobits(infobits);
	info->charset = ((infobits[7] & ROW25_COLUMN7_CHARACTER_SET) >> 1);
	info->delete = !!(infobits[3] & ROW25_COLUMN3_DELETE_PAGE);
	info->headline = !!(infobits[5] & ROW25_COLUMN5_INSERT_HEADLINE);
	info->subtitle = !!(infobits[5] & ROW25_COLUMN5_INSERT_SUBTITLE);
	info->supp_header = !!(infobits[6] & ROW25_COLUMN6_SUPPRESS_HEADER);
	info->update = !!(infobits[6] & ROW25_COLUMN6_UPDATE_PAGE);
	info->inter_seq = !!(infobits[6] & ROW25_COLUMN6_INTERRUPTED_SEQUENCE);
	info->dis_disp = !!(infobits[6] & ROW25_COLUMN6_SUPPRESS_DISPLAY);
	info->serial = !!(infobits[7] & ROW25_COLUMN7_SERIAL_MODE);
	info->notfound = !!(infobits[8] & ROW25_COLUMN8_PAGE_NOT_FOUND);
	info->pblf = !!(infobits[9] & ROW25_COLUMN9_PAGE_BEING_LOOKED_FOR);
	info->hamming = 0;
	for (column = 0; column <= 7; column++) {
	if (infobits[column] & ROW25_COLUMN0_TO_7_HAMMING_ERROR) {
	info->hamming = 1;
	break;
	}
	}
	if (!info->hamming && !info->notfound)
	t->is_searching[dau_no] = false;
	return 0;
	}

	/* Reads 1 videotext page buffer of the SAA5246A.
	*
	* req is used both as input and as output. It contains information which part
	* must be read. The videotext page is copied into req->buffer.
	*
	* Return value: 0 if successful
	*/
	static inline int saa5246a_get_page(struct saa5246a_device *t,
	vtx_pagereq_t *req)
	{
	int start, end, size;
	char *buf;
	int err;

	if (req->pgbuf < 0 \|\| req->pgbuf >= NUM_DAUS \|\|
	req->start < 0 \|\| req->start > req->end \|\| req->end >= VTX_PAGESIZE)
	return -EINVAL;

	buf = kmalloc(VTX_PAGESIZE, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	/* Read "normal" part of page */
	err = -EIO;

	end = min(req->end, VTX_PAGESIZE - 1);
	if (i2c_senddata(t, SAA5246A_REGISTER_R8,
	req->pgbuf \| R8_DO_NOT_CLEAR_MEMORY,
	ROW(req->start), COLUMN(req->start), COMMAND_END))
	goto out;
	if (i2c_getdata(t, end - req->start + 1, buf))
	goto out;
	err = -EFAULT;
	if (copy_to_user(req->buffer, buf, end - req->start + 1))
	goto out;

	/* Always get the time from buffer 4, since this stupid SAA5246A only
	* updates the currently displayed buffer...
	*/
	if (REQ_CONTAINS_TIME(req)) {
	start = max(req->start, POS_TIME_START);
	end = min(req->end, POS_TIME_END);
	size = end - start + 1;
	err = -EINVAL;
	if (size < 0)
	goto out;
	err = -EIO;
	if (i2c_senddata(t, SAA5246A_REGISTER_R8,
	R8_ACTIVE_CHAPTER_4 \| R8_DO_NOT_CLEAR_MEMORY,
	R9_CURSER_ROW_0, start, COMMAND_END))
	goto out;
	if (i2c_getdata(t, size, buf))
	goto out;
	err = -EFAULT;
	if (copy_to_user(req->buffer + start - req->start, buf, size))
	goto out;
	}
	/* Insert the header from buffer 4 only, if acquisition circuit is still searching for a page */
	if (REQ_CONTAINS_HEADER(req) && t->is_searching[req->pgbuf]) {
	start = max(req->start, POS_HEADER_START);
	end = min(req->end, POS_HEADER_END);
	size = end - start + 1;
	err = -EINVAL;
	if (size < 0)
	goto out;
	err = -EIO;
	if (i2c_senddata(t, SAA5246A_REGISTER_R8,
	R8_ACTIVE_CHAPTER_4 \| R8_DO_NOT_CLEAR_MEMORY,
	R9_CURSER_ROW_0, start, COMMAND_END))
	goto out;
	if (i2c_getdata(t, end - start + 1, buf))
	goto out;
	err = -EFAULT;
	if (copy_to_user(req->buffer + start - req->start, buf, size))
	goto out;
	}
	err = 0;
	out:
	kfree(buf);
	return err;
	}

