/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 Benno Rice.
 * Copyright (C) 2008 MARVELL INTERNATIONAL LTD.
 * Copyright (c) 2017 Semihalf.
 * All rights reserved.
 *
 * Adapted and extended for Marvell SoCs by Semihalf.
 *
 * 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 ``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 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.
 *
 * from: FreeBSD: //depot/projects/arm/src/sys/arm/xscale/pxa2x0/pxa2x0_gpio.c, rev 1
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/interrupt.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/rman.h>
#include <sys/queue.h>
#include <sys/timetc.h>
#include <sys/callout.h>
#include <sys/gpio.h>
#include <machine/bus.h>
#include <machine/intr.h>

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

#include <arm/mv/mvvar.h>
#include <arm/mv/mvreg.h>

#include "gpio_if.h"

#define GPIO_MAX_INTR_COUNT     8
#define GPIO_PINS_PER_REG       32
#define GPIO_GENERIC_CAP        (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT |             \
                                GPIO_PIN_OPENDRAIN | GPIO_PIN_PUSHPULL |        \
                                GPIO_PIN_TRISTATE | GPIO_PIN_PULLUP |           \
                                GPIO_PIN_PULLDOWN | GPIO_PIN_INVIN |            \
                                GPIO_PIN_INVOUT)

#define DEBOUNCE_CHECK_MS       1
#define DEBOUNCE_LO_HI_MS       2
#define DEBOUNCE_HI_LO_MS       2
#define DEBOUNCE_CHECK_TICKS    ((hz / 1000) * DEBOUNCE_CHECK_MS)

struct mv_gpio_softc {
        device_t                dev;
        device_t                sc_busdev;
        struct resource *       mem_res;
        int                     mem_rid;
        struct resource *       irq_res[GPIO_MAX_INTR_COUNT];
        int                     irq_rid[GPIO_MAX_INTR_COUNT];
        struct intr_event *     gpio_events[MV_GPIO_MAX_NPINS];
        void                    *ih_cookie[GPIO_MAX_INTR_COUNT];
        bus_space_tag_t         bst;
        bus_space_handle_t      bsh;
        uint32_t                offset;
        struct mtx              mutex;
        uint8_t                 pin_num;        /* number of GPIO pins */
        uint8_t                 irq_num;        /* number of real IRQs occupied by GPIO controller */
        struct gpio_pin         gpio_setup[MV_GPIO_MAX_NPINS];

        /* Used for debouncing. */
        uint32_t                debounced_state_lo;
        uint32_t                debounced_state_hi;
        struct callout          **debounce_callouts;
        int                     *debounce_counters;
};

struct mv_gpio_pindev {
        device_t dev;
        int pin;
};

static int      mv_gpio_probe(device_t);
static int      mv_gpio_attach(device_t);
static int      mv_gpio_intr(device_t, void *);

static void     mv_gpio_double_edge_init(device_t, int);

static int      mv_gpio_debounce_setup(device_t, int);
static int      mv_gpio_debounce_prepare(device_t, int);
static int      mv_gpio_debounce_init(device_t, int);
static void     mv_gpio_debounce_start(device_t, int);
static void     mv_gpio_debounce(void *);
static void     mv_gpio_debounced_state_set(device_t, int, uint8_t);
static uint32_t mv_gpio_debounced_state_get(device_t, int);

static void     mv_gpio_exec_intr_handlers(device_t, uint32_t, int);
static void     mv_gpio_intr_handler(device_t, int);
static uint32_t mv_gpio_reg_read(device_t, uint32_t);
static void     mv_gpio_reg_write(device_t, uint32_t, uint32_t);
static void     mv_gpio_reg_set(device_t, uint32_t, uint32_t);
static void     mv_gpio_reg_clear(device_t, uint32_t, uint32_t);

static void     mv_gpio_blink(device_t, uint32_t, uint8_t);
static void     mv_gpio_polarity(device_t, uint32_t, uint8_t, uint8_t);
static void     mv_gpio_level(device_t, uint32_t, uint8_t);
static void     mv_gpio_edge(device_t, uint32_t, uint8_t);
static void     mv_gpio_out_en(device_t, uint32_t, uint8_t);
static void     mv_gpio_int_ack(struct mv_gpio_pindev *);
static void     mv_gpio_value_set(device_t, uint32_t, uint8_t);
static uint32_t mv_gpio_value_get(device_t, uint32_t, uint8_t);

static void     mv_gpio_intr_mask(struct mv_gpio_pindev *);
static void     mv_gpio_intr_unmask(struct mv_gpio_pindev *);

void mv_gpio_finish_intrhandler(struct mv_gpio_pindev *);
int mv_gpio_setup_intrhandler(device_t, const char *,
    driver_filter_t *, void (*)(void *), void *,
    int, int, void **);
int mv_gpio_configure(device_t, uint32_t, uint32_t, uint32_t);
void mv_gpio_out(device_t, uint32_t, uint8_t, uint8_t);
uint8_t mv_gpio_in(device_t, uint32_t);

