/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
 * Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
 *
 * 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 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 AUTHOR 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/bus.h>
#include <sys/rman.h>
#include <sys/kernel.h>
#include <sys/reboot.h>
#include <sys/module.h>

#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include <dev/regulator/regulator.h>

#include "iicbus_if.h"
#include "regdev_if.h"

#define VSEL0   0x00
#define VSEL1   0x01

#define VSEL_BUCK_EN    (1 << 7)
#define VSEL_NSEL_MASK  0x3F
#define VSEL_VOLTAGE_BASE       712500 /* uV */
#define VSEL_VOLTAGE_STEP       12500  /* uV */

#define ID1     0x03
#define  ID1_VENDOR_MASK        0xE0
#define  ID1_VENDOR_SHIFT       5
#define  ID1_DIE_MASK           0xF

#define ID2     0x4
#define  ID2_DIE_REV_MASK       0xF

static struct ofw_compat_data compat_data[] = {
        { "silergy,syr827",                     1 },
        { NULL,                                 0 }
};

struct syr827_reg_sc {
        struct regnode          *regnode;
        device_t                base_dev;
        phandle_t               xref;
        struct regnode_std_param *param;

        int                     volt_reg;
        int                     suspend_reg;
};

struct syr827_softc {
        uint16_t                addr;
        struct intr_config_hook intr_hook;

        /* Regulator */
        struct syr827_reg_sc    *reg;
};

static int
syr827_read(device_t dev, uint8_t reg, uint8_t *data, uint8_t size)
{
        return (iicdev_readfrom(dev, reg, data, size, IIC_INTRWAIT));
}

static int
syr827_write(device_t dev, uint8_t reg, uint8_t val)
{
        return (iicdev_writeto(dev, reg, &val, 1, IIC_INTRWAIT));
}

static int
syr827_regnode_init(struct regnode *regnode)
{
        return (0);
}

static int
syr827_regnode_enable(struct regnode *regnode, bool enable, int *udelay)
{
        struct syr827_reg_sc *sc;
        uint8_t val;

        sc = regnode_get_softc(regnode);

        syr827_read(sc->base_dev, sc->volt_reg, &val, 1);
        if (enable)
                val &= ~VSEL_BUCK_EN;
        else
                val |= VSEL_BUCK_EN;
        syr827_write(sc->base_dev, sc->volt_reg, val);

        *udelay = sc->param->ramp_delay;

        return (0);
}

static int
syr827_regnode_set_voltage(struct regnode *regnode, int min_uvolt,
    int max_uvolt, int *udelay)
{
        struct syr827_reg_sc *sc;
        int cur_uvolt;
        uint8_t val;

        sc = regnode_get_softc(regnode);

        /* Get current voltage */
        syr827_read(sc->base_dev, sc->volt_reg, &val, 1);
        cur_uvolt = (val & VSEL_NSEL_MASK) * VSEL_VOLTAGE_STEP +
            VSEL_VOLTAGE_BASE;

        /* Set new voltage */
        val &= ~VSEL_NSEL_MASK;
        val |= ((min_uvolt - VSEL_VOLTAGE_BASE) / VSEL_VOLTAGE_STEP);
        syr827_write(sc->base_dev, sc->volt_reg, val);

        /* Time to delay is based on the number of voltage steps */
        *udelay = sc->param->ramp_delay *
            (abs(cur_uvolt - min_uvolt) / VSEL_VOLTAGE_STEP);

        return (0);
}

static int
syr827_regnode_get_voltage(struct regnode *regnode, int *uvolt)
{
        struct syr827_reg_sc *sc;
        uint8_t val;

        sc = regnode_get_softc(regnode);

        syr827_read(sc->base_dev, sc->volt_reg, &val, 1);
        *uvolt = (val & VSEL_NSEL_MASK) * VSEL_VOLTAGE_STEP +
            VSEL_VOLTAGE_BASE;

        return (0);
}

static regnode_method_t syr827_regnode_methods[] = {
        /* Regulator interface */
        REGNODEMETHOD(regnode_init,             syr827_regnode_init),
        REGNODEMETHOD(regnode_enable,           syr827_regnode_enable),
        REGNODEMETHOD(regnode_set_voltage,      syr827_regnode_set_voltage),
        REGNODEMETHOD(regnode_get_voltage,      syr827_regnode_get_voltage),
        REGNODEMETHOD_END
};
DEFINE_CLASS_1(syr827_regnode, syr827_regnode_class, syr827_regnode_methods,
    sizeof(struct syr827_reg_sc), regnode_class);

