/* $NetBSD: sunxi_lradc.c,v 1.6 2021/01/27 03:10:20 thorpej Exp $ */

/*-
 * Copyright (c) 2016, 2018 Manuel Bouyer
 * 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: sunxi_lradc.c,v 1.6 2021/01/27 03:10:20 thorpej 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/select.h>
#include <sys/mutex.h>
#include <sys/kmem.h>

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

#include <dev/fdt/fdtvar.h>

#include <arm/sunxi/sunxi_lradc.h>

struct sunxi_lradc_softc {
        device_t sc_dev;
        bus_space_tag_t sc_bst;
        bus_space_handle_t sc_bsh;
        kmutex_t sc_lock;
        void *sc_ih;
        struct fdtbus_regulator *sc_supply;
        int sc_vref;
        uint8_t sc_chans;
        uint8_t sc_level[2][32];
        const char *sc_name[2][32];
        int sc_nlevels[2];
        int sc_lastlevel[2];
        struct  sysmon_pswitch *sc_switches[2];
        uint32_t sc_ints; /* pending interrupts */
};

#define ADC_READ(sc, reg) \
    bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
#define ADC_WRITE(sc, reg, val) \
    bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))

static int      sunxi_lradc_match(device_t, cfdata_t, void *);
static void     sunxi_lradc_attach(device_t, device_t, void *);
static int      sunxi_lradc_intr(void *);
static void     sunxi_lradc_get_levels(struct sunxi_lradc_softc *, int, int);
static void     sunxi_lradc_print_levels(struct sunxi_lradc_softc *, int);
static bool     sunxi_lradc_register_switches(struct sunxi_lradc_softc *, int);

static const struct device_compatible_entry compat_data[] = {
        { .compat = "allwinner,sun4i-a10-lradc-keys" },
        DEVICE_COMPAT_EOL
};


CFATTACH_DECL_NEW(sunxi_lradc, sizeof(struct sunxi_lradc_softc),
        sunxi_lradc_match, sunxi_lradc_attach, NULL, NULL);

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

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

static void
sunxi_lradc_attach(device_t parent, device_t self, void *aux)
{
        struct sunxi_lradc_softc *sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;
        int i, error;
        uint32_t intc = 0;
        bus_addr_t addr;
        bus_size_t size;
        char intrstr[128];
        struct clk *clk;
        struct fdtbus_reset *rst;

        sc->sc_dev = self;
        mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_VM);

        sc->sc_bst = faa->faa_bst;
        if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh) != 0) {
                aprint_error(": couldn't map registers\n");
                return;
        }

        if (!fdtbus_intr_str(phandle, 0, intrstr, sizeof(intrstr))) {
                aprint_error(": failed to decode interrupt\n");
                return;
        }

        if ((clk = fdtbus_clock_get_index(phandle, 0)) != NULL) {
                if (clk_enable(clk) != 0) {
                        aprint_error(": couldn't enable clock\n");
                        return;
                }
        }

        if ((rst = fdtbus_reset_get_index(phandle, 0)) != NULL) {
                if (fdtbus_reset_deassert(rst) != 0) {
                        aprint_error(": couldn't de-assert reset\n");
                        return;
                }
        }

        sc->sc_chans = -1;
        aprint_naive("\n");
        aprint_normal(": LRADC, ");
        if (of_hasprop(phandle, "vref-supply")) {
                sc->sc_supply =
                    fdtbus_regulator_acquire(phandle, "vref-supply");
                if (sc->sc_supply == NULL) {
                        aprint_error(": couldn't acquire vref-supply\n");
                        return;
                }
        } else {
                aprint_normal("disabled (no vref-supply)\n");
                return;
        }
        error = fdtbus_regulator_get_voltage(sc->sc_supply, &sc->sc_vref);
        if (error) {
                aprint_error(": couldn't get vref (%d)\n", error);
                return;
        }
        
        for (i = 0; i < 2; i++)
                sunxi_lradc_get_levels(sc, phandle, i);

