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 /*

    tda9840 - 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/module.h>

#include <linux/ioctl.h>

#include <linux/i2c.h>

#include "tda9840.h"

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

module_param(debug, int, 0644);

MODULE_PARM_DESC(debug, "Turn on/off device debugging (default:off).");

#define dprintk(args...) \

            do { if (debug) { printk("%s: %s()[%d]: ", KBUILD_MODNAME, __FUNCTION__, __LINE__); printk(args); } } while (0)

#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_ADDR_TDA9840, I2C_CLIENT_END };

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

I2C_CLIENT_INSMOD;

static struct i2c_driver driver;

static struct i2c_client client_template;

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

{

        int result;

        int byte = *(int *)arg;

        switch (cmd) {

        case TDA9840_SWITCH:

                dprintk("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;

                }

                result = i2c_smbus_write_byte_data(client, SWITCH, byte);

                if (result)

                        dprintk("i2c_smbus_write_byte() failed, ret:%d\n", result);

                break;

        case TDA9840_LEVEL_ADJUST:

                dprintk("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;

                result = i2c_smbus_write_byte_data(client, LEVEL_ADJUST, byte);

                if (result)

                        dprintk("i2c_smbus_write_byte() failed, ret:%d\n", result);

                break;

        case TDA9840_STEREO_ADJUST:

                dprintk("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;

                result = i2c_smbus_write_byte_data(client, STEREO_ADJUST, byte);

                if (result)

                        dprintk("i2c_smbus_write_byte() failed, ret:%d\n", result);

                break;

        case TDA9840_DETECT: {

                int *ret = (int *)arg;

                byte = i2c_smbus_read_byte_data(client, STEREO_ADJUST);

                if (byte == -1) {

                        dprintk("i2c_smbus_read_byte_data() failed\n");

                        return -EIO;

                }

                if (0 != (byte & 0x80)) {

                        dprintk("TDA9840_DETECT: register contents invalid\n");

                        return -EINVAL;

                }

                dprintk("TDA9840_DETECT: byte: 0x%02x\n", byte);

                *ret = ((byte & 0x60) >> 5);

                result = 0;

                break;

        }

        case TDA9840_TEST:

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

                /* mask out irrelevant bits */

                byte &= 0x3;

                result = i2c_smbus_write_byte_data(client, TEST, byte);

                if (result)

                        dprintk("i2c_smbus_write_byte() failed, ret:%d\n", result);

                break;

        default:

                return -ENOIOCTLCMD;

        }

        if (result)

                return -EIO;

        return 0;

}

static int 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("not enough kernel memory\n");

                return -ENOMEM;

        }

        /* fill client structure */

        memcpy(client, &client_template, sizeof(struct i2c_client));

        client->addr = address;

        client->adapter = adapter;

        /* 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;

        result  = command(client, TDA9840_LEVEL_ADJUST, &byte);

        result += command(client, TDA9840_STEREO_ADJUST, &byte);

        byte = TDA9840_SET_MONO;

        result = command(client, TDA9840_SWITCH, &byte);

        if (result) {

                dprintk("could not initialize tda9840\n");

                return -ENODEV;

        }

        printk("tda9840: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);

        return 0;

}

static int attach(struct i2c_adapter *adapter)

{

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

        if (adapter->id != I2C_HW_SAA7146) {

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

                return -ENODEV;

        }

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

}

static int detach(struct i2c_client *client)

{

        int ret = i2c_detach_client(client);

        kfree(client);

        return ret;

}

static struct i2c_driver driver = {

        .driver = {

                .name = "tda9840",

        },

        .id     = I2C_DRIVERID_TDA9840,

        .attach_adapter = attach,

        .detach_client  = detach,

        .command        = command,

};

static struct i2c_client client_template = {

        .name = "tda9840",

        .driver = &driver,

};

static int __init this_module_init(void)

{

        return i2c_add_driver(&driver);

}

static void __exit this_module_exit(void)

{

        i2c_del_driver(&driver);

}

module_init(this_module_init);

module_exit(this_module_exit);

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

MODULE_DESCRIPTION("tda9840 driver");

MODULE_LICENSE("GPL");