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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");