        switch (sc->sc_chans) {
        case 0:
                aprint_normal("channel 0 enabled\n");
                break;
        case 1:
                aprint_normal("channel 1 enabled\n");
                break;
        case 2:
                aprint_normal("channel 0 & 1 enabled\n");
                break;
        default:
                aprint_normal("no channel enabled\n");
                break;
        }

        if (sc->sc_chans == 0 || sc->sc_chans == 2) {
                sunxi_lradc_print_levels(sc, 0);
        }
        if (sc->sc_chans == 1 || sc->sc_chans == 2) {
                sunxi_lradc_print_levels(sc, 1);
        }

        sc->sc_ih = fdtbus_intr_establish_xname(phandle, 0, IPL_VM,
            FDT_INTR_MPSAFE, sunxi_lradc_intr, sc, device_xname(self));
        if (sc->sc_ih == NULL) {
                aprint_error_dev(self, "couldn't establish interrupt on %s\n",
                    intrstr);
                return;
        }
        aprint_normal_dev(self, "interrupting on %s\n", intrstr);
        if (sc->sc_chans == 0 || sc->sc_chans == 2) {
                if (!sunxi_lradc_register_switches(sc, 0)) {
                        aprint_error_dev(self, "can't register switches\n");
                        return;
                }
        }
        if (sc->sc_chans == 1 || sc->sc_chans == 2) {
                if (!sunxi_lradc_register_switches(sc, 1)) {
                        aprint_error_dev(self, "can't register switches\n");
                        return;
                }
        }

        /*
         * init and enable LRADC
         * 250Hz, wait 2 cycles (8ms) on key press and release
         */
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, AWIN_LRADC_CTRL_REG,
            (2 << AWIN_LRADC_CTRL_FIRSTCONV_SHIFT) |
            (1 << AWIN_LRADC_CTRL_LV_A_B_CNT_SHIFT) |
            AWIN_LRADC_CTRL_HOLD_EN |
            AWIN_LRADC_CTRL_RATE_250 |
            (sc->sc_chans << AWIN_LRADC_CTRL_CHAN_SHIFT) |
            AWIN_LRADC_CTRL_EN);
        switch(sc->sc_chans) {
        case 0:
                intc = AWIN_LRADC_INT_KEY0 | AWIN_LRADC_INT_KEYUP0;
                break;
        case 1:
                intc = AWIN_LRADC_INT_KEY1 | AWIN_LRADC_INT_KEYUP1;
                break;
        case 2:
                intc = AWIN_LRADC_INT_KEY0 | AWIN_LRADC_INT_KEYUP0 |
                       AWIN_LRADC_INT_KEY1 | AWIN_LRADC_INT_KEYUP1;
                break;
        }
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, AWIN_LRADC_INTC_REG, intc);
}

static void
sunxi_lradc_get_levels(struct sunxi_lradc_softc *sc, int phandle, int chan)
{
        int i;
        int this_chan;
        int child;
        int32_t level;
        const char *name;
        const int vref = sc->sc_vref * 2 / 3;

        for (child = OF_child(phandle), i = 0; child; child = OF_peer(child)) {
                if (of_getprop_uint32(child, "channel", &this_chan) != 0)
                        continue;
                if (this_chan != chan)
                        continue;
                if (of_getprop_uint32(child, "voltage", &level) != 0)
                        continue;
                name = fdtbus_get_string(child, "label");
                if (name == NULL)
                        continue;
                sc->sc_level[chan][i] = level * 63 / vref;
                sc->sc_name[chan][i] = name;
                i++;
        }
        if (i > 0) {
                switch(chan) {
                case 0:
                        if (sc->sc_chans == 1)
                                sc->sc_chans = 2;
                        else
                                sc->sc_chans = 0;
                        break;
                case 1:
                        if (sc->sc_chans == 0)
                                sc->sc_chans = 2;
                        else
                                sc->sc_chans = 1;
                        break;
                default:
                        panic("lradc: chan %d", chan);
                }
                sc->sc_nlevels[chan] = i;
        }
}

static void
sunxi_lradc_print_levels(struct sunxi_lradc_softc *sc, int chan)
{
        int i;

        aprint_verbose_dev(sc->sc_dev, ": channel %d levels", chan);
        for (i = 0; i < 32; i++) {
                if (sc->sc_name[chan][i] == NULL)
                        break;
                aprint_verbose(" %d(%s)",
                    sc->sc_level[chan][i], sc->sc_name[chan][i]);
        }
        aprint_verbose("\n");
}

static bool
sunxi_lradc_register_switches(struct sunxi_lradc_softc *sc, int chan)
{
        