	/* Stops the acquisition circuit given in dau_no. The page buffer associated
	* with this acquisition circuit will no more be updated. The other daus are
	* not affected.
	*
	* Return value: 0 if successful
	*/
	static inline int saa5246a_stop_dau(struct saa5246a_device *t,
	unsigned char dau_no)
	{
	if (dau_no >= NUM_DAUS)
	return -EINVAL;
	if (i2c_senddata(t, SAA5246A_REGISTER_R2,

	R2_IN_R3_SELECT_PAGE_HUNDREDS \|
	dau_no << 4 \|
	R2_BANK_0 \|
	R2_HAMMING_CHECK_OFF,

	R3_PAGE_HUNDREDS_0 \|
	R3_HOLD_PAGE \|
	R3_PAGE_HUNDREDS_DO_NOT_CARE,

	COMMAND_END))
	{
	return -EIO;
	}
	t->is_searching[dau_no] = false;
	return 0;
	}

	/* Handles ioctls defined in videotext.h
	*
	* Returns 0 if successful
	*/
	static int do_saa5246a_ioctl(struct inode inode, struct file file,
	unsigned int cmd, void *arg)
	{
	struct video_device *vd = video_devdata(file);
	struct saa5246a_device *t=vd->priv;
	switch(cmd)
	{
	case VTXIOCGETINFO:
	{
	vtx_info_t *info = arg;

	info->version_major = MAJOR_VERSION;
	info->version_minor = MINOR_VERSION;
	info->numpages = NUM_DAUS;
	return 0;
	}

	case VTXIOCCLRPAGE:
	{
	vtx_pagereq_t *req = arg;

	if (req->pgbuf < 0 \|\| req->pgbuf >= NUM_DAUS)
	return -EINVAL;
	memset(t->pgbuf[req->pgbuf], ' ', sizeof(t->pgbuf[0]));
	return 0;
	}

	case VTXIOCCLRFOUND:
	{
	vtx_pagereq_t *req = arg;

	if (req->pgbuf < 0 \|\| req->pgbuf >= NUM_DAUS)
	return -EINVAL;
	return(saa5246a_clear_found_bit(t, req->pgbuf));
	}

	case VTXIOCPAGEREQ:
	{
	vtx_pagereq_t *req = arg;

	return(saa5246a_request_page(t, req));
	}

	case VTXIOCGETSTAT:
	{
	vtx_pagereq_t *req = arg;
	vtx_pageinfo_t info;
	int rval;

	if ((rval = saa5246a_get_status(t, &info, req->pgbuf)))
	return rval;
	if(copy_to_user(req->buffer, &info,
	sizeof(vtx_pageinfo_t)))
	return -EFAULT;
	return 0;
	}

	case VTXIOCGETPAGE:
	{
	vtx_pagereq_t *req = arg;

	return(saa5246a_get_page(t, req));
	}

	case VTXIOCSTOPDAU:
	{
	vtx_pagereq_t *req = arg;

	return(saa5246a_stop_dau(t, req->pgbuf));
	}

	case VTXIOCPUTPAGE:
	case VTXIOCSETDISP:
	case VTXIOCPUTSTAT:
	return 0;

	case VTXIOCCLRCACHE:
	{
	return 0;
	}

	case VTXIOCSETVIRT:
	{
	/* I do not know what "virtual mode" means */
	return 0;
	}
	}
	return -EINVAL;
	}

	/*
	* Translates old vtx IOCTLs to new ones
	*
	* This keeps new kernel versions compatible with old userspace programs.
	*/
	static inline unsigned int vtx_fix_command(unsigned int cmd)
	{
	switch (cmd) {
	case VTXIOCGETINFO_OLD:
	cmd = VTXIOCGETINFO;
	break;
	case VTXIOCCLRPAGE_OLD:
	cmd = VTXIOCCLRPAGE;
	break;
	case VTXIOCCLRFOUND_OLD:
	cmd = VTXIOCCLRFOUND;
	break;
	case VTXIOCPAGEREQ_OLD:
	cmd = VTXIOCPAGEREQ;
	break;
	case VTXIOCGETSTAT_OLD:
	cmd = VTXIOCGETSTAT;
	break;
	case VTXIOCGETPAGE_OLD:
	cmd = VTXIOCGETPAGE;
	break;
	case VTXIOCSTOPDAU_OLD:
	cmd = VTXIOCSTOPDAU;
	break;
	case VTXIOCPUTPAGE_OLD:
	cmd = VTXIOCPUTPAGE;
	break;
	case VTXIOCSETDISP_OLD:
	cmd = VTXIOCSETDISP;
	break;
	case VTXIOCPUTSTAT_OLD:
	cmd = VTXIOCPUTSTAT;
	break;
	case VTXIOCCLRCACHE_OLD:
	cmd = VTXIOCCLRCACHE;
	break;
	case VTXIOCSETVIRT_OLD:
	cmd = VTXIOCSETVIRT;
	break;
	}
	return cmd;
	}