/*
 * GPIO interface
 */
static device_t mv_gpio_get_bus(device_t);
static int mv_gpio_pin_max(device_t, int *);
static int mv_gpio_pin_getcaps(device_t, uint32_t, uint32_t *);
static int mv_gpio_pin_getflags(device_t, uint32_t, uint32_t *);
static int mv_gpio_pin_getname(device_t, uint32_t, char *);
static int mv_gpio_pin_setflags(device_t, uint32_t, uint32_t);
static int mv_gpio_pin_set(device_t, uint32_t, unsigned int);
static int mv_gpio_pin_get(device_t, uint32_t, unsigned int *);
static int mv_gpio_pin_toggle(device_t, uint32_t);
static int mv_gpio_map_gpios(device_t, phandle_t, phandle_t,
    int, pcell_t *, uint32_t *, uint32_t *);

#define MV_GPIO_LOCK()          mtx_lock_spin(&sc->mutex)
#define MV_GPIO_UNLOCK()        mtx_unlock_spin(&sc->mutex)
#define MV_GPIO_ASSERT_LOCKED() mtx_assert(&sc->mutex, MA_OWNED)

static device_method_t mv_gpio_methods[] = {
        DEVMETHOD(device_probe,         mv_gpio_probe),
        DEVMETHOD(device_attach,        mv_gpio_attach),

        /* GPIO protocol */
        DEVMETHOD(gpio_get_bus,         mv_gpio_get_bus),
        DEVMETHOD(gpio_pin_max,         mv_gpio_pin_max),
        DEVMETHOD(gpio_pin_getname,     mv_gpio_pin_getname),
        DEVMETHOD(gpio_pin_getflags,    mv_gpio_pin_getflags),
        DEVMETHOD(gpio_pin_getcaps,     mv_gpio_pin_getcaps),
        DEVMETHOD(gpio_pin_setflags,    mv_gpio_pin_setflags),
        DEVMETHOD(gpio_pin_get,         mv_gpio_pin_get),
        DEVMETHOD(gpio_pin_set,         mv_gpio_pin_set),
        DEVMETHOD(gpio_pin_toggle,      mv_gpio_pin_toggle),
        DEVMETHOD(gpio_map_gpios,       mv_gpio_map_gpios),

        DEVMETHOD_END
};

static driver_t mv_gpio_driver = {
        "gpio",
        mv_gpio_methods,
        sizeof(struct mv_gpio_softc),
};

EARLY_DRIVER_MODULE(mv_gpio, simplebus, mv_gpio_driver, 0, 0,
    BUS_PASS_INTERRUPT + BUS_PASS_ORDER_LAST);

struct ofw_compat_data compat_data[] = {
        { "mrvl,gpio", 1 },
        { "marvell,orion-gpio", 1 },
        { NULL, 0 }
};

static int
mv_gpio_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, "Marvell Integrated GPIO Controller");
        return (0);
}

static int
mv_gpio_setup_interrupts(struct mv_gpio_softc *sc, phandle_t node)
{
        phandle_t iparent;
        pcell_t irq_cells;
        int i, size;

        /* Find root interrupt controller */
        iparent = ofw_bus_find_iparent(node);
        if (iparent == 0) {
                device_printf(sc->dev, "No interrupt-parrent found. "
                                "Error in DTB\n");
                return (ENXIO);
        } else {
                /* While at parent - store interrupt cells prop */
                if (OF_searchencprop(OF_node_from_xref(iparent),
                    "#interrupt-cells", &irq_cells, sizeof(irq_cells)) == -1) {
                        device_printf(sc->dev, "DTB: Missing #interrupt-cells "
                            "property in interrupt parent node\n");
                        return (ENXIO);
                }
        }

        size = OF_getproplen(node, "interrupts");
        if (size != -1) {
                size = size / sizeof(pcell_t);
                size = size / irq_cells;
                sc->irq_num = size;
                device_printf(sc->dev, "%d IRQs available\n", sc->irq_num);
        } else {
                device_printf(sc->dev, "ERROR: no interrupts entry found!\n");
                return (ENXIO);
        }

