V4L/DVB (9200): bt819: convert i2c driver for new i2c API

[mirror_ubuntu-artful-kernel.git] / drivers / media / video / saa5246a.c

/*
 * 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/smp_lock.h>
#include <linux/mutex.h>
#include <linux/videotext.h>
#include <linux/videodev.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-i2c-drv-legacy.h>

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

#define MAJOR_VERSION 1         /* driver major version number */
#define MINOR_VERSION 8         /* driver minor version number */

/* Number of DAUs = number of pages that can be searched at the same time. */
#define NUM_DAUS 4

#define NUM_ROWS_PER_PAGE 40

/* first column is 0 (not 1) */
#define POS_TIME_START 32
#define POS_TIME_END 39

#define POS_HEADER_START 7
#define POS_HEADER_END 31

/* Returns 'true' if the part of the videotext page described with req contains
   (at least parts of) the time field */
#define REQ_CONTAINS_TIME(p_req) \
        ((p_req)->start <= POS_TIME_END && \
         (p_req)->end   >= POS_TIME_START)

/* Returns 'true' if the part of the videotext page described with req contains
   (at least parts of) the page header */
#define REQ_CONTAINS_HEADER(p_req) \
        ((p_req)->start <= POS_HEADER_END && \
         (p_req)->end   >= POS_HEADER_START)

/*****************************************************************************/
/* Mode register numbers of the SAA5246A                                     */
/*****************************************************************************/
#define SAA5246A_REGISTER_R0    0
#define SAA5246A_REGISTER_R1    1
#define SAA5246A_REGISTER_R2    2
#define SAA5246A_REGISTER_R3    3
#define SAA5246A_REGISTER_R4    4
#define SAA5246A_REGISTER_R5    5
#define SAA5246A_REGISTER_R6    6
#define SAA5246A_REGISTER_R7    7
#define SAA5246A_REGISTER_R8    8
#define SAA5246A_REGISTER_R9    9
#define SAA5246A_REGISTER_R10  10
#define SAA5246A_REGISTER_R11  11
#define SAA5246A_REGISTER_R11B 11

/* SAA5246A mode registers often autoincrement to the next register.
   Therefore we use variable argument lists. The following macro indicates
   the end of a command list. */
#define COMMAND_END (-1)

/*****************************************************************************/
/* Contents of the mode registers of the SAA5246A                            */
/*****************************************************************************/
/* Register R0 (Advanced Control) */
#define R0_SELECT_R11                                      0x00
#define R0_SELECT_R11B                                     0x01

#define R0_PLL_TIME_CONSTANT_LONG                          0x00
#define R0_PLL_TIME_CONSTANT_SHORT                         0x02

#define R0_ENABLE_nODD_EVEN_OUTPUT                         0x00
#define R0_DISABLE_nODD_EVEN_OUTPUT                        0x04

#define R0_ENABLE_HDR_POLL                                 0x00
#define R0_DISABLE_HDR_POLL                                0x10

#define R0_DO_NOT_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED 0x00
#define R0_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED        0x20

#define R0_NO_FREE_RUN_PLL                                 0x00
#define R0_FREE_RUN_PLL                                    0x40

#define R0_NO_AUTOMATIC_FASTEXT_PROMPT                     0x00
#define R0_AUTOMATIC_FASTEXT_PROMPT                        0x80

/* Register R1 (Mode) */
#define R1_INTERLACED_312_AND_HALF_312_AND_HALF_LINES      0x00
#define R1_NON_INTERLACED_312_313_LINES                    0x01
#define R1_NON_INTERLACED_312_312_LINES                    0x02
#define R1_FFB_LEADING_EDGE_IN_FIRST_BROAD_PULSE           0x03
#define R1_FFB_LEADING_EDGE_IN_SECOND_BROAD_PULSE          0x07

#define R1_DEW                                             0x00
#define R1_FULL_FIELD                                      0x08

#define R1_EXTENDED_PACKET_DISABLE                         0x00
#define R1_EXTENDED_PACKET_ENABLE                          0x10

#define R1_DAUS_ALL_ON                                     0x00
#define R1_DAUS_ALL_OFF                                    0x20

#define R1_7_BITS_PLUS_PARITY                              0x00
#define R1_8_BITS_NO_PARITY                                0x40

#define R1_VCS_TO_SCS                                      0x00
#define R1_NO_VCS_TO_SCS                                   0x80

/* Register R2 (Page request address) */
#define R2_IN_R3_SELECT_PAGE_HUNDREDS                      0x00
#define R2_IN_R3_SELECT_PAGE_TENS                          0x01
#define R2_IN_R3_SELECT_PAGE_UNITS                         0x02
#define R2_IN_R3_SELECT_HOURS_TENS                         0x03
#define R2_IN_R3_SELECT_HOURS_UNITS                        0x04
#define R2_IN_R3_SELECT_MINUTES_TENS                       0x05
#define R2_IN_R3_SELECT_MINUTES_UNITS                      0x06

