/*
 * Tiny I2C Adapter Driver
 *
 * Copyright (C) 2003 Greg Kroah-Hartman (greg@kroah.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, version 2 of the License.
 *
 * This driver shows how to create a minimal I2C bus and algorithm driver.
 *
 * Compile this driver with:

	echo "obj-m := tiny_i2c_adap.o" > Makefile
	make -C <path/to/kernel/src> SUBDIRS=$PWD modules
 */


#include <linux/kernel.h>
#include <linux/config.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/i2c.h>
#include <linux/init.h>


static s32 tiny_access(struct i2c_adapter *adap, u16 addr,
		       unsigned short flags, char read_write,
		       u8 command, int size, union i2c_smbus_data *data)
{
	int i;
	int len;

	dev_info(&adap->dev, "%s was called with the following parameters:\n",
		 __FUNCTION__);
	dev_info(&adap->dev, "addr = %.4x\n", addr);
	dev_info(&adap->dev, "flags = %.4x\n", flags);
	dev_info(&adap->dev, "read_write = %s\n",
		 read_write == I2C_SMBUS_WRITE ? "write" : "read");
	dev_info(&adap->dev, "command = %d\n", command);
	
	switch (size) {
	case I2C_SMBUS_PROC_CALL:
		dev_info(&adap->dev, "size = I2C_SMBUS_PROC_CALL\n");
		break;
	case I2C_SMBUS_QUICK:
		dev_info(&adap->dev, "size = I2C_SMBUS_QUICK\n");
		break;
	case I2C_SMBUS_BYTE:
		dev_info(&adap->dev, "size = I2C_SMBUS_BYTE\n");
		break;
	case I2C_SMBUS_BYTE_DATA:
		dev_info(&adap->dev, "size = I2C_SMBUS_BYTE_DATA\n");
		if (read_write == I2C_SMBUS_WRITE)
			dev_info(&adap->dev, "data = %.2x\n", data->byte);
		break;
	case I2C_SMBUS_WORD_DATA:
		dev_info(&adap->dev, "size = I2C_SMBUS_WORD_DATA\n");
		if (read_write == I2C_SMBUS_WRITE)
			dev_info(&adap->dev, "data = %.4x\n", data->word);
		break;
	case I2C_SMBUS_BLOCK_DATA:
		dev_info(&adap->dev, "size = I2C_SMBUS_BLOCK_DATA\n");
		if (read_write == I2C_SMBUS_WRITE) {
			dev_info(&adap->dev, "data = %.4x\n", data->word);
			len = data->block[0];
			if (len < 0)
				len = 0;
			if (len > 32)
				len = 32;
			for (i = 1; i <= len; i++)
				dev_info(&adap->dev, "data->block[%d] = %.2x\n",
					 i, data->block[i]);
		}
		break;
	}

	return 0;
}

static u32 tiny_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
		I2C_FUNC_SMBUS_BLOCK_DATA;
}

static struct i2c_algorithm tiny_algorithm = {
	.name		= "tiny algorithm",
	.id		= I2C_ALGO_SMBUS,
	.smbus_xfer	= tiny_access,
	.functionality	= tiny_func,
};

static struct i2c_adapter tiny_adapter = {
	.owner		= THIS_MODULE,
	.class		= I2C_ADAP_CLASS_SMBUS,
	.algo		= &tiny_algorithm,
	.name		= "tiny adapter",
};

static int __init tiny_init(void)
{
	return i2c_add_adapter(&tiny_adapter);
}

static void __exit tiny_exit(void)
{
	i2c_del_adapter(&tiny_adapter);
}

MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("Tiny i2c adapter");
MODULE_LICENSE("GPL");

module_init(tiny_init);
module_exit(tiny_exit);