/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org>
 * All rights reserved.
 *
 * 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/gpio.h>
#ifdef INTRNG
#include <sys/intr.h>
#endif
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/sbuf.h>

#include <dev/gpio/gpiobusvar.h>
#include <dev/gpio/gpiobus_internal.h>

#include "gpiobus_if.h"

#undef GPIOBUS_DEBUG
#ifdef GPIOBUS_DEBUG
#define dprintf printf
#else
#define dprintf(x, arg...)
#endif

static void gpiobus_print_pins(struct gpiobus_ivar *, struct sbuf *);
static int gpiobus_parse_pins(struct gpiobus_softc *, device_t, int);
static int gpiobus_probe(device_t);
static int gpiobus_suspend(device_t);
static int gpiobus_resume(device_t);
static void gpiobus_probe_nomatch(device_t, device_t);
static int gpiobus_print_child(device_t, device_t);
static device_t gpiobus_add_child(device_t, u_int, const char *, int);
static void gpiobus_hinted_child(device_t, const char *, int);

/*
 * GPIOBUS interface
 */
static int gpiobus_acquire_bus(device_t, device_t, int);
static void gpiobus_release_bus(device_t, device_t);
static int gpiobus_pin_setflags(device_t, device_t, uint32_t, uint32_t);
static int gpiobus_pin_getflags(device_t, device_t, uint32_t, uint32_t*);
static int gpiobus_pin_getcaps(device_t, device_t, uint32_t, uint32_t*);
static int gpiobus_pin_set(device_t, device_t, uint32_t, unsigned int);
static int gpiobus_pin_get(device_t, device_t, uint32_t, unsigned int*);
static int gpiobus_pin_toggle(device_t, device_t, uint32_t);

/*
 * gpiobus_pin flags
 *  The flags in struct gpiobus_pin are not related to the flags used by the
 *  low-level controller driver in struct gpio_pin.  Currently, only pins
 *  acquired via FDT data have gpiobus_pin.flags set, sourced from the flags in
 *  the FDT properties.  In theory, these flags are defined per-platform.  In
 *  practice they are always the flags from the dt-bindings/gpio/gpio.h file.
 *  The only one of those flags we currently support is for handling active-low
 *  pins, so we just define that flag here instead of including a GPL'd header.
 */
#define GPIO_ACTIVE_LOW 1

/*
 * XXX -> Move me to better place - gpio_subr.c?
 * Also, this function must be changed when interrupt configuration
 * data will be moved into struct resource.
 */
#ifdef INTRNG

struct resource *
gpio_alloc_intr_resource(device_t consumer_dev, int rid, u_int alloc_flags,
    gpio_pin_t pin, uint32_t intr_mode)
{
        u_int irq;
        struct intr_map_data_gpio *gpio_data;
        struct resource *res;

        gpio_data = (struct intr_map_data_gpio *)intr_alloc_map_data(
            INTR_MAP_DATA_GPIO, sizeof(*gpio_data), M_WAITOK | M_ZERO);
        gpio_data->gpio_pin_num = pin->pin;
        gpio_data->gpio_pin_flags = pin->flags;
        gpio_data->gpio_intr_mode = intr_mode;

        irq = intr_map_irq(pin->dev, 0, (struct intr_map_data *)gpio_data);
        res = bus_alloc_resource(consumer_dev, SYS_RES_IRQ, rid, irq, irq, 1,
            alloc_flags);
        if (res == NULL) {
                intr_unmap_irq(irq);
                return (NULL);
        }
        return (res);
}
#else
struct resource *
gpio_alloc_intr_resource(device_t consumer_dev, int rid, u_int alloc_flags,
    gpio_pin_t pin, uint32_t intr_mode)
{

        return (NULL);
}
#endif

int
gpio_check_flags(uint32_t caps, uint32_t flags)
{

        /* Filter unwanted flags. */
        flags &= caps;

