/*      $NetBSD: jbus-i2c.c,v 1.9 2025/09/18 02:51:03 thorpej Exp $     */

/*
 * Copyright (c) 2018 Michael Lorenz
 * 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: jbus-i2c.c,v 1.9 2025/09/18 02:51:03 thorpej Exp $");

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

#include <sys/bus.h>
#include <machine/autoconf.h>

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

#include <machine/openfirm.h>

#ifdef JBUSI2C_DEBUG
#define DPRINTF printf
#else
#define DPRINTF if (0) printf
#endif

/* I2C glue */
static int jbusi2c_i2c_send_start(void *, int);
static int jbusi2c_i2c_send_stop(void *, int);
static int jbusi2c_i2c_initiate_xfer(void *, i2c_addr_t, int);
static int jbusi2c_i2c_read_byte(void *, uint8_t *, int);
static int jbusi2c_i2c_write_byte(void *, uint8_t, int);

/* I2C bitbang glue */
static void jbusi2c_i2cbb_set_bits(void *, uint32_t);
static void jbusi2c_i2cbb_set_dir(void *, uint32_t);
static uint32_t jbusi2c_i2cbb_read(void *);

static const struct i2c_bitbang_ops jbusi2c_i2cbb_ops = {
        jbusi2c_i2cbb_set_bits,
        jbusi2c_i2cbb_set_dir,
        jbusi2c_i2cbb_read,
        {
                2,      /* bit 1 is data */
                1,      /* bit 0 is clock */
                3,      /* direction register for both out */
                1       /* data in, clock out */
        }
};

static  int     jbusi2c_match(device_t, cfdata_t, void *);
static  void    jbusi2c_attach(device_t, device_t, void *);

struct jbusi2c_softc {
        device_t sc_dev;
        struct i2c_controller sc_i2c;
        bus_space_tag_t sc_bustag;
        bus_space_handle_t sc_regh;
        int sc_node;
};

static void jbusi2c_setup_i2c(struct jbusi2c_softc *);

CFATTACH_DECL_NEW(jbusi2c, sizeof(struct jbusi2c_softc),
    jbusi2c_match, jbusi2c_attach, NULL, NULL);

/* schizo GPIO registers */
#define DATA    0
#define DIR     8

int
jbusi2c_match(device_t parent, cfdata_t match, void *aux)
{
        struct mainbus_attach_args *ma = aux;
        char *str;

        if (strcmp(ma->ma_name, "i2c") != 0)
                return (0);

        str = prom_getpropstring(ma->ma_node, "compatible");
        if (strcmp(str, "jbus-i2c") == 0)
                return (1);

        return (0);
}

void
jbusi2c_attach(device_t parent, device_t self, void *aux)
{
        struct jbusi2c_softc *sc = device_private(self);
        struct mainbus_attach_args *ma = aux;

        aprint_normal(": addr %" PRIx64 "\n", ma->ma_reg[0].ur_paddr);

        sc->sc_dev = self;
        sc->sc_node = ma->ma_node;
        sc->sc_bustag = ma->ma_bustag;

        if (bus_space_map(sc->sc_bustag, ma->ma_reg[0].ur_paddr, 16, 0,
            &sc->sc_regh)) {
                aprint_error(": failed to map registers\n");
                return;
        }

        jbusi2c_setup_i2c(sc);
}



static void
jbusi2c_setup_i2c(struct jbusi2c_softc *sc)
{
        prop_array_t cfg;
        prop_dictionary_t dev;
        prop_dictionary_t dict = device_properties(sc->sc_dev);
        int devs, regs[2], addr;
        char name[64], compat[256];

        iic_tag_init(&sc->sc_i2c);
        sc->sc_i2c.ic_cookie = sc;
        sc->sc_i2c.ic_send_start = jbusi2c_i2c_send_start;
        sc->sc_i2c.ic_send_stop = jbusi2c_i2c_send_stop;
        sc->sc_i2c.ic_initiate_xfer = jbusi2c_i2c_initiate_xfer;
        sc->sc_i2c.ic_read_byte = jbusi2c_i2c_read_byte;
        sc->sc_i2c.ic_write_byte = jbusi2c_i2c_write_byte;

        /* round up i2c devices */
        devs = OF_child(sc->sc_node);
        cfg = prop_array_create();
        prop_dictionary_set(dict, "i2c-child-devices", cfg);
        prop_object_release(cfg);
        while (devs != 0) {
                devhandle_t child_devhandle;

                if (OF_getprop(devs, "name", name, 256) <= 0)
                        goto skip;
                memset(compat, 0, sizeof(compat));
                if (OF_getprop(devs, "compatible",
                    compat, 255) <= 0)
                        goto skip;
                if (OF_getprop(devs, "reg", regs, 8) <= 0)
                        goto skip;
                if (regs[0] != 0) goto skip;
                addr = (regs[1] & 0xff) >> 1;
                DPRINTF("-> %s@%d,%x\n", name, regs[0], addr);
                dev = prop_dictionary_create();
                prop_dictionary_set_string(dev, "name", name);
                prop_dictionary_set_data(dev, "compatible", compat,
                    strlen(compat)+1);
                prop_dictionary_set_uint32(dev, "addr", addr);
                child_devhandle = devhandle_from_of(devhandle_invalid(), devs);
                prop_dictionary_set_data(dev, "devhandle", &child_devhandle,
                    sizeof(child_devhandle));
                prop_array_add(cfg, dev);
                prop_object_release(dev);
        skip:
                devs = OF_peer(devs);
        }
        iicbus_attach(sc->sc_dev, &sc->sc_i2c);
}

static inline void
jbusi2c_write(struct jbusi2c_softc *sc, int reg, uint64_t bits)
{
        bus_space_write_8(sc->sc_bustag, sc->sc_regh, reg, bits);
}

static inline uint64_t
jbusi2c_read(struct jbusi2c_softc *sc, int reg)
{
        return bus_space_read_8(sc->sc_bustag, sc->sc_regh, reg);
}

/* I2C bitbanging */
static void
jbusi2c_i2cbb_set_bits(void *cookie, uint32_t bits)
{
        struct jbusi2c_softc *sc = cookie;

        jbusi2c_write(sc, DATA, bits);
}

static void
jbusi2c_i2cbb_set_dir(void *cookie, uint32_t dir)
{
        struct jbusi2c_softc *sc = cookie;

        jbusi2c_write(sc, DIR, dir);
}

static uint32_t
jbusi2c_i2cbb_read(void *cookie)
{
        struct jbusi2c_softc *sc = cookie;

        return jbusi2c_read(sc, DATA);
}

/* higher level I2C stuff */
static int
jbusi2c_i2c_send_start(void *cookie, int flags)
{

        return i2c_bitbang_send_start(cookie, flags, &jbusi2c_i2cbb_ops);
}

static int
jbusi2c_i2c_send_stop(void *cookie, int flags)
{

        return i2c_bitbang_send_stop(cookie, flags, &jbusi2c_i2cbb_ops);
}

static int
jbusi2c_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
{

        return i2c_bitbang_initiate_xfer(cookie, addr, flags, 
            &jbusi2c_i2cbb_ops);
}

static int
jbusi2c_i2c_read_byte(void *cookie, uint8_t *valp, int flags)
{

        return i2c_bitbang_read_byte(cookie, valp, flags, &jbusi2c_i2cbb_ops);
}

static int
jbusi2c_i2c_write_byte(void *cookie, uint8_t val, int flags)
{

        return i2c_bitbang_write_byte(cookie, val, flags, &jbusi2c_i2cbb_ops);
}