/*-
 * Copyright (c) 1998, 2001 Nicolas Souchu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/dev/iicbus/iicsmb.c,v 1.18 2009/02/10 22:50:23 imp Exp $
 */

/*
 * I2C to SMB bridge
 *
 * Example:
 *
 *     smb bttv
 *       \ /
 *      smbus
 *       /  \
 *    iicsmb bti2c
 *       |
 *     iicbus
 *     /  |  \
 *  iicbb pcf ...
 *    |
 *  lpbb
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/uio.h>

#include <bus/iicbus/iiconf.h>
#include <bus/iicbus/iicbus.h>

#include <bus/smbus/smbconf.h>

#include "iicbus_if.h"
#include "smbus_if.h"

struct iicsmb_softc {

#define SMB_WAITING_ADDR        0x0
#define SMB_WAITING_LOW         0x1
#define SMB_WAITING_HIGH        0x2
#define SMB_DONE                0x3
        int state;

        u_char devaddr;                 /* slave device address */

        char low;                       /* low byte received first */
        char high;                      /* high byte */

        device_t smbus;
};

static int iicsmb_probe(device_t);
static int iicsmb_attach(device_t);
static int iicsmb_detach(device_t);
static void iicsmb_identify(driver_t *driver, device_t parent);

static int iicsmb_intr(device_t dev, int event, char *buf);
static int iicsmb_callback(device_t dev, int index, void *data);
static int iicsmb_quick(device_t dev, u_char slave, int how);
static int iicsmb_sendb(device_t dev, u_char slave, char byte);
static int iicsmb_recvb(device_t dev, u_char slave, char *byte);
static int iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte);
static int iicsmb_writew(device_t dev, u_char slave, char cmd, short word);
static int iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte);
static int iicsmb_readw(device_t dev, u_char slave, char cmd, short *word);
static int iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata);
static int iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf);
static int iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf);

static devclass_t iicsmb_devclass;

static device_method_t iicsmb_methods[] = {
        /* device interface */
        DEVMETHOD(device_identify,      iicsmb_identify),
        DEVMETHOD(device_probe,         iicsmb_probe),
        DEVMETHOD(device_attach,        iicsmb_attach),
        DEVMETHOD(device_detach,        iicsmb_detach),

        /* bus interface */
        DEVMETHOD(bus_driver_added,     bus_generic_driver_added),
        DEVMETHOD(bus_print_child,      bus_generic_print_child),

        /* iicbus interface */
        DEVMETHOD(iicbus_intr,          iicsmb_intr),

        /* smbus interface */
        DEVMETHOD(smbus_callback,       iicsmb_callback),
        DEVMETHOD(smbus_quick,          iicsmb_quick),
        DEVMETHOD(smbus_sendb,          iicsmb_sendb),
        DEVMETHOD(smbus_recvb,          iicsmb_recvb),
        DEVMETHOD(smbus_writeb,         iicsmb_writeb),
        DEVMETHOD(smbus_writew,         iicsmb_writew),
        DEVMETHOD(smbus_readb,          iicsmb_readb),
        DEVMETHOD(smbus_readw,          iicsmb_readw),
        DEVMETHOD(smbus_pcall,          iicsmb_pcall),
        DEVMETHOD(smbus_bwrite,         iicsmb_bwrite),
        DEVMETHOD(smbus_bread,          iicsmb_bread),

        DEVMETHOD_END
};

static driver_t iicsmb_driver = {
        "iicsmb",
        iicsmb_methods,
        sizeof(struct iicsmb_softc),
};

#define IICBUS_TIMEOUT  100     /* us */

static void
iicsmb_identify(driver_t *driver, device_t parent)
{

        if (device_find_child(parent, "iicsmb", -1) == NULL)
                BUS_ADD_CHILD(parent, parent, 0, "iicsmb", -1);
}

static int
iicsmb_probe(device_t dev)
{
        device_set_desc(dev, "SMBus over I2C bridge");
        return (0);
}

static int
iicsmb_attach(device_t dev)
{
        struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);

        sc->smbus = device_add_child(dev, "smbus", -1);