        for (i = 0; i < sc->irq_num; i++) {
                sc->irq_rid[i] = i;
                sc->irq_res[i] = bus_alloc_resource_any(sc->dev, SYS_RES_IRQ,
                        &sc->irq_rid[i], RF_ACTIVE);
                if (!sc->irq_res[i]) {
                        mtx_destroy(&sc->mutex);
                        device_printf(sc->dev,
                            "could not allocate gpio%d interrupt\n", i+1);
                        return (ENXIO);
                }
        }

        device_printf(sc->dev, "Disable interrupts (offset = %x + EDGE(0x18)\n", sc->offset);
        /* Disable all interrupts */
        bus_space_write_4(sc->bst, sc->bsh, sc->offset + GPIO_INT_EDGE_MASK, 0);
        device_printf(sc->dev, "Disable interrupts (offset = %x + LEV(0x1C))\n", sc->offset);
        bus_space_write_4(sc->bst, sc->bsh, sc->offset + GPIO_INT_LEV_MASK, 0);

        for (i = 0; i < sc->irq_num; i++) {
                device_printf(sc->dev, "Setup intr %d\n", i);
                if (bus_setup_intr(sc->dev, sc->irq_res[i],
                    INTR_TYPE_MISC,
                    (driver_filter_t *)mv_gpio_intr, NULL,
                    sc, &sc->ih_cookie[i]) != 0) {
                        mtx_destroy(&sc->mutex);
                        bus_release_resource(sc->dev, SYS_RES_IRQ,
                                sc->irq_rid[i], sc->irq_res[i]);
                        device_printf(sc->dev, "could not set up intr %d\n", i);
                        return (ENXIO);
                }
        }

        /* Clear interrupt status. */
        device_printf(sc->dev, "Clear int status (offset = %x)\n", sc->offset);
        bus_space_write_4(sc->bst, sc->bsh, sc->offset + GPIO_INT_CAUSE, 0);

        sc->debounce_callouts = (struct callout **)malloc(sc->pin_num *
            sizeof(struct callout *), M_DEVBUF, M_WAITOK | M_ZERO);
        if (sc->debounce_callouts == NULL)
                return (ENOMEM);

        sc->debounce_counters = (int *)malloc(sc->pin_num * sizeof(int),
            M_DEVBUF, M_WAITOK);
        if (sc->debounce_counters == NULL)
                return (ENOMEM);

        return (0);
}

static int
mv_gpio_attach(device_t dev)
{
        int i, rv;
        struct mv_gpio_softc *sc;
        phandle_t node;
        pcell_t pincnt = 0;

        sc = (struct mv_gpio_softc *)device_get_softc(dev);
        if (sc == NULL)
                return (ENXIO);

        node = ofw_bus_get_node(dev);
        sc->dev = dev;

        if (OF_getencprop(node, "pin-count", &pincnt, sizeof(pcell_t)) >= 0 ||
            OF_getencprop(node, "ngpios", &pincnt, sizeof(pcell_t)) >= 0) {
                sc->pin_num = MIN(pincnt, MV_GPIO_MAX_NPINS);
                if (bootverbose)
                        device_printf(dev, "%d pins available\n", sc->pin_num);
        } else {
                device_printf(dev, "ERROR: no pin-count or ngpios entry found!\n");
                return (ENXIO);
        }

        if (OF_getencprop(node, "offset", &sc->offset, sizeof(sc->offset)) == -1)
                sc->offset = 0;

        /* Assign generic capabilities to every gpio pin */
        for(i = 0; i < sc->pin_num; i++)
                sc->gpio_setup[i].gp_caps = GPIO_GENERIC_CAP;

        mtx_init(&sc->mutex, device_get_nameunit(dev), NULL, MTX_SPIN);

        sc->mem_rid = 0;
        sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->mem_rid,
                 RF_ACTIVE | RF_SHAREABLE );

        if (!sc->mem_res) {
                mtx_destroy(&sc->mutex);
                device_printf(dev, "could not allocate memory window\n");
                return (ENXIO);
        }

        sc->bst = rman_get_bustag(sc->mem_res);
        sc->bsh = rman_get_bushandle(sc->mem_res);

        rv = mv_gpio_setup_interrupts(sc, node);
        if (rv != 0)
                return (rv);

        sc->sc_busdev = gpiobus_add_bus(dev);
        if (sc->sc_busdev == NULL) {
                mtx_destroy(&sc->mutex);
                bus_release_resource(dev, SYS_RES_IRQ,
                        sc->irq_rid[i], sc->irq_res[i]);
                return (ENXIO);
        }

        bus_attach_children(dev);
        return (0);
}

static int
mv_gpio_intr(device_t dev, void *arg)
{
        uint32_t int_cause, gpio_val;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_LOCK();

