/* $NetBSD: gpioow.c,v 1.20 2023/05/10 00:09:31 riastradh Exp $ */
/*      $OpenBSD: gpioow.c,v 1.1 2006/03/04 16:27:03 grange Exp $       */

/*
 * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: gpioow.c,v 1.20 2023/05/10 00:09:31 riastradh Exp $");

/*
 * 1-Wire bus bit-banging through GPIO pin.
 */

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

#include <dev/gpio/gpiovar.h>

#include <dev/onewire/onewirevar.h>

#include "ioconf.h"

#define GPIOOW_NPINS            1
#define GPIOOW_PIN_DATA         0

struct gpioow_softc {
        void *                  sc_gpio;
        struct gpio_pinmap      sc_map;
        int                     _map[GPIOOW_NPINS];

        struct onewire_bus      sc_ow_bus;
        device_t                sc_ow_dev;

        int                     sc_data;
        int                     sc_dying;
};

static int      gpioow_match(device_t, cfdata_t, void *);
static void     gpioow_attach(device_t, device_t, void *);
static int      gpioow_detach(device_t, int);
static int      gpioow_activate(device_t, enum devact);

static int      gpioow_ow_reset(void *);
static int      gpioow_ow_read_bit(void *);
static void     gpioow_ow_write_bit(void *, int);

static void     gpioow_bb_rx(void *);
static void     gpioow_bb_tx(void *);
static int      gpioow_bb_get(void *);
static void     gpioow_bb_set(void *, int);

CFATTACH_DECL_NEW(gpioow, sizeof(struct gpioow_softc),
        gpioow_match, gpioow_attach, gpioow_detach, gpioow_activate);

static const struct onewire_bbops gpioow_bbops = {
        gpioow_bb_rx,
        gpioow_bb_tx,
        gpioow_bb_get,
        gpioow_bb_set
};

static int
gpioow_match(device_t parent, cfdata_t cf, void *aux)
{
        struct gpio_attach_args *ga = aux;

        if (strcmp(ga->ga_dvname, cf->cf_name))
                return 0;

        if (ga->ga_offset == -1)
                return 0;

        /* Check that we have enough pins */
        if (gpio_npins(ga->ga_mask) != GPIOOW_NPINS) {
                aprint_debug("%s: invalid pin mask 0x%02x\n", cf->cf_name,
                    ga->ga_mask);
                return 0;
        }
        return 1;
}

static void
gpioow_attach(device_t parent, device_t self, void *aux)
{
        struct gpioow_softc *sc = device_private(self);
        struct gpio_attach_args *ga = aux;
        struct onewirebus_attach_args oba;
        int caps;

        /* Map pins */
        sc->sc_gpio = ga->ga_gpio;
        sc->sc_map.pm_map = sc->_map;
        if (gpio_pin_map(sc->sc_gpio, ga->ga_offset, ga->ga_mask,
            &sc->sc_map)) {
                aprint_error(": can't map pins\n");
                goto finish;
        }

        /* Configure data pin */
        caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, GPIOOW_PIN_DATA);
        if (!(caps & GPIO_PIN_OUTPUT)) {
                aprint_error(": data pin is unable to drive output\n");
                gpio_pin_unmap(sc->sc_gpio, &sc->sc_map);
                goto finish;
        }
        if (!(caps & GPIO_PIN_INPUT)) {
                aprint_error(": data pin is unable to read input\n");
                gpio_pin_unmap(sc->sc_gpio, &sc->sc_map);
                goto finish;
        }
        aprint_normal(": DATA[%d]", sc->sc_map.pm_map[GPIOOW_PIN_DATA]);
        sc->sc_data = GPIO_PIN_OUTPUT;
        if (caps & GPIO_PIN_OPENDRAIN) {
                aprint_normal(" open-drain");
                sc->sc_data |= GPIO_PIN_OPENDRAIN;
        } else if ((caps & GPIO_PIN_PUSHPULL) && (caps & GPIO_PIN_TRISTATE)) {
                aprint_normal(" push-pull tri-state");
                sc->sc_data |= GPIO_PIN_PUSHPULL;
        }
        if (caps & GPIO_PIN_PULLUP) {
                aprint_normal(" pull-up");
                sc->sc_data |= GPIO_PIN_PULLUP;
        }
        gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOOW_PIN_DATA, sc->sc_data);

        aprint_normal("\n");

