/*-
 * Copyright (c) 2015 Justin Hibbits
 * Copyright (c) 2013 Thomas Skibo
 * 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/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/gpio.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <machine/stdarg.h>

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

#include "gpio_if.h"

#define MAXPIN		(7)

#define VALID_PIN(u)	((u) >= 0 && (u) <= MAXPIN)

#define GPIO_LOCK(sc)			mtx_lock(&(sc)->sc_mtx)
#define	GPIO_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
#define GPIO_LOCK_INIT(sc) \
	mtx_init(&(sc)->sc_mtx, device_get_nameunit((sc)->dev),	\
	    "gpio", MTX_DEF)
#define GPIO_LOCK_DESTROY(_sc)	mtx_destroy(&_sc->sc_mtx);

struct mpc85xx_gpio_softc {
	device_t	dev;
	device_t	busdev;
	struct mtx	sc_mtx;
	struct resource *out_res;	/* Memory resource */
	struct resource *in_res;
};

static device_t
mpc85xx_gpio_get_bus(device_t dev)
{
	struct mpc85xx_gpio_softc *sc;

	sc = device_get_softc(dev);

	return (sc->busdev);
}

static int
mpc85xx_gpio_pin_max(device_t dev, int *maxpin)
{

	*maxpin = MAXPIN;
	return (0);
}

/* Get a specific pin's capabilities. */
static int
mpc85xx_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
{

	if (!VALID_PIN(pin))
		return (EINVAL);

	*caps = (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT);

	return (0);
}

/* Get a specific pin's name. */
static int
mpc85xx_gpio_pin_getname(device_t dev, uint32_t pin, char *name)
{

	if (!VALID_PIN(pin))
		return (EINVAL);

	snprintf(name, GPIOMAXNAME, "GPIO%d", pin);
	name[GPIOMAXNAME-1] = '\0';

	return (0);
}

/* Set a specific output pin's value. */
static int
mpc85xx_gpio_pin_set(device_t dev, uint32_t pin, unsigned int value)
{
	struct mpc85xx_gpio_softc *sc = device_get_softc(dev);
	uint32_t outvals;
	uint8_t pinbit;

	if (!VALID_PIN(pin) || value > 1)
		return (EINVAL);

	GPIO_LOCK(sc);
	pinbit = 31 - pin;

	outvals = bus_read_4(sc->out_res, 0);
	outvals &= ~(1 << pinbit);
	outvals |= (value << pinbit);
	bus_write_4(sc->out_res, 0, outvals);

	GPIO_UNLOCK(sc);

	return (0);
}

/* Get a specific pin's input value. */
static int
mpc85xx_gpio_pin_get(device_t dev, uint32_t pin, unsigned int *value)
{
	struct mpc85xx_gpio_softc *sc = device_get_softc(dev);

	if (!VALID_PIN(pin))
		return (EINVAL);

	*value = (bus_read_4(sc->in_res, 0) >> (31 - pin)) & 1;

	return (0);
}

/* Toggle a pin's output value. */
static int
mpc85xx_gpio_pin_toggle(device_t dev, uint32_t pin)
{
	struct mpc85xx_gpio_softc *sc = device_get_softc(dev);
	uint32_t val;

	if (!VALID_PIN(pin))
		return (EINVAL);

	GPIO_LOCK(sc);

	val = bus_read_4(sc->out_res, 0);
	val ^= (1 << (31 - pin));
	bus_write_4(sc->out_res, 0, val);

	GPIO_UNLOCK(sc);

	return (0);
}

static int
mpc85xx_gpio_probe(device_t dev)
{
	uint32_t svr;

	if (!ofw_bus_status_okay(dev))
		return (ENXIO);

	if (!ofw_bus_is_compatible(dev, "gpio"))
		return (ENXIO);

	svr = mfspr(SPR_SVR);
	switch (SVR_VER(svr)) {
	case SVR_MPC8533:
	case SVR_MPC8533E:
		break;
	default:
		return (ENXIO);
	}

	device_set_desc(dev, "MPC85xx GPIO driver");
	return (0);
}

static int mpc85xx_gpio_detach(device_t dev);

static int
mpc85xx_gpio_attach(device_t dev)
{
	struct mpc85xx_gpio_softc *sc = device_get_softc(dev);
	int rid;

	sc->dev = dev;

	GPIO_LOCK_INIT(sc);

	/* Allocate memory. */
	rid = 0;
	sc->out_res = bus_alloc_resource_any(dev,
		     SYS_RES_MEMORY, &rid, RF_ACTIVE);
	if (sc->out_res == NULL) {
		device_printf(dev, "Can't allocate memory for device output port");
		mpc85xx_gpio_detach(dev);
		return (ENOMEM);
	}

	rid = 1;
	sc->in_res = bus_alloc_resource_any(dev,
		     SYS_RES_MEMORY, &rid, RF_ACTIVE);
	if (sc->in_res == NULL) {
		device_printf(dev, "Can't allocate memory for device input port");
		mpc85xx_gpio_detach(dev);
		return (ENOMEM);
	}

	sc->busdev = gpiobus_attach_bus(dev);
	if (sc->busdev == NULL) {
		mpc85xx_gpio_detach(dev);
		return (ENOMEM);
	}

	OF_device_register_xref(OF_xref_from_node(ofw_bus_get_node(dev)), dev);

	return (0);
}

static int
mpc85xx_gpio_detach(device_t dev)
{
	struct mpc85xx_gpio_softc *sc = device_get_softc(dev);

	gpiobus_detach_bus(dev);

	if (sc->out_res != NULL) {
		/* Release output port resource. */
		bus_release_resource(dev, SYS_RES_MEMORY,
				     rman_get_rid(sc->out_res), sc->out_res);
	}

	if (sc->in_res != NULL) {
		/* Release input port resource. */
		bus_release_resource(dev, SYS_RES_MEMORY,
				     rman_get_rid(sc->in_res), sc->in_res);
	}

	GPIO_LOCK_DESTROY(sc);

	return (0);
}

static device_method_t mpc85xx_gpio_methods[] = {
	/* device_if */
	DEVMETHOD(device_probe, 	mpc85xx_gpio_probe),
	DEVMETHOD(device_attach, 	mpc85xx_gpio_attach),
	DEVMETHOD(device_detach, 	mpc85xx_gpio_detach),

	/* GPIO protocol */
	DEVMETHOD(gpio_get_bus, 	mpc85xx_gpio_get_bus),
	DEVMETHOD(gpio_pin_max, 	mpc85xx_gpio_pin_max),
	DEVMETHOD(gpio_pin_getname, 	mpc85xx_gpio_pin_getname),
	DEVMETHOD(gpio_pin_getcaps, 	mpc85xx_gpio_pin_getcaps),
	DEVMETHOD(gpio_pin_get, 	mpc85xx_gpio_pin_get),
	DEVMETHOD(gpio_pin_set, 	mpc85xx_gpio_pin_set),
	DEVMETHOD(gpio_pin_toggle, 	mpc85xx_gpio_pin_toggle),

	DEVMETHOD_END
};

static driver_t mpc85xx_gpio_driver = {
	"gpio",
	mpc85xx_gpio_methods,
	sizeof(struct mpc85xx_gpio_softc),
};
static devclass_t mpc85xx_gpio_devclass;

EARLY_DRIVER_MODULE(mpc85xx_gpio, simplebus, mpc85xx_gpio_driver,
    mpc85xx_gpio_devclass, NULL, NULL,
    BUS_PASS_RESOURCE + BUS_PASS_ORDER_MIDDLE);