montecarlo/io/pcf8591_nct.c

	pcf8591_nct.c revision 03831d35f7499c87d51205817c93e9a8d42c4bae
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


#pragma ident   "%Z%%M% %I% %E% SMI"


/*
 * I2C leaf driver for the PCF8591
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/errno.h>
#include <sys/file.h>
#include <sys/termio.h>
#include <sys/termios.h>
#include <sys/cmn_err.h>
#include <sys/stream.h>
#include <sys/strsun.h>
#include <sys/stropts.h>
#include <sys/strtty.h>
#include <sys/debug.h>
#include <sys/eucioctl.h>
#include <sys/cred.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <sys/kmem.h>

#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/obpdefs.h>
#include <sys/conf.h>
#include <sys/modctl.h>
#include <sys/stat.h>
#include <sys/open.h>
#include <sys/uio.h>

#include <sys/i2c/misc/i2c_svc.h>
#include <sys/envctrl_gen.h>
#include <sys/netract_gen.h>
#include <sys/pcf8591_nct.h>


/*
 *      CONTROL OF CHIP
 * PCF8591 Temp sensing control register definitions
 *
 * ---------------------------------------------
 * | 0 | AOE | X | X | 0 | AIF | X | X |
 * ---------------------------------------------
 * AOE = Analog out enable.. not used on out implementation
 * 5 & 4 = Analog Input Programming.. see data sheet for bits..
 *
 * AIF = Auto increment flag
 * bits 1 & 0 are for the Chennel number.
 */


#define I2CTRANS_DATA   0
#define I2CRAW_DATA 1
#define TEMP_TABLE_SIZE 256

#define SHUTDOWN_TEMP_MIN   55
#define SHUTDOWN_TEMP_MAX   85

#ifdef DEBUG
#define dbg_print(level, str) cmn_err(level, str);
#else
#define dbg_print(level, str) {; }
#endif


extern int nct_i2c_transfer(i2c_client_hdl_t i2c_hdl, i2c_transfer_t *i2c_tran);
static uchar_t _cpu_temps[TEMP_TABLE_SIZE + 4]; /* see attach */

static void *pcf8591_soft_statep;

/*
 * cb ops (only need ioctl)
 */
static int pcf8591_open(dev_t *, int, int, cred_t *);
static int pcf8591_close(dev_t, int, int, cred_t *);
static int pcf8591_read(dev_t dev, struct uio *uiop, cred_t *cred_p);
static int pcf8591_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);

static struct cb_ops pcf8591_cbops = {
    pcf8591_open,           /* open */
    pcf8591_close,          /* close */
    nodev,              /* strategy */
    nodev,              /* print */
    nodev,              /* dump */
    pcf8591_read,           /* read */
    nodev,              /* write */
    pcf8591_ioctl,          /* ioctl */
    nodev,              /* devmap */
    nodev,              /* mmap */
    nodev,              /* segmap */
    nochpoll,           /* poll */
    ddi_prop_op,            /* cb_prop_op */
    NULL,               /* streamtab */
    D_NEW | D_MP | D_HOTPLUG,   /* Driver compatibility flag */
    CB_REV,             /* rev */
    nodev,              /* int (*cb_aread)() */
    nodev               /* int (*cb_awrite)() */
};

/*
 * dev ops
 */
static int pcf8591_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg,
        void **result);
static int pcf8591_attach(dev_info_t *dip, ddi_attach_cmd_t cmd);
static int pcf8591_detach(dev_info_t *dip, ddi_detach_cmd_t cmd);

/* kstat routines */
static int pcf8591_add_kstats(struct pcf8591_unit *);
static void pcf8591_delete_kstats(struct pcf8591_unit *);
static int pcf8591_temp_kstat_update(kstat_t *, int);
static int pcf8591_read_chip(struct pcf8591_unit *, uint8_t, int);
static int pcf8591_read_props(struct pcf8591_unit *unitp);

static struct dev_ops pcf8591_ops = {
    DEVO_REV,
    0,
    pcf8591_info,
    nulldev,
    nulldev,
    pcf8591_attach,
    pcf8591_detach,
    nodev,
    &pcf8591_cbops,
    NULL
};

extern struct mod_ops mod_driverops;

static struct modldrv pcf8591_modldrv = {
    &mod_driverops,     /* type of module - driver */
    "Netract pcf8591 (adio) %I% ",
    &pcf8591_ops,
};

static struct modlinkage pcf8591_modlinkage = {
    MODREV_1,
    &pcf8591_modldrv,
    0
};

char    _depends_on[] = "misc/i2c_svc";

int pcf8591_debug = 0x02;
static uint8_t translate_cputemp(uint8_t value);

int
_init(void)
{
    register int    error;

    error = mod_install(&pcf8591_modlinkage);
    if (error == 0) {
        (void) ddi_soft_state_init(&pcf8591_soft_statep,
            sizeof (struct pcf8591_unit), PCF8591_MAX_DEVS);
    }

    return (error);
}

int
_fini(void)
{
    register int    error;

    error = mod_remove(&pcf8591_modlinkage);
    if (error == 0) {
        ddi_soft_state_fini(&pcf8591_soft_statep);
    }

    return (error);
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&pcf8591_modlinkage, modinfop));
}