        /* Cannot mix input/output together. */
        if (flags & GPIO_PIN_INPUT && flags & GPIO_PIN_OUTPUT)
                return (EINVAL);
        /* Cannot mix pull-up/pull-down together. */
        if (flags & GPIO_PIN_PULLUP && flags & GPIO_PIN_PULLDOWN)
                return (EINVAL);
        /* Cannot mix output and interrupt flags together */
        if (flags & GPIO_PIN_OUTPUT && flags & GPIO_INTR_MASK)
                return (EINVAL);
        /* Only one interrupt flag can be defined at once */
        if ((flags & GPIO_INTR_MASK) & ((flags & GPIO_INTR_MASK) - 1))
                return (EINVAL);
        /* The interrupt attached flag cannot be set */
        if (flags & GPIO_INTR_ATTACHED)
                return (EINVAL);

        return (0);
}

int
gpio_pin_get_by_bus_pinnum(device_t busdev, uint32_t pinnum, gpio_pin_t *ppin)
{
        gpio_pin_t pin;
        int err;

        err = gpiobus_acquire_pin(busdev, pinnum);
        if (err != 0)
                return (EBUSY);

        pin = malloc(sizeof(*pin), M_DEVBUF, M_WAITOK | M_ZERO);

        pin->dev = device_get_parent(busdev);
        pin->pin = pinnum;
        pin->flags = 0;

        *ppin = pin;
        return (0);
}

int
gpio_pin_get_by_child_index(device_t childdev, uint32_t idx, gpio_pin_t *ppin)
{
        struct gpiobus_ivar *devi;

        devi = GPIOBUS_IVAR(childdev);
        if (idx >= devi->npins)
                return (EINVAL);

        return (gpio_pin_get_by_bus_pinnum(device_get_parent(childdev),
            devi->pins[idx], ppin));
}

int
gpio_pin_getcaps(gpio_pin_t pin, uint32_t *caps)
{

        KASSERT(pin != NULL, ("GPIO pin is NULL."));
        KASSERT(pin->dev != NULL, ("GPIO pin device is NULL."));
        return (GPIO_PIN_GETCAPS(pin->dev, pin->pin, caps));
}

int
gpio_pin_is_active(gpio_pin_t pin, bool *active)
{
        int rv;
        uint32_t tmp;

        KASSERT(pin != NULL, ("GPIO pin is NULL."));
        KASSERT(pin->dev != NULL, ("GPIO pin device is NULL."));
        rv = GPIO_PIN_GET(pin->dev, pin->pin, &tmp);
        if (rv  != 0) {
                return (rv);
        }

        if (pin->flags & GPIO_ACTIVE_LOW)
                *active = tmp == 0;
        else
                *active = tmp != 0;
        return (0);
}

/*
 * Note that this function should only
 * be used in cases where a pre-existing
 * gpiobus_pin structure exists. In most
 * cases, the gpio_pin_get_by_* functions
 * suffice.
 */
int
gpio_pin_acquire(gpio_pin_t gpio)
{
        device_t busdev;

        KASSERT(gpio != NULL, ("GPIO pin is NULL."));
        KASSERT(gpio->dev != NULL, ("GPIO pin device is NULL."));

        busdev = GPIO_GET_BUS(gpio->dev);
        if (busdev == NULL)
                return (ENXIO);

        return (gpiobus_acquire_pin(busdev, gpio->pin));
}

void
gpio_pin_release(gpio_pin_t gpio)
{
        device_t busdev;

        KASSERT(gpio != NULL, ("GPIO pin is NULL."));
        KASSERT(gpio->dev != NULL, ("GPIO pin device is NULL."));

        busdev = GPIO_GET_BUS(gpio->dev);
        KASSERT(busdev != NULL, ("gpiobus dev is NULL."));

        gpiobus_release_pin(busdev, gpio->pin);
        free(gpio, M_DEVBUF);
}

int
gpio_pin_set_active(gpio_pin_t pin, bool active)
{
        int rv;
        uint32_t tmp;

        if (pin->flags & GPIO_ACTIVE_LOW)
                tmp = active ? 0 : 1;
        else
                tmp = active ? 1 : 0;

        KASSERT(pin != NULL, ("GPIO pin is NULL."));
        KASSERT(pin->dev != NULL, ("GPIO pin device is NULL."));
        rv = GPIO_PIN_SET(pin->dev, pin->pin, tmp);
        return (rv);
}

int
gpio_pin_setflags(gpio_pin_t pin, uint32_t flags)
{
        int rv;