        /*
         * According to documentation, edge sensitive interrupts are asserted
         * when unmasked GPIO_INT_CAUSE register bits are set.
         */
        int_cause = mv_gpio_reg_read(dev, GPIO_INT_CAUSE);
        int_cause &= mv_gpio_reg_read(dev, GPIO_INT_EDGE_MASK);

        /*
         * Level sensitive interrupts are asserted when unmasked GPIO_DATA_IN
         * register bits are set.
         */
        gpio_val = mv_gpio_reg_read(dev, GPIO_DATA_IN);
        gpio_val &= mv_gpio_reg_read(dev, GPIO_INT_LEV_MASK);

        mv_gpio_exec_intr_handlers(dev, int_cause | gpio_val, 0);

        MV_GPIO_UNLOCK();

        return (FILTER_HANDLED);
}

/*
 * GPIO interrupt handling
 */

void
mv_gpio_finish_intrhandler(struct mv_gpio_pindev *s)
{
        /* When we acheive full interrupt support
         * This function will be opposite to
         * mv_gpio_setup_intrhandler
         */

        /* Now it exists only to remind that
         * there should be place to free mv_gpio_pindev
         * allocated by mv_gpio_setup_intrhandler
         */
        free(s, M_DEVBUF);
}

int
mv_gpio_setup_intrhandler(device_t dev, const char *name, driver_filter_t *filt,
    void (*hand)(void *), void *arg, int pin, int flags, void **cookiep)
{
        struct  intr_event *event;
        int     error;
        struct mv_gpio_pindev *s;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);
        s = malloc(sizeof(struct mv_gpio_pindev), M_DEVBUF, M_NOWAIT | M_ZERO);

        if (pin < 0 || pin >= sc->pin_num)
                return (ENXIO);
        event = sc->gpio_events[pin];
        if (event == NULL) {
                MV_GPIO_LOCK();
                if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_DEBOUNCE) {
                        error = mv_gpio_debounce_init(dev, pin);
                        if (error != 0) {
                                MV_GPIO_UNLOCK();
                                return (error);
                        }
                } else if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_IRQ_DOUBLE_EDGE)
                        mv_gpio_double_edge_init(dev, pin);
                MV_GPIO_UNLOCK();
                error = intr_event_create(&event, (void *)s, 0, pin,
                    (void (*)(void *))mv_gpio_intr_mask,
                    (void (*)(void *))mv_gpio_intr_unmask,
                    (void (*)(void *))mv_gpio_int_ack,
                    NULL,
                    "gpio%d:", pin);
                if (error != 0)
                        return (error);
                sc->gpio_events[pin] = event;
        }

        intr_event_add_handler(event, name, filt, hand, arg,
            intr_priority(flags), flags, cookiep);
        return (0);
}

static void
mv_gpio_intr_mask(struct mv_gpio_pindev *s)
{
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(s->dev);

        if (s->pin >= sc->pin_num)
                return;

        MV_GPIO_LOCK();

        if (sc->gpio_setup[s->pin].gp_flags & (MV_GPIO_IN_IRQ_EDGE |
            MV_GPIO_IN_IRQ_DOUBLE_EDGE))
                mv_gpio_edge(s->dev, s->pin, 0);
        else
                mv_gpio_level(s->dev, s->pin, 0);

        /*
         * The interrupt has to be acknowledged before scheduling an interrupt
         * thread. This way we allow for interrupt source to trigger again
         * (which can happen with shared IRQs e.g. PCI) while processing the
         * current event.
         */
        mv_gpio_int_ack(s);

        MV_GPIO_UNLOCK();

        return;
}

static void
mv_gpio_intr_unmask(struct mv_gpio_pindev *s)
{
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(s->dev);

        if (s->pin >= sc->pin_num)
                return;

        MV_GPIO_LOCK();

        if (sc->gpio_setup[s->pin].gp_flags & (MV_GPIO_IN_IRQ_EDGE |
            MV_GPIO_IN_IRQ_DOUBLE_EDGE))
                mv_gpio_edge(s->dev, s->pin, 1);
        else
                mv_gpio_level(s->dev, s->pin, 1);