/*ARGSUSED*/
static int
pcf8591_open(dev_t *devp, int flags, int otyp, cred_t *credp)
{
    int err = 0;
    struct pcf8591_unit *unitp;
    minor_t minor = getminor(*devp);

    int instance = PCF8591_MINOR_TO_DEVINST(minor);
    int channel = PCF8591_MINOR_TO_CHANNEL(minor);

    if (instance < 0) {
        return (ENXIO);
    }

    unitp = (struct pcf8591_unit *)
        ddi_get_soft_state(pcf8591_soft_statep, instance);

    if (unitp == NULL) {
        return (ENXIO);
    }

    if (otyp != OTYP_CHR) {
        return (EINVAL);
    }

    mutex_enter(&unitp->umutex);

    if (flags & FEXCL) {
        if (unitp->pcf8591_oflag[channel] != 0) {
            err = EBUSY;
        } else {
            unitp->pcf8591_oflag[channel] = FEXCL;
        }
    } else {
        if (unitp->pcf8591_oflag[channel] == FEXCL) {
            err = EBUSY;
        } else {
            unitp->pcf8591_oflag[channel] = FOPEN;
        }
    }

    mutex_exit(&unitp->umutex);

    return (err);
}

/*ARGSUSED*/
static int
pcf8591_close(dev_t devp, int flags, int otyp, cred_t *credp)
{
    struct pcf8591_unit *unitp;
    minor_t minor = getminor(devp);

    int instance = PCF8591_MINOR_TO_DEVINST(minor);
    int channel = PCF8591_MINOR_TO_CHANNEL(minor);

#ifdef lint
    flags = flags;
    otyp = otyp;
#endif

    if (instance < 0) {
        return (ENXIO);
    }

    unitp = (struct pcf8591_unit *)
        ddi_get_soft_state(pcf8591_soft_statep, instance);

    if (unitp == NULL) {
        return (ENXIO);
    }

    mutex_enter(&unitp->umutex);

    unitp->pcf8591_oflag[channel] = 0;

    mutex_exit(&unitp->umutex);

    return (DDI_SUCCESS);
}

static int
pcf8591_io(dev_t dev, struct uio *uiop, int rw)
{
    int err = 0;
    struct pcf8591_unit *unitp;
    minor_t minor = getminor(dev);

    int instance = PCF8591_MINOR_TO_DEVINST(minor);
    int channel = PCF8591_MINOR_TO_CHANNEL(minor);

    int     bytes_to_rw;
    int     translate = 0;

    /*
     * At this point we don't have a write operation to pcf8591.
     */
    if (rw == B_WRITE) {
        return (EACCES);
    }

    if (instance < 0) {
        return (ENXIO);
    }

    unitp = (struct pcf8591_unit *)
        ddi_get_soft_state(pcf8591_soft_statep, instance);
    if (unitp == NULL) {
        return (ENXIO);
    }

    if ((bytes_to_rw = uiop->uio_resid) > PCF8591_TRAN_SIZE) {
        return (EINVAL);
    }

    /*
     * Need to serialize all read operations, since there is a single
     * i2c_transfer_t structure allocated for all read and write ops.
     * We can't share the i2c bus among multiple transactions anyway,
     * so this does not affect performance.
     */
    mutex_enter(&unitp->umutex);
    while (unitp->pcf8591_flags == PCF8591_BUSY) {
        if (cv_wait_sig(&unitp->pcf8591_cv, &unitp->umutex) <= 0) {
            mutex_exit(&unitp->umutex);

            return (EINTR);
        }
    }
    unitp->pcf8591_flags = PCF8591_BUSY;
    mutex_exit(&unitp->umutex);

    if (bytes_to_rw == 1)
        translate = 1;
    /*
     * Event sequence:
     * 1. set up the control register write, for now we'll always read
     *    channel 0, which is the only active 8591 port on the Nordica
     *    TODO: We'll need a minor node for each port that is used.
     * 2. increment read count to read the throw-away byte
     * 3. start the write/read of control/data registers
     * 4. throw the first byte away
     * 5. then return the data
     */

    unitp->i2c_tran->i2c_flags = I2C_WR_RD;
    unitp->i2c_tran->i2c_wlen = 1;
    unitp->i2c_tran->i2c_wbuf[0] = (unitp->pcf8591_inprog |
        channel);
    /*
     * read extra byte to throw away the first, (PCF8591 datasheet)
     */
    unitp->i2c_tran->i2c_rlen = bytes_to_rw + 1;

