cx25821-i2c.c

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/*
 *  Driver for the Conexant CX25821 PCIe bridge
 *
 *  Copyright (C) 2009 Conexant Systems Inc.
 *  Authors  <[email protected]>, <[email protected]>
 *  Based on Steven Toth <[email protected]> cx23885 driver
 *
 *  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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "cx25821.h"
#include <linux/i2c.h>

static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

static unsigned int i2c_scan;
module_param(i2c_scan, int, 0444);
MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");

#define dprintk(level, fmt, arg...)                 \
do {                                    \
    if (i2c_debug >= level)                     \
        printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg);  \
} while (0)

#define I2C_WAIT_DELAY 32
#define I2C_WAIT_RETRY 64

#define I2C_EXTEND  (1 << 3)
#define I2C_NOSTOP  (1 << 4)

static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
{
    struct cx25821_i2c *bus = i2c_adap->algo_data;
    struct cx25821_dev *dev = bus->dev;
    return cx_read(bus->reg_stat) & 0x01;
}

static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
{
    struct cx25821_i2c *bus = i2c_adap->algo_data;
    struct cx25821_dev *dev = bus->dev;
    return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
}

static int i2c_wait_done(struct i2c_adapter *i2c_adap)
{
    int count;

    for (count = 0; count < I2C_WAIT_RETRY; count++) {
        if (!i2c_is_busy(i2c_adap))
            break;
        udelay(I2C_WAIT_DELAY);
    }

    if (I2C_WAIT_RETRY == count)
        return 0;

    return 1;
}

static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
             const struct i2c_msg *msg, int joined_rlen)
{
    struct cx25821_i2c *bus = i2c_adap->algo_data;
    struct cx25821_dev *dev = bus->dev;
    u32 wdata, addr, ctrl;
    int retval, cnt;

    if (joined_rlen)
        dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
            msg->len, joined_rlen);
    else
        dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);

    /* Deal with i2c probe functions with zero payload */
    if (msg->len == 0) {
        cx_write(bus->reg_addr, msg->addr << 25);
        cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));

        if (!i2c_wait_done(i2c_adap))
            return -EIO;

        if (!i2c_slave_did_ack(i2c_adap))
            return -EIO;

        dprintk(1, "%s(): returns 0\n", __func__);
        return 0;
    }

    /* dev, reg + first byte */
    addr = (msg->addr << 25) | msg->buf[0];
    wdata = msg->buf[0];

    ctrl = bus->i2c_period | (1 << 12) | (1 << 2);

    if (msg->len > 1)
        ctrl |= I2C_NOSTOP | I2C_EXTEND;
    else if (joined_rlen)
        ctrl |= I2C_NOSTOP;

    cx_write(bus->reg_addr, addr);
    cx_write(bus->reg_wdata, wdata);
    cx_write(bus->reg_ctrl, ctrl);

    retval = i2c_wait_done(i2c_adap);
    if (retval < 0)
        goto err;

    if (retval == 0)
        goto eio;

    if (i2c_debug) {
        if (!(ctrl & I2C_NOSTOP))
            printk(" >\n");
    }

    for (cnt = 1; cnt < msg->len; cnt++) {
        /* following bytes */
        wdata = msg->buf[cnt];
        ctrl = bus->i2c_period | (1 << 12) | (1 << 2);

        if (cnt < msg->len - 1)
            ctrl |= I2C_NOSTOP | I2C_EXTEND;
        else if (joined_rlen)
            ctrl |= I2C_NOSTOP;

        cx_write(bus->reg_addr, addr);
        cx_write(bus->reg_wdata, wdata);
        cx_write(bus->reg_ctrl, ctrl);

        retval = i2c_wait_done(i2c_adap);
        if (retval < 0)
            goto err;

        if (retval == 0)
            goto eio;

        if (i2c_debug) {
            dprintk(1, " %02x", msg->buf[cnt]);
            if (!(ctrl & I2C_NOSTOP))
                dprintk(1, " >\n");
        }
    }

    return msg->len;

eio:
    retval = -EIO;
err:
    if (i2c_debug)
        pr_err(" ERR: %d\n", retval);
    return retval;
}

static int i2c_readbytes(struct i2c_adapter *i2c_adap,
             const struct i2c_msg *msg, int joined)
{
    struct cx25821_i2c *bus = i2c_adap->algo_data;
    struct cx25821_dev *dev = bus->dev;
    u32 ctrl, cnt;
    int retval;

    if (i2c_debug && !joined)
        dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);