        MV_GPIO_UNLOCK();

        return;
}

static void
mv_gpio_exec_intr_handlers(device_t dev, uint32_t status, int high)
{
        int i, pin;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        i = 0;
        while (status != 0) {
                if (status & 1) {
                        pin = (high ? (i + GPIO_PINS_PER_REG) : i);
                        if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_DEBOUNCE)
                                mv_gpio_debounce_start(dev, pin);
                        else if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_IRQ_DOUBLE_EDGE) {
                                mv_gpio_polarity(dev, pin, 0, 1);
                                mv_gpio_intr_handler(dev, pin);
                        } else
                                mv_gpio_intr_handler(dev, pin);
                }
                status >>= 1;
                i++;
        }
}

static void
mv_gpio_intr_handler(device_t dev, int pin)
{
        struct intr_irqsrc isrc;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

#ifdef INTR_SOLO
        isrc.isrc_filter = NULL;
#endif
        isrc.isrc_event = sc->gpio_events[pin];

        if (isrc.isrc_event == NULL ||
            CK_SLIST_EMPTY(&isrc.isrc_event->ie_handlers))
                return;

        intr_isrc_dispatch(&isrc, NULL);
}

int
mv_gpio_configure(device_t dev, uint32_t pin, uint32_t flags, uint32_t mask)
{
        int error;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);
        error = 0;

        if (pin >= sc->pin_num)
                return (EINVAL);

        /* check flags consistency */
        if (((flags & mask) & (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT)) ==
            (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT))
                return (EINVAL);

        if (mask & MV_GPIO_IN_DEBOUNCE) {
                if (sc->irq_num == 0)
                        return (EINVAL);
                error = mv_gpio_debounce_prepare(dev, pin);
                if (error != 0)
                        return (error);
        }

        MV_GPIO_LOCK();

        if ((mask & flags) & GPIO_PIN_INPUT)
                mv_gpio_out_en(dev, pin, 0);
        if ((mask & flags) & GPIO_PIN_OUTPUT) {
                if ((flags & mask) & GPIO_PIN_OPENDRAIN)
                        mv_gpio_value_set(dev, pin, 0);
                else
                        mv_gpio_value_set(dev, pin, 1);
                mv_gpio_out_en(dev, pin, 1);
        }

        if (mask & MV_GPIO_OUT_BLINK)
                mv_gpio_blink(dev, pin, flags & MV_GPIO_OUT_BLINK);
        if (mask & MV_GPIO_IN_POL_LOW)
                mv_gpio_polarity(dev, pin, flags & MV_GPIO_IN_POL_LOW, 0);
        if (mask & MV_GPIO_IN_DEBOUNCE) {
                error = mv_gpio_debounce_setup(dev, pin);
                if (error) {
                        MV_GPIO_UNLOCK();
                        return (error);
                }
        }

        sc->gpio_setup[pin].gp_flags &= ~(mask);
        sc->gpio_setup[pin].gp_flags |= (flags & mask);

        MV_GPIO_UNLOCK();

        return (0);
}

static void
mv_gpio_double_edge_init(device_t dev, int pin)
{
        uint8_t raw_read;
        struct mv_gpio_softc *sc __unused;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        raw_read = (mv_gpio_value_get(dev, pin, 1) ? 1 : 0);

        if (raw_read)
                mv_gpio_polarity(dev, pin, 1, 0);
        else
                mv_gpio_polarity(dev, pin, 0, 0);
}

static int
mv_gpio_debounce_setup(device_t dev, int pin)
{
        struct callout *c;
        struct mv_gpio_softc *sc;

        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        c = sc->debounce_callouts[pin];
        if (c == NULL)
                return (ENXIO);

        if (callout_active(c))
                callout_deactivate(c);

        callout_stop(c);

        return (0);
}

static int
mv_gpio_debounce_prepare(device_t dev, int pin)
{
        struct callout *c;
        struct mv_gpio_softc *sc;

        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        c = sc->debounce_callouts[pin];
        if (c == NULL) {
                c = (struct callout *)malloc(sizeof(struct callout),
                    M_DEVBUF, M_WAITOK);
                sc->debounce_callouts[pin] = c;
                if (c == NULL)
                        return (ENOMEM);
                callout_init(c, 1);
        }

        return (0);
}

static int
mv_gpio_debounce_init(device_t dev, int pin)
{
        uint8_t raw_read;
        int *cnt;
        struct mv_gpio_softc *sc;