        /* probe and attach the smbus */
        bus_generic_attach(dev);

        return (0);
}

static int
iicsmb_detach(device_t dev)
{
        struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);

        bus_generic_detach(dev);
        if (sc->smbus) {
                device_delete_child(dev, sc->smbus);
        }

        return (0);
}

/*
 * iicsmb_intr()
 *
 * iicbus interrupt handler
 */
static int
iicsmb_intr(device_t dev, int event, char *buf)
{
        struct iicsmb_softc *sc = (struct iicsmb_softc *)device_get_softc(dev);

        switch (event) {
        case INTR_GENERAL:
        case INTR_START:
                sc->state = SMB_WAITING_ADDR;
                break;

        case INTR_STOP:
                /* call smbus intr handler */
                smbus_intr(sc->smbus, sc->devaddr,
                                sc->low, sc->high, SMB_ENOERR);
                break;

        case INTR_RECEIVE:
                switch (sc->state) {
                case SMB_DONE:
                        /* XXX too much data, discard */
                        kprintf("%s: too much data from 0x%x\n", __func__,
                                sc->devaddr & 0xff);
                        goto end;

                case SMB_WAITING_ADDR:
                        sc->devaddr = (u_char)*buf;
                        sc->state = SMB_WAITING_LOW;
                        break;

                case SMB_WAITING_LOW:
                        sc->low = *buf;
                        sc->state = SMB_WAITING_HIGH;
                        break;

                case SMB_WAITING_HIGH:
                        sc->high = *buf;
                        sc->state = SMB_DONE;
                        break;
                }
end:
                break;

        case INTR_TRANSMIT:
        case INTR_NOACK:
                break;

        case INTR_ERROR:
                switch (*buf) {
                case IIC_EBUSERR:
                        smbus_intr(sc->smbus, sc->devaddr, 0, 0, SMB_EBUSERR);
                        break;

                default:
                        kprintf("%s unknown error 0x%x!\n", __func__,
                                                                (int)*buf);
                        break;
                }
                break;

        default:
                panic("%s: unknown event (%d)!", __func__, event);
        }

        return (0);
}

static int
iicsmb_callback(device_t dev, int index, void *data)
{
        device_t parent = device_get_parent(dev);
        int error = 0;
        int how;

        switch (index) {
        case SMB_REQUEST_BUS:
                /* request underlying iicbus */
                how = *(int *)data;
                error = iicbus_request_bus(parent, dev, how);
                break;

        case SMB_RELEASE_BUS:
                /* release underlying iicbus */
                error = iicbus_release_bus(parent, dev);
                break;

        default:
                error = EINVAL;
        }

        return (error);
}

static int
iicsmb_quick(device_t dev, u_char slave, int how)
{
        device_t parent = device_get_parent(dev);
        int error;

        switch (how) {
        case SMB_QWRITE:
                error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT);
                break;

        case SMB_QREAD:
                error = iicbus_start(parent, slave | LSB, IICBUS_TIMEOUT);
                break;

        default:
                error = EINVAL;
                break;
        }

        if (!error)
                error = iicbus_stop(parent);

        return (error);
}

static int
iicsmb_sendb(device_t dev, u_char slave, char byte)
{
        device_t parent = device_get_parent(dev);
        int error, sent;

        error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT);

        if (!error) {
                error = iicbus_write(parent, &byte, 1, &sent, IICBUS_TIMEOUT);

                iicbus_stop(parent);
        }

        return (error);
}

static int
iicsmb_recvb(device_t dev, u_char slave, char *byte)
{
        device_t parent = device_get_parent(dev);
        int error, read;

        error = iicbus_start(parent, slave | LSB, 0);

        if (!error) {
                error = iicbus_read(parent, byte, 1, &read, IIC_LAST_READ, IICBUS_TIMEOUT);

                iicbus_stop(parent);
        }

        return (error);
}

static int
iicsmb_writeb(device_t dev, u_char slave, char cmd, char byte)
{
        device_t parent = device_get_parent(dev);
        int error, sent;

