/* $NetBSD: pcf8574.c,v 1.10 2021/06/21 03:12:54 christos Exp $ */

/*-
* Copyright (c) 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julian Coleman.
*
* 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/

/*
* A driver for Philips Semiconductor (NXP) PCF8574/PCF857A GPIO's.
* Uses device properties to connect pins to the appropriate subsystem.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pcf8574.c,v 1.10 2021/06/21 03:12:54 christos Exp $");

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

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

#include <dev/i2c/i2cvar.h>
#include <dev/led.h>

#ifdef PCF8574_DEBUG
#define DPRINTF printf
#else
#define DPRINTF if (0) printf
#endif

struct pcf8574_led {
       void *cookie;
       struct led_device *led;
       uint8_t mask, v_on, v_off;
};

struct pcf8574_pin {
       int pin_sensor;
       int pin_active;
       char pin_desc[ENVSYS_DESCLEN];
};

#define PCF8574_NPINS   8
struct pcf8574_softc {
       device_t        sc_dev;
       i2c_tag_t       sc_tag;
       i2c_addr_t      sc_addr;
       uint8_t         sc_state;
       uint8_t         sc_mask;

       uint8_t         sc_alert_mask;
#define PCF8574_DEFAULT_TIMER   60
       int             sc_callout_time;
       callout_t       sc_timer;

       int             sc_nleds;
       struct pcf8574_led sc_leds[PCF8574_NPINS];
       struct pcf8574_pin sc_pins[PCF8574_NPINS];

       struct sysmon_envsys *sc_sme;
       envsys_data_t   sc_sensor[PCF8574_NPINS];
};

static int      pcf8574_match(device_t, cfdata_t, void *);
static void     pcf8574_attach(device_t, device_t, void *);
static int      pcf8574_detach(device_t, int);

static int      pcf8574_read(struct pcf8574_softc *sc, uint8_t *);
static int      pcf8574_write(struct pcf8574_softc *sc, uint8_t);
static void     pcf8574_attach_led(
                       struct pcf8574_softc *, char *, int, int, int);
static int      pcf8574_attach_sysmon(
                       struct pcf8574_softc *, char *, int, int, int);
void            pcf8574_refresh(struct sysmon_envsys *, envsys_data_t *);
int             pcf8574_get_led(void *);
void            pcf8574_set_led(void *, int);
static void     pcf8574_timeout(void *);
static void     pcf8574_check(void *);
static void     pcf8574_check_alert(struct pcf8574_softc *, uint8_t, uint8_t);

CFATTACH_DECL_NEW(pcf8574io, sizeof(struct pcf8574_softc),
       pcf8574_match, pcf8574_attach, pcf8574_detach, NULL);

static const struct device_compatible_entry compat_data[] = {
       { .compat = "i2c-pcf8574" },
       DEVICE_COMPAT_EOL
};

static int
pcf8574_match(device_t parent, cfdata_t cf, void *aux)
{
       struct i2c_attach_args *ia = aux;
       int match_result;

       if (iic_use_direct_match(ia, cf, compat_data, &match_result))
               return match_result;

       /* We don't support indirect matches */
       return 0;
}

static void
pcf8574_attach(device_t parent, device_t self, void *aux)
{
       struct pcf8574_softc *sc = device_private(self);
       struct i2c_attach_args *ia = aux;
       prop_dictionary_t dict = device_properties(self);
       prop_array_t pins;
       prop_dictionary_t pin;
       int i, num, def, envc = 0;
       char name[32];
       const char *nptr = NULL, *spptr;
       bool ok = TRUE, act;

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

       sc->sc_sme = NULL;
#ifdef PCF8574_DEBUG
       sc->sc_callout_time = 60;       /* watch for changes when debugging */
#else
       sc->sc_callout_time = 0;
#endif

       /*
        * The PCF8574 requires input pins to be written with the value 1,
        * and then read.  Assume that all pins are input initially.
        * We'll use the mask when we write, because we have to write a
        * value for every pin, and we don't want to change input pins.
        */
       sc->sc_mask = 0xff;

       /* Try a read, and fail if this component isn't present */
       if (pcf8574_read(sc, &sc->sc_state)) {
               aprint_normal(": read failed\n");
               return;
       }