    if (nct_i2c_transfer(unitp->pcf8591_hdl,
            unitp->i2c_tran) != I2C_SUCCESS) {
        err = EIO;
    } else {
        /*
         * Throw away the first byte according to PCF8591 datasheet
         * If translating, use the second byte.
         */
        if (translate) {
            unitp->i2c_tran->i2c_rbuf[0] =
                translate_cputemp(unitp->i2c_tran->i2c_rbuf[1]);
        } else {
            unitp->i2c_tran->i2c_rbuf[0] =
                unitp->i2c_tran->i2c_rbuf[1];
            unitp->i2c_tran->i2c_rbuf[1] = 0;
        }

        err = uiomove(unitp->i2c_tran->i2c_rbuf,
            bytes_to_rw,
            UIO_READ,
            uiop);
    }
    mutex_enter(&unitp->umutex);
    unitp->pcf8591_flags = 0;
    cv_signal(&unitp->pcf8591_cv);
    mutex_exit(&unitp->umutex);

    return (err);
}

/*ARGSUSED*/
static int
pcf8591_read(dev_t dev, struct uio *uiop, cred_t *cred_p)
{
    return (pcf8591_io(dev, uiop, B_READ));
}

static int
call_copyin(caddr_t arg, struct pcf8591_unit *unitp, int mode)
{
    uchar_t *wbuf;
    uchar_t *rbuf;
    i2c_transfer_t i2ct;
    i2c_transfer_t *i2ctp = unitp->i2c_tran;


    if (ddi_copyin((void *)arg, (caddr_t)&i2ct,
        sizeof (i2c_transfer_t), mode) != DDI_SUCCESS) {
        return (I2C_FAILURE);
    }

    /*
     * Save the read and write buffer pointers in the transfer
     * structure, otherwise these will get overwritten when we
     * do a bcopy. Restore once done.
     */

    wbuf = i2ctp->i2c_wbuf;
    rbuf = i2ctp->i2c_rbuf;

    bcopy(&i2ct, i2ctp, sizeof (i2c_transfer_t));

    i2ctp->i2c_wbuf = wbuf;
    i2ctp->i2c_rbuf = rbuf;

    /*
     * copyin the read and write buffers to the saved buffers.
     */

    if (i2ct.i2c_wlen != 0) {
        if (ddi_copyin(i2ct.i2c_wbuf, (caddr_t)i2ctp->i2c_wbuf,
            i2ct.i2c_wlen, mode) != DDI_SUCCESS) {
                return (I2C_FAILURE);
            }
        }

    return (I2C_SUCCESS);
}

static int
call_copyout(caddr_t arg, struct pcf8591_unit *unitp, int mode)
{
    i2c_transfer_t i2ct;
    i2c_transfer_t *i2ctp = unitp->i2c_tran;
    uint16_t  i2c_actlen;

    /*
     * We will copyout the last three fields only, skipping
     * the remaining ones, before copying the rbuf to the
     * user buffer.
     */

    int uskip = sizeof (i2c_transfer_t) - 3*sizeof (int16_t),
        kskip = sizeof (i2c_transfer_t) - 3*sizeof (int16_t);

    /*
     * First copyin the user structure to the temporary i2ct,
     * so that we have the wbuf and rbuf addresses in it.
     */

    uskip = sizeof (i2c_transfer_t) - 3 * (sizeof (uint16_t));

    /*
     * copyout the last three out fields now.
     */

    if (ddi_copyout((void *)((intptr_t)i2ctp+kskip), (void *)
        ((intptr_t)arg + uskip), 3*sizeof (uint16_t), mode)
        != DDI_SUCCESS) {
        return (I2C_FAILURE);
        }

    /*
     * In case we have something to write, get the address of the read
     * buffer.
     */

    if (i2ctp->i2c_rlen - i2ctp->i2c_r_resid > 0) {

    if (ddi_copyin((void *)arg, &i2ct,
        sizeof (i2c_transfer_t), mode) != DDI_SUCCESS) {
        return (I2C_FAILURE);
    }

    /*
     * copyout the read buffer to the saved user buffer in i2ct.
     */

        i2c_actlen = i2ctp->i2c_rlen - i2ctp->i2c_r_resid;
        if (ddi_copyout(i2ctp->i2c_rbuf, i2ct.i2c_rbuf,
                i2c_actlen, mode) != DDI_SUCCESS) {
                return (I2C_FAILURE);
            }
        }

    return (I2C_SUCCESS);
}

/*
 * The ioctls will use the same name as the Javelin ioctls. We
 * will have a very restricted set for MC, and unlike Javelin
 * will not have a envctrl_chip structure to return values
 * from the driver. All we will have is a uint8_t value to
 * get or set values from the driver. Also, unlike the Javelin,
 * where 'index' is used to specify the input port from where
 * temperature is collected, here different minor nodes will be
 * created by the driver for each port, eliminating the need for
 * 'index' - leaving us with only the value to pass.
 */