#define R2_DAU_0                                           0x00
#define R2_DAU_1                                           0x10
#define R2_DAU_2                                           0x20
#define R2_DAU_3                                           0x30

#define R2_BANK_0                                          0x00
#define R2_BANK 1                                          0x40

#define R2_HAMMING_CHECK_ON                                0x80
#define R2_HAMMING_CHECK_OFF                               0x00

/* Register R3 (Page request data) */
#define R3_PAGE_HUNDREDS_0                                 0x00
#define R3_PAGE_HUNDREDS_1                                 0x01
#define R3_PAGE_HUNDREDS_2                                 0x02
#define R3_PAGE_HUNDREDS_3                                 0x03
#define R3_PAGE_HUNDREDS_4                                 0x04
#define R3_PAGE_HUNDREDS_5                                 0x05
#define R3_PAGE_HUNDREDS_6                                 0x06
#define R3_PAGE_HUNDREDS_7                                 0x07

#define R3_HOLD_PAGE                                       0x00
#define R3_UPDATE_PAGE                                     0x08

#define R3_PAGE_HUNDREDS_DO_NOT_CARE                       0x00
#define R3_PAGE_HUNDREDS_DO_CARE                           0x10

#define R3_PAGE_TENS_DO_NOT_CARE                           0x00
#define R3_PAGE_TENS_DO_CARE                               0x10

#define R3_PAGE_UNITS_DO_NOT_CARE                          0x00
#define R3_PAGE_UNITS_DO_CARE                              0x10

#define R3_HOURS_TENS_DO_NOT_CARE                          0x00
#define R3_HOURS_TENS_DO_CARE                              0x10

#define R3_HOURS_UNITS_DO_NOT_CARE                         0x00
#define R3_HOURS_UNITS_DO_CARE                             0x10

#define R3_MINUTES_TENS_DO_NOT_CARE                        0x00
#define R3_MINUTES_TENS_DO_CARE                            0x10

#define R3_MINUTES_UNITS_DO_NOT_CARE                       0x00
#define R3_MINUTES_UNITS_DO_CARE                           0x10

/* Register R4 (Display chapter) */
#define R4_DISPLAY_PAGE_0                                  0x00
#define R4_DISPLAY_PAGE_1                                  0x01
#define R4_DISPLAY_PAGE_2                                  0x02
#define R4_DISPLAY_PAGE_3                                  0x03
#define R4_DISPLAY_PAGE_4                                  0x04
#define R4_DISPLAY_PAGE_5                                  0x05
#define R4_DISPLAY_PAGE_6                                  0x06
#define R4_DISPLAY_PAGE_7                                  0x07

/* Register R5 (Normal display control) */
#define R5_PICTURE_INSIDE_BOXING_OFF                       0x00
#define R5_PICTURE_INSIDE_BOXING_ON                        0x01

#define R5_PICTURE_OUTSIDE_BOXING_OFF                      0x00
#define R5_PICTURE_OUTSIDE_BOXING_ON                       0x02

#define R5_TEXT_INSIDE_BOXING_OFF                          0x00
#define R5_TEXT_INSIDE_BOXING_ON                           0x04

#define R5_TEXT_OUTSIDE_BOXING_OFF                         0x00
#define R5_TEXT_OUTSIDE_BOXING_ON                          0x08

#define R5_CONTRAST_REDUCTION_INSIDE_BOXING_OFF            0x00
#define R5_CONTRAST_REDUCTION_INSIDE_BOXING_ON             0x10

#define R5_CONTRAST_REDUCTION_OUTSIDE_BOXING_OFF           0x00
#define R5_CONTRAST_REDUCTION_OUTSIDE_BOXING_ON            0x20

#define R5_BACKGROUND_COLOR_INSIDE_BOXING_OFF              0x00
#define R5_BACKGROUND_COLOR_INSIDE_BOXING_ON               0x40

#define R5_BACKGROUND_COLOR_OUTSIDE_BOXING_OFF             0x00
#define R5_BACKGROUND_COLOR_OUTSIDE_BOXING_ON              0x80

/* Register R6 (Newsflash display) */
#define R6_NEWSFLASH_PICTURE_INSIDE_BOXING_OFF             0x00
#define R6_NEWSFLASH_PICTURE_INSIDE_BOXING_ON              0x01

#define R6_NEWSFLASH_PICTURE_OUTSIDE_BOXING_OFF            0x00
#define R6_NEWSFLASH_PICTURE_OUTSIDE_BOXING_ON             0x02

