freebsd-dev/sys/dev/iicbus/ds3231.c

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/*-
* Copyright (c) 2014-2015 Luiz Otavio O Souza <loos@FreeBSD.org>
* 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 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Driver for Maxim DS3231[N] real-time clock/calendar.
*/
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#ifdef FDT
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif
#include <dev/iicbus/ds3231reg.h>
#include "clock_if.h"
#include "iicbus_if.h"
struct ds3231_softc {
device_t sc_dev;
int sc_last_c;
int sc_year0;
struct intr_config_hook enum_hook;
uint16_t sc_addr; /* DS3231 slave address. */
uint8_t sc_ctrl;
uint8_t sc_status;
};
static void ds3231_start(void *);
static int
ds3231_read(device_t dev, uint16_t addr, uint8_t reg, uint8_t *data, size_t len)
{
struct iic_msg msg[2] = {
{ addr, IIC_M_WR | IIC_M_NOSTOP, 1, &reg },
{ addr, IIC_M_RD, len, data },
};
return (iicbus_transfer(dev, msg, nitems(msg)));
}
static int
ds3231_write(device_t dev, uint16_t addr, uint8_t *data, size_t len)
{
struct iic_msg msg[1] = {
{ addr, IIC_M_WR, len, data },
};
return (iicbus_transfer(dev, msg, nitems(msg)));
}
static int
ds3231_ctrl_read(struct ds3231_softc *sc)
{
int error;
sc->sc_ctrl = 0;
error = ds3231_read(sc->sc_dev, sc->sc_addr, DS3231_CONTROL,
&sc->sc_ctrl, sizeof(sc->sc_ctrl));
if (error) {
device_printf(sc->sc_dev, "cannot read from RTC.\n");
return (error);
}
return (0);
}
static int
ds3231_ctrl_write(struct ds3231_softc *sc)
{
int error;
uint8_t data[2];
data[0] = DS3231_CONTROL;
/* Always enable the oscillator. Always disable both alarms. */
data[1] = sc->sc_ctrl & ~DS3231_CTRL_MASK;
error = ds3231_write(sc->sc_dev, sc->sc_addr, data, sizeof(data));
if (error != 0)
device_printf(sc->sc_dev, "cannot write to RTC.\n");
return (error);
}
static int
ds3231_status_read(struct ds3231_softc *sc)
{
int error;
sc->sc_status = 0;
error = ds3231_read(sc->sc_dev, sc->sc_addr, DS3231_STATUS,
&sc->sc_status, sizeof(sc->sc_status));
if (error) {
device_printf(sc->sc_dev, "cannot read from RTC.\n");
return (error);
}
return (0);
}
static int
ds3231_status_write(struct ds3231_softc *sc, int clear_a1, int clear_a2)
{
int error;
uint8_t data[2];
data[0] = DS3231_STATUS;
data[1] = sc->sc_status;
if (clear_a1 == 0)
data[1] |= DS3231_STATUS_A1F;
if (clear_a2 == 0)
data[1] |= DS3231_STATUS_A2F;
error = ds3231_write(sc->sc_dev, sc->sc_addr, data, sizeof(data));
if (error != 0)
device_printf(sc->sc_dev, "cannot write to RTC.\n");
return (error);
}
static int
ds3231_set_24hrs_mode(struct ds3231_softc *sc)
{
int error;
uint8_t data[2], hour;
hour = 0;
error = ds3231_read(sc->sc_dev, sc->sc_addr, DS3231_HOUR,
&hour, sizeof(hour));
if (error) {
device_printf(sc->sc_dev, "cannot read from RTC.\n");
return (error);
}
data[0] = DS3231_HOUR;
