/*
   * Copyright (C) 2004 Steven J. Hill
   * Copyright (C) 2001,2002,2003 Broadcom Corporation
   * Copyright (C) 1995-2000 Simon G. Vogl
   *
   * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/i2c.h>
  #include <linux/io.h>
  #include <asm/sibyte/sb1250_regs.h>
  #include <asm/sibyte/sb1250_smbus.h>
  
  
  struct i2c_algo_sibyte_data {
  	void *data;		/* private data */
  	int   bus;		/* which bus */
  	void *reg_base;		/* CSR base */
  };
  
  /* ----- global defines ----------------------------------------------- */
  #define SMB_CSR(a,r) ((long)(a->reg_base + r))
  
  
  static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr,
  		      unsigned short flags, char read_write,
  		      u8 command, int size, union i2c_smbus_data * data)
  {
  	struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
  	int data_bytes = 0;
  	int error;
  
  	while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
  		;
  
  	switch (size) {
  	case I2C_SMBUS_QUICK:
  		csr_out32((V_SMB_ADDR(addr) |
  			   (read_write == I2C_SMBUS_READ ? M_SMB_QDATA : 0) |
  			   V_SMB_TT_QUICKCMD), SMB_CSR(adap, R_SMB_START));
  		break;
  	case I2C_SMBUS_BYTE:
  		if (read_write == I2C_SMBUS_READ) {
  			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_RD1BYTE),
  				  SMB_CSR(adap, R_SMB_START));
  			data_bytes = 1;
  		} else {
  			csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR1BYTE),
  				  SMB_CSR(adap, R_SMB_START));
  		}
  		break;
  	case I2C_SMBUS_BYTE_DATA:
  		csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  		if (read_write == I2C_SMBUS_READ) {
  			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD1BYTE),
  				  SMB_CSR(adap, R_SMB_START));
  			data_bytes = 1;
  		} else {
  			csr_out32(V_SMB_LB(data->byte),
  				  SMB_CSR(adap, R_SMB_DATA));
  			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  				  SMB_CSR(adap, R_SMB_START));
  		}
  		break;
  	case I2C_SMBUS_WORD_DATA:
  		csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  		if (read_write == I2C_SMBUS_READ) {
  			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD2BYTE),
  				  SMB_CSR(adap, R_SMB_START));
  			data_bytes = 2;
  		} else {
  			csr_out32(V_SMB_LB(data->word & 0xff),
  				  SMB_CSR(adap, R_SMB_DATA));
  			csr_out32(V_SMB_MB(data->word >> 8),
  				  SMB_CSR(adap, R_SMB_DATA));
  			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  				  SMB_CSR(adap, R_SMB_START));
  		}
  		break;
  	default:
  		return -EOPNOTSUPP;
  	}
  
  	while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
  		;
  
  	error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
  	if (error & M_SMB_ERROR) {
  		/* Clear error bit by writing a 1 */
  		csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
  		return (error & M_SMB_ERROR_TYPE) ? -EIO : -ENXIO;
  	}
  
  	if (data_bytes == 1)
  		data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
  	if (data_bytes == 2)
  		data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
  
  	return 0;
  }
  
  static u32 bit_func(struct i2c_adapter *adap)
  {
  	return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
  		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
  }
  
  
  /* -----exported algorithm data: -------------------------------------	*/
  
  static const struct i2c_algorithm i2c_sibyte_algo = {
  	.smbus_xfer	= smbus_xfer,
  	.functionality	= bit_func,
  };
  
  /*
   * registering functions to load algorithms at runtime
   */
  static int __init i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
  {
  	struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
  
  	/* Register new adapter to i2c module... */
  	i2c_adap->algo = &i2c_sibyte_algo;
  
  	/* Set the requested frequency. */
  	csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
  	csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
  
  	return i2c_add_numbered_adapter(i2c_adap);
  }
  
  
  static struct i2c_algo_sibyte_data sibyte_board_data[2] = {
  	{ NULL, 0, (void *) (CKSEG1+A_SMB_BASE(0)) },
  	{ NULL, 1, (void *) (CKSEG1+A_SMB_BASE(1)) }
  };
  
  static struct i2c_adapter sibyte_board_adapter[2] = {
  	{
  		.owner		= THIS_MODULE,
  		.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
  		.algo		= NULL,
  		.algo_data	= &sibyte_board_data[0],
  		.nr		= 0,
  		.name		= "SiByte SMBus 0",
  	},
  	{
  		.owner		= THIS_MODULE,
  		.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
  		.algo		= NULL,
  		.algo_data	= &sibyte_board_data[1],
  		.nr		= 1,
  		.name		= "SiByte SMBus 1",
  	},
  };
  
  static int __init i2c_sibyte_init(void)
  {
  	pr_info("i2c-sibyte: i2c SMBus adapter module for SiByte board
  ");
  	if (i2c_sibyte_add_bus(&sibyte_board_adapter[0], K_SMB_FREQ_100KHZ) < 0)
  		return -ENODEV;
  	if (i2c_sibyte_add_bus(&sibyte_board_adapter[1],
  			       K_SMB_FREQ_400KHZ) < 0) {
  		i2c_del_adapter(&sibyte_board_adapter[0]);
  		return -ENODEV;
  	}
  	return 0;
  }
  
  static void __exit i2c_sibyte_exit(void)
  {
  	i2c_del_adapter(&sibyte_board_adapter[0]);
  	i2c_del_adapter(&sibyte_board_adapter[1]);
  }
  
  module_init(i2c_sibyte_init);
  module_exit(i2c_sibyte_exit);
  
  MODULE_AUTHOR("Kip Walker (Broadcom Corp.), Steven J. Hill <sjhill@realitydiluted.com>");
  MODULE_DESCRIPTION("SMBus adapter routines for SiByte boards");
  MODULE_LICENSE("GPL");