au0828-i2c.c

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/*
 *  Driver for the Auvitek AU0828 USB bridge
 *
 *  Copyright (c) 2008 Steven Toth <[email protected]>
 *
 *  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.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/io.h>

#include "au0828.h"
#include "media/tuner.h"
#include <media/v4l2-common.h>

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

#define I2C_WAIT_DELAY 25
#define I2C_WAIT_RETRY 1000

static inline int i2c_slave_did_write_ack(struct i2c_adapter *i2c_adap)
{
    struct au0828_dev *dev = i2c_adap->algo_data;
    return au0828_read(dev, AU0828_I2C_STATUS_201) &
        AU0828_I2C_STATUS_NO_WRITE_ACK ? 0 : 1;
}

static inline int i2c_slave_did_read_ack(struct i2c_adapter *i2c_adap)
{
    struct au0828_dev *dev = i2c_adap->algo_data;
    return au0828_read(dev, AU0828_I2C_STATUS_201) &
        AU0828_I2C_STATUS_NO_READ_ACK ? 0 : 1;
}

static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
{
    int count;

    for (count = 0; count < I2C_WAIT_RETRY; count++) {
        if (!i2c_slave_did_read_ack(i2c_adap))
            break;
        udelay(I2C_WAIT_DELAY);
    }

    if (I2C_WAIT_RETRY == count)
        return 0;

    return 1;
}

static inline int i2c_is_read_busy(struct i2c_adapter *i2c_adap)
{
    struct au0828_dev *dev = i2c_adap->algo_data;
    return au0828_read(dev, AU0828_I2C_STATUS_201) &
        AU0828_I2C_STATUS_READ_DONE ? 0 : 1;
}

static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
{
    int count;

    for (count = 0; count < I2C_WAIT_RETRY; count++) {
        if (!i2c_is_read_busy(i2c_adap))
            break;
        udelay(I2C_WAIT_DELAY);
    }

    if (I2C_WAIT_RETRY == count)
        return 0;

    return 1;
}

static inline int i2c_is_write_done(struct i2c_adapter *i2c_adap)
{
    struct au0828_dev *dev = i2c_adap->algo_data;
    return au0828_read(dev, AU0828_I2C_STATUS_201) &
        AU0828_I2C_STATUS_WRITE_DONE ? 1 : 0;
}

static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
{
    int count;

    for (count = 0; count < I2C_WAIT_RETRY; count++) {
        if (i2c_is_write_done(i2c_adap))
            break;
        udelay(I2C_WAIT_DELAY);
    }

    if (I2C_WAIT_RETRY == count)
        return 0;

    return 1;
}

static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
{
    struct au0828_dev *dev = i2c_adap->algo_data;
    return au0828_read(dev, AU0828_I2C_STATUS_201) &
        AU0828_I2C_STATUS_BUSY ? 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;
}

/* FIXME: Implement join handling correctly */
static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
    const struct i2c_msg *msg, int joined_rlen)
{
    int i, strobe = 0;
    struct au0828_dev *dev = i2c_adap->algo_data;

    dprintk(4, "%s()\n", __func__);

    au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);

    /* Set the I2C clock */
    if (((dev->board.tuner_type == TUNER_XC5000) ||
         (dev->board.tuner_type == TUNER_XC5000C)) &&
        (dev->board.tuner_addr == msg->addr) &&
        (msg->len == 64)) {
        /* Hack to speed up firmware load.  The xc5000 lets us do up
           to 400 KHz when in firmware download mode */
        au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
                 AU0828_I2C_CLK_250KHZ);
    } else {
        /* Use the i2c clock speed in the board configuration */
        au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
                 dev->board.i2c_clk_divider);
    }

    /* Hardware needs 8 bit addresses */
    au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);

    dprintk(4, "SEND: %02x\n", msg->addr);

    /* Deal with i2c_scan */
    if (msg->len == 0) {
        /* The analog tuner detection code makes use of the SMBUS_QUICK
           message (which involves a zero length i2c write).  To avoid
           checking the status register when we didn't strobe out any
           actual bytes to the bus, just do a read check.  This is
           consistent with how I saw i2c device checking done in the
           USB trace of the Windows driver */
        au0828_write(dev, AU0828_I2C_TRIGGER_200,
                 AU0828_I2C_TRIGGER_READ);

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

        if (i2c_wait_read_ack(i2c_adap))
            return -EIO;

        return 0;
    }

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

        dprintk(4, " %02x\n", msg->buf[i]);

        au0828_write(dev, AU0828_I2C_WRITE_FIFO_205, msg->buf[i]);

        strobe++;
        i++;

        if ((strobe >= 4) || (i >= msg->len)) {

            /* Strobe the byte into the bus */
            if (i < msg->len)
                au0828_write(dev, AU0828_I2C_TRIGGER_200,
                         AU0828_I2C_TRIGGER_WRITE |
                         AU0828_I2C_TRIGGER_HOLD);
            else
                au0828_write(dev, AU0828_I2C_TRIGGER_200,
                         AU0828_I2C_TRIGGER_WRITE);

