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 /*
    tda9840.h - i2c-driver for the tda9840 by SGS Thomson  

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

    The tda9840 is a stereo/dual sound processor with digital
    identification. It can be found at address 0x42 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 "tda9840.h"

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

#define SWITCH          0x00
#define LEVEL_ADJUST    0x02
#define STEREO_ADJUST   0x03
#define TEST            0x04

/* addresses to scan, found only at 0x42 (7-Bit) */
static unsigned short normal_i2c[] = {I2C_TDA9840, I2C_CLIENT_END};
static unsigned short normal_i2c_range[] = {I2C_CLIENT_END};

/* magic definition of all other variables and things */
I2C_CLIENT_INSMOD;

/* unique ID allocation */
static int tda9840_id = 0;

static struct i2c_driver driver;

static int tda9840_command(struct i2c_client *client, unsigned int cmd, void* arg)
{
        int result = 0;

        switch (cmd) {
                case TDA9840_SWITCH:
                {
                        int byte = *(int*)arg;

                        dprintk("tda9840.o: TDA9840_SWITCH: 0x%02x\n",byte);

                        if (    byte != TDA9840_SET_MONO
                             && byte != TDA9840_SET_MUTE
                             && byte != TDA9840_SET_STEREO
                             && byte != TDA9840_SET_LANG1
                             && byte != TDA9840_SET_LANG2
                             && byte != TDA9840_SET_BOTH
                             && byte != TDA9840_SET_BOTH_R
                             && byte != TDA9840_SET_EXTERNAL ) {
                                return -EINVAL;
                        }
                       
                        if ( 0 != (result = i2c_smbus_write_byte_data(client, SWITCH, byte))) {
                                printk("tda9840.o: TDA9840_SWITCH error.\n");
                                return -EFAULT;
                        }
                       
                        return 0;
                }

                case TDA9840_LEVEL_ADJUST:
                {
                        int  byte = *(int*)arg;

                        dprintk("tda9840.o: TDA9840_LEVEL_ADJUST: %d\n",byte);

                        /* check for correct range */
                        if ( byte > 25 || byte < -20 )
                                return -EINVAL;
                       
                        /* calculate actual value to set, see specs, page 18 */
                        byte /= 5;
                        if ( 0 < byte )
                                byte += 0x8;
                        else
                                byte = -byte;

                        if ( 0 != (result = i2c_smbus_write_byte_data(client, LEVEL_ADJUST, byte))) {
                                printk("tda9840.o: TDA9840_LEVEL_ADJUST error.\n");
                                return -EFAULT;
                        }
                       
                        return 0;
                }

                case TDA9840_STEREO_ADJUST:
                {
                        int  byte = *(int*)arg;

                        dprintk("tda9840.o: TDA9840_STEREO_ADJUST: %d\n",byte);

                        /* check for correct range */
                        if ( byte > 25 || byte < -24 )
                                return -EINVAL;
                       
                        /* calculate actual value to set */
                        byte /= 5;
                        if ( 0 < byte )
                                byte += 0x20;
                        else
                                byte = -byte;

                        if ( 0 != (result = i2c_smbus_write_byte_data(client, STEREO_ADJUST, byte))) {
                                printk("tda9840.o: TDA9840_STEREO_ADJUST error.\n");
                                return -EFAULT;
                        }
                       
                        return 0;
                }

                case TDA9840_DETECT:
                {
                        int byte = 0x0;

                        if ( -1 == (byte = i2c_smbus_read_byte_data(client, STEREO_ADJUST))) {
                                printk("tda9840.o: TDA9840_DETECT error while reading.\n");
                                return -EFAULT;
                        }                      

                        if( 0 != (byte & 0x80)) {
                                dprintk("tda9840.o: TDA9840_DETECT, register contents invalid.\n");
                                return -EFAULT;
                        }

                        dprintk("tda9840.o: TDA9840_DETECT, result: 0x%02x (original byte)\n",byte);

                        return ((byte & 0x60) >> 5);                           
                }

                case TDA9840_TEST:
                {
                        int  byte = *(int*)arg;

