/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020 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/bio.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/endian.h>
#include <sys/fcntl.h>
#include <sys/ioccom.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/slicer.h>
#include <sys/sysctl.h>
#include <sys/time.h>

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

#include <dev/regulator/regulator.h>

#include <dev/backlight/backlight.h>

#include <dev/pwm/ofw_pwm.h>

#include "backlight_if.h"
#include "pwmbus_if.h"

struct pwm_backlight_softc {
        device_t        pwmdev;
        struct cdev     *cdev;

        pwm_channel_t   channel;
        uint32_t        *levels;
        ssize_t         nlevels;
        int             default_level;
        ssize_t         current_level;

        regulator_t     power_supply;
        uint64_t        period;
        uint64_t        duty;
        bool            enabled;
};

static int pwm_backlight_find_level_per_percent(struct pwm_backlight_softc *sc, int percent);

static struct ofw_compat_data compat_data[] = {
        { "pwm-backlight",      1 },
        { NULL,                 0 }
};

static int
pwm_backlight_probe(device_t dev)
{

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

        device_set_desc(dev, "PWM Backlight");
        return (BUS_PROBE_DEFAULT);
}

static int
pwm_backlight_attach(device_t dev)
{
        struct pwm_backlight_softc *sc;
        phandle_t node;
        int rv;

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

        rv = pwm_get_by_ofw_propidx(dev, node, "pwms", 0, &sc->channel);
        if (rv != 0) {
                device_printf(dev, "Cannot map pwm channel %d\n", rv);
                return (ENXIO);
        }

        if (regulator_get_by_ofw_property(dev, 0, "power-supply",
            &sc->power_supply) != 0) {
                device_printf(dev, "No power-supply property\n");
                return (ENXIO);
        }

        if (OF_hasprop(node, "brightness-levels")) {
                sc->nlevels = OF_getencprop_alloc(node, "brightness-levels",
                    (void **)&sc->levels);
                if (sc->nlevels <= 0) {
                        device_printf(dev, "Cannot parse brightness levels\n");
                        return (ENXIO);
                }
                sc->nlevels /= sizeof(uint32_t);

                if (OF_getencprop(node, "default-brightness-level",
                    &sc->default_level, sizeof(uint32_t)) <= 0) {
                        device_printf(dev, "No default-brightness-level while brightness-levels is specified\n");
                        return (ENXIO);
                } else {
                        if (sc->default_level > sc->nlevels) {
                                device_printf(dev, "default-brightness-level isn't present in brightness-levels range\n");
                                return (ENXIO);
                        }
                        sc->channel->duty = sc->channel->period * sc->levels[sc->default_level] / 100;
                }

                if (bootverbose) {
                        device_printf(dev, "Number of levels: %zd\n", sc->nlevels);
                        device_printf(dev, "Configured period time: %ju\n", (uintmax_t)sc->channel->period);
                        device_printf(dev, "Default duty cycle: %ju\n", (uintmax_t)sc->channel->duty);
                }
        } else {
                /* Get the current backlight level */
                PWMBUS_CHANNEL_GET_CONFIG(sc->channel->dev,
                    sc->channel->channel,
                    (unsigned int *)&sc->channel->period,
                    (unsigned int *)&sc->channel->duty);
                if (sc->channel->duty > sc->channel->period)
                        sc->channel->duty = sc->channel->period;
                if (bootverbose) {
                        device_printf(dev, "Configured period time: %ju\n", (uintmax_t)sc->channel->period);
                        device_printf(dev, "Default duty cycle: %ju\n", (uintmax_t)sc->channel->duty);
                }
        }

        regulator_enable(sc->power_supply);
        sc->channel->enabled = true;
        PWMBUS_CHANNEL_CONFIG(sc->channel->dev, sc->channel->channel,
            sc->channel->period, sc->channel->duty);
        PWMBUS_CHANNEL_ENABLE(sc->channel->dev, sc->channel->channel,
            sc->channel->enabled);

        sc->current_level = pwm_backlight_find_level_per_percent(sc,
            sc->channel->period / sc->channel->duty);
        sc->cdev = backlight_register("pwm_backlight", dev);
        if (sc->cdev == NULL)
                device_printf(dev, "Cannot register as a backlight\n");

