/*-
 * Copyright (c) 2013 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/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/sysctl.h>

#include <machine/bus.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include "am335x_pwm.h"

#define ECAP_TSCTR              0x00
#define ECAP_CAP1               0x08
#define ECAP_CAP2               0x0C
#define ECAP_CAP3               0x10
#define ECAP_CAP4               0x14
#define ECAP_ECCTL2             0x2A
#define         ECCTL2_MODE_APWM                (1 << 9)
#define         ECCTL2_SYNCO_SEL                (3 << 6)
#define         ECCTL2_TSCTRSTOP_FREERUN        (1 << 4)

#define ECAP_READ2(_sc, reg)    bus_read_2((_sc)->sc_mem_res, reg);
#define ECAP_WRITE2(_sc, reg, value)    \
    bus_write_2((_sc)->sc_mem_res, reg, value);
#define ECAP_READ4(_sc, reg)    bus_read_4((_sc)->sc_mem_res, reg);
#define ECAP_WRITE4(_sc, reg, value)    \
    bus_write_4((_sc)->sc_mem_res, reg, value);

#define PWM_LOCK(_sc)           mtx_lock(&(_sc)->sc_mtx)
#define PWM_UNLOCK(_sc)         mtx_unlock(&(_sc)->sc_mtx)
#define PWM_LOCK_INIT(_sc)      mtx_init(&(_sc)->sc_mtx, \
    device_get_nameunit(_sc->sc_dev), "am335x_ecap softc", MTX_DEF)
#define PWM_LOCK_DESTROY(_sc)   mtx_destroy(&(_sc)->sc_mtx)

static device_probe_t am335x_ecap_probe;
static device_attach_t am335x_ecap_attach;
static device_detach_t am335x_ecap_detach;

struct am335x_ecap_softc {
        device_t                sc_dev;
        struct mtx              sc_mtx;
        struct resource         *sc_mem_res;
        int                     sc_mem_rid;
};

static struct ofw_compat_data compat_data[] = {
        {"ti,am3352-ecap",      true},
        {"ti,am33xx-ecap",      true},
        {NULL,                  false},
};
SIMPLEBUS_PNP_INFO(compat_data);

static device_method_t am335x_ecap_methods[] = {
        DEVMETHOD(device_probe,         am335x_ecap_probe),
        DEVMETHOD(device_attach,        am335x_ecap_attach),
        DEVMETHOD(device_detach,        am335x_ecap_detach),

        DEVMETHOD_END
};

static driver_t am335x_ecap_driver = {
        "am335x_ecap",
        am335x_ecap_methods,
        sizeof(struct am335x_ecap_softc),
};

/*
 * API function to set period/duty cycles for ECAPx
 */
int
am335x_pwm_config_ecap(int unit, int period, int duty)
{
        device_t dev;
        struct am335x_ecap_softc *sc;
        uint16_t reg;

        dev = devclass_get_device(devclass_find(am335x_ecap_driver.name), unit);
        if (dev == NULL)
                return (ENXIO);

        if (duty > period)
                return (EINVAL);

        if (period == 0)
                return (EINVAL);

        sc = device_get_softc(dev);
        PWM_LOCK(sc);

        reg = ECAP_READ2(sc, ECAP_ECCTL2);
        reg |= ECCTL2_MODE_APWM | ECCTL2_TSCTRSTOP_FREERUN | ECCTL2_SYNCO_SEL;
        ECAP_WRITE2(sc, ECAP_ECCTL2, reg);

        /* CAP3 in APWM mode is APRD shadow register */
        ECAP_WRITE4(sc, ECAP_CAP3, period - 1);

        /* CAP4 in APWM mode is ACMP shadow register */
        ECAP_WRITE4(sc, ECAP_CAP4, duty);
        /* Restart counter */
        ECAP_WRITE4(sc, ECAP_TSCTR, 0);

        PWM_UNLOCK(sc);

        return (0);
}

static int
am335x_ecap_probe(device_t dev)
{

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

        if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
                return (ENXIO);

        device_set_desc(dev, "AM335x eCAP");

        return (BUS_PROBE_DEFAULT);
}

static int
am335x_ecap_attach(device_t dev)
{
        struct am335x_ecap_softc *sc;

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

        PWM_LOCK_INIT(sc);

        sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
            &sc->sc_mem_rid, RF_ACTIVE);
        if (sc->sc_mem_res == NULL) {
                device_printf(dev, "cannot allocate memory resources\n");
                goto fail;
        }

        return (0);

fail:
        PWM_LOCK_DESTROY(sc);
        return (ENXIO);
}

static int
am335x_ecap_detach(device_t dev)
{
        struct am335x_ecap_softc *sc;

        sc = device_get_softc(dev);

        PWM_LOCK(sc);
        if (sc->sc_mem_res)
                bus_release_resource(dev, SYS_RES_MEMORY,
                    sc->sc_mem_rid, sc->sc_mem_res);
        PWM_UNLOCK(sc);

        PWM_LOCK_DESTROY(sc);

        return (0);
}

DRIVER_MODULE(am335x_ecap, am335x_pwmss, am335x_ecap_driver, 0, 0);
MODULE_VERSION(am335x_ecap, 1);
MODULE_DEPEND(am335x_ecap, am335x_pwmss, 1, 1, 1);