/* $NetBSD: gpiobutton.c,v 1.3 2015/10/04 18:35:44 jmcneill 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 "locators.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: gpiobutton.c,v 1.3 2015/10/04 18:35:44 jmcneill Exp $");

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

#include <dev/sysmon/sysmonvar.h>
#include <dev/sysmon/sysmon_taskq.h>

#include <dev/gpio/gpiovar.h>

#define GPIOBUTTON_POLL_INTERVAL        mstohz(200)

#define GPIOBUTTON_POLARITY_MASK        0x80
#define GPIOBUTTON_POLARITY_ACTIVE_LOW  0
#define GPIOBUTTON_POLARITY_ACTIVE_HIGH 1
#define GPIOBUTTON_TYPE_MASK            0x0f
#define GPIOBUTTON_TYPE_POWER           1
#define GPIOBUTTON_TYPE_SLEEP           2

static int      gpiobutton_match(device_t, cfdata_t, void *);
static void     gpiobutton_attach(device_t, device_t, void *);

struct gpiobutton_softc {
        device_t                sc_dev;
        void                    *sc_gpio;
        struct gpio_pinmap      sc_map;
        int                     sc_pinmap[1];
        bool                    sc_active_high;

        struct sysmon_pswitch   sc_smpsw;

        callout_t               sc_tick;
        bool                    sc_state;
};

static bool     gpiobutton_is_pressed(struct gpiobutton_softc *);
static void     gpiobutton_tick(void *);
static void     gpiobutton_task(void *);

CFATTACH_DECL_NEW(gpiobutton, sizeof(struct gpiobutton_softc),
        gpiobutton_match, gpiobutton_attach, NULL, NULL);

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

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

        if (ga->ga_offset == -1 || gpio_npins(ga->ga_mask) != 1)
                return 0;

        const u_int type = __SHIFTOUT(ga->ga_flags, GPIOBUTTON_TYPE_MASK);

        switch (type) {
        case GPIOBUTTON_TYPE_POWER:
        case GPIOBUTTON_TYPE_SLEEP:
                return 1;
        default:
                return 0;
        }
}

static void
gpiobutton_attach(device_t parent, device_t self, void *aux)
{
        struct gpiobutton_softc * const sc = device_private(self);
        struct gpio_attach_args * const ga = aux;
        const char *desc;
        int caps;

        const u_int type = __SHIFTOUT(ga->ga_flags, GPIOBUTTON_TYPE_MASK);
        const u_int pol = __SHIFTOUT(ga->ga_flags, GPIOBUTTON_POLARITY_MASK);

        sc->sc_dev = self;
        sc->sc_gpio = ga->ga_gpio;
        sc->sc_map.pm_map = sc->sc_pinmap;
        if (gpio_pin_map(sc->sc_gpio, ga->ga_offset, ga->ga_mask,
            &sc->sc_map)) {
                aprint_error(": couldn't map pins\n");
                return;
        }
        sc->sc_active_high = pol == GPIOBUTTON_POLARITY_ACTIVE_HIGH;

        caps = gpio_pin_caps(sc->sc_gpio, &sc->sc_map, 0);
        if ((caps & GPIO_PIN_INPUT) == 0) {
                aprint_error(": pin is not an input pin\n");
                return;
        }

        gpio_pin_ctl(sc->sc_gpio, &sc->sc_map, 0, GPIO_PIN_INPUT);

        sc->sc_smpsw.smpsw_name = device_xname(self);
        switch (type) {
        case GPIOBUTTON_TYPE_POWER:
                sc->sc_smpsw.smpsw_type = PSWITCH_TYPE_POWER;
                desc = "Power";
                break;
        case GPIOBUTTON_TYPE_SLEEP:
                sc->sc_smpsw.smpsw_type = PSWITCH_TYPE_SLEEP;
                desc = "Sleep";
                break;
        default:
                panic("%s: impossible", __func__);
        }

        aprint_naive("\n");
        aprint_normal(": %s button\n", desc);

        sysmon_pswitch_register(&sc->sc_smpsw);

        callout_init(&sc->sc_tick, CALLOUT_MPSAFE);
        callout_setfunc(&sc->sc_tick, gpiobutton_tick, sc);

        gpiobutton_tick(sc);
}

static bool
gpiobutton_is_pressed(struct gpiobutton_softc *sc)
{
        int val;

        val = gpio_pin_read(sc->sc_gpio, &sc->sc_map, 0);
        if (!sc->sc_active_high)
                val = !val;

        return val;
}

static void
gpiobutton_tick(void *priv)
{
        struct gpiobutton_softc * const sc = priv;

        const bool new_state = gpiobutton_is_pressed(sc);
        if (new_state != sc->sc_state) {
                sc->sc_state = new_state;
                sysmon_task_queue_sched(0, gpiobutton_task, sc);
        }
        callout_schedule(&sc->sc_tick, GPIOBUTTON_POLL_INTERVAL);
}

static void
gpiobutton_task(void *priv)
{
        struct gpiobutton_softc * const sc = priv;

        sysmon_pswitch_event(&sc->sc_smpsw,
            sc->sc_state ? PSWITCH_EVENT_PRESSED : PSWITCH_EVENT_RELEASED);
}