                        dprintk("tda9840.o: TDA9840_TEST: 0x%02x\n",byte);

                        /* mask out irrelevant bits */
                        byte &= 0x3;

                        if ( 0 != (result = i2c_smbus_write_byte_data(client, TEST, byte))) {
                                printk("tda9840.o: TDA9840_TEST error.\n");
                                return -EFAULT;
                        }
               
                        return 0;
                }

                default:
                        return -ENOIOCTLCMD;
        }

        return 0;
}

static int tda9840_detect(struct i2c_adapter *adapter, int address, unsigned short flags, int kind)
{
        struct  i2c_client *client;
        int result = 0;

        int byte = 0x0;
                       
        /* let's see whether this adapter can support what we need */
        if ( 0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA|I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
                return 0;
        }

        /* allocate memory for client structure */
        client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
        if (0 == client) {
                printk("tda9840.o: not enough kernel memory.\n");
                return -ENOMEM;
        }
        memset(client, 0, sizeof(struct i2c_client));
               
        /* fill client structure */
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
        sprintf(client->name,"tda9840 (0x%02x)", address);
#else
        sprintf(client->dev.name,"tda9840 (0x%02x)", address);
#endif
        client->id = tda9840_id++;
        client->flags = 0;
        client->addr = address;
        client->adapter = adapter;
        client->driver = &driver;

        /* tell the i2c layer a new client has arrived */
        if (0 != (result = i2c_attach_client(client))) {
                kfree(client);
                return result;
        }

        /* set initial values for level & stereo - adjustment, mode */
        byte = 0;
        if ( 0 != (result = tda9840_command(client, TDA9840_LEVEL_ADJUST, &byte))) {
                printk("tda9840.o: could not initialize ic #1. continuing anyway. (result:%d)\n",result);
        }
       
        if ( 0 != (result = tda9840_command(client, TDA9840_STEREO_ADJUST, &byte))) {
                printk("tda9840.o: could not initialize ic #2. continuing anyway. (result:%d)\n",result);
        }

        byte = TDA9840_SET_MONO;
        if ( 0 != (result = tda9840_command(client, TDA9840_SWITCH, &byte))) {
                printk("tda9840.o: could not initialize ic #3. continuing anyway. (result:%d)\n",result);
        }
       
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
        printk("tda9840.o: detected @ 0x%02x on adapter %s\n",address,&client->adapter->name[0]);
#else
        printk("tda9840.o: detected @ 0x%02x on adapter %s\n",address,&client->adapter->dev.name[0]);
#endif
        return 0;
}

static int tda9840_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("tda9840.o: refusing to probe on unknown adapter [name='%s',id=0x%x]\n",adapter->name,adapter->id);
#else
                dprintk("tda9840.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,&tda9840_detect);
}

static int tda9840_detach(struct i2c_client *client)
{
        int err = 0;

        if ( 0 != (err = i2c_detach_client(client))) {
                printk("tda9840.o: Client deregistration failed, client not detached.\n");
                return err;
        }
       
        kfree(client);

        return 0;
}

static void tda9840_inc_use(struct i2c_client *client)
{
#ifdef MODULE
        MOD_INC_USE_COUNT;
#endif
}

static void tda9840_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           = "tda9840 driver",
        .id             = I2C_DRIVERID_TDA9840,
        .flags          = I2C_DF_NOTIFY,
        .attach_adapter = tda9840_attach,
        .detach_client  = tda9840_detach,
        .command        = tda9840_command,
        .inc_use        = tda9840_inc_use,
        .dec_use        = tda9840_dec_use,
};

static int tda9840_init_module(void)
{
        i2c_add_driver(&driver);
        return 0;
}

static void tda9840_cleanup_module(void)
{
        i2c_del_driver(&driver);
}

module_init(tda9840_init_module);
module_exit(tda9840_cleanup_module);

MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
MODULE_DESCRIPTION("tda9840 driver");
MODULE_LICENSE("GPL");