            /* Reset strobe trigger */
            strobe = 0;

            if (!i2c_wait_write_done(i2c_adap))
                return -EIO;

        }

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

    dprintk(4, "\n");

    return msg->len;
}

/* FIXME: Implement join handling correctly */
static int i2c_readbytes(struct i2c_adapter *i2c_adap,
    const struct i2c_msg *msg, int joined)
{
    struct au0828_dev *dev = i2c_adap->algo_data;
    int i;

    dprintk(4, "%s()\n", __func__);

    au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);

    /* Set the I2C clock */
    au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
             dev->board.i2c_clk_divider);

    /* Hardware needs 8 bit addresses */
    au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);

    dprintk(4, " RECV:\n");

    /* Deal with i2c_scan */
    if (msg->len == 0) {
        au0828_write(dev, AU0828_I2C_TRIGGER_200,
                 AU0828_I2C_TRIGGER_READ);

        if (i2c_wait_read_ack(i2c_adap))
            return -EIO;
        return 0;
    }

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

        i++;

        if (i < msg->len)
            au0828_write(dev, AU0828_I2C_TRIGGER_200,
                     AU0828_I2C_TRIGGER_READ |
                     AU0828_I2C_TRIGGER_HOLD);
        else
            au0828_write(dev, AU0828_I2C_TRIGGER_200,
                     AU0828_I2C_TRIGGER_READ);

        if (!i2c_wait_read_done(i2c_adap))
            return -EIO;

        msg->buf[i-1] = au0828_read(dev, AU0828_I2C_READ_FIFO_209) &
            0xff;

        dprintk(4, " %02x\n", msg->buf[i-1]);
    }
    if (!i2c_wait_done(i2c_adap))
        return -EIO;

    dprintk(4, "\n");

    return msg->len;
}

static int i2c_xfer(struct i2c_adapter *i2c_adap,
            struct i2c_msg *msgs, int num)
{
    int i, retval = 0;

    dprintk(4, "%s(num = %d)\n", __func__, num);

    for (i = 0; i < num; i++) {
        dprintk(4, "%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 au0828_functionality(struct i2c_adapter *adap)
{
    return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
}

static struct i2c_algorithm au0828_i2c_algo_template = {
    .master_xfer    = i2c_xfer,
    .functionality  = au0828_functionality,
};

/* ----------------------------------------------------------------------- */

static struct i2c_adapter au0828_i2c_adap_template = {
    .name              = DRIVER_NAME,
    .owner             = THIS_MODULE,
    .algo              = &au0828_i2c_algo_template,
};

static struct i2c_client au0828_i2c_client_template = {
    .name   = "au0828 internal",
};

static char *i2c_devs[128] = {
    [0x8e >> 1] = "au8522",
    [0xa0 >> 1] = "eeprom",
    [0xc2 >> 1] = "tuner/xc5000",
};

static void do_i2c_scan(char *name, struct i2c_client *c)
{
    unsigned char buf;
    int i, rc;

    for (i = 0; i < 128; i++) {
        c->addr = i;
        rc = i2c_master_recv(c, &buf, 0);
        if (rc < 0)
            continue;
        printk(KERN_INFO "%s: i2c scan: found device @ 0x%x  [%s]\n",
               name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
    }
}

/* init + register i2c adapter */
int au0828_i2c_register(struct au0828_dev *dev)
{
    dprintk(1, "%s()\n", __func__);

    memcpy(&dev->i2c_adap, &au0828_i2c_adap_template,
           sizeof(dev->i2c_adap));
    memcpy(&dev->i2c_algo, &au0828_i2c_algo_template,
           sizeof(dev->i2c_algo));
    memcpy(&dev->i2c_client, &au0828_i2c_client_template,
           sizeof(dev->i2c_client));

    dev->i2c_adap.dev.parent = &dev->usbdev->dev;

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

    dev->i2c_adap.algo = &dev->i2c_algo;
    dev->i2c_adap.algo_data = dev;
    i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
    i2c_add_adapter(&dev->i2c_adap);

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

    if (0 == dev->i2c_rc) {
        printk(KERN_INFO "%s: i2c bus registered\n", DRIVER_NAME);
        if (i2c_scan)
            do_i2c_scan(DRIVER_NAME, &dev->i2c_client);
    } else
        printk(KERN_INFO "%s: i2c bus register FAILED\n", DRIVER_NAME);

    return dev->i2c_rc;
}

int au0828_i2c_unregister(struct au0828_dev *dev)
{
    i2c_del_adapter(&dev->i2c_adap);
    return 0;
}