        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        cnt = &sc->debounce_counters[pin];
        raw_read = (mv_gpio_value_get(dev, pin, 1) ? 1 : 0);
        if (raw_read) {
                mv_gpio_polarity(dev, pin, 1, 0);
                *cnt = DEBOUNCE_HI_LO_MS / DEBOUNCE_CHECK_MS;
        } else {
                mv_gpio_polarity(dev, pin, 0, 0);
                *cnt = DEBOUNCE_LO_HI_MS / DEBOUNCE_CHECK_MS;
        }

        mv_gpio_debounced_state_set(dev, pin, raw_read);

        return (0);
}

static void
mv_gpio_debounce_start(device_t dev, int pin)
{
        struct callout *c;
        struct mv_gpio_pindev s = {dev, pin};
        struct mv_gpio_pindev *sd;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        c = sc->debounce_callouts[pin];
        if (c == NULL) {
                mv_gpio_int_ack(&s);
                return;
        }

        if (callout_pending(c) || callout_active(c)) {
                mv_gpio_int_ack(&s);
                return;
        }

        sd = (struct mv_gpio_pindev *)malloc(sizeof(struct mv_gpio_pindev),
            M_DEVBUF, M_WAITOK);
        if (sd == NULL) {
                mv_gpio_int_ack(&s);
                return;
        }
        sd->pin = pin;
        sd->dev = dev;

        callout_reset(c, DEBOUNCE_CHECK_TICKS, mv_gpio_debounce, sd);
}

static void
mv_gpio_debounce(void *arg)
{
        uint8_t raw_read, last_state;
        int pin;
        device_t dev;
        int *debounce_counter;
        struct mv_gpio_softc *sc;
        struct mv_gpio_pindev *s;

        s = (struct mv_gpio_pindev *)arg;
        dev = s->dev;
        pin = s->pin;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_LOCK();

        raw_read = (mv_gpio_value_get(dev, pin, 1) ? 1 : 0);
        last_state = (mv_gpio_debounced_state_get(dev, pin) ? 1 : 0);
        debounce_counter = &sc->debounce_counters[pin];

        if (raw_read == last_state) {
                if (last_state)
                        *debounce_counter = DEBOUNCE_HI_LO_MS /
                            DEBOUNCE_CHECK_MS;
                else
                        *debounce_counter = DEBOUNCE_LO_HI_MS /
                            DEBOUNCE_CHECK_MS;

                callout_reset(sc->debounce_callouts[pin],
                    DEBOUNCE_CHECK_TICKS, mv_gpio_debounce, arg);
        } else {
                *debounce_counter = *debounce_counter - 1;
                if (*debounce_counter != 0)
                        callout_reset(sc->debounce_callouts[pin],
                            DEBOUNCE_CHECK_TICKS, mv_gpio_debounce, arg);
                else {
                        mv_gpio_debounced_state_set(dev, pin, raw_read);

                        if (last_state)
                                *debounce_counter = DEBOUNCE_HI_LO_MS /
                                    DEBOUNCE_CHECK_MS;
                        else
                                *debounce_counter = DEBOUNCE_LO_HI_MS /
                                    DEBOUNCE_CHECK_MS;

                        if (((sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_POL_LOW) &&
                            (raw_read == 0)) ||
                            (((sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_POL_LOW) == 0) &&
                            raw_read) ||
                            (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_IRQ_DOUBLE_EDGE))
                                mv_gpio_intr_handler(dev, pin);

                        /* Toggle polarity for next edge. */
                        mv_gpio_polarity(dev, pin, 0, 1);

                        free(arg, M_DEVBUF);
                        callout_deactivate(sc->debounce_callouts[pin]);
                }
        }

        MV_GPIO_UNLOCK();
}

static void
mv_gpio_debounced_state_set(device_t dev, int pin, uint8_t new_state)
{
        uint32_t *old_state;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        if (pin >= GPIO_PINS_PER_REG) {
                old_state = &sc->debounced_state_hi;
                pin -= GPIO_PINS_PER_REG;
        } else
                old_state = &sc->debounced_state_lo;

        if (new_state)
                *old_state |= (1 << pin);
        else
                *old_state &= ~(1 << pin);
}

static uint32_t
mv_gpio_debounced_state_get(device_t dev, int pin)
{
        uint32_t *state;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        if (pin >= GPIO_PINS_PER_REG) {
                state = &sc->debounced_state_hi;
                pin -= GPIO_PINS_PER_REG;
        } else
                state = &sc->debounced_state_lo;

        return (*state & (1 << pin));
}

void
mv_gpio_out(device_t dev, uint32_t pin, uint8_t val, uint8_t enable)
{
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_LOCK();

        mv_gpio_value_set(dev, pin, val);
        mv_gpio_out_en(dev, pin, enable);