static struct syr827_reg_sc *
syr827_reg_attach(device_t dev, phandle_t node)
{
        struct syr827_reg_sc *reg_sc;
        struct regnode_init_def initdef;
        struct regnode *regnode;
        int suspend_reg;

        memset(&initdef, 0, sizeof(initdef));
        regulator_parse_ofw_stdparam(dev, node, &initdef);
        initdef.id = 0;
        initdef.ofw_node = node;
        regnode = regnode_create(dev, &syr827_regnode_class, &initdef);
        if (regnode == NULL) {
                device_printf(dev, "cannot create regulator\n");
                return (NULL);
        }

        reg_sc = regnode_get_softc(regnode);
        reg_sc->regnode = regnode;
        reg_sc->base_dev = dev;
        reg_sc->xref = OF_xref_from_node(node);
        reg_sc->param = regnode_get_stdparam(regnode);

        if (OF_getencprop(node, "fcs,suspend-voltage-selector", &suspend_reg,
            sizeof(uint32_t)) <= 0)
                suspend_reg = 0;

        switch (suspend_reg) {
        case 0:
                reg_sc->suspend_reg = VSEL0;
                reg_sc->volt_reg = VSEL1;
                break;
        case 1:
                reg_sc->suspend_reg = VSEL1;
                reg_sc->volt_reg = VSEL0;
                break;
        }

        regnode_register(regnode);

        return (reg_sc);
}

static int
syr827_regdev_map(device_t dev, phandle_t xref, int ncells, pcell_t *cells,
    intptr_t *num)
{
        struct syr827_softc *sc;

        sc = device_get_softc(dev);

        if (sc->reg->xref != xref)
                return (ENXIO);

        *num = 0;

        return (0);
}

static int
syr827_probe(device_t dev)
{
        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
                return (ENXIO);

        device_set_desc(dev, "Silergy SYR827 regulator");

        return (BUS_PROBE_DEFAULT);
}

static void
syr827_start(void *pdev)
{
        struct syr827_softc *sc;
        device_t dev;
        uint8_t val;

        dev = pdev;
        sc = device_get_softc(dev);

        if (bootverbose) {
                syr827_read(dev, ID1, &val, 1);
                device_printf(dev, "Vendor ID: %x, DIE ID: %x\n",
                    (val & ID1_VENDOR_MASK) >> ID1_VENDOR_SHIFT,
                    val & ID1_DIE_MASK);
                syr827_read(dev, ID2, &val, 1);
                device_printf(dev, "DIE Rev: %x\n", val & ID2_DIE_REV_MASK);
        }

        config_intrhook_disestablish(&sc->intr_hook);
}

static int
syr827_attach(device_t dev)
{
        struct syr827_softc *sc;
        phandle_t node;

        sc = device_get_softc(dev);
        node = ofw_bus_get_node(dev);

        sc->addr = iicbus_get_addr(dev);

        sc->intr_hook.ich_func = syr827_start;
        sc->intr_hook.ich_arg = dev;

        if (config_intrhook_establish(&sc->intr_hook) != 0)
                return (ENOMEM);

        sc->reg = syr827_reg_attach(dev, node);
        if (sc->reg == NULL) {
                device_printf(dev, "cannot attach regulator\n");
                return (ENXIO);
        }

        return (0);
}

static device_method_t syr827_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         syr827_probe),
        DEVMETHOD(device_attach,        syr827_attach),

        /* Regdev interface */
        DEVMETHOD(regdev_map,           syr827_regdev_map),

        DEVMETHOD_END
};

static driver_t syr827_driver = {
        "syr827",
        syr827_methods,
        sizeof(struct syr827_softc),
};

EARLY_DRIVER_MODULE(syr827, iicbus, syr827_driver, 0, 0, BUS_PASS_RESOURCE);
MODULE_VERSION(syr827, 1);
MODULE_DEPEND(syr827, iicbus, 1, 1, 1);
IICBUS_FDT_PNP_INFO(compat_data);