/*ARGSUSED*/
static int
pcf8591_ioctl(dev_t dev, int cmd, intptr_t arg, int mode,
        cred_t *credp, int *rvalp)
{
    int err = 0;
    struct pcf8591_unit *unitp;
    minor_t minor = getminor(dev);

    int instance = PCF8591_MINOR_TO_DEVINST(minor);
    int channel = PCF8591_MINOR_TO_CHANNEL(minor);

    unitp = (struct pcf8591_unit *)
        ddi_get_soft_state(pcf8591_soft_statep, instance);

    mutex_enter(&unitp->umutex);
    while (unitp->pcf8591_flags == PCF8591_BUSY) {
        if (cv_wait_sig(&unitp->pcf8591_cv, &unitp->umutex) <= 0) {
            mutex_exit(&unitp->umutex);

            return (EINTR);
        }
    }
    unitp->pcf8591_flags = PCF8591_BUSY;
    mutex_exit(&unitp->umutex);

    switch (cmd) {

    case ENVC_IOC_GETTEMP: {
        /*
         * Read the status byte from pcf8591 chip. The value will
         * be already converted to Celcius by translate_cputemp.
         */
        pcf8591_read_chip(unitp, channel, 1);
        if (ddi_copyout(unitp->i2c_tran->i2c_rbuf,
            (caddr_t)arg, sizeof (uint8_t), mode) != DDI_SUCCESS) {
            err = EFAULT;
        }
        break;
    }

    case ENVC_IOC_GETMODE: {
        uint8_t curr_mode = unitp->current_mode;

        if (ddi_copyout((caddr_t)&curr_mode, (caddr_t)arg,
            sizeof (uint8_t), mode) != DDI_SUCCESS) {
            err = EFAULT;
        }
        break;
    }

    case ENVC_IOC_SETMODE: {
        uint8_t curr_mode;
        if (ddi_copyin((caddr_t)arg, (caddr_t)&curr_mode,
            sizeof (uint8_t), mode) != DDI_SUCCESS) {
                err = EFAULT;
                break;
        }
        if (curr_mode == ENVCTRL_DIAG_MODE ||
            curr_mode == ENVCTRL_NORMAL_MODE) {
            unitp->current_mode = curr_mode; /* Don't do anything */
        }
        break;
    }

    /* Testing, may be removed */
    case I2CDEV_TRAN:
        if (call_copyin((caddr_t)arg, unitp, mode) != I2C_SUCCESS) {
            err = EFAULT;
            break;
        }
        if (nct_i2c_transfer(unitp->pcf8591_hdl, unitp->i2c_tran)
                != I2C_SUCCESS) {
            err = EFAULT;
            break;
        }
        if (call_copyout((caddr_t)arg, unitp, mode) != I2C_SUCCESS) {
            err = EFAULT;
            break;
        }
        break;

    /*
     * TESTING TRANSLATION from "adc" "table" property
     * translate thermistor index into temp Celcius
     */
    case I2CDEV_GETTEMP: {
        struct i2c_transfer *tp;
        if (call_copyin((caddr_t)arg, unitp, mode) != I2C_SUCCESS) {
            err = EFAULT;
            break;
        }
        tp = unitp->i2c_tran;
        if (tp->i2c_rlen != 1) {
            err = EINVAL;
            break;
        }
        /*
         * Throw away the first byte according to PCF8591 datasheet,
         * so read two bytes
         */
        tp->i2c_rlen = 2;
        if (nct_i2c_transfer(unitp->pcf8591_hdl, unitp->i2c_tran)
                != I2C_SUCCESS) {
            err = EFAULT;
            break;
        }
#ifdef DEBUG
        if (pcf8591_debug & 0x0010)
            cmn_err(CE_NOTE,
            "pcf8591_ioctl: i2c_rlen=%d; i2c_rbuf[0,1]=0x%x,0x%x\n",
            tp->i2c_rlen, tp->i2c_rbuf[0], tp->i2c_rbuf[1]);
#endif /* DEBUG */
        /*
         * Throw away the first byte according to PCF8591 datasheet
         */
        if ((tp->i2c_rbuf[0] = translate_cputemp(tp->i2c_rbuf[1]))
                == 0) {
            err = EINVAL;
            break;
        }
        tp->i2c_rbuf[1] = 0;

        if (call_copyout((caddr_t)arg, unitp, mode) != I2C_SUCCESS) {
            err = EFAULT;
            break;
        }
        break;
    }

    case I2CDEV_GETTABLES: {
        break;
    }
    default:
        err = EINVAL;
    }

    mutex_enter(&unitp->umutex);
    unitp->pcf8591_flags = 0;
    cv_signal(&unitp->pcf8591_cv);
    mutex_exit(&unitp->umutex);

    return (err);
}

static int
pcf8591_do_detach(dev_info_t *dip)
{
    register struct pcf8591_unit *unitp;
    int instance;
    uint_t attach_flag;

    instance = ddi_get_instance(dip);
    unitp = ddi_get_soft_state(pcf8591_soft_statep, instance);
    attach_flag = unitp->attach_flag;

    if (attach_flag & PCF8591_KSTAT_INIT) {
        pcf8591_delete_kstats(unitp);
    }

    if (attach_flag & PCF8591_LOCK_INIT) {
        mutex_destroy(&unitp->umutex);
        cv_destroy(&unitp->pcf8591_cv);
    }