        MV_GPIO_UNLOCK();
}

uint8_t
mv_gpio_in(device_t dev, uint32_t pin)
{
        uint8_t state;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_DEBOUNCE) {
                if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_POL_LOW)
                        state = (mv_gpio_debounced_state_get(dev, pin) ? 0 : 1);
                else
                        state = (mv_gpio_debounced_state_get(dev, pin) ? 1 : 0);
        } else if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_IRQ_DOUBLE_EDGE) {
                if (sc->gpio_setup[pin].gp_flags & MV_GPIO_IN_POL_LOW)
                        state = (mv_gpio_value_get(dev, pin, 1) ? 0 : 1);
                else
                        state = (mv_gpio_value_get(dev, pin, 1) ? 1 : 0);
        } else
                state = (mv_gpio_value_get(dev, pin, 0) ? 1 : 0);

        return (state);
}

static uint32_t
mv_gpio_reg_read(device_t dev, uint32_t reg)
{
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        return (bus_space_read_4(sc->bst, sc->bsh, sc->offset + reg));
}

static void
mv_gpio_reg_write(device_t dev, uint32_t reg, uint32_t val)
{
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        bus_space_write_4(sc->bst, sc->bsh, sc->offset + reg, val);
}

static void
mv_gpio_reg_set(device_t dev, uint32_t reg, uint32_t pin)
{
        uint32_t reg_val;

        reg_val = mv_gpio_reg_read(dev, reg);
        reg_val |= GPIO(pin);
        mv_gpio_reg_write(dev, reg, reg_val);
}

static void
mv_gpio_reg_clear(device_t dev, uint32_t reg, uint32_t pin)
{
        uint32_t reg_val;

        reg_val = mv_gpio_reg_read(dev, reg);
        reg_val &= ~(GPIO(pin));
        mv_gpio_reg_write(dev, reg, reg_val);
}

static void
mv_gpio_out_en(device_t dev, uint32_t pin, uint8_t enable)
{
        uint32_t reg;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_DATA_OUT_EN_CTRL;

        if (enable)
                mv_gpio_reg_clear(dev, reg, pin);
        else
                mv_gpio_reg_set(dev, reg, pin);
}

static void
mv_gpio_blink(device_t dev, uint32_t pin, uint8_t enable)
{
        uint32_t reg;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_BLINK_EN;

        if (enable)
                mv_gpio_reg_set(dev, reg, pin);
        else
                mv_gpio_reg_clear(dev, reg, pin);
}

static void
mv_gpio_polarity(device_t dev, uint32_t pin, uint8_t enable, uint8_t toggle)
{
        uint32_t reg, reg_val;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_DATA_IN_POLAR;

        if (toggle) {
                reg_val = mv_gpio_reg_read(dev, reg) & GPIO(pin);
                if (reg_val)
                        mv_gpio_reg_clear(dev, reg, pin);
                else
                        mv_gpio_reg_set(dev, reg, pin);
        } else if (enable)
                mv_gpio_reg_set(dev, reg, pin);
        else
                mv_gpio_reg_clear(dev, reg, pin);
}

static void
mv_gpio_level(device_t dev, uint32_t pin, uint8_t enable)
{
        uint32_t reg;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_INT_LEV_MASK;

        if (enable)
                mv_gpio_reg_set(dev, reg, pin);
        else
                mv_gpio_reg_clear(dev, reg, pin);
}

static void
mv_gpio_edge(device_t dev, uint32_t pin, uint8_t enable)
{
        uint32_t reg;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_INT_EDGE_MASK;

        if (enable)
                mv_gpio_reg_set(dev, reg, pin);
        else
                mv_gpio_reg_clear(dev, reg, pin);
}

static void
mv_gpio_int_ack(struct mv_gpio_pindev *s)
{
        uint32_t reg, pin;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(s->dev);
        pin = s->pin;