#ifdef PCF8574_DEBUG
       aprint_normal(": GPIO: state = 0x%02x\n", sc->sc_state);
#else
       aprint_normal(": GPIO\n");
#endif

       pins = prop_dictionary_get(dict, "pins");
       if (pins == NULL)
               return;

       for (i = 0; i < prop_array_count(pins); i++) {
               pin = prop_array_get(pins, i);
               ok &= prop_dictionary_get_string(pin, "name", &nptr);
               ok &= prop_dictionary_get_uint32(pin, "pin", &num);
               ok &= prop_dictionary_get_bool(pin, "active_high", &act);
               /* optional default state */
               def = -1;
               prop_dictionary_get_int32(pin, "default_state", &def);
               if (!ok)
                       continue;
               /* Extract pin type from the name */
               spptr = strstr(nptr, " ");
               if (spptr == NULL)
                       continue;
               spptr += 1;
               strncpy(name, spptr, 31);
               sc->sc_pins[i].pin_active = act;
               if (!strncmp(nptr, "LED ", 4)) {
                       sc->sc_mask &= ~(1 << num);
                       pcf8574_attach_led(sc, name, num, act, def);
               }
               if (!strncmp(nptr, "INDICATOR ", 10)) {
                       if (pcf8574_attach_sysmon(sc, name, envc, num, act))
                               return;
                       envc++;
               }
               if (!strncmp(nptr, "ALERT ", 6)) {
                       u_int64_t alert_time;

                       if (pcf8574_attach_sysmon(sc, name, envc, num, act))
                               return;

                       /* Adjust our timeout if the alert times out. */
                       if (def != -1)
                               alert_time = def / 2;
                       else
                               alert_time = PCF8574_DEFAULT_TIMER;

                       if (sc->sc_callout_time == 0 ||
                           alert_time < sc->sc_callout_time)
                               sc->sc_callout_time = alert_time;

                       sc->sc_alert_mask |= (1 << num);
                       envc++;
               }
       }

       if (sc->sc_sme != NULL) {
               sc->sc_sme->sme_name = device_xname(self);
               sc->sc_sme->sme_cookie = sc;
               sc->sc_sme->sme_refresh = pcf8574_refresh;
               if (sysmon_envsys_register(sc->sc_sme)) {
                       aprint_error_dev(self,
                           "unable to register with sysmon\n");
                       sysmon_envsys_destroy(sc->sc_sme);
                       sc->sc_sme = NULL;
                       return;
               }
       }

       if (sc->sc_callout_time) {
               callout_init(&sc->sc_timer, CALLOUT_MPSAFE);
               callout_reset(&sc->sc_timer, hz * sc->sc_callout_time,
                   pcf8574_timeout, sc);
       }
}

static int
pcf8574_detach(device_t self, int flags)
{
       struct pcf8574_softc *sc = device_private(self);
       int i;

       if (sc->sc_callout_time) {
               callout_halt(&sc->sc_timer, NULL);
               callout_destroy(&sc->sc_timer);
               sc->sc_callout_time = 0;
       }

       if (sc->sc_sme != NULL) {
               sysmon_envsys_unregister(sc->sc_sme);
               sc->sc_sme = NULL;
       }

       for (i = 0; i < sc->sc_nleds; i++)
               led_detach(sc->sc_leds[i].led);

       return 0;
}

static int
pcf8574_read(struct pcf8574_softc *sc, uint8_t *val)
{
       int err = 0;

       if ((err = iic_acquire_bus(sc->sc_tag, 0)) != 0)
               return err;
       err = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
           sc->sc_addr, NULL, 0, val, 1, 0);
       iic_release_bus(sc->sc_tag, 0);
       return err;
}

static int
pcf8574_write(struct pcf8574_softc *sc, uint8_t val)
{
       int err = 0;

       if ((err = iic_acquire_bus(sc->sc_tag, 0)) != 0)
               return err;
       err = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
           &val, 1, NULL, 0, 0);
       iic_release_bus(sc->sc_tag, 0);
       return err;
}

static void
pcf8574_attach_led(struct pcf8574_softc *sc, char *name, int pin, int act,
       int def)
{
       struct pcf8574_led *l;

       l = &sc->sc_leds[sc->sc_nleds];
       l->cookie = sc;
       l->mask = 1 << pin;
       l->v_on = act ? l->mask : 0;
       l->v_off = act ? 0 : l->mask;
       led_attach(name, l, pcf8574_get_led, pcf8574_set_led);
       if (def != -1)
               pcf8574_set_led(l, def);
       DPRINTF("%s: attached LED: %02x %02x %02x def %d\n",
           device_xname(sc->sc_dev), l->mask, l->v_on, l->v_off, def);
       sc->sc_nleds++;
}

static int
pcf8574_attach_sysmon(struct pcf8574_softc *sc, char *name, int envc, int pin,
       int act)
{
       int ret;