        error = iicbus_start(parent, slave & ~LSB, 0);

        if (!error) {
                if (!(error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                        error = iicbus_write(parent, &byte, 1, &sent, IICBUS_TIMEOUT);

                iicbus_stop(parent);
        }

        return (error);
}

static int
iicsmb_writew(device_t dev, u_char slave, char cmd, short word)
{
        device_t parent = device_get_parent(dev);
        int error, sent;

        char low = (char)(word & 0xff);
        char high = (char)((word & 0xff00) >> 8);

        error = iicbus_start(parent, slave & ~LSB, 0);

        if (!error) {
                if (!(error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                  if (!(error = iicbus_write(parent, &low, 1, &sent, IICBUS_TIMEOUT)))
                    error = iicbus_write(parent, &high, 1, &sent, IICBUS_TIMEOUT);

                iicbus_stop(parent);
        }

        return (error);
}

static int
iicsmb_readb(device_t dev, u_char slave, char cmd, char *byte)
{
        device_t parent = device_get_parent(dev);
        int error, sent, read;

        if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
                return (error);

        if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_read(parent, byte, 1, &read, IIC_LAST_READ, IICBUS_TIMEOUT)))
                goto error;

error:
        iicbus_stop(parent);
        return (error);
}

#define BUF2SHORT(low,high) \
        ((short)(((high) & 0xff) << 8) | (short)((low) & 0xff))

static int
iicsmb_readw(device_t dev, u_char slave, char cmd, short *word)
{
        device_t parent = device_get_parent(dev);
        int error, sent, read;
        char buf[2];

        if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
                return (error);

        if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_read(parent, buf, 2, &read, IIC_LAST_READ, IICBUS_TIMEOUT)))
                goto error;

        /* first, receive low, then high byte */
        *word = BUF2SHORT(buf[0], buf[1]);

error:
        iicbus_stop(parent);
        return (error);
}

static int
iicsmb_pcall(device_t dev, u_char slave, char cmd, short sdata, short *rdata)
{
        device_t parent = device_get_parent(dev);
        int error, sent, read;
        char buf[2];

        if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
                return (error);

        if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                goto error;

        /* first, send low, then high byte */
        buf[0] = (char)(sdata & 0xff);
        buf[1] = (char)((sdata & 0xff00) >> 8);

        if ((error = iicbus_write(parent, buf, 2, &sent, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_read(parent, buf, 2, &read, IIC_LAST_READ, IICBUS_TIMEOUT)))
                goto error;

        /* first, receive low, then high byte */
        *rdata = BUF2SHORT(buf[0], buf[1]);

error:
        iicbus_stop(parent);
        return (error);
}

static int
iicsmb_bwrite(device_t dev, u_char slave, char cmd, u_char count, char *buf)
{
        device_t parent = device_get_parent(dev);
        int error, sent;

        if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_write(parent, buf, (int)count, &sent, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_stop(parent)))
                goto error;

error:
        return (error);
}

static int
iicsmb_bread(device_t dev, u_char slave, char cmd, u_char *count, char *buf)
{
        device_t parent = device_get_parent(dev);
        int error, sent, read;

        if ((error = iicbus_start(parent, slave & ~LSB, IICBUS_TIMEOUT)))
                return (error);

        if ((error = iicbus_write(parent, &cmd, 1, &sent, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_repeated_start(parent, slave | LSB, IICBUS_TIMEOUT)))
                goto error;

        if ((error = iicbus_read(parent, buf, (int)*count, &read,
                                                IIC_LAST_READ, IICBUS_TIMEOUT)))
                goto error;
        *count = read;

error:
        iicbus_stop(parent);
        return (error);
}

DRIVER_MODULE(iicsmb, iicbus, iicsmb_driver, iicsmb_devclass, NULL, NULL);
DRIVER_MODULE(smbus, iicsmb, smbus_driver, smbus_devclass, NULL, NULL);
MODULE_DEPEND(iicsmb, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
MODULE_DEPEND(iicsmb, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
MODULE_VERSION(iicsmb, 1);