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_INT_CAUSE;

        mv_gpio_reg_clear(s->dev, reg, pin);
}

static uint32_t
mv_gpio_value_get(device_t dev, uint32_t pin, uint8_t exclude_polar)
{
        uint32_t reg, polar_reg, reg_val, polar_reg_val;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        if (pin >= sc->pin_num)
                return (0);

        reg = GPIO_DATA_IN;
        polar_reg = GPIO_DATA_IN_POLAR;

        reg_val = mv_gpio_reg_read(dev, reg);

        if (exclude_polar) {
                polar_reg_val = mv_gpio_reg_read(dev, polar_reg);
                return ((reg_val & GPIO(pin)) ^ (polar_reg_val & GPIO(pin)));
        } else
                return (reg_val & GPIO(pin));
}

static void
mv_gpio_value_set(device_t dev, uint32_t pin, uint8_t val)
{
        uint32_t reg;
        struct mv_gpio_softc *sc;
        sc = (struct mv_gpio_softc *)device_get_softc(dev);

        MV_GPIO_ASSERT_LOCKED();

        if (pin >= sc->pin_num)
                return;

        reg = GPIO_DATA_OUT;

        if (val)
                mv_gpio_reg_set(dev, reg, pin);
        else
                mv_gpio_reg_clear(dev, reg, pin);
}

/*
 * GPIO interface methods
 */

static int
mv_gpio_pin_max(device_t dev, int *maxpin)
{
        struct mv_gpio_softc *sc;
        if (maxpin == NULL)
                return (EINVAL);

        sc = device_get_softc(dev);
        *maxpin = sc->pin_num;

        return (0);
}

static int
mv_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);
        if (caps == NULL)
                return (EINVAL);

        if (pin >= sc->pin_num)
                return (EINVAL);

        MV_GPIO_LOCK();
        *caps = sc->gpio_setup[pin].gp_caps;
        MV_GPIO_UNLOCK();

        return (0);
}

static int
mv_gpio_pin_getflags(device_t dev, uint32_t pin, uint32_t *flags)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);
        if (flags == NULL)
                return (EINVAL);

        if (pin >= sc->pin_num)
                return (EINVAL);

        MV_GPIO_LOCK();
        *flags = sc->gpio_setup[pin].gp_flags;
        MV_GPIO_UNLOCK();

        return (0);
}

static int
mv_gpio_pin_getname(device_t dev, uint32_t pin, char *name)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);
        if (name == NULL)
                return (EINVAL);

        if (pin >= sc->pin_num)
                return (EINVAL);

        MV_GPIO_LOCK();
        memcpy(name, sc->gpio_setup[pin].gp_name, GPIOMAXNAME);
        MV_GPIO_UNLOCK();

        return (0);
}

static int
mv_gpio_pin_setflags(device_t dev, uint32_t pin, uint32_t flags)
{
        int ret;
        struct mv_gpio_softc *sc = device_get_softc(dev);
        if (pin >= sc->pin_num)
                return (EINVAL);

        /* Check for unwanted flags. */
        if ((flags & sc->gpio_setup[pin].gp_caps) != flags)
                return (EINVAL);

        ret = mv_gpio_configure(dev, pin, flags, ~0);

        return (ret);
}

static int
mv_gpio_pin_set(device_t dev, uint32_t pin, unsigned int value)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);
        if (pin >= sc->pin_num)
                return (EINVAL);

        MV_GPIO_LOCK();
        mv_gpio_value_set(dev, pin, value);
        MV_GPIO_UNLOCK();

        return (0);
}

static int
mv_gpio_pin_get(device_t dev, uint32_t pin, unsigned int *value)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);
        if (value == NULL)
                return (EINVAL);

        if (pin >= sc->pin_num)
                return (EINVAL);

        MV_GPIO_LOCK();
        *value = mv_gpio_in(dev, pin);
        MV_GPIO_UNLOCK();

        return (0);
}

static int
mv_gpio_pin_toggle(device_t dev, uint32_t pin)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);
        uint32_t value;
        if (pin >= sc->pin_num)
                return (EINVAL);

        MV_GPIO_LOCK();
        value = mv_gpio_in(dev, pin);
        value = (~value) & 1;
        mv_gpio_value_set(dev, pin, value);
        MV_GPIO_UNLOCK();

        return (0);
}

static device_t
mv_gpio_get_bus(device_t dev)
{
        struct mv_gpio_softc *sc = device_get_softc(dev);

        return (sc->sc_busdev);
}

static int
mv_gpio_map_gpios(device_t bus, phandle_t dev, phandle_t gparent, int gcells,
    pcell_t *gpios, uint32_t *pin, uint32_t *flags)
{
        struct mv_gpio_softc *sc = device_get_softc(bus);

        if (gpios[0] >= sc->pin_num)
                return (EINVAL);

        *pin = gpios[0];
        *flags = gpios[1];
        mv_gpio_configure(bus, *pin, *flags, ~0);

        return (0);
}