        KASSERT(pin != NULL, ("GPIO pin is NULL."));
        KASSERT(pin->dev != NULL, ("GPIO pin device is NULL."));

        rv = GPIO_PIN_SETFLAGS(pin->dev, pin->pin, flags);
        return (rv);
}

static void
gpiobus_print_pins(struct gpiobus_ivar *devi, struct sbuf *sb)
{
        int i, range_start, range_stop, need_coma;

        if (devi->npins == 0)
                return;

        need_coma = 0;
        range_start = range_stop = devi->pins[0];
        for (i = 1; i < devi->npins; i++) {
                if (devi->pins[i] != (range_stop + 1)) {
                        if (need_coma)
                                sbuf_cat(sb, ",");
                        if (range_start != range_stop)
                                sbuf_printf(sb, "%d-%d", range_start, range_stop);
                        else
                                sbuf_printf(sb, "%d", range_start);
                        range_start = range_stop = devi->pins[i];
                        need_coma = 1;
                }
                else
                        range_stop++;
        }

        if (need_coma)
                sbuf_cat(sb, ",");
        if (range_start != range_stop)
                sbuf_printf(sb, "%d-%d", range_start, range_stop);
        else
                sbuf_printf(sb, "%d", range_start);
}

device_t
gpiobus_add_bus(device_t dev)
{
        device_t busdev;

        busdev = device_add_child(dev, "gpiobus", DEVICE_UNIT_ANY);
        if (busdev == NULL)
                return (NULL);
#ifdef FDT
        ofw_gpiobus_register_provider(dev);
#endif
        return (busdev);
}

int
gpiobus_detach_bus(device_t dev)
{
#ifdef FDT
        ofw_gpiobus_unregister_provider(dev);
#endif
        return (bus_generic_detach(dev));
}

int
gpiobus_init_softc(device_t dev)
{
        struct gpiobus_softc *sc;

        sc = GPIOBUS_SOFTC(dev);
        sc->sc_busdev = dev;
        sc->sc_dev = device_get_parent(dev);
        sc->sc_intr_rman.rm_type = RMAN_ARRAY;
        sc->sc_intr_rman.rm_descr = "GPIO Interrupts";
        if (rman_init(&sc->sc_intr_rman) != 0 ||
            rman_manage_region(&sc->sc_intr_rman, 0, ~0) != 0)
                panic("%s: failed to set up rman.", __func__);

        if (GPIO_PIN_MAX(sc->sc_dev, &sc->sc_npins) != 0)
                return (ENXIO);

        KASSERT(sc->sc_npins >= 0, ("GPIO device with no pins"));

        /* Pins = GPIO_PIN_MAX() + 1 */
        sc->sc_npins++;

        sc->sc_pins = malloc(sizeof(*sc->sc_pins) * sc->sc_npins, M_DEVBUF,
            M_NOWAIT | M_ZERO);
        if (sc->sc_pins == NULL)
                return (ENOMEM);

        /* Initialize the bus lock. */
        GPIOBUS_LOCK_INIT(sc);

        return (0);
}

int
gpiobus_add_gpioc(device_t dev)
{
        struct gpiobus_ivar *devi;
        struct gpiobus_softc *sc;
        device_t gpioc;
        int err;

        gpioc = BUS_ADD_CHILD(dev, 0, "gpioc", DEVICE_UNIT_ANY);
        if (gpioc == NULL)
                return (ENXIO);

        sc = device_get_softc(dev);
        devi = device_get_ivars(gpioc);

        devi->npins = sc->sc_npins;
        err = gpiobus_alloc_ivars(devi);
        if (err != 0) {
                device_delete_child(dev, gpioc);
                return (err);
        }

        err = GPIO_GET_PIN_LIST(sc->sc_dev, devi->pins);
        if (err != 0) {
                device_delete_child(dev, gpioc);
                gpiobus_free_ivars(devi);
        }

        return (err);
}

int
gpiobus_alloc_ivars(struct gpiobus_ivar *devi)
{

        /* Allocate pins and flags memory. */
        devi->pins = malloc(sizeof(uint32_t) * devi->npins, M_DEVBUF,
            M_NOWAIT | M_ZERO);
        if (devi->pins == NULL)
                return (ENOMEM);
        return (0);
}

void
gpiobus_free_ivars(struct gpiobus_ivar *devi)
{

        if (devi->pins) {
                free(devi->pins, M_DEVBUF);
                devi->pins = NULL;
        }
        devi->npins = 0;
}

int
gpiobus_acquire_pin(device_t bus, uint32_t pin)
{
        struct gpiobus_softc *sc;

        sc = device_get_softc(bus);
        /* Consistency check. */
        if (pin >= sc->sc_npins) {
                panic("%s: invalid pin %d, max: %d",
                    device_get_nameunit(bus), pin, sc->sc_npins - 1);
        }
        /* Mark pin as mapped and give warning if it's already mapped. */
        if (sc->sc_pins[pin].mapped) {
                device_printf(bus, "warning: pin %d is already mapped\n", pin);
                return (EBUSY);
        }
        sc->sc_pins[pin].mapped = 1;