        return (0);
}

static int
pwm_backlight_detach(device_t dev)
{
        struct pwm_backlight_softc *sc;

        sc = device_get_softc(dev);
        if (sc->nlevels > 0)
                OF_prop_free(sc->levels);
        regulator_disable(sc->power_supply);
        backlight_destroy(sc->cdev);
        return (0);
}

static int
pwm_backlight_find_level_per_percent(struct pwm_backlight_softc *sc, int percent)
{
        int i;
        int diff;

        if (percent < 0 || percent > 100)
                return (-1);

        for (i = 0, diff = 0; i < sc->nlevels; i++) {
                if (sc->levels[i] == percent)
                        return (i);
                else if (sc->levels[i] < percent)
                        diff = percent - sc->levels[i];
                else {
                        if (diff < abs((percent - sc->levels[i])))
                                return (i - 1);
                        else
                                return (i);
                }
        }

        return (-1);
}

static int
pwm_backlight_update_status(device_t dev, struct backlight_props *props)
{
        struct pwm_backlight_softc *sc;
        int reg_status;
        int error;

        sc = device_get_softc(dev);

        if (sc->nlevels != 0) {
                error = pwm_backlight_find_level_per_percent(sc,
                    props->brightness);
                if (error < 0)
                        return (ERANGE);
                sc->current_level = error;
                sc->channel->duty = sc->channel->period *
                        sc->levels[sc->current_level] / 100;
        } else {
                if (props->brightness > 100 || props->brightness < 0)
                        return (ERANGE);
                sc->channel->duty = sc->channel->period *
                        props->brightness / 100;
        }
        sc->channel->enabled = true;
        PWMBUS_CHANNEL_CONFIG(sc->channel->dev, sc->channel->channel,
            sc->channel->period, sc->channel->duty);
        PWMBUS_CHANNEL_ENABLE(sc->channel->dev, sc->channel->channel,
            sc->channel->enabled);
        error = regulator_status(sc->power_supply, &reg_status);
        if (error != 0)
                device_printf(dev,
                    "Cannot get power-supply status: %d\n", error);
        else {
                if (props->brightness > 0) {
                        if (reg_status != REGULATOR_STATUS_ENABLED)
                                regulator_enable(sc->power_supply);
                } else {
                        if (reg_status == REGULATOR_STATUS_ENABLED)
                                regulator_disable(sc->power_supply);
                }
        }

        return (0);
}

static int
pwm_backlight_get_status(device_t dev, struct backlight_props *props)
{
        struct pwm_backlight_softc *sc;
        int i;

        sc = device_get_softc(dev);

        if (sc->nlevels != 0) {
                props->brightness = sc->levels[sc->current_level];
                props->nlevels = sc->nlevels;
                for (i = 0; i < sc->nlevels; i++)
                        props->levels[i] = sc->levels[i];
        } else {
                props->brightness = sc->channel->duty * 100 / sc->channel->period;
                props->nlevels = 0;
        }
        return (0);
}

static int
pwm_backlight_get_info(device_t dev, struct backlight_info *info)
{

        info->type = BACKLIGHT_TYPE_PANEL;
        strlcpy(info->name, "pwm-backlight", BACKLIGHTMAXNAMELENGTH);
        return (0);
}

static device_method_t pwm_backlight_methods[] = {
        /* device_if */
        DEVMETHOD(device_probe, pwm_backlight_probe),
        DEVMETHOD(device_attach, pwm_backlight_attach),
        DEVMETHOD(device_detach, pwm_backlight_detach),

        /* backlight interface */
        DEVMETHOD(backlight_update_status, pwm_backlight_update_status),
        DEVMETHOD(backlight_get_status, pwm_backlight_get_status),
        DEVMETHOD(backlight_get_info, pwm_backlight_get_info),
        DEVMETHOD_END
};

driver_t pwm_backlight_driver = {
        "pwm_backlight",
        pwm_backlight_methods,
        sizeof(struct pwm_backlight_softc),
};

DRIVER_MODULE(pwm_backlight, simplebus, pwm_backlight_driver, 0, 0);
MODULE_DEPEND(pwm_backlight, backlight, 1, 1, 1);
OFWBUS_PNP_INFO(compat_data);