	/*
	* Handle the locking
	*/
	static int saa5246a_ioctl(struct inode inode, struct file file,
	unsigned int cmd, unsigned long arg)
	{
	struct video_device *vd = video_devdata(file);
	struct saa5246a_device *t = vd->priv;
	int err;

	cmd = vtx_fix_command(cmd);
	mutex_lock(&t->lock);
	err = video_usercopy(inode, file, cmd, arg, do_saa5246a_ioctl);
	mutex_unlock(&t->lock);
	return err;
	}

	static int saa5246a_open(struct inode inode, struct file file)
	{
	struct video_device *vd = video_devdata(file);
	struct saa5246a_device *t = vd->priv;
	int err;

	err = video_exclusive_open(inode,file);
	if (err < 0)
	return err;

	if (t->client==NULL) {
	err = -ENODEV;
	goto fail;
	}

	if (i2c_senddata(t, SAA5246A_REGISTER_R0,

	R0_SELECT_R11 \|
	R0_PLL_TIME_CONSTANT_LONG \|
	R0_ENABLE_nODD_EVEN_OUTPUT \|
	R0_ENABLE_HDR_POLL \|
	R0_DO_NOT_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED \|
	R0_NO_FREE_RUN_PLL \|
	R0_NO_AUTOMATIC_FASTEXT_PROMPT,

	R1_NON_INTERLACED_312_312_LINES \|
	R1_DEW \|
	R1_EXTENDED_PACKET_DISABLE \|
	R1_DAUS_ALL_ON \|
	R1_8_BITS_NO_PARITY \|
	R1_VCS_TO_SCS,

	COMMAND_END) \|\|
	i2c_senddata(t, SAA5246A_REGISTER_R4,

	/* We do not care much for the TV display but nevertheless we
	* need the currently displayed page later because only on that
	* page the time is updated. */
	R4_DISPLAY_PAGE_4,

	COMMAND_END))
	{
	err = -EIO;
	goto fail;
	}

	return 0;

	fail:
	video_exclusive_release(inode,file);
	return err;
	}

	static int saa5246a_release(struct inode inode, struct file file)
	{
	struct video_device *vd = video_devdata(file);
	struct saa5246a_device *t = vd->priv;

	/* Stop all acquisition circuits. */
	i2c_senddata(t, SAA5246A_REGISTER_R1,

	R1_INTERLACED_312_AND_HALF_312_AND_HALF_LINES \|
	R1_DEW \|
	R1_EXTENDED_PACKET_DISABLE \|
	R1_DAUS_ALL_OFF \|
	R1_8_BITS_NO_PARITY \|
	R1_VCS_TO_SCS,

	COMMAND_END);
	video_exclusive_release(inode,file);
	return 0;
	}

	static int __init init_saa_5246a (void)
	{
	printk(KERN_INFO
	"SAA5246A (or compatible) Teletext decoder driver version %d.%d\n",
	MAJOR_VERSION, MINOR_VERSION);
	return i2c_add_driver(&i2c_driver_videotext);
	}

	static void __exit cleanup_saa_5246a (void)
	{
	i2c_del_driver(&i2c_driver_videotext);
	}

	module_init(init_saa_5246a);
	module_exit(cleanup_saa_5246a);

	static const struct file_operations saa_fops = {
	.owner = THIS_MODULE,
	.open = saa5246a_open,
	.release = saa5246a_release,
	.ioctl = saa5246a_ioctl,
	.llseek = no_llseek,
	};

	static struct video_device saa_template =
	{
	.name = IF_NAME,
	.fops = &saa_fops,
	.release = video_device_release,
	.minor = -1,
	};