/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 Ian Lepore <ian@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/bus.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/lock.h>
#include <sys/module.h>

#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
#include <dev/pwm/pwmbus.h>

#include "pwmbus_if.h"

struct ofw_pwmbus_ivars {
        struct pwmbus_ivars     base;
        struct ofw_bus_devinfo  devinfo;
};

struct ofw_pwmbus_softc {
        struct pwmbus_softc     base;
};

/*
 * bus_if methods...
 */

static device_t
ofw_pwmbus_add_child(device_t dev, u_int order, const char *name, int unit)
{
        device_t child;
        struct ofw_pwmbus_ivars *ivars;

        if ((ivars = malloc(sizeof(struct ofw_pwmbus_ivars), M_DEVBUF,
            M_NOWAIT | M_ZERO)) == NULL) {
                return (NULL);
        }

        if ((child = device_add_child_ordered(dev, order, name, unit)) == NULL) {
                free(ivars, M_DEVBUF);
                return (NULL);
        }

        ivars->devinfo.obd_node = -1;
        device_set_ivars(child, ivars);

        return (child);
}

static void
ofw_pwmbus_child_deleted(device_t dev, device_t child)
{
        struct ofw_pwmbus_ivars *ivars;

        ivars = device_get_ivars(child);
        if (ivars != NULL) {
                ofw_bus_gen_destroy_devinfo(&ivars->devinfo);
                free(ivars, M_DEVBUF);
        }
}

static const struct ofw_bus_devinfo *
ofw_pwmbus_get_devinfo(device_t bus, device_t dev)
{
        struct ofw_pwmbus_ivars *ivars;

        ivars = device_get_ivars(dev);
        return (&ivars->devinfo);
}

/*
 * device_if methods...
 */

static int
ofw_pwmbus_probe(device_t dev)
{

        if (ofw_bus_get_node(dev) == -1) {
                return (ENXIO);
        }
        device_set_desc(dev, "OFW PWM bus");

        return (BUS_PROBE_DEFAULT);
}

static int
ofw_pwmbus_attach(device_t dev)
{
        struct ofw_pwmbus_softc *sc;
        struct ofw_pwmbus_ivars *ivars;
        phandle_t node;
        device_t child, parent;
        pcell_t  chan;
        bool any_children;

        sc = device_get_softc(dev);
        sc->base.dev = dev;
        parent = device_get_parent(dev);

        if (PWMBUS_CHANNEL_COUNT(parent, &sc->base.nchannels) != 0 ||
            sc->base.nchannels == 0) {
                device_printf(dev, "No channels on parent %s\n",
                    device_get_nameunit(parent));
                return (ENXIO);
        }

        /*
         * Attach the children found in the fdt node of the hardware controller.
         * Hardware controllers must implement the ofw_bus_get_node method so
         * that our call to ofw_bus_get_node() gets back the controller's node.
         */
        any_children = false;
        node = ofw_bus_get_node(dev);
        for (node = OF_child(node); node != 0; node = OF_peer(node)) {
                /*
                 * The child has to have a reg property; its value is the
                 * channel number so range-check it.
                 */
                if (OF_getencprop(node, "reg", &chan, sizeof(chan)) == -1)
                        continue;
                if (chan >= sc->base.nchannels)
                        continue;

                if ((child = ofw_pwmbus_add_child(dev, 0, NULL,
                    DEVICE_UNIT_ANY)) == NULL)
                        continue;

                ivars = device_get_ivars(child);
                ivars->base.pi_channel = chan;

                /* Set up the standard ofw devinfo. */
                if (ofw_bus_gen_setup_devinfo(&ivars->devinfo, node) != 0) {
                        device_delete_child(dev, child);
                        continue;
                }
                any_children = true;
        }

        /*
         * If we didn't find any children in the fdt data, add a pwmc(4) child
         * for each channel, like the base pwmbus does.  The idea is that if
         * there is any fdt data, then we do exactly what it says and nothing
         * more, otherwise we just provide generic userland access to all the
         * pwm channels that exist like the base pwmbus's attach code does.
         */
        if (!any_children) {
                for (chan = 0; chan < sc->base.nchannels; ++chan) {
                        child = ofw_pwmbus_add_child(dev, 0, "pwmc",
                            DEVICE_UNIT_ANY);
                        if (child == NULL) {
                                device_printf(dev, "failed to add pwmc child "
                                    " device for channel %u\n", chan);
                                continue;
                        }
                        ivars = device_get_ivars(child);
                        ivars->base.pi_channel = chan;
                }
        }
        bus_enumerate_hinted_children(dev);
        bus_identify_children(dev);
        bus_attach_children(dev);

        return (0);
}

static device_method_t ofw_pwmbus_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,           ofw_pwmbus_probe),
        DEVMETHOD(device_attach,          ofw_pwmbus_attach),

        /* Bus interface */
        DEVMETHOD(bus_child_pnpinfo,      ofw_bus_gen_child_pnpinfo),
        DEVMETHOD(bus_add_child,          ofw_pwmbus_add_child),
        DEVMETHOD(bus_child_deleted,      ofw_pwmbus_child_deleted),

        /* ofw_bus interface */
        DEVMETHOD(ofw_bus_get_devinfo,    ofw_pwmbus_get_devinfo),
        DEVMETHOD(ofw_bus_get_compat,     ofw_bus_gen_get_compat),
        DEVMETHOD(ofw_bus_get_model,      ofw_bus_gen_get_model),
        DEVMETHOD(ofw_bus_get_name,       ofw_bus_gen_get_name),
        DEVMETHOD(ofw_bus_get_node,       ofw_bus_gen_get_node),
        DEVMETHOD(ofw_bus_get_type,       ofw_bus_gen_get_type),

        DEVMETHOD_END
};

DEFINE_CLASS_1(pwmbus, ofw_pwmbus_driver, ofw_pwmbus_methods,
    sizeof(struct pwmbus_softc), pwmbus_driver);
EARLY_DRIVER_MODULE(ofw_pwmbus, pwm, ofw_pwmbus_driver, 0, 0,
    BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
MODULE_VERSION(ofw_pwmbus, 1);
MODULE_DEPEND(ofw_pwmbus, pwmbus, 1, 1, 1);