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 /*
    tea6420.o - i2c-driver for the tea6420 by SGS Thomson

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

    The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
    4 stereo outputs and gain control for each output.
    It is cascadable, i.e. it can be found at the adresses 0x98
    and 0x9a 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 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., 675 Mass 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 "tea6420.h"

static int debug = 0;   /* insmod parameter */
MODULE_PARM(debug,"i");
#define dprintk if (debug) printk

/* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
static unsigned short normal_i2c[] = {I2C_TEA6420_1, I2C_TEA6420_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 tea6420_id = 0;

/* make a connection between the input 'i' and the output 'o'
   with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
{
        u8      byte = 0;
       
        int     result = 0;
       
        dprintk("tea6420.o: tea6420_switch: adr:0x%02x, i:%d, o:%d, g:%d\n",client->addr,i,o,g);

        /* check if the paramters are valid */
        if ( i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g%2 != 0 )
                return -1;

        byte  = ((o-1)<<5);
        byte |=  (i-1);

        /* to understand this, have a look at the tea6420-specs (p.5) */
        switch(g) {
                case 0:
                        byte |= (3<<3);
                        break;
                case 2:
                        byte |= (2<<3);
                        break;
                case 4:
                        byte |= (1<<3);
                        break;
                case 6:
                        break;
        }

        /* fixme?: 1 != ... => 0 != */
        if ( 0 != (result = i2c_smbus_write_byte(client,byte))) {
                printk("tea6402:%d\n",result);
                dprintk(KERN_ERR "tea6420.o: could not switch, result:%d\n",result);
                return -EFAULT;
        }
       
        return 0;
}

/* this function is called by i2c_probe */
static int tea6420_detect(struct i2c_adapter *adapter, int address, unsigned short flags, int kind)
{
        struct  i2c_client *client;
        int err = 0, i = 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,"tea6420 (0x%02x)", address);
#else
        sprintf(client->dev.name,"tea6420 (0x%02x)", address);
#endif
        client->id = tea6420_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;
        }

        /* set initial values: set "mute"-input to all outputs at gain 0 */
        err = 0;
        for(i = 1; i < 5; i++) {
                err += tea6420_switch(client, 6, i, 0);
        }
        if( 0 != err) {
                printk("tea6420.o: could not initialize chipset. continuing anyway.\n");
        }
       
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
        printk("tea6420.o: detected @ 0x%02x on adapter %s\n",address,&client->adapter->name[0]);
#else
        printk("tea6420.o: detected @ 0x%02x on adapter %s\n",address,&client->adapter->dev.name[0]);
#endif
        return 0;
}

static int tea6420_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("tea6420.o: refusing to probe on unknown adapter [name='%s',id=0x%x]\n",adapter->name,adapter->id);
#else
                dprintk("tea6420.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,&tea6420_detect);
}

static int tea6420_detach(struct i2c_client *client)
{
        int err = 0;

        if ( 0 != (err = i2c_detach_client(client))) {
                printk("tea6420.o: Client deregistration failed, client not detached.\n");
                return err;
        }
       
        kfree(client);

        return 0;
}

static int tea6420_command(struct i2c_client *client, unsigned int cmd, void* arg)
{
        struct tea6420_multiplex *a = (struct tea6420_multiplex*)arg;
        int result = 0;

        switch (cmd) {
                case TEA6420_SWITCH: {
                        result = tea6420_switch(client,a->in,a->out,a->gain);
                        break;
                }
                default: {
                        return -ENOIOCTLCMD;
                }
        }

        if ( 0 != result )
                return result;
       
        return 0;
}
static void tea6420_inc_use(struct i2c_client *client)
{
#ifdef MODULE
        MOD_INC_USE_COUNT;
#endif
}

static void tea6420_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           = "tea6420 driver",
        .id             = I2C_DRIVERID_TEA6420,
        .flags          = I2C_DF_NOTIFY,
        .attach_adapter = tea6420_attach,
        .detach_client  = tea6420_detach,
        .command        = tea6420_command,
        .inc_use        = tea6420_inc_use,
        .dec_use        = tea6420_dec_use,
};

static int tea6420_init_module(void)
{
        i2c_add_driver(&driver);
        return 0;
}

static void tea6420_cleanup_module(void)
{
        i2c_del_driver(&driver);
}

module_init(tea6420_init_module);
module_exit(tea6420_cleanup_module);

MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
MODULE_DESCRIPTION("tea6420 driver");
MODULE_LICENSE("GPL");