i2c-sibyte.c

Go to the documentation of this file.

/*
 * 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\n");
    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 <[email protected]>");
MODULE_DESCRIPTION("SMBus adapter routines for SiByte boards");
MODULE_LICENSE("GPL");