    /*
     * Restore the lengths of the rbuf and wbuf, which was originally
     * allocated so that the appropriate amount of rbuf and wbuf are
     * freed.
     */
    if (attach_flag & PCF8591_ALLOC_TRANSFER) {
        unitp->i2c_tran->i2c_wlen = MAX_WLEN;
        unitp->i2c_tran->i2c_rlen = MAX_RLEN;
        i2c_transfer_free(unitp->pcf8591_hdl, unitp->i2c_tran);
    }

    if (attach_flag & PCF8591_REGISTER_CLIENT) {
        i2c_client_unregister(unitp->pcf8591_hdl);
    }

    if (attach_flag & PCF8591_MINORS_CREATED) {
        ddi_remove_minor_node(dip, NULL);
    }

    /*
     * Free the memory allocated for the properties.
     */
    if (attach_flag & PCF8591_PROPS_READ) {
        ddi_prop_free(unitp->props.name);
        if (unitp->props.num_chans_used) {
            ddi_prop_free(unitp->props.channels_in_use);
        }

        if (unitp->props.channels_description) {
            ddi_prop_free(unitp->props.channels_description);
        }
    }

    if (attach_flag & PCF8591_SOFT_STATE_ALLOC) {
        ddi_soft_state_free(pcf8591_soft_statep, instance);
    }

    return (DDI_SUCCESS);
}

static int
pcf8591_do_suspend(dev_info_t *dip)
{
    int instance = ddi_get_instance(dip);
    struct pcf8591_unit *unitp = (struct pcf8591_unit *)
        ddi_get_soft_state(pcf8591_soft_statep, instance);

    if (unitp == NULL) {
        return (ENXIO);
    }

    /*
     * Set the busy flag so that future transactions block
     * until resume.
     */
    mutex_enter(&unitp->umutex);
    while (unitp->pcf8591_flags == PCF8591_BUSY) {
        if (cv_wait_sig(&unitp->pcf8591_cv,
            &unitp->umutex) <= 0) {
            mutex_exit(&unitp->umutex);

            return (DDI_FAILURE);
        }
    }
    unitp->pcf8591_flags = PCF8591_BUSY;
    mutex_exit(&unitp->umutex);

    return (DDI_SUCCESS);
}

static int
pcf8591_do_resume(dev_info_t *dip)
{
    int instance = ddi_get_instance(dip);
    struct pcf8591_unit *unitp = (struct pcf8591_unit *)
            ddi_get_soft_state(pcf8591_soft_statep, instance);
    if (unitp == NULL) {
        return (ENXIO);
    }

    mutex_enter(&unitp->umutex);
    unitp->pcf8591_flags = 0;
    cv_signal(&unitp->pcf8591_cv);
    mutex_exit(&unitp->umutex);

    return (DDI_SUCCESS);
}

static int
pcf8591_do_attach(dev_info_t *dip)
{
    register struct pcf8591_unit *unitp;
    int i, instance;
    char name[MAXNAMELEN];
    minor_t minor;

    instance = ddi_get_instance(dip);

    if (ddi_soft_state_zalloc(pcf8591_soft_statep, instance) != 0) {
        return (DDI_FAILURE);
    }

    unitp = ddi_get_soft_state(pcf8591_soft_statep, instance);

    if (unitp == NULL) {
        return (DDI_FAILURE);
    }

    unitp->dip = dip;

    unitp->attach_flag = PCF8591_SOFT_STATE_ALLOC;

    if (pcf8591_read_props(unitp) != DDI_PROP_SUCCESS) {
        pcf8591_do_detach(dip);

        return (DDI_FAILURE);
    }

    unitp->attach_flag |= PCF8591_PROPS_READ;

    /*
     * Set the current operating mode to NORMAL_MODE.
     */
    unitp->current_mode = ENVCTRL_NORMAL_MODE; /* normal mode */

    snprintf(unitp->pcf8591_name, PCF8591_NAMELEN,
        "%s%d", ddi_driver_name(dip), instance);