        return (0);
}

/* Release mapped pin */
void
gpiobus_release_pin(device_t bus, uint32_t pin)
{
        struct gpiobus_softc *sc;

        sc = device_get_softc(bus);
        /* Consistency check. */
        if (pin >= sc->sc_npins) {
                panic("%s: invalid pin %d, max: %d",
                    device_get_nameunit(bus), pin, sc->sc_npins - 1);
        }

        if (!sc->sc_pins[pin].mapped)
                panic("%s: pin %d is not mapped", device_get_nameunit(bus),
                    pin);

        sc->sc_pins[pin].mapped = 0;
}

static int
gpiobus_acquire_child_pins(device_t dev, device_t child)
{
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);
        int i;

        for (i = 0; i < devi->npins; i++) {
                /* Reserve the GPIO pin. */
                if (gpiobus_acquire_pin(dev, devi->pins[i]) != 0) {
                        device_printf(child, "cannot acquire pin %d\n",
                            devi->pins[i]);
                        while (--i >= 0) {
                                gpiobus_release_pin(dev, devi->pins[i]);
                        }
                        gpiobus_free_ivars(devi);
                        return (EBUSY);
                }
        }
        for (i = 0; i < devi->npins; i++) {
                /* Use the child name as pin name. */
                GPIOBUS_PIN_SETNAME(dev, devi->pins[i],
                    device_get_nameunit(child));

        }
        return (0);
}

static int
gpiobus_parse_pins(struct gpiobus_softc *sc, device_t child, int mask)
{
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);
        int i, npins;

        npins = 0;
        for (i = 0; i < 32; i++) {
                if (mask & (1 << i))
                        npins++;
        }
        if (npins == 0) {
                device_printf(child, "empty pin mask\n");
                return (EINVAL);
        }
        devi->npins = npins;
        if (gpiobus_alloc_ivars(devi) != 0) {
                device_printf(child, "cannot allocate device ivars\n");
                return (EINVAL);
        }
        npins = 0;
        for (i = 0; i < 32; i++) {
                if ((mask & (1 << i)) == 0)
                        continue;
                devi->pins[npins++] = i;
        }

        return (0);
}

static int
gpiobus_parse_pin_list(struct gpiobus_softc *sc, device_t child,
    const char *pins)
{
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);
        const char *p;
        char *endp;
        unsigned long pin;
        int i, npins;

        npins = 0;
        p = pins;
        for (;;) {
                pin = strtoul(p, &endp, 0);
                if (endp == p)
                        break;
                npins++;
                if (*endp == '\0')
                        break;
                p = endp + 1;
        }

        if (*endp != '\0') {
                device_printf(child, "garbage in the pin list: %s\n", endp);
                return (EINVAL);
        }
        if (npins == 0) {
                device_printf(child, "empty pin list\n");
                return (EINVAL);
        }

        devi->npins = npins;
        if (gpiobus_alloc_ivars(devi) != 0) {
                device_printf(child, "cannot allocate device ivars\n");
                return (EINVAL);
        }

        i = 0;
        p = pins;
        for (;;) {
                pin = strtoul(p, &endp, 0);

                devi->pins[i] = pin;

                if (*endp == '\0')
                        break;
                i++;
                p = endp + 1;
        }

        return (0);
}

static int
gpiobus_probe(device_t dev)
{
        device_set_desc(dev, "GPIO bus");

        return (BUS_PROBE_GENERIC);
}

int
gpiobus_attach(device_t dev)
{
        int err;

        err = gpiobus_init_softc(dev);
        if (err != 0)
                return (err);

        err = gpiobus_add_gpioc(dev);
        if (err != 0)
                return (err);

        /*
         * Get parent's pins and mark them as unmapped
         */
        bus_identify_children(dev);
        bus_enumerate_hinted_children(dev);

        bus_attach_children(dev);
        return (0);
}

/*
 * Since this is not a self-enumerating bus, and since we always add
 * children in attach, we have to always delete children here.
 */
int
gpiobus_detach(device_t dev)
{
        struct gpiobus_softc *sc;
        int i, err;

        sc = GPIOBUS_SOFTC(dev);
        KASSERT(mtx_initialized(&sc->sc_mtx),
            ("gpiobus mutex not initialized"));
        GPIOBUS_LOCK_DESTROY(sc);

        if ((err = bus_generic_detach(dev)) != 0)
                return (err);

