/*      $OpenBSD: rkiic.c,v 1.8 2026/01/05 20:06:15 patrick Exp $       */
/*
 * Copyright (c) 2017 Mark Kettenis <kettenis@openbsd.org>
 *
 * 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/systm.h>
#include <sys/device.h>

#include <machine/intr.h>
#include <machine/bus.h>
#include <machine/fdt.h>

#define _I2C_PRIVATE
#include <dev/i2c/i2cvar.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_clock.h>
#include <dev/ofw/ofw_misc.h>
#include <dev/ofw/ofw_pinctrl.h>
#include <dev/ofw/fdt.h>

/* Registers. */
#define RKI2C_CON               0x0000
#define  RKI2C_CON_ACT2NAK              (1 << 6)
#define  RKI2C_CON_ACK                  (0 << 5)
#define  RKI2C_CON_NAK                  (1 << 5)
#define  RKI2C_CON_STOP                 (1 << 4)
#define  RKI2C_CON_START                (1 << 3)
#define  RKI2C_CON_I2C_MODE_MASK        (3 << 1)
#define  RKI2C_CON_I2C_MODE_TX          (0 << 1)
#define  RKI2C_CON_I2C_MODE_RRX         (1 << 1)
#define  RKI2C_CON_I2C_MODE_RX          (2 << 1)
#define  RKI2C_CON_I2C_MODE_BROKEN      (3 << 1)
#define  RKI2C_CON_I2C_EN               (1 << 0)
#define RKI2C_CLKDIV            0x0004
#define RKI2C_MRXADDR           0x0008
#define  RKI2C_MRXADDR_ADDLVLD          (1 << 24)
#define RKI2C_MRXRADDR          0x000c
#define  RKI2C_MRXRADDR_SRADDLVLD       (1 << 24)
#define RKI2C_MTXCNT            0x0010
#define RKI2C_MRXCNT            0x0014
#define RKI2C_IEN               0x0018
#define  RKI2C_IEN_START                (1 << 4)
#define RKI2C_IPD               0x001c
#define  RKI2C_IPD_STOP                 (1 << 5)
#define  RKI2C_IPD_START                (1 << 4)
#define  RKI2C_IPD_MBRF                 (1 << 3)
#define  RKI2C_IPD_MBTF                 (1 << 2)
#define  RKI2C_IPD_ALL                  0xff
#define RKI2C_FCNT              0x0020
#define RKI2C_SCL_OE_DB         0x0024
#define RKI2C_TXDATA0           0x0100
#define RKI2C_RXDATA0           0x0200
#define RKI2C_ST                0x0220

#define HREAD4(sc, reg)                                                 \
        (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
#define HWRITE4(sc, reg, val)                                           \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
#define HSET4(sc, reg, bits)                                            \
        HWRITE4((sc), (reg), HREAD4((sc), (reg)) | (bits))
#define HCLR4(sc, reg, bits)                                            \
        HWRITE4((sc), (reg), HREAD4((sc), (reg)) & ~(bits))

struct rkiic_softc {
        struct device           sc_dev;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;

        int                     sc_node;
        struct i2c_controller   sc_ic;
        struct i2c_bus          sc_ib;
};

int rkiic_match(struct device *, void *, void *);
void rkiic_attach(struct device *, struct device *, void *);

const struct cfattach   rkiic_ca = {
        sizeof (struct rkiic_softc), rkiic_match, rkiic_attach
};

struct cfdriver rkiic_cd = {
        NULL, "rkiic", DV_DULL
};

int     rkiic_acquire_bus(void *, int);
void    rkiic_release_bus(void *, int);
int     rkiic_send_start(void *, int);
int     rkiic_send_stop(void *, int);
int     rkiic_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
            void *, size_t, int);

void    rkiic_bus_scan(struct device *, struct i2cbus_attach_args *, void *);

int
rkiic_match(struct device *parent, void *match, void *aux)
{
        struct fdt_attach_args *faa = aux;

        return (OF_is_compatible(faa->fa_node, "rockchip,rk3288-i2c") ||
            OF_is_compatible(faa->fa_node, "rockchip,rk3328-i2c") ||
            OF_is_compatible(faa->fa_node, "rockchip,rk3399-i2c"));
}

void
rkiic_attach(struct device *parent, struct device *self, void *aux)
{
        struct rkiic_softc *sc = (struct rkiic_softc *)self;
        struct fdt_attach_args *faa = aux;
        struct i2cbus_attach_args iba;
        uint32_t clock_speed, bus_speed;
        uint32_t div, divl, divh;
        uint32_t clkdivl, clkdivh;