    /*
     * Create a minor node corresponding to channel 0 to 3
     */
    for (i = 0; i < PCF8591_MAX_CHANS; i++) {
    if (i == 0) {
        (void) sprintf(name, "cputemp");
    } else {
        (void) sprintf(name, "%d", i);
    }
    minor = PCF8591_MINOR_NUM(instance, i);
    if (ddi_create_minor_node(dip, name, S_IFCHR, minor,
        PCF8591_NODE_TYPE, NULL) == DDI_FAILURE) {
            ddi_remove_minor_node(dip, NULL);
            pcf8591_do_detach(dip);

            return (DDI_FAILURE);
        }
    }

    unitp->attach_flag |= PCF8591_MINORS_CREATED;

    if (i2c_client_register(dip, &unitp->pcf8591_hdl)
        != I2C_SUCCESS) {
        pcf8591_do_detach(dip);

        return (DDI_FAILURE);
    }

    unitp->attach_flag |= PCF8591_REGISTER_CLIENT;

    /*
     * We allocate a single i2c_transfer_t structure for all
     * i2c transactions.
     */
    if (i2c_transfer_alloc(unitp->pcf8591_hdl, &unitp->i2c_tran,
        MAX_WLEN, MAX_RLEN, KM_SLEEP) != I2C_SUCCESS) {
        pcf8591_do_detach(dip);

        return (DDI_FAILURE);
    }

    unitp->attach_flag |= PCF8591_ALLOC_TRANSFER;

    /*
     * The flags will be set to I2C_WR because for all reads from
     * the 8591 we need to also write the control byte.
     */
    unitp->i2c_tran->i2c_flags = I2C_WR;
    unitp->i2c_tran->i2c_version = I2C_XFER_REV;


    /*
     * Set the analog programming mode to default. Upper nibble
     * in control byte. Four single ended inputs, output not enabled.
     */
    unitp->pcf8591_inprog = PCF8591_4SINGLE | PCF8591_ANALOG_INPUT_EN;

    /*
     * Set the open flag for each channel to 0.
     */
    for (i = 0; i < PCF8591_MAX_CHANS; i++) {
        unitp->pcf8591_oflag[i] = 0;
    }

    /*
     * Set the busy flag to 0.
     */
    unitp->pcf8591_flags = 0;

    mutex_init(&unitp->umutex, NULL, MUTEX_DRIVER, NULL);
    cv_init(&unitp->pcf8591_cv, NULL, CV_DRIVER, NULL);

    unitp->attach_flag |= PCF8591_LOCK_INIT;

    if (pcf8591_add_kstats(unitp) != DDI_SUCCESS) {
        pcf8591_do_detach(dip);

        return (DDI_FAILURE);
    }

    unitp->attach_flag |= PCF8591_KSTAT_INIT;

    ddi_report_dev(dip);

    return (DDI_SUCCESS);
}

/* ARGSUSED */
static int
pcf8591_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
    dev_t   dev;
    int instance;

    if (infocmd == DDI_INFO_DEVT2INSTANCE) {
        dev = (dev_t)arg;
        instance = PCF8591_MINOR_TO_DEVINST(getminor(dev));
        *result = (void *)(uintptr_t)instance;
        return (DDI_SUCCESS);
    }
    return (DDI_FAILURE);
}

static int
pcf8591_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
    switch (cmd) {
    case DDI_ATTACH:
        return (pcf8591_do_attach(dip));
    case DDI_RESUME:
        return (pcf8591_do_resume(dip));
    default:
        return (DDI_FAILURE);
    }
}

static int
pcf8591_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
    switch (cmd) {
    case DDI_DETACH:
        return (pcf8591_do_detach(dip));
    case DDI_SUSPEND:
        return (pcf8591_do_suspend(dip));
    default:
        return (DDI_FAILURE);
    }
}

static uint8_t
translate_cputemp(uint8_t value)
{
    return (_cpu_temps[value]);
}

static int
pcf8591_add_kstats(struct pcf8591_unit *unitp)
{
    if ((unitp->tempksp = kstat_create(I2C_PCF8591_NAME,
        unitp->instance, I2C_KSTAT_CPUTEMP, "misc",
        KSTAT_TYPE_RAW, sizeof (unitp->temp_kstats),
        KSTAT_FLAG_PERSISTENT | KSTAT_FLAG_WRITABLE)) == NULL) {

        return (DDI_FAILURE);
    }

    /*
     * The kstat fields are already initialized in the attach routine..
     */

    unitp->tempksp->ks_update = pcf8591_temp_kstat_update;
    unitp->tempksp->ks_private = (void *)unitp;

    strcpy(unitp->temp_kstats.label,
        unitp->props.channels_description[0]);
    unitp->temp_kstats.type = ENVC_NETRACT_CPU_SENSOR;

    kstat_install(unitp->tempksp);

    return (DDI_SUCCESS);
}

static void
pcf8591_delete_kstats(struct pcf8591_unit *unitp)
{
    kstat_delete(unitp->tempksp);
}