        KASSERT(sc->sc_nlevels[chan] > 0);
        sc->sc_switches[chan] = kmem_zalloc(
            sizeof(struct sysmon_pswitch) * sc->sc_nlevels[chan] , KM_SLEEP);

        if (sc->sc_switches[chan] == NULL)
                return false;

        for (int i = 0; i < sc->sc_nlevels[chan]; i++) {
                struct sysmon_pswitch *sw = &sc->sc_switches[chan][i];
                sw->smpsw_name = sc->sc_name[chan][i];
                sw->smpsw_type = PSWITCH_TYPE_HOTKEY;
                sysmon_pswitch_register(sw);
        }
        return true;
}

static void
sunxi_lradc_intr_ev(struct sunxi_lradc_softc *sc, int chan, int event)
{
        int32_t val;
        int diff = 64;


        if (event == PSWITCH_EVENT_RELEASED) {
                sysmon_pswitch_event(
                    &sc->sc_switches[chan][sc->sc_lastlevel[chan]], event);
                return;
        }

        val = bus_space_read_4(sc->sc_bst, sc->sc_bsh,
            chan == 0 ? AWIN_LRADC_DATA0_REG : AWIN_LRADC_DATA1_REG);

        KASSERT(sc->sc_nlevels[chan] > 0);
        for (int i = 0; i < sc->sc_nlevels[chan]; i++) {
                int curdiff;
                curdiff = val - sc->sc_level[chan][i];
                if (curdiff < 0)
                        curdiff = -curdiff;
                if (diff > curdiff) {
                        diff = curdiff;
                        sc->sc_lastlevel[chan] = i;
                }
        }
        sysmon_pswitch_event(
            &sc->sc_switches[chan][sc->sc_lastlevel[chan]], event);
}

static void
sunxi_lradc_intr_task(void *arg)
{
        struct sunxi_lradc_softc *sc = arg;
        mutex_enter(&sc->sc_lock);
        if (sc->sc_chans == 0 || sc->sc_chans == 2) {
                if (sc->sc_ints & AWIN_LRADC_INT_KEY0) {
                        sunxi_lradc_intr_ev(sc, 0, PSWITCH_EVENT_PRESSED);
                }
                if (sc->sc_ints & AWIN_LRADC_INT_KEYUP0) {
                        sunxi_lradc_intr_ev(sc, 0, PSWITCH_EVENT_RELEASED);
                }
        }
        if (sc->sc_chans == 1 || sc->sc_chans == 2) {
                if (sc->sc_ints & AWIN_LRADC_INT_KEY1) {
                        sunxi_lradc_intr_ev(sc, 1, PSWITCH_EVENT_PRESSED);
                }
                if (sc->sc_ints & AWIN_LRADC_INT_KEYUP1) {
                        sunxi_lradc_intr_ev(sc, 1, PSWITCH_EVENT_RELEASED);
                }
        }
        sc->sc_ints = 0;
        mutex_exit(&sc->sc_lock);
}

static int
sunxi_lradc_intr(void *arg)
{
        struct sunxi_lradc_softc *sc = arg;
        int error;

        mutex_enter(&sc->sc_lock);
        sc->sc_ints = bus_space_read_4(sc->sc_bst, sc->sc_bsh,
            AWIN_LRADC_INTS_REG);
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, AWIN_LRADC_INTS_REG,
            sc->sc_ints);
        mutex_exit(&sc->sc_lock);
        error = sysmon_task_queue_sched(0, sunxi_lradc_intr_task, sc);
        if (error != 0) {
                printf("%s: sysmon_task_queue_sched failed (%d)\n",
                    device_xname(sc->sc_dev), error);
        }
        return 1;
}