/*-
 * Copyright (c) 2015 Rubicon Communications, LLC (Netgate)
 * 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>
/*
 * GPIO driver for the ADI Engineering RCC-VE and RCC-DFF/DFFv2.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/gpio.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>

#include <machine/bus.h>

#include <dev/gpio/gpiobusvar.h>
#include <isa/isavar.h>

#include "gpio_if.h"

#define RCC_GPIO_BASE           0x500
#define RCC_GPIO_USE_SEL        0x00
#define RCC_GPIO_IO_SEL         0x04
#define RCC_GPIO_GP_LVL         0x08

struct rcc_gpio_pin {
        uint32_t                pin;
        const char              *name;
        uint32_t                caps;
};

static struct rcc_gpio_pin rcc_pins[] = {
        { .pin = (1 << 11), .name = "reset switch", .caps = GPIO_PIN_INPUT },
        { .pin = (1 << 15), .name = "red LED", .caps = GPIO_PIN_OUTPUT },
        { .pin = (1 << 17), .name = "green LED", .caps = GPIO_PIN_OUTPUT },
#if 0
        { .pin = (1 << 16), .name = "HD1 LED", .caps = GPIO_PIN_OUTPUT },
        { .pin = (1 << 18), .name = "HD2 LED", .caps = GPIO_PIN_OUTPUT },
#endif
};

struct rcc_gpio_softc {
        device_t                sc_dev;
        device_t                sc_busdev;
        struct mtx              sc_mtx;
        struct resource         *sc_io_res;
        bus_space_tag_t         sc_bst;
        bus_space_handle_t      sc_bsh;
        uint32_t                sc_output;
        int                     sc_io_rid;
        int                     sc_gpio_npins;
};

#define RCC_GPIO_LOCK(_sc)      mtx_lock(&(_sc)->sc_mtx)
#define RCC_GPIO_UNLOCK(_sc)    mtx_unlock(&(_sc)->sc_mtx)
#define RCC_WRITE(_sc, _off, _val)                              \
        bus_space_write_4((_sc)->sc_bst, (_sc)->sc_bsh, _off, _val)
#define RCC_READ(_sc, _off)                                     \
        bus_space_read_4((_sc)->sc_bst, (_sc)->sc_bsh, _off)

static void
rcc_gpio_modify_bits(struct rcc_gpio_softc *sc, uint32_t reg, uint32_t mask,
        uint32_t writebits)
{
        uint32_t value;

        RCC_GPIO_LOCK(sc);
        value = RCC_READ(sc, reg);
        value &= ~mask;
        value |= writebits;
        RCC_WRITE(sc, reg, value);
        RCC_GPIO_UNLOCK(sc);
}

static device_t
rcc_gpio_get_bus(device_t dev)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);

        return (sc->sc_busdev);
}

static int
rcc_gpio_pin_max(device_t dev, int *maxpin)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        *maxpin = sc->sc_gpio_npins - 1;

        return (0);
}

static int
rcc_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        *caps = rcc_pins[pin].caps;

        return (0);
}

static int
rcc_gpio_pin_getflags(device_t dev, uint32_t pin, uint32_t *flags)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        /* Flags cannot be changed. */
        *flags = rcc_pins[pin].caps;

        return (0);
}

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

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        memcpy(name, rcc_pins[pin].name, GPIOMAXNAME);

        return (0);
}

static int
rcc_gpio_pin_setflags(device_t dev, uint32_t pin, uint32_t flags)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        /* Flags cannot be changed - risk of short-circuit!!! */

        return (0);
}

static int
rcc_gpio_pin_set(device_t dev, uint32_t pin, unsigned int value)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        if ((rcc_pins[pin].caps & GPIO_PIN_OUTPUT) == 0)
                return (EINVAL);

        RCC_GPIO_LOCK(sc);
        if (value)
                sc->sc_output |= (1 << rcc_pins[pin].pin);
        else
                sc->sc_output &= ~(1 << rcc_pins[pin].pin);
        RCC_WRITE(sc, RCC_GPIO_GP_LVL, sc->sc_output);
        RCC_GPIO_UNLOCK(sc);

        return (0);
}

static int
rcc_gpio_pin_get(device_t dev, uint32_t pin, unsigned int *val)
{
        struct rcc_gpio_softc *sc;
        uint32_t value;

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        RCC_GPIO_LOCK(sc);
        if (rcc_pins[pin].caps & GPIO_PIN_INPUT)
                value = RCC_READ(sc, RCC_GPIO_GP_LVL);
        else
                value = sc->sc_output;
        RCC_GPIO_UNLOCK(sc);
        *val = (value & (1 << rcc_pins[pin].pin)) ? 1 : 0;

        return (0);
}

static int
rcc_gpio_pin_toggle(device_t dev, uint32_t pin)
{
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        if (pin >= sc->sc_gpio_npins)
                return (EINVAL);

        if ((rcc_pins[pin].caps & GPIO_PIN_OUTPUT) == 0)
                return (EINVAL);

