/*      $NetBSD: rtciic.c,v 1.5 2021/08/07 16:19:00 thorpej Exp $       */
/*
* Copyright (c) 2011 KIYOHARA Takashi
* 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 ``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 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: rtciic.c,v 1.5 2021/08/07 16:19:00 thorpej Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/errno.h>

#include <machine/autoconf.h>

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

#include "locators.h"

#ifdef RTCIIC_DEBUG
#define DPRINTF(x) printf x
#else
#define DPRINTF(x)
#endif

#define RTCIIC_SDAR     (1 << 3)        /* received serial data */
#define RTCIIC_SDAW     (1 << 2)        /* sended serial data */
#define RTCIIC_SCL      (1 << 1)        /* serial clock */
#define RTCIIC_RW       (1 << 0)        /* data direction (0:write, 1:read) */

/* This device is Big Endian */
#define RTCIIC_READ(sc) \
       bswap16(bus_space_read_2((sc)->sc_iot, (sc)->sc_ioh, 0))
#define RTCIIC_WRITE(sc, val) \
       bus_space_write_2((sc)->sc_iot, (sc)->sc_ioh, 0, bswap16(val))

struct rtciic_softc {
       device_t sc_dev;

       bus_space_tag_t sc_iot;
       bus_space_handle_t sc_ioh;

       struct i2c_controller sc_i2c;
       struct i2c_bitbang_ops sc_bops;

       int sc_rw;
};

static int rtciic_match(device_t, cfdata_t , void *);
static void rtciic_attach(device_t, device_t, void *);

static int rtciic_send_start(void *, int);
static int rtciic_send_stop(void *, int);
static int rtciic_initiate_xfer(void *, i2c_addr_t, int);
static int rtciic_read_byte(void *, uint8_t *, int);
static int rtciic_write_byte(void *, uint8_t, int);

static void rtciic_set_dir(void *, uint32_t);
static void rtciic_set_bits(void *, uint32_t);
static uint32_t rtciic_read_bits(void *);

CFATTACH_DECL_NEW(rtciic, sizeof(struct rtciic_softc),
   rtciic_match, rtciic_attach, NULL, NULL);

static int
rtciic_match(device_t parent, cfdata_t match, void *aux)
{
       struct mainbus_attach_args *ma = aux;

       if (strcmp(ma->ma_name, match->cf_name) != 0)
               return 0;

       /* Disallow wildcarded values. */
       if (ma->ma_addr1 == MAINBUSCF_ADDR1_DEFAULT)
               return 0;

       /* no irq */
       if (ma->ma_irq1 != MAINBUSCF_IRQ1_DEFAULT)
               return 0;

       return 1;
}

void
rtciic_attach(device_t parent, device_t self, void *aux)
{
       struct rtciic_softc *sc = device_private(self);
       struct mainbus_attach_args *ma = aux;
       struct i2cbus_attach_args iba;

       sc->sc_dev = self;

       aprint_normal("\n");
       aprint_naive("\n");

       /* Map I/O space(16bit). */
       sc->sc_iot = 0;
       if (bus_space_map(sc->sc_iot, ma->ma_addr1, 2, 0, &sc->sc_ioh)) {
               aprint_error_dev(self, "can't map registers\n");
               return;
       }
       sc->sc_rw = RTCIIC_READ(sc) & RTCIIC_RW;

       /* register with iic */
       iic_tag_init(&sc->sc_i2c);
       sc->sc_i2c.ic_cookie = sc;
       sc->sc_i2c.ic_send_start = rtciic_send_start;
       sc->sc_i2c.ic_send_stop = rtciic_send_stop;
       sc->sc_i2c.ic_initiate_xfer = rtciic_initiate_xfer;
       sc->sc_i2c.ic_read_byte = rtciic_read_byte;
       sc->sc_i2c.ic_write_byte = rtciic_write_byte;

       sc->sc_bops.ibo_set_dir = rtciic_set_dir;
       sc->sc_bops.ibo_set_bits = rtciic_set_bits;
       sc->sc_bops.ibo_read_bits = rtciic_read_bits;
       sc->sc_bops.ibo_bits[I2C_BIT_SDA] = RTCIIC_SDAW;
       sc->sc_bops.ibo_bits[I2C_BIT_SCL] = RTCIIC_SCL;
       sc->sc_bops.ibo_bits[I2C_BIT_OUTPUT] = 0;
       sc->sc_bops.ibo_bits[I2C_BIT_INPUT] = RTCIIC_RW;

       memset(&iba, 0, sizeof(iba));
       iba.iba_tag = &sc->sc_i2c;
       config_found(sc->sc_dev, &iba, iicbus_print, CFARGS_NONE);
}

static int
rtciic_send_start(void *arg, int flags)
{
       struct rtciic_softc *sc = arg;

       return i2c_bitbang_send_start(sc, flags, &sc->sc_bops);
}

static int
rtciic_send_stop(void *arg, int flags)
{
       struct rtciic_softc *sc = arg;

       return i2c_bitbang_send_stop(sc, flags, &sc->sc_bops);
}

static int
rtciic_initiate_xfer(void *arg, i2c_addr_t addr, int flags)
{
       struct rtciic_softc *sc = arg;

       return i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_bops);
}

static int
rtciic_read_byte(void *arg, uint8_t *vp, int flags)
{
       struct rtciic_softc *sc = arg;

       return i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_bops);
}

static int
rtciic_write_byte(void *arg, uint8_t v, int flags)
{
       struct rtciic_softc *sc = arg;

       return i2c_bitbang_write_byte(sc, v, flags, &sc->sc_bops);
}


static void
rtciic_set_dir(void *arg, uint32_t bits)
{
       struct rtciic_softc *sc = arg;
       uint16_t reg;

       DPRINTF(("%s: set dir %s\n",
           device_xname(sc->sc_dev), (bits & RTCIIC_RW) ? "READ" : "WRITE"));

       if (sc->sc_rw != (bits & RTCIIC_RW)) {
               reg = RTCIIC_READ(sc);
               reg &= ~RTCIIC_RW;
               reg |= bits;
               RTCIIC_WRITE(sc, reg);
               delay(30);
               sc->sc_rw = bits & RTCIIC_RW;
       }
}

static void
rtciic_set_bits(void *arg, uint32_t bits)
{
       struct rtciic_softc *sc = arg;

       DPRINTF(("%s: %s\n",
           device_xname(sc->sc_dev),
           (bits == (RTCIIC_SDAW | RTCIIC_SCL)) ? "set SDA/SCL" :
           ((bits == RTCIIC_SDAW) ? "set SDA" :
           ((bits == RTCIIC_SCL) ? "set SCL" : "reset"))));

       if (sc->sc_rw & RTCIIC_RW) {
               bits &= RTCIIC_SCL;
               bits |= RTCIIC_RW;
       }
       RTCIIC_WRITE(sc, bits);
       delay(40);
}

static uint32_t
rtciic_read_bits(void *arg)
{
       struct rtciic_softc *sc = arg;
       uint8_t rv, v;

       v = RTCIIC_READ(sc);
       rv = v & RTCIIC_SCL;
       if (v & RTCIIC_SDAR)
               rv |= RTCIIC_SDAW;

       DPRINTF(("%s: read %s\n",
           device_xname(sc->sc_dev),
           (rv == (RTCIIC_SDAW | RTCIIC_SCL)) ? "SDA/SCL" :
           ((rv == RTCIIC_SDAW) ? "SDA" :
           ((rv == RTCIIC_SCL) ? "SCL" : "no"))));

       return (uint32_t)rv;
}

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