        /* Attach 1-Wire bus */
        sc->sc_ow_bus.bus_cookie = sc;
        sc->sc_ow_bus.bus_reset = gpioow_ow_reset;
        sc->sc_ow_bus.bus_read_bit = gpioow_ow_read_bit;
        sc->sc_ow_bus.bus_write_bit = gpioow_ow_write_bit;

        memset(&oba, 0, sizeof(oba));
        oba.oba_bus = &sc->sc_ow_bus;
        sc->sc_ow_dev = config_found(self, &oba, onewirebus_print, CFARGS_NONE);

        if (!pmf_device_register(self, NULL, NULL))
                aprint_error("%s: could not establish power handler\n",
                    device_xname(self));
finish:
        return;
}

static int
gpioow_detach(device_t self, int flags)
{
        struct gpioow_softc *sc = device_private(self);
        int error;

        error = config_detach_children(self, flags);
        if (error)
                return error;

        gpio_pin_unmap(sc->sc_gpio, &sc->sc_map);
        pmf_device_deregister(self);
        return 0;
}

static int
gpioow_activate(device_t self, enum devact act)
{
        struct gpioow_softc *sc = device_private(self);

        switch (act) {
        case DVACT_DEACTIVATE:
                sc->sc_dying = 1;
                return 0;
        default:
                return EOPNOTSUPP;
        }
}

static int
gpioow_ow_reset(void *arg)
{
        return (onewire_bb_reset(&gpioow_bbops, arg));
}

static int
gpioow_ow_read_bit(void *arg)
{
        return (onewire_bb_read_bit(&gpioow_bbops, arg));
}

static void
gpioow_ow_write_bit(void *arg, int value)
{
        onewire_bb_write_bit(&gpioow_bbops, arg, value);
}

static void
gpioow_bb_rx(void *arg)
{
        struct gpioow_softc *sc = arg;
        int data = sc->sc_data;

        data &= ~(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT | GPIO_PIN_TRISTATE);
        data |= GPIO_PIN_INPUT;
        if (data & GPIO_PIN_PUSHPULL)
                data |= GPIO_PIN_TRISTATE;
        if (sc->sc_data != data) {
                sc->sc_data = data;
                gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOOW_PIN_DATA,
                    sc->sc_data);
        }
}

static void
gpioow_bb_tx(void *arg)
{
        struct gpioow_softc *sc = arg;
        int data = sc->sc_data;

        data &= ~(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT | GPIO_PIN_TRISTATE);
        data |= GPIO_PIN_OUTPUT;
        if (sc->sc_data != data) {
                sc->sc_data = data;
                gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, GPIOOW_PIN_DATA,
                    sc->sc_data);
        }
}

static int
gpioow_bb_get(void *arg)
{
        struct gpioow_softc *sc = arg;

        return (gpio_pin_read(sc->sc_gpio, &sc->sc_map, GPIOOW_PIN_DATA) ==
            GPIO_PIN_HIGH ? 1 : 0);
}

static void
gpioow_bb_set(void *arg, int value)
{
        struct gpioow_softc *sc = arg;

        gpio_pin_write(sc->sc_gpio, &sc->sc_map, GPIOOW_PIN_DATA,
            value ? GPIO_PIN_HIGH : GPIO_PIN_LOW);
}

MODULE(MODULE_CLASS_DRIVER, gpioow, "gpio,onewire");

#ifdef _MODULE
#include "ioconf.c"
#endif

static int
gpioow_modcmd(modcmd_t cmd, void *opaque)
{
        int error;

        error = 0;
        switch (cmd) {
        case MODULE_CMD_INIT:
#ifdef _MODULE
                error = config_init_component(cfdriver_ioconf_gpioow,
                    cfattach_ioconf_gpioow, cfdata_ioconf_gpioow);
                if (error)
                        aprint_error("%s: unable to init component\n",
                            gpioow_cd.cd_name);
#endif
                break;
        case MODULE_CMD_FINI:
#ifdef _MODULE
                config_fini_component(cfdriver_ioconf_gpioow,
                    cfattach_ioconf_gpioow, cfdata_ioconf_gpioow);
#endif
                break;
        default:
                error = ENOTTY;
        }
        return error;
}