#define R6_NEWSFLASH_TEXT_INSIDE_BOXING_OFF                0x00
#define R6_NEWSFLASH_TEXT_INSIDE_BOXING_ON                 0x04

#define R6_NEWSFLASH_TEXT_OUTSIDE_BOXING_OFF               0x00
#define R6_NEWSFLASH_TEXT_OUTSIDE_BOXING_ON                0x08

#define R6_NEWSFLASH_CONTRAST_REDUCTION_INSIDE_BOXING_OFF  0x00
#define R6_NEWSFLASH_CONTRAST_REDUCTION_INSIDE_BOXING_ON   0x10

#define R6_NEWSFLASH_CONTRAST_REDUCTION_OUTSIDE_BOXING_OFF 0x00
#define R6_NEWSFLASH_CONTRAST_REDUCTION_OUTSIDE_BOXING_ON  0x20

#define R6_NEWSFLASH_BACKGROUND_COLOR_INSIDE_BOXING_OFF    0x00
#define R6_NEWSFLASH_BACKGROUND_COLOR_INSIDE_BOXING_ON     0x40

#define R6_NEWSFLASH_BACKGROUND_COLOR_OUTSIDE_BOXING_OFF   0x00
#define R6_NEWSFLASH_BACKGROUND_COLOR_OUTSIDE_BOXING_ON    0x80

/* Register R7 (Display mode) */
#define R7_BOX_OFF_ROW_0                                   0x00
#define R7_BOX_ON_ROW_0                                    0x01

#define R7_BOX_OFF_ROW_1_TO_23                             0x00
#define R7_BOX_ON_ROW_1_TO_23                              0x02

#define R7_BOX_OFF_ROW_24                                  0x00
#define R7_BOX_ON_ROW_24                                   0x04

#define R7_SINGLE_HEIGHT                                   0x00
#define R7_DOUBLE_HEIGHT                                   0x08

#define R7_TOP_HALF                                        0x00
#define R7_BOTTOM_HALF                                     0x10

#define R7_REVEAL_OFF                                      0x00
#define R7_REVEAL_ON                                       0x20

#define R7_CURSER_OFF                                      0x00
#define R7_CURSER_ON                                       0x40

#define R7_STATUS_BOTTOM                                   0x00
#define R7_STATUS_TOP                                      0x80

/* Register R8 (Active chapter) */
#define R8_ACTIVE_CHAPTER_0                                0x00
#define R8_ACTIVE_CHAPTER_1                                0x01
#define R8_ACTIVE_CHAPTER_2                                0x02
#define R8_ACTIVE_CHAPTER_3                                0x03
#define R8_ACTIVE_CHAPTER_4                                0x04
#define R8_ACTIVE_CHAPTER_5                                0x05
#define R8_ACTIVE_CHAPTER_6                                0x06
#define R8_ACTIVE_CHAPTER_7                                0x07

#define R8_CLEAR_MEMORY                                    0x08
#define R8_DO_NOT_CLEAR_MEMORY                             0x00

/* Register R9 (Curser row) */
#define R9_CURSER_ROW_0                                    0x00
#define R9_CURSER_ROW_1                                    0x01
#define R9_CURSER_ROW_2                                    0x02
#define R9_CURSER_ROW_25                                   0x19

/* Register R10 (Curser column) */
#define R10_CURSER_COLUMN_0                                0x00
#define R10_CURSER_COLUMN_6                                0x06
#define R10_CURSER_COLUMN_8                                0x08

/*****************************************************************************/
/* Row 25 control data in column 0 to 9                                      */
/*****************************************************************************/
#define ROW25_COLUMN0_PAGE_UNITS                           0x0F

#define ROW25_COLUMN1_PAGE_TENS                            0x0F

#define ROW25_COLUMN2_MINUTES_UNITS                        0x0F

#define ROW25_COLUMN3_MINUTES_TENS                         0x07
#define ROW25_COLUMN3_DELETE_PAGE                          0x08

#define ROW25_COLUMN4_HOUR_UNITS                           0x0F

#define ROW25_COLUMN5_HOUR_TENS                            0x03
#define ROW25_COLUMN5_INSERT_HEADLINE                      0x04
#define ROW25_COLUMN5_INSERT_SUBTITLE                      0x08

#define ROW25_COLUMN6_SUPPRESS_HEADER                      0x01
#define ROW25_COLUMN6_UPDATE_PAGE                          0x02
#define ROW25_COLUMN6_INTERRUPTED_SEQUENCE                 0x04
#define ROW25_COLUMN6_SUPPRESS_DISPLAY                     0x08