        RCC_GPIO_LOCK(sc);
        if ((sc->sc_output & (1 << rcc_pins[pin].pin)) == 0)
                sc->sc_output |= (1 << rcc_pins[pin].pin);
        else
                sc->sc_output &= ~(1 << rcc_pins[pin].pin);
        RCC_WRITE(sc, RCC_GPIO_GP_LVL, sc->sc_output);
        RCC_GPIO_UNLOCK(sc);

        return (0);
}

static int
rcc_gpio_probe(device_t dev)
{
        char *prod;
        int port;

        /*
         * We don't know of any PnP ID's for this GPIO controller.
         */
        if (isa_get_logicalid(dev) != 0)
                return (ENXIO);

        /*
         * We have to have an IO port hint that is valid.
         */
        port = isa_get_port(dev);
        if (port != RCC_GPIO_BASE)
                return (ENXIO);

        prod = kern_getenv("smbios.system.product");
        if (prod == NULL ||
            (strcmp(prod, "RCC-VE") != 0 && strcmp(prod, "RCC-DFF") != 0))
                return (ENXIO);

        device_set_desc(dev, "RCC-VE/DFF GPIO controller");

        return (BUS_PROBE_DEFAULT);
}

static int
rcc_gpio_attach(device_t dev)
{
        int i;
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        sc->sc_dev = dev;

        /* Allocate IO resources. */
        sc->sc_io_rid = 0;
        sc->sc_io_res = bus_alloc_resource_any(dev, SYS_RES_IOPORT,
            &sc->sc_io_rid, RF_ACTIVE);
        if (sc->sc_io_res == NULL) {
                device_printf(dev, "cannot allocate memory window\n");
                return (ENXIO);
        }
        sc->sc_bst = rman_get_bustag(sc->sc_io_res);
        sc->sc_bsh = rman_get_bushandle(sc->sc_io_res);
        mtx_init(&sc->sc_mtx, "rcc-gpio", "gpio", MTX_DEF);

        /* Initialize the pins. */
        sc->sc_gpio_npins = nitems(rcc_pins);
        for (i = 0; i < sc->sc_gpio_npins; i++) {
                /* Enable it for GPIO. */
                rcc_gpio_modify_bits(sc, RCC_GPIO_USE_SEL, 0, rcc_pins[i].pin);
                /* Set the pin as input or output. */
                if (rcc_pins[i].caps & GPIO_PIN_OUTPUT)
                        rcc_gpio_modify_bits(sc, RCC_GPIO_IO_SEL,
                            rcc_pins[i].pin, 0);
                else
                        rcc_gpio_modify_bits(sc, RCC_GPIO_IO_SEL,
                            0, rcc_pins[i].pin);
        }
        RCC_WRITE(sc, RCC_GPIO_GP_LVL, sc->sc_output);

        /* Attach the gpiobus. */
        sc->sc_busdev = gpiobus_add_bus(dev);
        if (sc->sc_busdev == NULL) {
                bus_release_resource(dev, SYS_RES_IOPORT, sc->sc_io_rid,
                    sc->sc_io_res);
                mtx_destroy(&sc->sc_mtx);
                return (ENXIO);
        }

        bus_attach_children(dev);
        return (0);
}

static int
rcc_gpio_detach(device_t dev)
{
        int i;
        struct rcc_gpio_softc *sc;

        sc = device_get_softc(dev);
        gpiobus_detach_bus(dev);

        /* Disable the GPIO function. */
        for (i = 0; i < sc->sc_gpio_npins; i++)
                rcc_gpio_modify_bits(sc, RCC_GPIO_USE_SEL, rcc_pins[i].pin, 0);

        if (sc->sc_io_res != NULL)
                bus_release_resource(dev, SYS_RES_IOPORT, sc->sc_io_rid,
                    sc->sc_io_res);
        mtx_destroy(&sc->sc_mtx);

        return (0);
}

static device_method_t rcc_gpio_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         rcc_gpio_probe),
        DEVMETHOD(device_attach,        rcc_gpio_attach),
        DEVMETHOD(device_detach,        rcc_gpio_detach),

        /* GPIO protocol */
        DEVMETHOD(gpio_get_bus,         rcc_gpio_get_bus),
        DEVMETHOD(gpio_pin_max,         rcc_gpio_pin_max),
        DEVMETHOD(gpio_pin_getname,     rcc_gpio_pin_getname),
        DEVMETHOD(gpio_pin_getflags,    rcc_gpio_pin_getflags),
        DEVMETHOD(gpio_pin_getcaps,     rcc_gpio_pin_getcaps),
        DEVMETHOD(gpio_pin_setflags,    rcc_gpio_pin_setflags),
        DEVMETHOD(gpio_pin_get,         rcc_gpio_pin_get),
        DEVMETHOD(gpio_pin_set,         rcc_gpio_pin_set),
        DEVMETHOD(gpio_pin_toggle,      rcc_gpio_pin_toggle),

        DEVMETHOD_END
};

static driver_t rcc_gpio_driver = {
        "gpio",
        rcc_gpio_methods,
        sizeof(struct rcc_gpio_softc),
};

DRIVER_MODULE(rcc_gpio, isa, rcc_gpio_driver, 0, 0);
MODULE_DEPEND(rcc_gpio, gpiobus, 1, 1, 1);