        if (faa->fa_nreg < 1) {
                printf(": no registers\n");
                return;
        }

        sc->sc_iot = faa->fa_iot;
        sc->sc_node = faa->fa_node;

        if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
            faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
                printf(": can't map registers\n");
                return;
        }

        printf("\n");

        pinctrl_byname(sc->sc_node, "default");

        clock_set_assigned(sc->sc_node);
        clock_enable(sc->sc_node, "i2c");
        clock_enable(sc->sc_node, "pclk");

        clock_speed = clock_get_frequency(sc->sc_node, "i2c");
        bus_speed = OF_getpropint(sc->sc_node, "clock-frequency", 100000);

        div = 2;
        while (clock_speed > div * bus_speed * 8)
                div++;
        divl = div / 2;
        divh = div - divl;
        clkdivl = (divl - 1) & 0xffff;
        clkdivh = (divh - 1) & 0xffff;
        HWRITE4(sc, RKI2C_CLKDIV, clkdivh << 16 | clkdivl);

        sc->sc_ic.ic_cookie = sc;
        sc->sc_ic.ic_acquire_bus = rkiic_acquire_bus;
        sc->sc_ic.ic_release_bus = rkiic_release_bus;
        sc->sc_ic.ic_exec = rkiic_exec;

        /* Configure its children */
        memset(&iba, 0, sizeof(iba));
        iba.iba_name = "iic";
        iba.iba_tag = &sc->sc_ic;
        iba.iba_bus_scan = rkiic_bus_scan;
        iba.iba_bus_scan_arg = &sc->sc_node;

        config_found(&sc->sc_dev, &iba, iicbus_print);

        sc->sc_ib.ib_node = sc->sc_node;
        sc->sc_ib.ib_ic = &sc->sc_ic;
        i2c_register(&sc->sc_ib);
}

int
rkiic_acquire_bus(void *cookie, int flags)
{
        struct rkiic_softc *sc = cookie;

        HSET4(sc, RKI2C_CON, RKI2C_CON_I2C_EN);
        return 0;
}

void
rkiic_release_bus(void *cookie, int flags)
{
        struct rkiic_softc *sc = cookie;
        
        HCLR4(sc, RKI2C_CON, RKI2C_CON_I2C_EN);
}

int
rkiic_send_start(void *cookie, int flags)
{
        struct rkiic_softc *sc = cookie;
        int timo;

        HSET4(sc, RKI2C_IPD, RKI2C_IPD_START);
        HSET4(sc, RKI2C_CON, RKI2C_CON_START);
        for (timo = 1000; timo > 0; timo--) {
                if (HREAD4(sc, RKI2C_IPD) & RKI2C_IPD_START)
                        break;
                delay(10);
        }
        HCLR4(sc, RKI2C_CON, RKI2C_CON_START);
        if (timo == 0)
                return ETIMEDOUT;
        return 0;
}

int
rkiic_send_stop(void *cookie, int flags)
{
        struct rkiic_softc *sc = cookie;
        int timo;

        HSET4(sc, RKI2C_IPD, RKI2C_IPD_STOP);
        HSET4(sc, RKI2C_CON, RKI2C_CON_STOP);
        for (timo = 1000; timo > 0; timo--) {
                if (HREAD4(sc, RKI2C_IPD) & RKI2C_IPD_STOP)
                        break;
                delay(10);
        }
        HCLR4(sc, RKI2C_CON, RKI2C_CON_STOP);
        if (timo == 0)
                return ETIMEDOUT;
        return 0;
}

int
rkiic_write(struct rkiic_softc *sc, i2c_addr_t addr, const void *cmd,
    size_t cmdlen, void *buf, size_t buflen)
{
        uint8_t txbuf[32];
        int len = 0;
        int timo, i;

        /* 
         * Lump slave address, command and data into one single buffer
         * and transfer it in a single operation.
         */
        txbuf[len++] = addr << 1;
        for (i = 0; i < cmdlen; i++)
                txbuf[len++] = ((uint8_t *)cmd)[i];
        for (i = 0; i < buflen; i++)
                txbuf[len++] = ((uint8_t *)buf)[i];

        for (i = 0; i < len; i += 4) {
                HWRITE4(sc, RKI2C_TXDATA0 + i,
                        *((uint32_t *)&txbuf[i]));
        }

        /* Start operation. */
        HWRITE4(sc, RKI2C_MTXCNT, len);