       if (sc->sc_sme == NULL) {
               sc->sc_sme = sysmon_envsys_create();
               sc->sc_sme->sme_events_timeout = 0;
       }

       strlcpy(sc->sc_pins[pin].pin_desc, name,
           sizeof(sc->sc_pins[pin].pin_desc));
       /* envsys sensor # to pin # mapping */
       sc->sc_pins[envc].pin_sensor = pin;
       sc->sc_sensor[envc].state = ENVSYS_SINVALID;
       sc->sc_sensor[envc].units = ENVSYS_INDICATOR;
       strlcpy(sc->sc_sensor[envc].desc, name,
           sizeof(sc->sc_sensor[envc].desc));
       ret = sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor[envc]);
       if (ret) {
               sysmon_envsys_destroy(sc->sc_sme);
               sc->sc_sme = NULL;
               aprint_error_dev(sc->sc_dev,
                   "unable to attach pin %d at sysmon\n", pin);
               return ret;
       }
       DPRINTF("%s: added sysmon: pin %d sensor %d (%s)\n",
           device_xname(sc->sc_dev), pin, envc, name);
       return 0;
}

void
pcf8574_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
{
       struct pcf8574_softc *sc = sme->sme_cookie;
       int pin = sc->sc_pins[edata->sensor].pin_sensor;
       int act = sc->sc_pins[pin].pin_active;
       u_int8_t prev_state = sc->sc_state;

       pcf8574_read(sc, &sc->sc_state);
       if (act)
               edata->value_cur = sc->sc_state & 1 << pin ? TRUE : FALSE;
       else
               edata->value_cur = sc->sc_state & 1 << pin ? FALSE : TRUE;
       edata->state = ENVSYS_SVALID;

       /* We read all the pins, so check for alerts on any pin now */
       if (sc->sc_state != prev_state) {
               DPRINTF("%s: (refresh) status change: 0x%02x > 0x%02x\n",
                   device_xname(sc->sc_dev), prev_state, sc->sc_state);
               pcf8574_check_alert(sc, prev_state, sc->sc_state);
       }
}

int
pcf8574_get_led(void *cookie)
{
       struct pcf8574_led *l = cookie;
       struct pcf8574_softc *sc = l->cookie;

       return ((sc->sc_state & l->mask) == l->v_on);
}

void
pcf8574_set_led(void *cookie, int val)
{
       struct pcf8574_led *l = cookie;
       struct pcf8574_softc *sc = l->cookie;
       uint32_t newstate;

       newstate = sc->sc_state & ~l->mask;
       newstate |= val ? l->v_on : l->v_off;
       DPRINTF("%s: set LED: %02x -> %02x, %02x %02x %02x\n",
           device_xname(sc->sc_dev), sc->sc_state, newstate, l->mask, l->v_on, l->v_off);
       if (newstate != sc->sc_state) {
               pcf8574_write(sc, newstate | sc->sc_mask);
               pcf8574_read(sc, &sc->sc_state);
       }
}

static void
pcf8574_timeout(void *v)
{
       struct pcf8574_softc *sc = v;

       sysmon_task_queue_sched(0, pcf8574_check, sc);
       callout_reset(&sc->sc_timer, hz * sc->sc_callout_time,
           pcf8574_timeout, sc);
}

static void
pcf8574_check(void *v)
{
       struct pcf8574_softc *sc = v;
       uint8_t prev_state = sc->sc_state;

       pcf8574_read(sc, &sc->sc_state);
       if (sc->sc_state != prev_state) {
               DPRINTF("%s: (check) status change: 0x%02x > 0x%02x\n",
                   device_xname(sc->sc_dev), prev_state, sc->sc_state);
               pcf8574_check_alert(sc, prev_state, sc->sc_state);
       }
}


static void
pcf8574_check_alert(struct pcf8574_softc *sc, uint8_t prev_state,
       uint8_t curr_state)
{
       int i;
       uint8_t pin_chg;

       for (i = 0; i < PCF8574_NPINS; i++) {
               pin_chg = (sc->sc_state & 1 << i) ^ (prev_state & 1 << i);
               if (pin_chg & sc->sc_alert_mask) {
                       if (sc->sc_pins[i].pin_active)
                               printf("%s: Alert: %s = %s\n",
                                   device_xname(sc->sc_dev),
                                   sc->sc_pins[i].pin_desc,
                                   sc->sc_state & 1 << i ?  "True" : "False");
                       else
                               printf("%s: Alert: %s = %s\n",
                                   device_xname(sc->sc_dev),
                                   sc->sc_pins[i].pin_desc,
                                   sc->sc_state & 1 << i ?  "False" : "True");
               }
       }
}

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