go7007-i2c.c

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/*
 * Copyright (C) 2005-2006 Micronas USA Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (Version 2) as
 * published by the Free Software Foundation.
 *
 * 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/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/unistd.h>
#include <linux/time.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>

#include "go7007-priv.h"
#include "wis-i2c.h"

/********************* Driver for on-board I2C adapter *********************/

/* #define GO7007_I2C_DEBUG */

#define SPI_I2C_ADDR_BASE       0x1400
#define STATUS_REG_ADDR         (SPI_I2C_ADDR_BASE + 0x2)
#define I2C_CTRL_REG_ADDR       (SPI_I2C_ADDR_BASE + 0x6)
#define I2C_DEV_UP_ADDR_REG_ADDR    (SPI_I2C_ADDR_BASE + 0x7)
#define I2C_LO_ADDR_REG_ADDR        (SPI_I2C_ADDR_BASE + 0x8)
#define I2C_DATA_REG_ADDR       (SPI_I2C_ADDR_BASE + 0x9)
#define I2C_CLKFREQ_REG_ADDR        (SPI_I2C_ADDR_BASE + 0xa)

#define I2C_STATE_MASK          0x0007
#define I2C_READ_READY_MASK     0x0008

/* There is only one I2C port on the TW2804 that feeds all four GO7007 VIPs
 * on the Adlink PCI-MPG24, so access is shared between all of them. */
static DEFINE_MUTEX(adlink_mpg24_i2c_lock);

static int go7007_i2c_xfer(struct go7007 *go, u16 addr, int read,
        u16 command, int flags, u8 *data)
{
    int i, ret = -1;
    u16 val;

    if (go->status == STATUS_SHUTDOWN)
        return -1;

#ifdef GO7007_I2C_DEBUG
    if (read)
        printk(KERN_DEBUG "go7007-i2c: reading 0x%02x on 0x%02x\n",
            command, addr);
    else
        printk(KERN_DEBUG
            "go7007-i2c: writing 0x%02x to 0x%02x on 0x%02x\n",
            *data, command, addr);
#endif

    mutex_lock(&go->hw_lock);

    if (go->board_id == GO7007_BOARDID_ADLINK_MPG24) {
        /* Bridge the I2C port on this GO7007 to the shared bus */
        mutex_lock(&adlink_mpg24_i2c_lock);
        go7007_write_addr(go, 0x3c82, 0x0020);
    }

    /* Wait for I2C adapter to be ready */
    for (i = 0; i < 10; ++i) {
        if (go7007_read_addr(go, STATUS_REG_ADDR, &val) < 0)
            goto i2c_done;
        if (!(val & I2C_STATE_MASK))
            break;
        msleep(100);
    }
    if (i == 10) {
        printk(KERN_ERR "go7007-i2c: I2C adapter is hung\n");
        goto i2c_done;
    }

    /* Set target register (command) */
    go7007_write_addr(go, I2C_CTRL_REG_ADDR, flags);
    go7007_write_addr(go, I2C_LO_ADDR_REG_ADDR, command);

    /* If we're writing, send the data and target address and we're done */
    if (!read) {
        go7007_write_addr(go, I2C_DATA_REG_ADDR, *data);
        go7007_write_addr(go, I2C_DEV_UP_ADDR_REG_ADDR,
                    (addr << 9) | (command >> 8));
        ret = 0;
        goto i2c_done;
    }

    /* Otherwise, we're reading.  First clear i2c_rx_data_rdy. */
    if (go7007_read_addr(go, I2C_DATA_REG_ADDR, &val) < 0)
        goto i2c_done;

    /* Send the target address plus read flag */
    go7007_write_addr(go, I2C_DEV_UP_ADDR_REG_ADDR,
            (addr << 9) | 0x0100 | (command >> 8));

