/*-
 * Copyright (c) 2016 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/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>

#include <machine/bus.h>

#include <arm/ti/am335x/am335x_scm.h>
#include <arm/ti/ti_cpuid.h>
#include <arm/ti/ti_scm.h>

#include <dev/syscon/syscon.h>
#include "syscon_if.h"

#define TZ_ZEROC        2731

struct am335x_scm_softc {
        int                     sc_last_temp;
        struct sysctl_oid       *sc_temp_oid;
        struct syscon           *syscon;
};

static int
am335x_scm_temp_sysctl(SYSCTL_HANDLER_ARGS)
{
        device_t dev;
        int i, temp;
        struct am335x_scm_softc *sc;
        uint32_t reg;

        dev = (device_t)arg1;
        sc = device_get_softc(dev);

        /* Read the temperature and convert to Kelvin. */
        for(i = 50; i > 0; i--) {
                reg = SYSCON_READ_4(sc->syscon, SCM_BGAP_CTRL);
                if ((reg & SCM_BGAP_EOCZ) == 0)
                        break;
                DELAY(50);
        }
        if ((reg & SCM_BGAP_EOCZ) == 0) {
                sc->sc_last_temp =
                    (reg >> SCM_BGAP_TEMP_SHIFT) & SCM_BGAP_TEMP_MASK;
                sc->sc_last_temp *= 10;
        }
        temp = sc->sc_last_temp + TZ_ZEROC;

        return (sysctl_handle_int(oidp, &temp, 0, req));
}

static void
am335x_scm_identify(driver_t *driver, device_t parent)
{
        device_t child;

        /* AM335x only. */
        if (ti_chip() != CHIP_AM335X)
                return;

        /* Make sure we attach only once. */
        if (device_find_child(parent, "am335x_scm", DEVICE_UNIT_ANY) != NULL)
                return;

        child = device_add_child(parent, "am335x_scm", DEVICE_UNIT_ANY);
        if (child == NULL)
                device_printf(parent, "cannot add ti_scm child\n");
}

static int
am335x_scm_probe(device_t dev)
{
        /* Just allow the first one */
        if (strcmp(device_get_nameunit(dev), "am335x_scm0") != 0)
                return (ENXIO);

        device_set_desc(dev, "AM335x Control Module Extension");

        return (BUS_PROBE_DEFAULT);
}

static int
am335x_scm_attach(device_t dev)
{
        struct am335x_scm_softc *sc;
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid_list *tree;
        uint32_t reg;
        phandle_t opp_table;
        int err;

        sc = device_get_softc(dev);

        /* FIXME: For now; Go and kidnap syscon from opp-table */
        opp_table = OF_finddevice("/opp-table");
        if (opp_table == -1) {
                device_printf(dev, "Cant find /opp-table\n");
                return (ENXIO);
        }
        if (!OF_hasprop(opp_table, "syscon")) {
                device_printf(dev, "/opp-table missing syscon property\n");
                return (ENXIO);
        }
        err = syscon_get_by_ofw_property(dev, opp_table, "syscon", &sc->syscon);
        if (err) {
                device_printf(dev, "Failed to get syscon\n");
                return (ENXIO);
        }

        /* Reset the digital outputs. */
        SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, 0);
        reg = SYSCON_READ_4(sc->syscon, SCM_BGAP_CTRL);
        DELAY(500);
        /* Set continuous mode. */
        SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, SCM_BGAP_CONTCONV);
        reg = SYSCON_READ_4(sc->syscon, SCM_BGAP_CTRL);
        DELAY(500);
        /* Start the ADC conversion. */
        reg = SCM_BGAP_CLRZ | SCM_BGAP_CONTCONV | SCM_BGAP_SOC;
        SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, reg);

        /* Temperature sysctl. */
        ctx = device_get_sysctl_ctx(dev);
        tree = SYSCTL_CHILDREN(device_get_sysctl_tree(dev));
        sc->sc_temp_oid = SYSCTL_ADD_PROC(ctx, tree, OID_AUTO,
            "temperature", CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
            dev, 0, am335x_scm_temp_sysctl, "IK", "Current temperature");

        return (0);
}

static int
am335x_scm_detach(device_t dev)
{
        struct am335x_scm_softc *sc;

        sc = device_get_softc(dev);

        /* Remove temperature sysctl. */
        if (sc->sc_temp_oid != NULL)
                sysctl_remove_oid(sc->sc_temp_oid, 1, 0);

        /* Stop the bandgap ADC. */
        SYSCON_WRITE_4(sc->syscon, SCM_BGAP_CTRL, SCM_BGAP_BGOFF);

        return (0);
}

static device_method_t am335x_scm_methods[] = {
        DEVMETHOD(device_identify,      am335x_scm_identify),
        DEVMETHOD(device_probe,         am335x_scm_probe),
        DEVMETHOD(device_attach,        am335x_scm_attach),
        DEVMETHOD(device_detach,        am335x_scm_detach),

        DEVMETHOD_END
};

static driver_t am335x_scm_driver = {
        "am335x_scm",
        am335x_scm_methods,
        sizeof(struct am335x_scm_softc),
};

DRIVER_MODULE(am335x_scm, ti_scm, am335x_scm_driver, 0, 0);
MODULE_VERSION(am335x_scm, 1);
MODULE_DEPEND(am335x_scm, ti_scm_syscon, 1, 1, 1);