gpio.c

/*-
 * 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);
}