        /* Wait for completion. */
        for (timo = 1000; timo > 0; timo--) {
                if (HREAD4(sc, RKI2C_IPD) & RKI2C_IPD_MBTF)
                        break;
                delay(10);
        }
        if (timo == 0)
                return ETIMEDOUT;

        return 0;
}

int
rkiic_read(struct rkiic_softc *sc, i2c_addr_t addr, const void *cmd,
    size_t cmdlen, void *buf, size_t buflen)
{
        uint32_t mrxraddr, rxdata;
        size_t pos = 0;
        uint32_t con;
        int timo, i;

        HWRITE4(sc, RKI2C_MRXADDR, (addr << 1) | RKI2C_MRXADDR_ADDLVLD);

        /* Send the command as "register address". */
        mrxraddr = 0;
        for (i = 0; i < cmdlen; i++) {
                mrxraddr |= ((uint8_t *)cmd)[i] << (i * 8);
                mrxraddr |= RKI2C_MRXRADDR_SRADDLVLD << i;
        }
        HWRITE4(sc, RKI2C_MRXRADDR, mrxraddr);

        while (1) {
                /* Indicate that we're done after this operation. */
                if (buflen <= 32)
                        HSET4(sc, RKI2C_CON, RKI2C_CON_NAK);

                /* Start operation. */
                HWRITE4(sc, RKI2C_MRXCNT, MIN(buflen, 32));

                /* Wait for completion. */
                for (timo = 1000; timo > 0; timo--) {
                        if (HREAD4(sc, RKI2C_IPD) & RKI2C_IPD_MBRF)
                                break;
                        delay(10);
                }
                if (timo == 0)
                        return ETIMEDOUT;

                /* Ack interrupt. */
                HWRITE4(sc, RKI2C_IPD, RKI2C_IPD_MBRF);

                for (i = 0; i < MIN(buflen, 32); i++) {
                        if (i % 4 == 0)
                                rxdata = HREAD4(sc, RKI2C_RXDATA0 + i);
                        ((uint8_t *)buf)[pos++] = rxdata;
                        rxdata >>= 8;
                }

                if (buflen <= 32)
                        return 0;

                /* Switch transfer mode after the first block. */
                if (pos <= 32) {
                        con = HREAD4(sc, RKI2C_CON);
                        con &= ~RKI2C_CON_I2C_MODE_MASK;
                        con |= RKI2C_CON_I2C_MODE_RX;
                        HWRITE4(sc, RKI2C_CON, con);
                }
                buflen -= 32;
        }
}

int
rkiic_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 rkiic_softc *sc = cookie;
        uint32_t con;
        int error;

        if (cmdlen > 3 || (I2C_OP_WRITE_P(op) && buflen > 28))
                return EINVAL;

        /* Clear interrupts.  */
        HWRITE4(sc, RKI2C_IPD, RKI2C_IPD_ALL);

        /* Configure transfer mode. */
        con = HREAD4(sc, RKI2C_CON);
        con &= ~RKI2C_CON_I2C_MODE_MASK;
        if (I2C_OP_WRITE_P(op))
                con |= RKI2C_CON_I2C_MODE_TX;
        else
                con |= RKI2C_CON_I2C_MODE_RRX;
        con &= ~RKI2C_CON_NAK;
        con |= RKI2C_CON_ACT2NAK;
        HWRITE4(sc, RKI2C_CON, con);

        error = rkiic_send_start(sc, flags);
        if (error)
                return error;

        if (I2C_OP_WRITE_P(op))
                error = rkiic_write(sc, addr, cmd, cmdlen, buf, buflen);
        else
                error = rkiic_read(sc, addr, cmd, cmdlen, buf, buflen);

        if (I2C_OP_STOP_P(op))
                rkiic_send_stop(sc, flags);

        return error;
}

void
rkiic_bus_scan(struct device *self, struct i2cbus_attach_args *iba, void *arg)
{
        int iba_node = *(int *)arg;
        struct i2c_attach_args ia;
        char name[32];
        uint32_t reg[1];
        int node;

        for (node = OF_child(iba_node); node; node = OF_peer(node)) {
                memset(name, 0, sizeof(name));
                memset(reg, 0, sizeof(reg));

                if (!OF_is_enabled(node))
                        continue;

                if (OF_getprop(node, "compatible", name, sizeof(name)) == -1)
                        continue;
                if (name[0] == '\0')
                        continue;

                if (OF_getprop(node, "reg", &reg, sizeof(reg)) != sizeof(reg))
                        continue;

                memset(&ia, 0, sizeof(ia));
                ia.ia_tag = iba->iba_tag;
                ia.ia_addr = bemtoh32(&reg[0]);
                ia.ia_name = name;
                ia.ia_cookie = &node;
                config_found(self, &ia, iic_print);
        }
}