        rman_fini(&sc->sc_intr_rman);
        if (sc->sc_pins) {
                for (i = 0; i < sc->sc_npins; i++) {
                        if (sc->sc_pins[i].name != NULL)
                                free(sc->sc_pins[i].name, M_DEVBUF);
                        sc->sc_pins[i].name = NULL;
                }
                free(sc->sc_pins, M_DEVBUF);
                sc->sc_pins = NULL;
        }

        return (0);
}

static int
gpiobus_suspend(device_t dev)
{

        return (bus_generic_suspend(dev));
}

static int
gpiobus_resume(device_t dev)
{

        return (bus_generic_resume(dev));
}

static void
gpiobus_probe_nomatch(device_t dev, device_t child)
{
        char pins[128];
        struct sbuf sb;
        struct gpiobus_ivar *devi;

        devi = GPIOBUS_IVAR(child);
        sbuf_new(&sb, pins, sizeof(pins), SBUF_FIXEDLEN);
        gpiobus_print_pins(devi, &sb);
        sbuf_finish(&sb);
        device_printf(dev, "<unknown device> at pin%s %s",
            devi->npins > 1 ? "s" : "", sbuf_data(&sb));
        resource_list_print_type(&devi->rl, "irq", SYS_RES_IRQ, "%jd");
        printf("\n");
}

static int
gpiobus_print_child(device_t dev, device_t child)
{
        char pins[128];
        struct sbuf sb;
        int retval = 0;
        struct gpiobus_ivar *devi;

        devi = GPIOBUS_IVAR(child);
        retval += bus_print_child_header(dev, child);
        if (devi->npins > 0) {
                if (devi->npins > 1)
                        retval += printf(" at pins ");
                else
                        retval += printf(" at pin ");
                sbuf_new(&sb, pins, sizeof(pins), SBUF_FIXEDLEN);
                gpiobus_print_pins(devi, &sb);
                sbuf_finish(&sb);
                retval += printf("%s", sbuf_data(&sb));
        }
        resource_list_print_type(&devi->rl, "irq", SYS_RES_IRQ, "%jd");
        retval += bus_print_child_footer(dev, child);

        return (retval);
}

int
gpiobus_child_location(device_t bus, device_t child, struct sbuf *sb)
{
        struct gpiobus_ivar *devi;

        devi = GPIOBUS_IVAR(child);
        sbuf_printf(sb, "pins=");
        gpiobus_print_pins(devi, sb);

        return (0);
}

device_t
gpiobus_add_child_common(device_t dev, u_int order, const char *name, int unit,
    size_t ivars_size)
{
        device_t child;
        struct gpiobus_ivar *devi;

        KASSERT(ivars_size >= sizeof(struct gpiobus_ivar),
            ("child ivars must include gpiobus_ivar as their first member"));
        child = device_add_child_ordered(dev, order, name, unit);
        if (child == NULL) 
                return (child);
        devi = malloc(ivars_size, M_DEVBUF, M_NOWAIT | M_ZERO);
        if (devi == NULL) {
                device_delete_child(dev, child);
                return (NULL);
        }
        resource_list_init(&devi->rl);
        device_set_ivars(child, devi);

        return (child);
}

static device_t
gpiobus_add_child(device_t dev, u_int order, const char *name, int unit)
{
        return (gpiobus_add_child_common(dev, order, name, unit,
            sizeof(struct gpiobus_ivar)));
}

void
gpiobus_child_deleted(device_t dev, device_t child)
{
        struct gpiobus_ivar *devi;

        devi = GPIOBUS_IVAR(child);
        if (devi == NULL)
                return;
        gpiobus_free_ivars(devi);
        resource_list_free(&devi->rl);
        free(devi, M_DEVBUF);
}

static int
gpiobus_rescan(device_t dev)
{

        /*
         * Re-scan is supposed to remove and add children, but if someone has
         * deleted the hints for a child we attached earlier, we have no easy
         * way to handle that.  So this just attaches new children for whom new
         * hints or drivers have arrived since we last tried.
         */
        bus_enumerate_hinted_children(dev);
        bus_attach_children(dev);
        return (0);
}

static void
gpiobus_hinted_child(device_t bus, const char *dname, int dunit)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(bus);
        device_t child;
        const char *pins;
        int irq, pinmask;

        if (device_find_child(bus, dname, dunit) != NULL) {
                return;
        }

