/*      $NetBSD: tsciic.c,v 1.4 2021/08/07 16:18:41 thorpej Exp $       */

/*
* Copyright (c) 2013 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julian Coleman.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

#include <sys/cdefs.h>

__KERNEL_RCSID(0, "$NetBSD: tsciic.c,v 1.4 2021/08/07 16:18:41 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <alpha/pci/tsreg.h>
#include <alpha/pci/tsvar.h>

#include <dev/i2c/i2cvar.h>
#include <dev/i2c/i2c_bitbang.h>
#include <dev/i2c/ddcvar.h>

/* I2C glue */
static int tsciic_send_start(void *, int);
static int tsciic_send_stop(void *, int);
static int tsciic_initiate_xfer(void *, i2c_addr_t, int);
static int tsciic_read_byte(void *, uint8_t *, int);
static int tsciic_write_byte(void *, uint8_t, int);

/* I2C bitbang glue */
static void tsciicbb_set_bits(void *, uint32_t);
static void tsciicbb_set_dir(void *, uint32_t);
static uint32_t tsciicbb_read(void *);

#define MPD_BIT_SDA 0x01
#define MPD_BIT_SCL 0x02
static const struct i2c_bitbang_ops tsciicbb_ops = {
       tsciicbb_set_bits,
       tsciicbb_set_dir,
       tsciicbb_read,
       {
               MPD_BIT_SDA,
               MPD_BIT_SCL,
               0,
               0
       }
};

void
tsciic_init(device_t self)
{
       struct tsciic_softc *sc = device_private(self);
       struct i2cbus_attach_args iba;

       iic_tag_init(&sc->sc_i2c);
       sc->sc_i2c.ic_cookie = sc;
       sc->sc_i2c.ic_send_start = tsciic_send_start;
       sc->sc_i2c.ic_send_stop = tsciic_send_stop;
       sc->sc_i2c.ic_initiate_xfer = tsciic_initiate_xfer;
       sc->sc_i2c.ic_read_byte = tsciic_read_byte;
       sc->sc_i2c.ic_write_byte = tsciic_write_byte;

       memset(&iba, 0, sizeof(iba));
       iba.iba_tag = &sc->sc_i2c;

       config_found(self, &iba, iicbus_print, CFARGS_NONE);
}

/* I2C bitbanging */
static void
tsciicbb_set_bits(void *cookie, uint32_t bits)
{
       uint64_t val;

       val = (bits & MPD_BIT_SDA ? MPD_DS : 0) |
           (bits & MPD_BIT_SCL ? MPD_CKS : 0);
       alpha_mb();
       STQP(TS_C_MPD) = val;
       alpha_mb();
}

static void
tsciicbb_set_dir(void *cookie, uint32_t dir)
{
       /* Nothing to do */
}

static uint32_t
tsciicbb_read(void *cookie)
{
       uint64_t val;
       uint32_t bits;

       val = LDQP(TS_C_MPD);
       bits = (val & MPD_DR ? MPD_BIT_SDA : 0) |
           (val & MPD_CKR ? MPD_BIT_SCL : 0);
       return bits;
}

/* higher level I2C stuff */
static int
tsciic_send_start(void *cookie, int flags)
{
       return (i2c_bitbang_send_start(cookie, flags, &tsciicbb_ops));
}

static int
tsciic_send_stop(void *cookie, int flags)
{
       return (i2c_bitbang_send_stop(cookie, flags, &tsciicbb_ops));
}

static int
tsciic_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
{
       return (i2c_bitbang_initiate_xfer(cookie, addr, flags,
           &tsciicbb_ops));
}

static int
tsciic_read_byte(void *cookie, uint8_t *valp, int flags)
{
       return (i2c_bitbang_read_byte(cookie, valp, flags, &tsciicbb_ops));
}

static int
tsciic_write_byte(void *cookie, uint8_t val, int flags)
{
       return (i2c_bitbang_write_byte(cookie, val, flags, &tsciicbb_ops));
}