/*      $OpenBSD: pcf8591_ofw.c,v 1.6 2021/10/24 17:05:03 mpi Exp $ */

/*
 * Copyright (c) 2006 Damien Miller <djm@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/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/sensors.h>

#include <dev/ofw/openfirm.h>
#include <dev/i2c/i2cvar.h>

#define PCF8591_CHANNELS        4

struct pcfadc_channel {
        u_int           chan_num;
        struct ksensor  chan_sensor;
};

struct pcfadc_softc {
        struct device           sc_dev;
        i2c_tag_t               sc_tag;
        i2c_addr_t              sc_addr;
        u_char                  sc_xlate[256];
        u_int                   sc_nchan;
        struct pcfadc_channel   sc_channels[PCF8591_CHANNELS];
        struct ksensordev       sc_sensordev;
};

int     pcfadc_match(struct device *, void *, void *);
void    pcfadc_attach(struct device *, struct device *, void *);
void    pcfadc_refresh(void *);

const struct cfattach pcfadc_ca = {
        sizeof(struct pcfadc_softc), pcfadc_match, pcfadc_attach
};

struct cfdriver pcfadc_cd = {
        NULL, "pcfadc", DV_DULL
};

int
pcfadc_match(struct device *parent, void *match, void *aux)
{
        struct i2c_attach_args *ia = aux;

        if (strcmp(ia->ia_name, "i2cpcf,8591") != 0)
                return (0);

        return (1);
}

void
pcfadc_attach(struct device *parent, struct device *self, void *aux)
{
        struct pcfadc_softc *sc = (struct pcfadc_softc *)self;
        u_char chanuse[PCF8591_CHANNELS * 4], desc[PCF8591_CHANNELS * 32];
        u_char *cp;
        u_int8_t junk[PCF8591_CHANNELS + 1];
        u_int32_t transinfo[PCF8591_CHANNELS * 4];
        struct i2c_attach_args *ia = aux;
        int dlen, clen, tlen, node = *(int *)ia->ia_cookie;
        u_int i;

        if ((dlen = OF_getprop(node, "channels-description", desc,
            sizeof(desc))) < 0) {
                printf(": couldn't find \"channels-description\" property\n");
                return;
        }
        if (dlen > sizeof(desc) || desc[dlen - 1] != '\0') {
                printf(": bad \"channels-description\" property\n");
                return;
        }
        if ((clen = OF_getprop(node, "channels-in-use", chanuse,
            sizeof(chanuse))) < 0) {
                printf(": couldn't find \"channels-in-use\" property\n");
                return;
        }
        if ((clen % 4) != 0) {
                printf(": invalid \"channels-in-use\" length %d\n", clen);
                return;
        }
        sc->sc_nchan = clen / 4;
        if (sc->sc_nchan > PCF8591_CHANNELS) {
                printf(": invalid number of channels (%d)\n", sc->sc_nchan);
                return;
        }

        if ((tlen = OF_getprop(node, "tables", sc->sc_xlate,
            sizeof(sc->sc_xlate))) < 0) {
                printf(": couldn't find \"tables\" property\n");
                return;
        }
        /* We only support complete, single width tables */
        if (tlen != 256) {
                printf(": invalid \"tables\" length %d\n", tlen);
                return;
        }

        if ((tlen = OF_getprop(node, "translation", transinfo,
            sizeof(transinfo))) < 0) {
                printf(": couldn't find \"translation\" property\n");
                return;
        }
        if (tlen != (sc->sc_nchan * 4 * 4)) {
                printf(": invalid \"translation\" length %d\n", tlen);
                return;
        }

        cp = desc;
        for (i = 0; i < sc->sc_nchan; i++) {
                struct pcfadc_channel *chp = &sc->sc_channels[i];

                chp->chan_sensor.type = SENSOR_TEMP;

                if (cp >= desc + dlen) {
                        printf(": invalid \"channels-description\"\n");
                        return;
                }
                strlcpy(chp->chan_sensor.desc, cp,
                    sizeof(chp->chan_sensor.desc));
                cp += strlen(cp) + 1;

                /*
                 * We only support input temperature channels, with
                 * valid channel numbers, and basic (unscaled) translation
                 * 
                 * XXX TODO: support voltage (type 2) channels and type 4
                 * (scaled) translation tables
                 */
                if (chanuse[(i * 4)] > PCF8591_CHANNELS || /* channel # */
                    chanuse[(i * 4) + 1] != 0 ||        /* dir == input */
                    chanuse[(i * 4) + 2] != 1 ||        /* type == temp */
                    transinfo[(i * 4)] != 3 ||          /* xlate == table */
                    transinfo[(i * 4) + 2] != 0 ||      /* no xlate offset */
                    transinfo[(i * 4) + 3] != 0x100) {  /* xlate tbl length */
                        printf(": unsupported sensor %d\n", i);
                        return;
                }
                chp->chan_num = chanuse[(i * 4)];
        }

        sc->sc_tag = ia->ia_tag;
        sc->sc_addr = ia->ia_addr;

        iic_acquire_bus(sc->sc_tag, 0);

        /* Try a read now, so we can fail if it doesn't work */
        if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
            NULL, 0, junk, sc->sc_nchan + 1, 0)) {
                printf(": read failed\n");
                iic_release_bus(sc->sc_tag, 0);
                return;
        }

        iic_release_bus(sc->sc_tag, 0);

        /* Initialize sensor data. */
        strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
            sizeof(sc->sc_sensordev.xname));

        for (i = 0; i < sc->sc_nchan; i++)
                sensor_attach(&sc->sc_sensordev, 
                    &sc->sc_channels[i].chan_sensor);

        if (sensor_task_register(sc, pcfadc_refresh, 5) == NULL) {
                printf(": unable to register update task\n");
                return;
        }

        sensordev_install(&sc->sc_sensordev);

        printf("\n");
}

void
pcfadc_refresh(void *arg)
{
        struct pcfadc_softc *sc = arg;
        u_int i;
        u_int8_t data[PCF8591_CHANNELS + 1];

        iic_acquire_bus(sc->sc_tag, 0);
        /* NB: first byte out is stale, so read num_channels + 1 */
        if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
            NULL, 0, data, PCF8591_CHANNELS + 1, 0)) {
                iic_release_bus(sc->sc_tag, 0);
                return;
        }
        iic_release_bus(sc->sc_tag, 0);

        /* XXX: so far this only supports temperature channels */
        for (i = 0; i < sc->sc_nchan; i++) {
                struct pcfadc_channel *chp = &sc->sc_channels[i];

                chp->chan_sensor.value = 273150000 + 1000000 * 
                    sc->sc_xlate[data[1 + chp->chan_num]];
        }
}