usbvision-i2c.c

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/*
 * usbvision_i2c.c
 *  i2c algorithm for USB-I2C Bridges
 *
 * Copyright (c) 1999-2007 Joerg Heckenbach <[email protected]>
 *                         Dwaine Garden <[email protected]>
 *
 * This module is part of usbvision driver project.
 * Updates to driver completed by Dwaine P. Garden
 *
 * 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/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include "usbvision.h"

#define DBG_I2C     (1 << 0)

static int i2c_debug;

module_param(i2c_debug, int, 0644);         /* debug_i2c_usb mode of the device driver */
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

#define PDEBUG(level, fmt, args...) { \
        if (i2c_debug & (level)) \
            printk(KERN_INFO KBUILD_MODNAME ":[%s:%d] " fmt, \
                __func__, __LINE__ , ## args); \
    }

static int usbvision_i2c_write(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
                short len);
static int usbvision_i2c_read(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
               short len);

static inline int try_write_address(struct i2c_adapter *i2c_adap,
                    unsigned char addr, int retries)
{
    struct usb_usbvision *usbvision;
    int i, ret = -1;
    char buf[4];

    usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);
    buf[0] = 0x00;
    for (i = 0; i <= retries; i++) {
        ret = (usbvision_i2c_write(usbvision, addr, buf, 1));
        if (ret == 1)
            break;  /* success! */
        udelay(5);
        if (i == retries)   /* no success */
            break;
        udelay(10);
    }
    if (i) {
        PDEBUG(DBG_I2C, "Needed %d retries for address %#2x", i, addr);
        PDEBUG(DBG_I2C, "Maybe there's no device at this address");
    }
    return ret;
}

static inline int try_read_address(struct i2c_adapter *i2c_adap,
                   unsigned char addr, int retries)
{
    struct usb_usbvision *usbvision;
    int i, ret = -1;
    char buf[4];

    usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);
    for (i = 0; i <= retries; i++) {
        ret = (usbvision_i2c_read(usbvision, addr, buf, 1));
        if (ret == 1)
            break;  /* success! */
        udelay(5);
        if (i == retries)   /* no success */
            break;
        udelay(10);
    }
    if (i) {
        PDEBUG(DBG_I2C, "Needed %d retries for address %#2x", i, addr);
        PDEBUG(DBG_I2C, "Maybe there's no device at this address");
    }
    return ret;
}

static inline int usb_find_address(struct i2c_adapter *i2c_adap,
                   struct i2c_msg *msg, int retries,
                   unsigned char *add)
{
    unsigned short flags = msg->flags;

    unsigned char addr;
    int ret;

    addr = (msg->addr << 1);
    if (flags & I2C_M_RD)
        addr |= 1;

    add[0] = addr;
    if (flags & I2C_M_RD)
        ret = try_read_address(i2c_adap, addr, retries);
    else
        ret = try_write_address(i2c_adap, addr, retries);

    if (ret != 1)
        return -EREMOTEIO;

    return 0;
}

static int
usbvision_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
{
    struct i2c_msg *pmsg;
    struct usb_usbvision *usbvision;
    int i, ret;
    unsigned char addr = 0;

    usbvision = (struct usb_usbvision *)i2c_get_adapdata(i2c_adap);

    for (i = 0; i < num; i++) {
        pmsg = &msgs[i];
        ret = usb_find_address(i2c_adap, pmsg, i2c_adap->retries, &addr);
        if (ret != 0) {
            PDEBUG(DBG_I2C, "got NAK from device, message #%d", i);
            return (ret < 0) ? ret : -EREMOTEIO;
        }

        if (pmsg->flags & I2C_M_RD) {
            /* read bytes into buffer */
            ret = (usbvision_i2c_read(usbvision, addr, pmsg->buf, pmsg->len));
            if (ret < pmsg->len)
                return (ret < 0) ? ret : -EREMOTEIO;
        } else {
            /* write bytes from buffer */
            ret = (usbvision_i2c_write(usbvision, addr, pmsg->buf, pmsg->len));
            if (ret < pmsg->len)
                return (ret < 0) ? ret : -EREMOTEIO;
        }
    }
    return num;
}

static u32 functionality(struct i2c_adapter *adap)
{
    return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

/* -----exported algorithm data: -------------------------------------  */

static struct i2c_algorithm usbvision_algo = {
    .master_xfer   = usbvision_i2c_xfer,
    .smbus_xfer    = NULL,
    .functionality = functionality,
};


