/*      $NetBSD: nslu2_iic.c,v 1.12 2021/08/07 16:18:50 thorpej Exp $   */

/*-
* Copyright (c) 2006 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Steve C. Woodford.
*
* 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/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/mutex.h>
#include <sys/bus.h>

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

#include <arm/xscale/ixp425reg.h>
#include <arm/xscale/ixp425var.h>

#include <evbarm/nslu2/nslu2reg.h>

struct slugiic_softc {
       struct i2c_controller sc_ic;
       struct i2c_bitbang_ops sc_ibo;
       uint32_t sc_dirout;
};

static int
slugiic_send_start(void *arg, int flags)
{
       struct slugiic_softc *sc = arg;

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

static int
slugiic_send_stop(void *arg, int flags)
{
       struct slugiic_softc *sc = arg;

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

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

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

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

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

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

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

static void
slugiic_set_dir(void *arg, uint32_t bits)
{
       struct slugiic_softc *sc = arg;
       uint32_t reg;
       int s;

       if (sc->sc_dirout == bits)
               return;

       s = splhigh();

       sc->sc_dirout = bits;

       if (sc->sc_dirout) {
               /* SDA is output; enable SDA output if SDA OUTR is low */
               reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
               if ((reg & GPIO_I2C_SDA_BIT) == 0) {
                       reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
                       reg &= ~GPIO_I2C_SDA_BIT;
                       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
               }
       } else {
               /* SDA is input; disable SDA output */
               reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
               reg |= GPIO_I2C_SDA_BIT;
               GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
       }

       splx(s);
}

static void
slugiic_set_bits(void *arg, uint32_t bits)
{
       struct slugiic_softc *sc = arg;
       uint32_t oer, outr;
       int s;

       s = splhigh();

       /*
        * Enable SCL output if the SCL line is to be driven low.
        * Enable SDA output if the SDA line is to be driven low and
        * SDA direction is output.
        * Otherwise switch them to input even if directions are output
        * so that we can emulate open collector output with the pullup
        * resistors.
        * If lines are to be set to high, disable OER first then set OUTR.
        * If lines are to be set to low, set OUTR first then enable OER.
        */
       oer = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
       if ((bits & GPIO_I2C_SCL_BIT) != 0)
               oer |= GPIO_I2C_SCL_BIT;
       if ((bits & GPIO_I2C_SDA_BIT) != 0)
               oer |= GPIO_I2C_SDA_BIT;
       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer);

       outr = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
       outr &= ~(GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT);
       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, outr | bits);

       if ((bits & GPIO_I2C_SCL_BIT) == 0)
               oer &= ~GPIO_I2C_SCL_BIT;
       if ((bits & GPIO_I2C_SDA_BIT) == 0 && sc->sc_dirout)
               oer &= ~GPIO_I2C_SDA_BIT;
       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer);

       splx(s);
}

static uint32_t
slugiic_read_bits(void *arg)
{
       uint32_t reg;

       reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPINR);
       return (reg & (GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT));
}

static void
slugiic_deferred_attach(device_t self)
{
       struct slugiic_softc *sc = device_private(self);
       struct i2cbus_attach_args iba;
       uint32_t reg;

       reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
       reg |= GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT;
       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, reg);

       reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
       reg &= ~GPIO_I2C_SCL_BIT;
       reg |= GPIO_I2C_SDA_BIT;
       GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);

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

static int
slugiic_match(device_t parent, cfdata_t cf, void *aux)
{

       return (1);
}

static void
slugiic_attach(device_t parent, device_t self, void *aux)
{
       struct slugiic_softc *sc = device_private(self);

       aprint_naive("\n");
       aprint_normal(": I2C bus\n");

       iic_tag_init(&sc->sc_ic);
       sc->sc_ic.ic_cookie = sc;
       sc->sc_ic.ic_send_start = slugiic_send_start;
       sc->sc_ic.ic_send_stop = slugiic_send_stop;
       sc->sc_ic.ic_initiate_xfer = slugiic_initiate_xfer;
       sc->sc_ic.ic_read_byte = slugiic_read_byte;
       sc->sc_ic.ic_write_byte = slugiic_write_byte;

       sc->sc_ibo.ibo_set_dir = slugiic_set_dir;
       sc->sc_ibo.ibo_set_bits = slugiic_set_bits;
       sc->sc_ibo.ibo_read_bits = slugiic_read_bits;
       sc->sc_ibo.ibo_bits[I2C_BIT_SDA] = GPIO_I2C_SDA_BIT;
       sc->sc_ibo.ibo_bits[I2C_BIT_SCL] = GPIO_I2C_SCL_BIT;
       sc->sc_ibo.ibo_bits[I2C_BIT_OUTPUT] = 1;
       sc->sc_ibo.ibo_bits[I2C_BIT_INPUT] = 0;

       sc->sc_dirout = 0;

       /*
        * Defer until ixp425_softc has been initialised
        */
       config_interrupts(self, slugiic_deferred_attach);
}

CFATTACH_DECL_NEW(slugiic, sizeof(struct slugiic_softc),
   slugiic_match, slugiic_attach, NULL, NULL);

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