    /* Wait for i2c_rx_data_rdy */
    for (i = 0; i < 10; ++i) {
        if (go7007_read_addr(go, STATUS_REG_ADDR, &val) < 0)
            goto i2c_done;
        if (val & I2C_READ_READY_MASK)
            break;
        msleep(100);
    }
    if (i == 10) {
        printk(KERN_ERR "go7007-i2c: I2C adapter is hung\n");
        goto i2c_done;
    }

    /* Retrieve the read byte */
    if (go7007_read_addr(go, I2C_DATA_REG_ADDR, &val) < 0)
        goto i2c_done;
    *data = val;
    ret = 0;

i2c_done:
    if (go->board_id == GO7007_BOARDID_ADLINK_MPG24) {
        /* Isolate the I2C port on this GO7007 from the shared bus */
        go7007_write_addr(go, 0x3c82, 0x0000);
        mutex_unlock(&adlink_mpg24_i2c_lock);
    }
    mutex_unlock(&go->hw_lock);
    return ret;
}

static int go7007_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
        unsigned short flags, char read_write,
        u8 command, int size, union i2c_smbus_data *data)
{
    struct go7007 *go = i2c_get_adapdata(adapter);

    if (size != I2C_SMBUS_BYTE_DATA)
        return -1;
    return go7007_i2c_xfer(go, addr, read_write == I2C_SMBUS_READ, command,
            flags & I2C_CLIENT_SCCB ? 0x10 : 0x00, &data->byte);
}

/* VERY LIMITED I2C master xfer function -- only needed because the
 * SMBus functions only support 8-bit commands and the SAA7135 uses
 * 16-bit commands.  The I2C interface on the GO7007, as limited as
 * it is, does support this mode. */

static int go7007_i2c_master_xfer(struct i2c_adapter *adapter,
                    struct i2c_msg msgs[], int num)
{
    struct go7007 *go = i2c_get_adapdata(adapter);
    int i;

    for (i = 0; i < num; ++i) {
        /* We can only do two things here -- write three bytes, or
         * write two bytes and read one byte. */
        if (msgs[i].len == 2) {
            if (i + 1 == num || msgs[i].addr != msgs[i + 1].addr ||
                    (msgs[i].flags & I2C_M_RD) ||
                    !(msgs[i + 1].flags & I2C_M_RD) ||
                    msgs[i + 1].len != 1)
                return -1;
            if (go7007_i2c_xfer(go, msgs[i].addr, 1,
                    (msgs[i].buf[0] << 8) | msgs[i].buf[1],
                    0x01, &msgs[i + 1].buf[0]) < 0)
                return -1;
            ++i;
        } else if (msgs[i].len == 3) {
            if (msgs[i].flags & I2C_M_RD)
                return -1;
            if (msgs[i].len != 3)
                return -1;
            if (go7007_i2c_xfer(go, msgs[i].addr, 0,
                    (msgs[i].buf[0] << 8) | msgs[i].buf[1],
                    0x01, &msgs[i].buf[2]) < 0)
                return -1;
        } else
            return -1;
    }

    return 0;
}

static u32 go7007_functionality(struct i2c_adapter *adapter)
{
    return I2C_FUNC_SMBUS_BYTE_DATA;
}

static struct i2c_algorithm go7007_algo = {
    .smbus_xfer = go7007_smbus_xfer,
    .master_xfer    = go7007_i2c_master_xfer,
    .functionality  = go7007_functionality,
};

static struct i2c_adapter go7007_adap_templ = {
    .owner          = THIS_MODULE,
    .name           = "WIS GO7007SB",
    .algo           = &go7007_algo,
};

int go7007_i2c_init(struct go7007 *go)
{
    memcpy(&go->i2c_adapter, &go7007_adap_templ,
            sizeof(go7007_adap_templ));
    go->i2c_adapter.dev.parent = go->dev;
    i2c_set_adapdata(&go->i2c_adapter, go);
    if (i2c_add_adapter(&go->i2c_adapter) < 0) {
        printk(KERN_ERR
            "go7007-i2c: error: i2c_add_adapter failed\n");
        return -1;
    }
    return 0;
}