static int
pcf8591_temp_kstat_update(kstat_t *ksp, int rw)
{
    struct pcf8591_unit *unitp;
    char *kstatp;
    int err = 0;
    int channel = 0;
    int warn_temp = 0;
    int shutdown_temp = 0;

    unitp = (struct pcf8591_unit *)ksp->ks_private;

    mutex_enter(&unitp->umutex);
    while (unitp->pcf8591_flags == PCF8591_BUSY) {
        if (cv_wait_sig(&unitp->pcf8591_cv,
            &unitp->umutex) <= 0) {
            mutex_exit(&unitp->umutex);

            return (EINTR);
        }
    }

    unitp->pcf8591_flags = PCF8591_BUSY;
    mutex_exit(&unitp->umutex);

    kstatp = (char *)ksp->ks_data;

    if (rw == KSTAT_WRITE) {

        /* check for the size of buffer */
        if (ksp->ks_data_size != sizeof (unitp->temp_kstats)) {
            err = EIO;
            goto bail;
        }

        warn_temp = ((envctrl_temp_t *)kstatp)->warning_threshold;
        shutdown_temp = ((envctrl_temp_t *)kstatp)->shutdown_threshold;

        if (shutdown_temp < SHUTDOWN_TEMP_MIN || shutdown_temp >
                            SHUTDOWN_TEMP_MAX) {
            err = EIO;
            goto bail;
        }

        if (warn_temp < 0 || shutdown_temp <= warn_temp) {
            err = EIO;
            goto bail;
        }

        /* write into kstat fields */
        unitp->temp_kstats.warning_threshold = warn_temp;
        unitp->temp_kstats.shutdown_threshold = shutdown_temp;

    } else {

        pcf8591_read_chip(unitp, channel, 1);
        unitp->temp_kstats.value =
            unitp->i2c_tran->i2c_rbuf[0];
        bcopy((caddr_t)&unitp->temp_kstats, kstatp,
            sizeof (unitp->temp_kstats));
    }

bail:

    mutex_enter(&unitp->umutex);
    unitp->pcf8591_flags = 0;
    cv_signal(&unitp->pcf8591_cv);
    mutex_exit(&unitp->umutex);

    return (err);
}

static int
pcf8591_read_chip(struct pcf8591_unit *unitp, uint8_t channel,
int size)
{
    int retval = I2C_SUCCESS;

    /*
     * We need to read an extra byte, since as per specification
     * the first byte read should be discarded.
     */
    i2c_transfer_t *tp = unitp->i2c_tran;
    tp->i2c_flags = I2C_WR_RD;
    tp->i2c_rlen = size+1;
    tp->i2c_wlen = 1;
    tp->i2c_wbuf[0] = (unitp->pcf8591_inprog |
        channel);

    retval = nct_i2c_transfer(unitp->pcf8591_hdl, tp);
    if (retval == I2C_SUCCESS) {
        tp->i2c_rbuf[0] = translate_cputemp(tp->i2c_rbuf[1]);
    }

    if (tp->i2c_rbuf[0] == 0) {
        retval = I2C_FAILURE;
    }

    return (retval);
}

/*
 * Reads the properties of the pcf8591 device.
 */
static int
pcf8591_read_props(struct pcf8591_unit *unitp)
{
    dev_info_t *dip = unitp->dip;
    int i, retval = 0, prop_len;
    int instance = ddi_get_instance(dip);
    int warning_temp, shutdown_temp;
    uint32_t *prop_value = NULL;
    uchar_t *creg_prop;
    char *function;
    uint_t      tblsz;

#ifdef lint
    instance = instance;
#endif
    /*
     * Check for the pcf8591_function property, and make sure it's
     * cputemp.
     */
    if (ddi_prop_lookup_string(DDI_DEV_T_ANY, dip, DDI_PROP_DONTPASS,
        "pcf8591_function", &function) != DDI_SUCCESS) {
        dbg_print(CE_WARN, "Couldn't find pcf8591_function property");

        return (DDI_FAILURE);
    }

    if (strcmp(function, "cputemp") != 0) {
        dbg_print(CE_WARN, "pcf8591_function is not cputemp");
        ddi_prop_free(function);

        return (DDI_FAILURE);
    }

    ddi_prop_free(function);

    retval = ddi_prop_lookup_string(DDI_DEV_T_ANY, dip, DDI_PROP_DONTPASS,
            "name", &unitp->props.name);
    if (retval != DDI_PROP_SUCCESS) {

        return (retval);
    }
#ifdef DEBUG
    else if (pcf8591_debug & 0x02)
        cmn_err(CE_NOTE,
            "pcf8591_read_props:ddi_prop_lookup_string(%s): \
            found  %s ", "name", unitp->props.name);
#endif /* DEBUG */