        child = BUS_ADD_CHILD(bus, 0, dname, dunit);
        if (resource_int_value(dname, dunit, "pins", &pinmask) == 0) {
                if (gpiobus_parse_pins(sc, child, pinmask)) {
                        device_delete_child(bus, child);
                        return;
                }
        }
        else if (resource_string_value(dname, dunit, "pin_list", &pins) == 0) {
                if (gpiobus_parse_pin_list(sc, child, pins)) {
                        device_delete_child(bus, child);
                        return;
                }
        }
        if (resource_int_value(dname, dunit, "irq", &irq) == 0) {
                if (bus_set_resource(child, SYS_RES_IRQ, 0, irq, 1) != 0)
                        device_printf(bus,
                            "warning: bus_set_resource() failed\n");
        }
}

int
gpiobus_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{
        struct gpiobus_ivar *devi;

        devi = GPIOBUS_IVAR(child);
        switch (which) {
        case GPIOBUS_IVAR_NPINS:
                *result = devi->npins;
                break;
        case GPIOBUS_IVAR_PINS:
                /* Children do not ever need to directly examine this. */
                return (ENOTSUP);
        default:
                return (ENOENT);
        }

        return (0);
}

static int
gpiobus_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
{
        struct gpiobus_ivar *devi;
        const uint32_t *ptr;
        int i;

        devi = GPIOBUS_IVAR(child);
        switch (which) {
        case GPIOBUS_IVAR_NPINS:
                /* GPIO ivars are set once. */
                if (devi->npins != 0) {
                        return (EBUSY);
                }
                devi->npins = value;
                if (gpiobus_alloc_ivars(devi) != 0) {
                        device_printf(child, "cannot allocate device ivars\n");
                        devi->npins = 0;
                        return (ENOMEM);
                }
                break;
        case GPIOBUS_IVAR_PINS:
                ptr = (const uint32_t *)value;
                for (i = 0; i < devi->npins; i++)
                        devi->pins[i] = ptr[i];
                if (gpiobus_acquire_child_pins(dev, child) != 0)
                        return (EBUSY);
                break;
        default:
                return (ENOENT);
        }

        return (0);
}

static struct rman *
gpiobus_get_rman(device_t bus, int type, u_int flags)
{
        struct gpiobus_softc *sc;

        sc = device_get_softc(bus);
        switch (type) {
        case SYS_RES_IRQ:
                return (&sc->sc_intr_rman);
        default:
                return (NULL);
        }
}

static struct resource *
gpiobus_alloc_resource(device_t bus, device_t child, int type, int rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
        struct resource_list *rl;
        struct resource_list_entry *rle;
        int isdefault;

        isdefault = (RMAN_IS_DEFAULT_RANGE(start, end) && count == 1);
        if (isdefault) {
                rl = BUS_GET_RESOURCE_LIST(bus, child);
                if (rl == NULL)
                        return (NULL);
                rle = resource_list_find(rl, type, rid);
                if (rle == NULL)
                        return (NULL);
                start = rle->start;
                count = rle->count;
                end = rle->end;
        }
        return (bus_generic_rman_alloc_resource(bus, child, type, rid, start,
            end, count, flags));
}

static int
gpiobus_release_resource(device_t dev, device_t child, struct resource *r)
{
        int err;
#ifdef INTRNG
        u_int irq;

        irq = rman_get_start(r);
        MPASS(irq == rman_get_end(r));
#endif
        err = bus_generic_rman_release_resource(dev, child, r);
        if (err != 0)
                return (err);
#ifdef INTRNG
        intr_unmap_irq(irq);
#endif
        return (0);
}

static struct resource_list *
gpiobus_get_resource_list(device_t bus __unused, device_t child)
{
        struct gpiobus_ivar *ivar;

        ivar = GPIOBUS_IVAR(child);

        return (&ivar->rl);
}

static int
gpiobus_acquire_bus(device_t busdev, device_t child, int how)
{
        struct gpiobus_softc *sc;

        sc = device_get_softc(busdev);
        GPIOBUS_ASSERT_UNLOCKED(sc);
        GPIOBUS_LOCK(sc);
        if (sc->sc_owner != NULL) {
                if (sc->sc_owner == child)
                        panic("%s: %s still owns the bus.",
                            device_get_nameunit(busdev),
                            device_get_nameunit(child));
                if (how == GPIOBUS_DONTWAIT) {
                        GPIOBUS_UNLOCK(sc);
                        return (EWOULDBLOCK);
                }
                while (sc->sc_owner != NULL)
                        mtx_sleep(sc, &sc->sc_mtx, 0, "gpiobuswait", 0);
        }
        sc->sc_owner = child;
        GPIOBUS_UNLOCK(sc);

        return (0);
}

static void
gpiobus_release_bus(device_t busdev, device_t child)
{
        struct gpiobus_softc *sc;

