text:  /*
      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 0x84 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, 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 */
  	sprintf(client->name,"tda9840 (0x%02x)", address);
  	client->id = tda9840_id++;
  	client->flags = 0;
  	client->addr = address;
  	client->adapter = adapter;
  	client->driver = &driver;
  	i2c_set_clientdata(client, NULL);
  
  	/* 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);
  	} 
  	
  	printk("tda9840.o: detected @ 0x%02x on adapter %s\n",2*address,&client->adapter->name[0]);
  
  	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 ) {
  		dprintk("tda9840.o: refusing to probe on unknown adapter [name='%s',id=0x%x]\n",adapter->name,adapter->id);
  		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 struct i2c_driver driver = {
  	.owner		= THIS_MODULE,
  	.name		= "tda9840 driver",
  	.id		= I2C_DRIVERID_TDA9840,
  	.flags		= I2C_DF_NOTIFY,
          .attach_adapter = tda9840_attach,
          .detach_client	= tda9840_detach,
          .command	= tda9840_command,
  };
  
  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");
  
  