    /* Deal with i2c probe functions with zero payload */
    if (msg->len == 0) {
        cx_write(bus->reg_addr, msg->addr << 25);
        cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
        if (!i2c_wait_done(i2c_adap))
            return -EIO;
        if (!i2c_slave_did_ack(i2c_adap))
            return -EIO;

        dprintk(1, "%s(): returns 0\n", __func__);
        return 0;
    }

    if (i2c_debug) {
        if (joined)
            dprintk(1, " R");
        else
            dprintk(1, " <R %02x", (msg->addr << 1) + 1);
    }

    for (cnt = 0; cnt < msg->len; cnt++) {

        ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;

        if (cnt < msg->len - 1)
            ctrl |= I2C_NOSTOP | I2C_EXTEND;

        cx_write(bus->reg_addr, msg->addr << 25);
        cx_write(bus->reg_ctrl, ctrl);

        retval = i2c_wait_done(i2c_adap);
        if (retval < 0)
            goto err;
        if (retval == 0)
            goto eio;
        msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;

        if (i2c_debug) {
            dprintk(1, " %02x", msg->buf[cnt]);
            if (!(ctrl & I2C_NOSTOP))
                dprintk(1, " >\n");
        }
    }

    return msg->len;
eio:
    retval = -EIO;
err:
    if (i2c_debug)
        pr_err(" ERR: %d\n", retval);
    return retval;
}

static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
    struct cx25821_i2c *bus = i2c_adap->algo_data;
    struct cx25821_dev *dev = bus->dev;
    int i, retval = 0;

    dprintk(1, "%s(num = %d)\n", __func__, num);

    for (i = 0; i < num; i++) {
        dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
            __func__, num, msgs[i].addr, msgs[i].len);

        if (msgs[i].flags & I2C_M_RD) {
            /* read */
            retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
        } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
               msgs[i].addr == msgs[i + 1].addr) {
            /* write then read from same address */
            retval = i2c_sendbytes(i2c_adap, &msgs[i],
                    msgs[i + 1].len);

            if (retval < 0)
                goto err;
            i++;
            retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
        } else {
            /* write */
            retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
        }

        if (retval < 0)
            goto err;
    }
    return num;

err:
    return retval;
}


static u32 cx25821_functionality(struct i2c_adapter *adap)
{
    return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
        I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
}

static struct i2c_algorithm cx25821_i2c_algo_template = {
    .master_xfer = i2c_xfer,
    .functionality = cx25821_functionality,
#ifdef NEED_ALGO_CONTROL
    .algo_control = dummy_algo_control,
#endif
};

static struct i2c_adapter cx25821_i2c_adap_template = {
    .name = "cx25821",
    .owner = THIS_MODULE,
    .algo = &cx25821_i2c_algo_template,
};

static struct i2c_client cx25821_i2c_client_template = {
    .name = "cx25821 internal",
};

/* init + register i2c adapter */
int cx25821_i2c_register(struct cx25821_i2c *bus)
{
    struct cx25821_dev *dev = bus->dev;

    dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);

    bus->i2c_adap = cx25821_i2c_adap_template;
    bus->i2c_client = cx25821_i2c_client_template;
    bus->i2c_adap.dev.parent = &dev->pci->dev;

    strlcpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));

    bus->i2c_adap.algo_data = bus;
    i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
    i2c_add_adapter(&bus->i2c_adap);

    bus->i2c_client.adapter = &bus->i2c_adap;

    /* set up the I2c */
    bus->i2c_client.addr = (0x88 >> 1);

    return bus->i2c_rc;
}

int cx25821_i2c_unregister(struct cx25821_i2c *bus)
{
    i2c_del_adapter(&bus->i2c_adap);
    return 0;
}

void cx25821_av_clk(struct cx25821_dev *dev, int enable)
{
    /* write 0 to bus 2 addr 0x144 via i2x_xfer() */
    char buffer[3];
    struct i2c_msg msg;
    dprintk(1, "%s(enabled = %d)\n", __func__, enable);

    /* Register 0x144 */
    buffer[0] = 0x01;
    buffer[1] = 0x44;
    if (enable == 1)
        buffer[2] = 0x05;
    else
        buffer[2] = 0x00;

    msg.addr = 0x44;
    msg.flags = I2C_M_TEN;
    msg.len = 3;
    msg.buf = buffer;

    i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
}

int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
{
    struct i2c_client *client = &bus->i2c_client;
    int v = 0;
    u8 addr[2] = { 0, 0 };
    u8 buf[4] = { 0, 0, 0, 0 };

    struct i2c_msg msgs[2] = {
        {
            .addr = client->addr,
            .flags = 0,
            .len = 2,
            .buf = addr,
        }, {
            .addr = client->addr,
            .flags = I2C_M_RD,
            .len = 4,
            .buf = buf,
        }
    };

    addr[0] = (reg_addr >> 8);
    addr[1] = (reg_addr & 0xff);
    msgs[0].addr = 0x44;
    msgs[1].addr = 0x44;

    i2c_xfer(client->adapter, msgs, 2);

    v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
    *value = v;

    return v;
}

int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
{
    struct i2c_client *client = &bus->i2c_client;
    int retval = 0;
    u8 buf[6] = { 0, 0, 0, 0, 0, 0 };

    struct i2c_msg msgs[1] = {
        {
            .addr = client->addr,
            .flags = 0,
            .len = 6,
            .buf = buf,
        }
    };

    buf[0] = reg_addr >> 8;
    buf[1] = reg_addr & 0xff;
    buf[5] = (value >> 24) & 0xff;
    buf[4] = (value >> 16) & 0xff;
    buf[3] = (value >> 8) & 0xff;
    buf[2] = value & 0xff;
    client->flags = 0;
    msgs[0].addr = 0x44;

    retval = i2c_xfer(client->adapter, msgs, 1);

    return retval;
}