/* ----------------------------------------------------------------------- */
/* usbvision specific I2C functions                                        */
/* ----------------------------------------------------------------------- */
static struct i2c_adapter i2c_adap_template;

int usbvision_i2c_register(struct usb_usbvision *usbvision)
{
    static unsigned short saa711x_addrs[] = {
        0x4a >> 1, 0x48 >> 1,   /* SAA7111, SAA7111A and SAA7113 */
        0x42 >> 1, 0x40 >> 1,   /* SAA7114, SAA7115 and SAA7118 */
        I2C_CLIENT_END };

    if (usbvision->registered_i2c)
        return 0;

    memcpy(&usbvision->i2c_adap, &i2c_adap_template,
           sizeof(struct i2c_adapter));

    sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name,
        usbvision->dev->bus->busnum, usbvision->dev->devpath);
    PDEBUG(DBG_I2C, "Adaptername: %s", usbvision->i2c_adap.name);
    usbvision->i2c_adap.dev.parent = &usbvision->dev->dev;

    i2c_set_adapdata(&usbvision->i2c_adap, &usbvision->v4l2_dev);

    if (usbvision_write_reg(usbvision, USBVISION_SER_MODE, USBVISION_IIC_LRNACK) < 0) {
        printk(KERN_ERR "usbvision_i2c_register: can't write reg\n");
        return -EBUSY;
    }

    PDEBUG(DBG_I2C, "I2C   debugging is enabled [i2c]");
    PDEBUG(DBG_I2C, "ALGO   debugging is enabled [i2c]");

    /* register new adapter to i2c module... */

    usbvision->i2c_adap.algo = &usbvision_algo;

    usbvision->i2c_adap.timeout = 100;  /* default values, should       */
    usbvision->i2c_adap.retries = 3;    /* be replaced by defines       */

    i2c_add_adapter(&usbvision->i2c_adap);

    PDEBUG(DBG_I2C, "i2c bus for %s registered", usbvision->i2c_adap.name);

    /* Request the load of the i2c modules we need */
    switch (usbvision_device_data[usbvision->dev_model].codec) {
    case CODEC_SAA7113:
    case CODEC_SAA7111:
        /* Without this delay the detection of the saa711x is
           hit-and-miss. */
        mdelay(10);
        v4l2_i2c_new_subdev(&usbvision->v4l2_dev,
                &usbvision->i2c_adap,
                "saa7115_auto", 0, saa711x_addrs);
        break;
    }
    if (usbvision_device_data[usbvision->dev_model].tuner == 1) {
        struct v4l2_subdev *sd;
        enum v4l2_i2c_tuner_type type;
        struct tuner_setup tun_setup;

        sd = v4l2_i2c_new_subdev(&usbvision->v4l2_dev,
                &usbvision->i2c_adap,
                "tuner", 0, v4l2_i2c_tuner_addrs(ADDRS_DEMOD));
        /* depending on whether we found a demod or not, select
           the tuner type. */
        type = sd ? ADDRS_TV_WITH_DEMOD : ADDRS_TV;

        sd = v4l2_i2c_new_subdev(&usbvision->v4l2_dev,
                &usbvision->i2c_adap,
                "tuner", 0, v4l2_i2c_tuner_addrs(type));

        if (sd == NULL)
            return -ENODEV;
        if (usbvision->tuner_type != -1) {
            tun_setup.mode_mask = T_ANALOG_TV | T_RADIO;
            tun_setup.type = usbvision->tuner_type;
            tun_setup.addr = v4l2_i2c_subdev_addr(sd);
            call_all(usbvision, tuner, s_type_addr, &tun_setup);
        }
    }
    usbvision->registered_i2c = 1;

    return 0;
}

int usbvision_i2c_unregister(struct usb_usbvision *usbvision)
{
    if (!usbvision->registered_i2c)
        return 0;

    i2c_del_adapter(&(usbvision->i2c_adap));
    usbvision->registered_i2c = 0;

    PDEBUG(DBG_I2C, "i2c bus for %s unregistered", usbvision->i2c_adap.name);

    return 0;
}

static int
usbvision_i2c_read_max4(struct usb_usbvision *usbvision, unsigned char addr,
             char *buf, short len)
{
    int rc, retries;

    for (retries = 5;;) {
        rc = usbvision_write_reg(usbvision, USBVISION_SER_ADRS, addr);
        if (rc < 0)
            return rc;

        /* Initiate byte read cycle                    */
        /* USBVISION_SER_CONT <- d0-d2 n. of bytes to r/w */
        /*                    d3 0=Wr 1=Rd             */
        rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
                      (len & 0x07) | 0x18);
        if (rc < 0)
            return rc;

