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 /*

    tea6415c.h - i2c-driver for the tea6415c by SGS Thomson  

    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>

    The tea6415c is a bus controlled video-matrix-switch

    with 8 inputs and 6 outputs.

    It is cascadable, i.e. it can be found at the addresses

    0x43 and 0x03 on the i2c-bus.

    For detailed informations download the specifications directly

    from SGS Thomson at http://www.st.com

    This program is free software; you can redistribute it and/or modify

    it under the terms of the GNU General Public License vs 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., 675 Mvss Ave, Cambridge, MA 02139, USA.

 */

#include <linux/version.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/poll.h>

#include <linux/slab.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include "tea6415c.h"

static int debug = 0;   /* insmod parameter */

MODULE_PARM(debug,"i");

#define dprintk if (debug) printk

#define TEA6415C_NUM_INPUTS     8

#define TEA6415C_NUM_OUTPUTS    6

/* addresses to scan, found only at 0x03 and/or 0x43 (7-bit) */

static unsigned short normal_i2c[] = {I2C_TEA6415C_1, I2C_TEA6415C_2, I2C_CLIENT_END};

static unsigned short normal_i2c_range[] = {I2C_CLIENT_END};

/* magic definition of all other variables and things */

I2C_CLIENT_INSMOD;

static struct i2c_driver driver;

/* unique ID allocation */

static int tea6415c_id = 0;

/* this function is called by i2c_probe */

static int tea6415c_detect(struct i2c_adapter *adapter, int address, unsigned short flags, int kind)

{

        struct  i2c_client *client = 0;

        int err = 0;

        /* let's see whether this adapter can support what we need */

        if ( 0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {

                return 0;

        }

        /* allocate memory for client structure */

        client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);

        if (0 == client) {

                return -ENOMEM;

        }

        memset(client, 0, sizeof(struct i2c_client));

        /* fill client structure */

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))

        sprintf(client->name,"tea6415c (0x%02x)", address);

#else

        sprintf(client->dev.name,"tea6415c (0x%02x)", address);

#endif

        client->id = tea6415c_id++;

        client->flags = 0;

        client->addr = address;

        client->adapter = adapter;

        client->driver = &driver;

        /* tell the i2c layer a new client has arrived */

        if (0 != (err = i2c_attach_client(client))) {

                kfree(client);

                return err;

        }

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))

        printk("tea6415c.o: detected @ 0x%02x on adapter %s\n",address,&client->adapter->name[0]);

#else

        printk("tea6415c.o: detected @ 0x%02x on adapter %s\n",address,&client->adapter->dev.name[0]);

#endif

        return 0;

}

static int tea6415c_attach(struct i2c_adapter *adapter)

{

        /* let's see whether this is a know adapter we can attach to */

        if( adapter->id != I2C_ALGO_SAA7146 ) {

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))

                dprintk("tea6415c.o: refusing to probe on unknown adapter [name='%s',id=0x%x]\n",adapter->name,adapter->id);

#else

                dprintk("tea6415c.o: refusing to probe on unknown adapter [name='%s',id=0x%x]\n",adapter->dev.name,adapter->id);

#endif

                return -ENODEV;

        }

        return i2c_probe(adapter,&addr_data,&tea6415c_detect);

}

static int tea6415c_detach(struct i2c_client *client)

{

        int err = 0;

        if ( 0 != (err = i2c_detach_client(client))) {

                printk("tea6415c.o: Client deregistration failed, client not detached.\n");

                return err;

        }

        kfree(client);

        return 0;

}

/* makes a connection between the input-pin 'i' and the output-pin 'o'

   for the tea6415c-client 'client' */

static int tea6415c_switch(struct i2c_client *client, int i, int o)

{

        u8      byte = 0;

        dprintk("tea6415c.o: tea6415c_switch: adr:0x%02x, i:%d, o:%d\n", client->addr, i, o);

        /* check if the pins are valid */

        if ( 0 == ((  1 == i ||  3 == i ||  5 == i ||  6 == i ||  8 == i || 10 == i || 20 == i || 11 == i ) &&

                    (18 == o || 17 == o || 16 == o || 15 == o || 14 == o || 13 == o )))

                return -1;

        /* to understand this, have a look at the tea6415c-specs (p.5) */

        switch(o) {

                case 18:

                        byte = 0x00;

                        break;

                case 14:

                        byte = 0x20;

                        break;

                case 16:

                        byte = 0x10;

                        break;

                case 17:

                        byte = 0x08;

                        break;

                case 15:

                        byte = 0x18;

                        break;

                case 13:

                        byte = 0x28;

                        break;

        };

        switch(i) {

                case 5:

                        byte |= 0x00;

                        break;

                case 8:

                        byte |= 0x04;

                        break;

                case 3:

                        byte |= 0x02;

                        break;

                case 20:

                        byte |= 0x06;

                        break;

                case 6:

                        byte |= 0x01;

                        break;

                case 10:

                        byte |= 0x05;

                        break;

                case 1:

                        byte |= 0x03;

                        break;

                case 11:

                        byte |= 0x07;

                        break;

        };

        if ( 0 != i2c_smbus_write_byte(client,byte)) {

                dprintk("tea6415c.o: tea6415c_switch: could not write to tea6415c\n");

                return -1;

        }

        return 0;

}

static int tea6415c_command(struct i2c_client *client, unsigned int cmd, void* arg)

{

        struct tea6415c_multiplex *v = (struct tea6415c_multiplex*)arg;

        int result = 0;

        switch (cmd) {

                case TEA6415C_SWITCH: {

                        result = tea6415c_switch(client,v->in,v->out);

                        break;

                }

                default: {

                        return -ENOIOCTLCMD;

                }

        }

        if ( 0 != result )

                return result;

        return 0;

}

static void tea6415c_inc_use(struct i2c_client *client)

{

#ifdef MODULE

        MOD_INC_USE_COUNT;

#endif

}

static void tea6415c_dec_use(struct i2c_client *client)

{

#ifdef MODULE

        MOD_DEC_USE_COUNT;

#endif

}

static struct i2c_driver driver = {

#if LINUX_VERSION_CODE > KERNEL_VERSION(2,5,54)

        .owner          = THIS_MODULE,

#endif

        .name           = "tea6415c driver",

        .id             = I2C_DRIVERID_TEA6415C,

        .flags          = I2C_DF_NOTIFY,

        .attach_adapter = tea6415c_attach,

        .detach_client  = tea6415c_detach,

        .command        = tea6415c_command,

        .inc_use        = tea6415c_inc_use,

        .dec_use        = tea6415c_dec_use,

};

static int tea6415c_init_module(void)

{

        i2c_add_driver(&driver);

        return 0;

}

static void tea6415c_cleanup_module(void)

{

        i2c_del_driver(&driver);

}

module_init(tea6415c_init_module);

module_exit(tea6415c_cleanup_module);

MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");

MODULE_DESCRIPTION("tea6415c driver");

MODULE_LICENSE("GPL");