    retval = ddi_getlongprop(DDI_DEV_T_ANY, dip,
            DDI_PROP_DONTPASS | DDI_PROP_CANSLEEP,
            "reg", (caddr_t)&prop_value, &prop_len);
    if (retval == DDI_PROP_SUCCESS) {
        unitp->props.i2c_bus        = (uint16_t)prop_value[0];
        unitp->props.slave_address  = (uint16_t)prop_value[1];
        kmem_free(prop_value, prop_len);
#ifdef DEBUG
        if (pcf8591_debug & 0x02)
            cmn_err(CE_NOTE,
                "pcf8591:ddi_getlongprop(%s) returns %d,"
                " i2c_bus,slave=0x%x,0x%x",
                    "reg", retval,  unitp->props.i2c_bus,
                    unitp->props.slave_address);
#endif /* DEBUG */
    } else {
        unitp->props.i2c_bus        = (uint16_t)-1;
        unitp->props.slave_address  = (uint16_t)-1;
#ifdef DEBUG
        cmn_err(CE_WARN,
            "pcf8591_read_props:ddi_getlongprop(%s) returns %d,"
            " default it to 0x%x:0x%X",
                "reg", retval,  unitp->props.i2c_bus,
                unitp->props.slave_address);
#endif /* DEBUG */
    }
    ddi_getproplen(DDI_DEV_T_ANY, dip, DDI_PROP_DONTPASS,
                    "channels-in-use", &prop_len);
    retval = ddi_prop_lookup_byte_array(DDI_DEV_T_ANY,
                dip, DDI_PROP_DONTPASS,
                "channels-in-use",
                (uchar_t **)&unitp->props.channels_in_use,
                &unitp->props.num_chans_used);
    if (retval == DDI_PROP_SUCCESS) {
        unitp->props.num_chans_used /= sizeof (pcf8591_channel_t);
    } else {
        unitp->props.num_chans_used = 0;
    }

#ifdef DEBUG
    if (pcf8591_debug & 0x0002)
        cmn_err(CE_NOTE,
            "pcf8591_read_props:ddi_prop_lookup_byte_array(%s)"
            "returns %d\n"
            "\t\tlength=%d, #elements=%d",
            "channels-in-use", retval,
            prop_len, unitp->props.num_chans_used);
#endif /* DEBUG */

    retval = ddi_prop_lookup_string_array(DDI_DEV_T_ANY, dip,
        DDI_PROP_DONTPASS, "channels-description",
        (char ***)&unitp->props.channels_description,
        (uint_t *)&prop_len);

    if (retval != DDI_PROP_SUCCESS) {
        prop_len = 0;
        unitp->props.channels_description = NULL;
    }

#ifdef DEBUG
    if (pcf8591_debug & 0x0002) {
        cmn_err(CE_NOTE,
            "pcf8591_read_props:ddi_prop_lookup_string_array(%s)"
            "returns %d, length=%d",
            "channels-description", retval, prop_len);
        for (i = 0; i < prop_len; ++i) {
            cmn_err(CE_NOTE, "channels-description[%d]=<%s>",
                i, unitp->props.channels_description[i]);
        }
    }
#endif /* DEBUG */

    /*
     * The following code was borrowed from envctrltwo.c
     * I haven't yet investigated why the copy target is index + 2
     */
    retval = ddi_prop_lookup_byte_array(DDI_DEV_T_ANY, dip,
        DDI_PROP_DONTPASS, "tables", &creg_prop, (uint_t *)&prop_len);

    if (retval != DDI_PROP_SUCCESS) {
#ifdef DEBUG
        cmn_err(CE_WARN, "%s%d: Unable to read pcf8591 tables property",
            ddi_get_name(dip), instance);
#endif /* DEBUG */

        return (DDI_NOT_WELL_FORMED);
    }

    tblsz = (sizeof (_cpu_temps) / sizeof (uchar_t));
    if (prop_len <= tblsz) {
        for (i = 0; i < prop_len; i++) {
            _cpu_temps[i] = creg_prop[i];
        }
    }
#ifdef DEBUG
    if (pcf8591_debug & 0x0002)
        cmn_err(CE_NOTE, "pcf8591_read_props: _cpu_temps size=%d; "
            "tables prop_len=%d\n", tblsz, prop_len);
#endif /* DEBUG */

    ddi_prop_free(creg_prop);

    /*
     * Read shutdown temp and warning temp properties.
     */
    warning_temp = (int)ddi_getprop(DDI_DEV_T_ANY, dip,
        DDI_PROP_DONTPASS, "warning-temp", PCF8591_WARNING_TEMP);

    shutdown_temp = (int)ddi_getprop(DDI_DEV_T_ANY, dip,
        DDI_PROP_DONTPASS, "shutdown-temp", PCF8591_SHUTDOWN_TEMP);

    /*
     * Fill up the warning and shutdown temp values in kstat structure.
     */
    unitp->temp_kstats.warning_threshold = warning_temp;
    unitp->temp_kstats.shutdown_threshold = shutdown_temp;

    return (DDI_PROP_SUCCESS);
}