        sc = device_get_softc(busdev);
        GPIOBUS_ASSERT_UNLOCKED(sc);
        GPIOBUS_LOCK(sc);
        if (sc->sc_owner == NULL)
                panic("%s: %s releasing unowned bus.",
                    device_get_nameunit(busdev),
                    device_get_nameunit(child));
        if (sc->sc_owner != child)
                panic("%s: %s trying to release bus owned by %s",
                    device_get_nameunit(busdev),
                    device_get_nameunit(child),
                    device_get_nameunit(sc->sc_owner));
        sc->sc_owner = NULL;
        wakeup(sc);
        GPIOBUS_UNLOCK(sc);
}

static int
gpiobus_pin_setflags(device_t dev, device_t child, uint32_t pin, 
    uint32_t flags)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);
        uint32_t caps;

        if (pin >= devi->npins)
                return (EINVAL);
        if (GPIO_PIN_GETCAPS(sc->sc_dev, devi->pins[pin], &caps) != 0)
                return (EINVAL);
        if (gpio_check_flags(caps, flags) != 0)
                return (EINVAL);

        return (GPIO_PIN_SETFLAGS(sc->sc_dev, devi->pins[pin], flags));
}

static int
gpiobus_pin_getflags(device_t dev, device_t child, uint32_t pin, 
    uint32_t *flags)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (pin >= devi->npins)
                return (EINVAL);

        return (GPIO_PIN_GETFLAGS(sc->sc_dev, devi->pins[pin], flags));
}

static int
gpiobus_pin_getcaps(device_t dev, device_t child, uint32_t pin, 
    uint32_t *caps)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (pin >= devi->npins)
                return (EINVAL);

        return (GPIO_PIN_GETCAPS(sc->sc_dev, devi->pins[pin], caps));
}

static int
gpiobus_pin_set(device_t dev, device_t child, uint32_t pin, 
    unsigned int value)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (pin >= devi->npins)
                return (EINVAL);

        return (GPIO_PIN_SET(sc->sc_dev, devi->pins[pin], value));
}

static int
gpiobus_pin_get(device_t dev, device_t child, uint32_t pin, 
    unsigned int *value)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (pin >= devi->npins)
                return (EINVAL);

        return (GPIO_PIN_GET(sc->sc_dev, devi->pins[pin], value));
}

static int
gpiobus_pin_toggle(device_t dev, device_t child, uint32_t pin)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (pin >= devi->npins)
                return (EINVAL);

        return (GPIO_PIN_TOGGLE(sc->sc_dev, devi->pins[pin]));
}

/*
 * Verify that a child has all the pins they are requesting
 * to access in their ivars.
 */
static bool
gpiobus_pin_verify_32(struct gpiobus_ivar *devi, uint32_t first_pin,
    uint32_t num_pins)
{
        if (first_pin + num_pins > devi->npins)
                return (false);

        /* Make sure the pins are consecutive. */
        for (uint32_t pin = first_pin; pin < first_pin + num_pins - 1; pin++) {
                if (devi->pins[pin] + 1 != devi->pins[pin + 1])
                        return (false);
        }

        return (true);
}

static int
gpiobus_pin_access_32(device_t dev, device_t child, uint32_t first_pin,
    uint32_t clear_pins, uint32_t change_pins, uint32_t *orig_pins)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (!gpiobus_pin_verify_32(devi, first_pin, 32))
                return (EINVAL);

        return (GPIO_PIN_ACCESS_32(sc->sc_dev, devi->pins[first_pin],
            clear_pins, change_pins, orig_pins));
}

static int
gpiobus_pin_config_32(device_t dev, device_t child, uint32_t first_pin,
    uint32_t num_pins, uint32_t *pin_flags)
{
        struct gpiobus_softc *sc = GPIOBUS_SOFTC(dev);
        struct gpiobus_ivar *devi = GPIOBUS_IVAR(child);

        if (num_pins > 32)
                return (EINVAL);
        if (!gpiobus_pin_verify_32(devi, first_pin, num_pins))
                return (EINVAL);

        return (GPIO_PIN_CONFIG_32(sc->sc_dev,
            devi->pins[first_pin], num_pins, pin_flags));
}

static int
gpiobus_pin_getname(device_t dev, uint32_t pin, char *name)
{
        struct gpiobus_softc *sc;

        sc = GPIOBUS_SOFTC(dev);
        if (pin > sc->sc_npins)
                return (EINVAL);
        /* Did we have a name for this pin ? */
        if (sc->sc_pins[pin].name != NULL) {
                memcpy(name, sc->sc_pins[pin].name, GPIOMAXNAME);
                return (0);
        }

