/*      $NetBSD: apple_iic.c,v 1.3 2025/09/16 11:55:16 thorpej Exp $    */
/*      $OpenBSD: apliic.c,v 1.3 2022/02/14 14:55:53 kettenis Exp $     */

/*-
 * Copyright (c) 2022 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Nick Hudson
 *
 * 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.
 */

/*
 * Copyright (c) 2021 Patrick Wildt <patrick@blueri.se>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>

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

#include <dev/i2c/i2cvar.h>

#include <dev/fdt/fdtvar.h>

/* Registers. */
#define I2C_MTXFIFO             0x00
#define  I2C_MTXFIFO_DATA_MASK          __BITS(7,0)
#define  I2C_MTXFIFO_START              __BIT(8)
#define  I2C_MTXFIFO_STOP               __BIT(9)
#define  I2C_MTXFIFO_READ               __BIT(10)
#define I2C_MRXFIFO             0x04
#define  I2C_MRXFIFO_DATA_MASK          __BITS(7,0)
#define  I2C_MRXFIFO_EMPTY              __BIT(8)
#define I2C_SMSTA               0x14
#define  I2C_SMSTA_MTN                  __BIT(21)
#define  I2C_SMSTA_XEN                  __BIT(27)
#define  I2C_SMSTA_XBUSY                __BIT(28)
#define I2C_CTL                 0x1c
#define  I2C_CTL_CLK_MASK               __BITS(7,0)
#define  I2C_CTL_MTR                    __BIT(9)
#define  I2C_CTL_MRR                    __BIT(10)
#define  I2C_CTL_EN                     __BIT(11)
#define I2C_REV                 0x28

#define IIC_READ(sc, reg)                                               \
        (bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg)))
#define IIC_WRITE(sc, reg, val)                                         \
        bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))
#define HSET4(sc, reg, bits)                                            \
        IIC_WRITE((sc), (reg), IIC_READ((sc), (reg)) | (bits))
#define HCLR4(sc, reg, bits)                                            \
        IIC_WRITE((sc), (reg), IIC_READ((sc), (reg)) & ~(bits))

struct apple_iic_softc {
        device_t                sc_dev;
        bus_space_tag_t         sc_bst;
        bus_space_handle_t      sc_bsh;

        struct clk *            sc_clk;
        int                     sc_hwrev;
        uint32_t                sc_clkdiv;
        struct i2c_controller   sc_i2c;
};


static int
apple_iic_acquire_bus(void *cookie, int flags)
{
        return 0;
}

static void
apple_iic_release_bus(void *cookie, int flags)
{
}

static int
apple_iic_exec(void *cookie, i2c_op_t op, i2c_addr_t addr, const void *cmd,
    size_t cmdlen, void *buf, size_t buflen, int flags)
{
        struct apple_iic_softc *sc = cookie;
        const uint8_t * const cmdbytes = cmd;
        uint8_t * const bufbytes = buf;
        uint32_t reg;
        int i;

        if (!I2C_OP_STOP_P(op))
                return EINVAL;

        IIC_WRITE(sc, I2C_SMSTA, 0xffffffff);

        if (cmdlen > 0) {
                IIC_WRITE(sc, I2C_MTXFIFO, I2C_MTXFIFO_START | addr << 1);
                for (i = 0; i < cmdlen - 1; i++)
                        IIC_WRITE(sc, I2C_MTXFIFO, cmdbytes[i]);
                IIC_WRITE(sc, I2C_MTXFIFO, cmdbytes[cmdlen - 1] |
                    (buflen == 0 ? I2C_MTXFIFO_STOP : 0));
        }

        if (buflen == 0)
                return 0;

        if (I2C_OP_READ_P(op)) {
                IIC_WRITE(sc, I2C_MTXFIFO, I2C_MTXFIFO_START | addr << 1 | 1);
                IIC_WRITE(sc, I2C_MTXFIFO, I2C_MTXFIFO_READ | buflen |
                    I2C_MTXFIFO_STOP);
                for (i = 10; i > 0; i--) {
                        delay(1000);
                        reg = IIC_READ(sc, I2C_SMSTA);
                        if (reg & I2C_SMSTA_XEN)
                                break;
                }
                if (reg & I2C_SMSTA_MTN)
                        return ENXIO;
                if (i == 0)
                        return ETIMEDOUT;
                IIC_WRITE(sc, I2C_SMSTA, I2C_SMSTA_XEN);
                for (i = 0; i < buflen; i++) {
                        reg = IIC_READ(sc, I2C_MRXFIFO);
                        if (reg & I2C_MRXFIFO_EMPTY)
                                return EIO;
                        bufbytes[i] = reg & I2C_MRXFIFO_DATA_MASK;
                }
        } else {
                if (cmdlen == 0)
                        IIC_WRITE(sc, I2C_MTXFIFO, I2C_MTXFIFO_START | addr << 1);
                for (i = 0; i < buflen - 1; i++)
                        IIC_WRITE(sc, I2C_MTXFIFO, bufbytes[i]);
                IIC_WRITE(sc, I2C_MTXFIFO, bufbytes[buflen - 1] |
                    I2C_MTXFIFO_STOP);
        }

        return 0;
}


static const struct device_compatible_entry compat_data[] = {
        { .compat = "apple,i2c" },
        DEVICE_COMPAT_EOL
};

static int
apple_iic_match(device_t parent, cfdata_t cf, void *aux)
{
        struct fdt_attach_args * const faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
apple_iic_attach(device_t parent, device_t self, void *aux)
{
        struct apple_iic_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;
        uint32_t clock_speed, bus_speed;
        bus_addr_t addr;
        bus_size_t size;

        sc->sc_dev = self;
        sc->sc_bst = faa->faa_bst;

        int error = fdtbus_get_reg(phandle, 0, &addr, &size);
        if (error) {
                aprint_error(": unable to get device registers\n");
                return;
        }

        /* Enable clock */
        sc->sc_clk = fdtbus_clock_get_index(phandle, 0);
        if (sc->sc_clk == NULL) {
                aprint_error(": couldn't acquire clock\n");
                return;
        }

        if (clk_enable(sc->sc_clk) != 0) {
                aprint_error(": failed to enable clock\n");
                return;
        }

        clock_speed = clk_get_rate(sc->sc_clk);

        if (of_getprop_uint32(phandle, "clock-frequency",
            &bus_speed) != 0) {
                bus_speed = 100000;
        }
        bus_speed *= 16;

        if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh)) {
                aprint_error(": unable to map device\n");
                return;
        }

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

        sc->sc_clkdiv = howmany(clock_speed, bus_speed);
        KASSERT(sc->sc_clkdiv <= __SHIFTOUT_MASK(I2C_CTL_CLK_MASK));

        sc->sc_hwrev = IIC_READ(sc, I2C_REV);

        IIC_WRITE(sc, I2C_CTL,
            __SHIFTIN(sc->sc_clkdiv, I2C_CTL_CLK_MASK) |
            I2C_CTL_MTR | I2C_CTL_MRR |
            (sc->sc_hwrev >= 6 ? I2C_CTL_EN : 0));

        iic_tag_init(&sc->sc_i2c);
        sc->sc_i2c.ic_cookie = sc;
        sc->sc_i2c.ic_acquire_bus = apple_iic_acquire_bus;
        sc->sc_i2c.ic_release_bus = apple_iic_release_bus;
        sc->sc_i2c.ic_exec = apple_iic_exec;

        iicbus_attach(self, &sc->sc_i2c);
}


CFATTACH_DECL_NEW(apple_iic, sizeof(struct apple_iic_softc),
    apple_iic_match, apple_iic_attach, NULL, NULL);