/*      $OpenBSD: qcrtc.c,v 1.4 2024/05/13 01:15:50 jsg Exp $   */
/*
 * Copyright (c) 2022 Patrick Wildt <patrick@blueri.se>
 *
 * 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/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <machine/bus.h>
#include <machine/fdt.h>

#include <dev/fdt/spmivar.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_misc.h>
#include <dev/ofw/fdt.h>

#include <dev/clock_subr.h>

/* Registers. */
#define RTC_WRITE               0x40
#define RTC_CTRL                0x46
#define  RTC_CTRL_EN                    (1U << 7)
#define RTC_READ                0x48

struct qcrtc_softc {
        struct device           sc_dev;
        int                     sc_node;
        spmi_tag_t              sc_tag;
        int8_t                  sc_sid;
        uint16_t                sc_addr;

        struct todr_chip_handle sc_todr;
};

int qcrtc_match(struct device *, void *, void *);
void qcrtc_attach(struct device *, struct device *, void *);

const struct cfattach   qcrtc_ca = {
        sizeof (struct qcrtc_softc), qcrtc_match, qcrtc_attach
};

struct cfdriver qcrtc_cd = {
        NULL, "qcrtc", DV_DULL
};

int     qcrtc_gettime(struct todr_chip_handle *, struct timeval *);
int     qcrtc_settime(struct todr_chip_handle *, struct timeval *);

extern int qcscm_uefi_rtc_get(uint32_t *);
extern int qcscm_uefi_rtc_set(uint32_t);

int
qcrtc_match(struct device *parent, void *match, void *aux)
{
        struct spmi_attach_args *saa = aux;

        return OF_is_compatible(saa->sa_node, "qcom,pmk8350-rtc");
}

void
qcrtc_attach(struct device *parent, struct device *self, void *aux)
{
        struct qcrtc_softc *sc = (struct qcrtc_softc *)self;
        struct spmi_attach_args *saa = aux;
        uint32_t reg[2];

        if (OF_getpropintarray(saa->sa_node, "reg",
            reg, sizeof(reg)) != sizeof(reg)) {
                printf(": can't find registers\n");
                return;
        }

        sc->sc_node = saa->sa_node;
        sc->sc_tag = saa->sa_tag;
        sc->sc_sid = saa->sa_sid;
        sc->sc_addr = reg[0];

        printf("\n");

        sc->sc_todr.cookie = sc;
        sc->sc_todr.todr_gettime = qcrtc_gettime;
        sc->sc_todr.todr_settime = qcrtc_settime;
        sc->sc_todr.todr_quality = 0;
        todr_attach(&sc->sc_todr);
}

int
qcrtc_gettime(struct todr_chip_handle *handle, struct timeval *tv)
{
        struct qcrtc_softc *sc = handle->cookie;
        uint32_t reg, off;
        int error;

        /* Read current counting RTC value. */
        error = spmi_cmd_read(sc->sc_tag, sc->sc_sid, SPMI_CMD_EXT_READL,
            sc->sc_addr + RTC_READ, &reg, sizeof(reg));
        if (error) {
                printf("%s: error reading RTC\n", sc->sc_dev.dv_xname);
                return error;
        }

        /* Retrieve RTC offset from either NVRAM or UEFI. */
        error = nvmem_read_cell(sc->sc_node, "offset", &off, sizeof(off));
        if (error == ENXIO || (!error && off == 0))
                error = qcscm_uefi_rtc_get(&off);
        if (error)
                return error;

        tv->tv_sec = off + reg;
        tv->tv_usec = 0;
        return 0;
}

int
qcrtc_settime(struct todr_chip_handle *handle, struct timeval *tv)
{
        struct qcrtc_softc *sc = handle->cookie;
        uint32_t reg, off;
        int error;

        error = spmi_cmd_read(sc->sc_tag, sc->sc_sid, SPMI_CMD_EXT_READL,
            sc->sc_addr + RTC_READ, &reg, sizeof(reg));
        if (error) {
                printf("%s: error reading RTC\n", sc->sc_dev.dv_xname);
                return error;
        }

        /* Store RTC offset in either NVRAM or UEFI. */
        off = tv->tv_sec - reg;
        error = nvmem_write_cell(sc->sc_node, "offset", &off, sizeof(off));
        if (error == ENXIO)
                error = qcscm_uefi_rtc_set(off);

        return error;
}