#define ROW25_COLUMN7_SERIAL_MODE                          0x01
#define ROW25_COLUMN7_CHARACTER_SET                        0x0E

#define ROW25_COLUMN8_PAGE_HUNDREDS                        0x07
#define ROW25_COLUMN8_PAGE_NOT_FOUND                       0x10

#define ROW25_COLUMN9_PAGE_BEING_LOOKED_FOR                0x20

#define ROW25_COLUMN0_TO_7_HAMMING_ERROR                   0x10

/*****************************************************************************/
/* Helper macros for extracting page, hour and minute digits                 */
/*****************************************************************************/
/* BYTE_POS  0 is at row 0, column 0,
   BYTE_POS  1 is at row 0, column 1,
   BYTE_POS 40 is at row 1, column 0, (with NUM_ROWS_PER_PAGE = 40)
   BYTE_POS 41 is at row 1, column 1, (with NUM_ROWS_PER_PAGE = 40),
   ... */
#define ROW(BYTE_POS)    (BYTE_POS / NUM_ROWS_PER_PAGE)
#define COLUMN(BYTE_POS) (BYTE_POS % NUM_ROWS_PER_PAGE)

/*****************************************************************************/
/* Helper macros for extracting page, hour and minute digits                 */
/*****************************************************************************/
/* Macros for extracting hundreds, tens and units of a page number which
   must be in the range 0 ... 0x799.
   Note that page is coded in hexadecimal, i.e. 0x123 means page 123.
   page 0x.. means page 8.. */
#define HUNDREDS_OF_PAGE(page) (((page) / 0x100) & 0x7)
#define TENS_OF_PAGE(page)     (((page) / 0x10)  & 0xF)
#define UNITS_OF_PAGE(page)     ((page) & 0xF)

/* Macros for extracting tens and units of a hour information which
   must be in the range 0 ... 0x24.
   Note that hour is coded in hexadecimal, i.e. 0x12 means 12 hours */
#define TENS_OF_HOUR(hour)  ((hour) / 0x10)
#define UNITS_OF_HOUR(hour) ((hour) & 0xF)

/* Macros for extracting tens and units of a minute information which
   must be in the range 0 ... 0x59.
   Note that minute is coded in hexadecimal, i.e. 0x12 means 12 minutes */
#define TENS_OF_MINUTE(minute)  ((minute) / 0x10)
#define UNITS_OF_MINUTE(minute) ((minute) & 0xF)

#define HOUR_MAX   0x23
#define MINUTE_MAX 0x59
#define PAGE_MAX   0x8FF


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

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

/*
 *      I2C interfaces
 */

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 saa5246a_device *t = video_drvdata(file);

        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 saa5246a_device *t = video_drvdata(file);
        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 saa5246a_device *t = video_drvdata(file);

        if (t->client == NULL)
                return -ENODEV;

        if (test_and_set_bit(0, &t->in_use))
                return -EBUSY;

        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))
        {
                clear_bit(0, &t->in_use);
                return -EIO;
        }
        return 0;
}

static int saa5246a_release(struct inode *inode, struct file *file)
{
        struct saa5246a_device *t = video_drvdata(file);

        /* 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);
        clear_bit(0, &t->in_use);
        return 0;
}

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     = "saa5246a",
        .fops     = &saa_fops,
        .release  = video_device_release,
        .minor    = -1,
};

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x22 >> 1, I2C_CLIENT_END };

I2C_CLIENT_INSMOD;

static int saa5246a_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        int pgbuf;
        int err;
        struct video_device *vd;
        struct saa5246a_device *t;

        v4l_info(client, "chip found @ 0x%x (%s)\n",
                        client->addr << 1, client->adapter->name);
        v4l_info(client, "VideoText version %d.%d\n",
                        MAJOR_VERSION, MINOR_VERSION);
        t = kzalloc(sizeof(*t), GFP_KERNEL);
        if (t == NULL)
                return -ENOMEM;
        mutex_init(&t->lock);

        /* Now create a video4linux device */
        vd = video_device_alloc();
        if (vd == NULL) {
                kfree(t);
                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;
        }
        video_set_drvdata(vd, t);

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

static int saa5246a_remove(struct i2c_client *client)
{
        struct video_device *vd = i2c_get_clientdata(client);

        video_unregister_device(vd);
        kfree(video_get_drvdata(vd));
        return 0;
}

static const struct i2c_device_id saa5246a_id[] = {
        { "saa5246a", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, saa5246a_id);

static struct v4l2_i2c_driver_data v4l2_i2c_data = {
        .name = "saa5246a",
        .driverid = I2C_DRIVERID_SAA5249,
        .probe = saa5246a_probe,
        .remove = saa5246a_remove,
        .id_table = saa5246a_id,
};