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NetBSD/sys/dev/i2c/pcf8574.c

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/* $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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