/* $NetBSD: fixedregulator.c,v 1.10 2021/01/27 03:10:21 thorpej Exp $ */

/*-
 * Copyright (c) 2015 Jared D. McNeill <jmcneill@invisible.ca>
 * 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 ``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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fixedregulator.c,v 1.10 2021/01/27 03:10:21 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/bus.h>
#include <sys/gpio.h>

#include <dev/fdt/fdtvar.h>

static int      fixedregulator_match(device_t, cfdata_t, void *);
static void     fixedregulator_attach(device_t, device_t, void *);

static int      fixedregulator_acquire(device_t);
static void     fixedregulator_release(device_t);
static int      fixedregulator_enable(device_t, bool);
static int      fixedregulator_set_voltage(device_t, u_int, u_int);
static int      fixedregulator_get_voltage(device_t, u_int *);

struct fdtbus_regulator_controller_func fixedregulator_funcs = {
        .acquire = fixedregulator_acquire,
        .release = fixedregulator_release,
        .enable = fixedregulator_enable,
        .set_voltage = fixedregulator_set_voltage,
        .get_voltage = fixedregulator_get_voltage,
};

struct fixedregulator_softc {
        device_t        sc_dev;
        int             sc_phandle;

        struct fdtbus_gpio_pin *sc_pin;
        bool            sc_always_on;
        bool            sc_boot_on;
        bool            sc_enable_val;
        uint32_t        sc_delay;
        uint32_t        sc_min_uvol;
        uint32_t        sc_max_uvol;

        int             sc_gpioflags;
        bool            sc_deferred;
};

CFATTACH_DECL_NEW(fregulator, sizeof(struct fixedregulator_softc),
    fixedregulator_match, fixedregulator_attach, NULL, NULL);

static const struct device_compatible_entry compat_data[] = {
        { .compat = "regulator-fixed" },
        DEVICE_COMPAT_EOL
};

static int
fixedregulator_match(device_t parent, cfdata_t cf, void *aux)
{
        const struct fdt_attach_args *faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
fixedregulator_attach(device_t parent, device_t self, void *aux)
{
        struct fixedregulator_softc * const sc = device_private(self);
        const struct fdt_attach_args *faa = aux;
        const int phandle = faa->faa_phandle;
        char *name;
        int len;

        sc->sc_dev = self;
        sc->sc_phandle = phandle;

        aprint_naive("\n");

        len = OF_getproplen(phandle, "regulator-name");
        if (len > 0) {
                name = kmem_zalloc(len, KM_SLEEP);
                if (OF_getprop(phandle, "regulator-name", name, len) == len) {
                        aprint_normal(": %s\n", name);
                } else {
                        aprint_normal("\n");
                }
                kmem_free(name, len);
        } else {
                aprint_normal("\n");
        }

        sc->sc_gpioflags = GPIO_PIN_OUTPUT;
        if (of_getprop_bool(phandle, "gpio-open-drain"))
                sc->sc_gpioflags |= GPIO_PIN_OPENDRAIN;

        sc->sc_always_on = of_getprop_bool(phandle, "regulator-always-on");
        sc->sc_boot_on = of_getprop_bool(phandle, "regulator-boot-on");
        sc->sc_enable_val = of_getprop_bool(phandle, "enable-active-high");
        if (of_getprop_uint32(phandle, "startup-delay-us", &sc->sc_delay) != 0)
                sc->sc_delay = 0;
        of_getprop_uint32(phandle, "regulator-min-microvolt", &sc->sc_min_uvol);
        of_getprop_uint32(phandle, "regulator-max-microvolt", &sc->sc_max_uvol);

        sc->sc_pin = fdtbus_gpio_acquire(phandle, "gpio", sc->sc_gpioflags);
        if (sc->sc_pin == NULL)
                sc->sc_always_on = OF_getproplen(phandle, "gpio") <= 0;

        fdtbus_register_regulator_controller(self, phandle,
            &fixedregulator_funcs);

        /*
         * If the regulator is flagged as always on or enabled at boot,
         * ensure that it is enabled
         */
        if (sc->sc_always_on || sc->sc_boot_on)
                fixedregulator_enable(self, true);
}

static int
fixedregulator_acquire(device_t dev)
{
        struct fixedregulator_softc * const sc = device_private(dev);

        if (sc->sc_pin == NULL && !sc->sc_always_on) {
                sc->sc_pin = fdtbus_gpio_acquire(sc->sc_phandle, "gpio",
                    sc->sc_gpioflags);
                if (sc->sc_pin == NULL)
                        return ENXIO;
        }

        return 0;
}

static void
fixedregulator_release(device_t dev)
{
}

static int
fixedregulator_enable(device_t dev, bool enable)
{
        struct fixedregulator_softc * const sc = device_private(dev);

        if (enable) {
                if (sc->sc_pin != NULL)
                        fdtbus_gpio_write_raw(sc->sc_pin, sc->sc_enable_val);
                if (sc->sc_delay > 0)
                        delay(sc->sc_delay);
        } else {
                if (sc->sc_always_on)
                        return EIO;
                fdtbus_gpio_write_raw(sc->sc_pin, !sc->sc_enable_val);
        }
        return 0;
}

static int
fixedregulator_set_voltage(device_t dev, u_int min_uvol, u_int max_uvol)
{
        struct fixedregulator_softc * const sc = device_private(dev);

        if (sc->sc_min_uvol > max_uvol || sc->sc_max_uvol < min_uvol)
                return EINVAL;

        return 0;
}

static int
fixedregulator_get_voltage(device_t dev, u_int *uvol)
{
        struct fixedregulator_softc * const sc = device_private(dev);

        *uvol = sc->sc_min_uvol;

        return 0;
}