        /* Return the default pin name. */
        return (GPIO_PIN_GETNAME(device_get_parent(dev), pin, name));
}

static int
gpiobus_pin_setname(device_t dev, uint32_t pin, const char *name)
{
        struct gpiobus_softc *sc;

        sc = GPIOBUS_SOFTC(dev);
        if (pin > sc->sc_npins)
                return (EINVAL);
        if (name == NULL)
                return (EINVAL);
        /* Save the pin name. */
        if (sc->sc_pins[pin].name == NULL)
                sc->sc_pins[pin].name = malloc(GPIOMAXNAME, M_DEVBUF,
                    M_WAITOK | M_ZERO);
        strlcpy(sc->sc_pins[pin].name, name, GPIOMAXNAME);

        return (0);
}

static device_method_t gpiobus_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         gpiobus_probe),
        DEVMETHOD(device_attach,        gpiobus_attach),
        DEVMETHOD(device_detach,        gpiobus_detach),
        DEVMETHOD(device_shutdown,      bus_generic_shutdown),
        DEVMETHOD(device_suspend,       gpiobus_suspend),
        DEVMETHOD(device_resume,        gpiobus_resume),

        /* Bus interface */
        DEVMETHOD(bus_setup_intr,       bus_generic_setup_intr),
        DEVMETHOD(bus_config_intr,      bus_generic_config_intr),
        DEVMETHOD(bus_teardown_intr,    bus_generic_teardown_intr),
        DEVMETHOD(bus_delete_resource,  bus_generic_rl_delete_resource),
        DEVMETHOD(bus_get_resource,     bus_generic_rl_get_resource),
        DEVMETHOD(bus_set_resource,     bus_generic_rl_set_resource),
        DEVMETHOD(bus_alloc_resource,   gpiobus_alloc_resource),
        DEVMETHOD(bus_release_resource, gpiobus_release_resource),
        DEVMETHOD(bus_activate_resource,        bus_generic_rman_activate_resource),
        DEVMETHOD(bus_deactivate_resource,      bus_generic_rman_deactivate_resource),
        DEVMETHOD(bus_get_resource_list,        gpiobus_get_resource_list),
        DEVMETHOD(bus_get_rman,         gpiobus_get_rman),
        DEVMETHOD(bus_add_child,        gpiobus_add_child),
        DEVMETHOD(bus_child_deleted,    gpiobus_child_deleted),
        DEVMETHOD(bus_rescan,           gpiobus_rescan),
        DEVMETHOD(bus_probe_nomatch,    gpiobus_probe_nomatch),
        DEVMETHOD(bus_print_child,      gpiobus_print_child),
        DEVMETHOD(bus_child_location,   gpiobus_child_location),
        DEVMETHOD(bus_hinted_child,     gpiobus_hinted_child),
        DEVMETHOD(bus_read_ivar,        gpiobus_read_ivar),
        DEVMETHOD(bus_write_ivar,       gpiobus_write_ivar),

        /* GPIO protocol */
        DEVMETHOD(gpiobus_acquire_bus,  gpiobus_acquire_bus),
        DEVMETHOD(gpiobus_release_bus,  gpiobus_release_bus),
        DEVMETHOD(gpiobus_pin_getflags, gpiobus_pin_getflags),
        DEVMETHOD(gpiobus_pin_getcaps,  gpiobus_pin_getcaps),
        DEVMETHOD(gpiobus_pin_setflags, gpiobus_pin_setflags),
        DEVMETHOD(gpiobus_pin_get,      gpiobus_pin_get),
        DEVMETHOD(gpiobus_pin_set,      gpiobus_pin_set),
        DEVMETHOD(gpiobus_pin_toggle,   gpiobus_pin_toggle),
        DEVMETHOD(gpiobus_pin_access_32,gpiobus_pin_access_32),
        DEVMETHOD(gpiobus_pin_config_32,gpiobus_pin_config_32),
        DEVMETHOD(gpiobus_pin_getname,  gpiobus_pin_getname),
        DEVMETHOD(gpiobus_pin_setname,  gpiobus_pin_setname),

        DEVMETHOD_END
};

driver_t gpiobus_driver = {
        "gpiobus",
        gpiobus_methods,
        sizeof(struct gpiobus_softc)
};

EARLY_DRIVER_MODULE(gpiobus, gpio, gpiobus_driver, 0, 0,
    BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
MODULE_VERSION(gpiobus, 1);