        /* Test for Busy and ACK */
        do {
            /* USBVISION_SER_CONT -> d4 == 0 busy */
            rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
        } while (rc > 0 && ((rc & 0x10) != 0)); /* Retry while busy */
        if (rc < 0)
            return rc;

        /* USBVISION_SER_CONT -> d5 == 1 Not ack */
        if ((rc & 0x20) == 0)   /* Ack? */
            break;

        /* I2C abort */
        rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);
        if (rc < 0)
            return rc;

        if (--retries < 0)
            return -1;
    }

    switch (len) {
    case 4:
        buf[3] = usbvision_read_reg(usbvision, USBVISION_SER_DAT4);
    case 3:
        buf[2] = usbvision_read_reg(usbvision, USBVISION_SER_DAT3);
    case 2:
        buf[1] = usbvision_read_reg(usbvision, USBVISION_SER_DAT2);
    case 1:
        buf[0] = usbvision_read_reg(usbvision, USBVISION_SER_DAT1);
        break;
    default:
        printk(KERN_ERR
               "usbvision_i2c_read_max4: buffer length > 4\n");
    }

    if (i2c_debug & DBG_I2C) {
        int idx;

        for (idx = 0; idx < len; idx++)
            PDEBUG(DBG_I2C, "read %x from address %x", (unsigned char)buf[idx], addr);
    }
    return len;
}


static int usbvision_i2c_write_max4(struct usb_usbvision *usbvision,
                 unsigned char addr, const char *buf,
                 short len)
{
    int rc, retries;
    int i;
    unsigned char value[6];
    unsigned char ser_cont;

    ser_cont = (len & 0x07) | 0x10;

    value[0] = addr;
    value[1] = ser_cont;
    for (i = 0; i < len; i++)
        value[i + 2] = buf[i];

    for (retries = 5;;) {
        rc = usb_control_msg(usbvision->dev,
                     usb_sndctrlpipe(usbvision->dev, 1),
                     USBVISION_OP_CODE,
                     USB_DIR_OUT | USB_TYPE_VENDOR |
                     USB_RECIP_ENDPOINT, 0,
                     (__u16) USBVISION_SER_ADRS, value,
                     len + 2, HZ);

        if (rc < 0)
            return rc;

        rc = usbvision_write_reg(usbvision, USBVISION_SER_CONT,
                      (len & 0x07) | 0x10);
        if (rc < 0)
            return rc;

        /* Test for Busy and ACK */
        do {
            rc = usbvision_read_reg(usbvision, USBVISION_SER_CONT);
        } while (rc > 0 && ((rc & 0x10) != 0)); /* Retry while busy */
        if (rc < 0)
            return rc;

        if ((rc & 0x20) == 0)   /* Ack? */
            break;

        /* I2C abort */
        usbvision_write_reg(usbvision, USBVISION_SER_CONT, 0x00);

        if (--retries < 0)
            return -1;

    }

    if (i2c_debug & DBG_I2C) {
        int idx;

        for (idx = 0; idx < len; idx++)
            PDEBUG(DBG_I2C, "wrote %x at address %x", (unsigned char)buf[idx], addr);
    }
    return len;
}

static int usbvision_i2c_write(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
                short len)
{
    char *buf_ptr = buf;
    int retval;
    int wrcount = 0;
    int count;
    int max_len = 4;

    while (len > 0) {
        count = (len > max_len) ? max_len : len;
        retval = usbvision_i2c_write_max4(usbvision, addr, buf_ptr, count);
        if (retval > 0) {
            len -= count;
            buf_ptr += count;
            wrcount += count;
        } else
            return (retval < 0) ? retval : -EFAULT;
    }
    return wrcount;
}

static int usbvision_i2c_read(struct usb_usbvision *usbvision, unsigned char addr, char *buf,
               short len)
{
    char temp[4];
    int retval, i;
    int rdcount = 0;
    int count;

    while (len > 0) {
        count = (len > 3) ? 4 : len;
        retval = usbvision_i2c_read_max4(usbvision, addr, temp, count);
        if (retval > 0) {
            for (i = 0; i < len; i++)
                buf[rdcount + i] = temp[i];
            len -= count;
            rdcount += count;
        } else
            return (retval < 0) ? retval : -EFAULT;
    }
    return rdcount;
}

static struct i2c_adapter i2c_adap_template = {
    .owner = THIS_MODULE,
    .name              = "usbvision",
};

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-basic-offset: 8
 * End:
 */