data[1] = hour & ~DS3231_C_MASK;
error = ds3231_write(sc->sc_dev, sc->sc_addr, data, sizeof(data));
if (error != 0)
device_printf(sc->sc_dev, "cannot write to RTC.\n");
return (error);
}
static int
ds3231_temp_read(struct ds3231_softc *sc, int *temp)
{
int error, neg, t;
uint8_t buf8[2];
uint16_t buf;
error = ds3231_read(sc->sc_dev, sc->sc_addr, DS3231_TEMP,
buf8, sizeof(buf8));
if (error != 0)
return (error);
buf = (buf8[0] << 8) | (buf8[1] & 0xff);
neg = 0;
if (buf & DS3231_NEG_BIT) {
buf = ~(buf & DS3231_TEMP_MASK) + 1;
neg = 1;
}
*temp = ((int16_t)buf >> 8) * 10;
t = 0;
if (buf & DS3231_0250C)
t += 250;
if (buf & DS3231_0500C)
t += 500;
t /= 100;
*temp += t;
if (neg)
*temp = -(*temp);
*temp += TZ_ZEROC;
return (0);
}
static int
ds3231_temp_sysctl(SYSCTL_HANDLER_ARGS)
{
int error, temp;
struct ds3231_softc *sc;
sc = (struct ds3231_softc *)arg1;
if (ds3231_temp_read(sc, &temp) != 0)
return (EIO);
error = sysctl_handle_int(oidp, &temp, 0, req);
return (error);
}
static int
ds3231_conv_sysctl(SYSCTL_HANDLER_ARGS)
{
int error, conv, newc;
struct ds3231_softc *sc;
sc = (struct ds3231_softc *)arg1;
error = ds3231_ctrl_read(sc);
if (error != 0)
return (error);
newc = conv = (sc->sc_ctrl & DS3231_CTRL_CONV) ? 1 : 0;
error = sysctl_handle_int(oidp, &newc, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (conv == 0 && newc != 0) {
error = ds3231_status_read(sc);
if (error != 0)
return (error);
if (sc->sc_status & DS3231_STATUS_BUSY)
return (0);
sc->sc_ctrl |= DS3231_CTRL_CONV;
error = ds3231_ctrl_write(sc);
if (error != 0)
return (error);
}
return (error);
}
static int
ds3231_bbsqw_sysctl(SYSCTL_HANDLER_ARGS)
{
int bbsqw, error, newb;
struct ds3231_softc *sc;
sc = (struct ds3231_softc *)arg1;
error = ds3231_ctrl_read(sc);
if (error != 0)
return (error);
bbsqw = newb = (sc->sc_ctrl & DS3231_CTRL_BBSQW) ? 1 : 0;
error = sysctl_handle_int(oidp, &newb, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (bbsqw != newb) {
sc->sc_ctrl &= ~DS3231_CTRL_BBSQW;
if (newb)
sc->sc_ctrl |= DS3231_CTRL_BBSQW;
error = ds3231_ctrl_write(sc);
if (error != 0)
return (error);
}
return (error);
}
static int
ds3231_sqw_freq_sysctl(SYSCTL_HANDLER_ARGS)
{
int ds3231_sqw_freq[] = { 1, 1024, 4096, 8192 };
int error, freq, i, newf, tmp;
struct ds3231_softc *sc;
sc = (struct ds3231_softc *)arg1;
error = ds3231_ctrl_read(sc);
if (error != 0)
return (error);
tmp = (sc->sc_ctrl & DS3231_CTRL_RS_MASK) >> DS3231_CTRL_RS_SHIFT;
if (tmp >= nitems(ds3231_sqw_freq))
tmp = nitems(ds3231_sqw_freq) - 1;
freq = ds3231_sqw_freq[tmp];
error = sysctl_handle_int(oidp, &freq, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (freq != ds3231_sqw_freq[tmp]) {
newf = 0;
for (i = 0; i < nitems(ds3231_sqw_freq); i++)
if (freq >= ds3231_sqw_freq[i])
newf = i;
sc->sc_ctrl &= ~DS3231_CTRL_RS_MASK;
sc->sc_ctrl |= newf << DS3231_CTRL_RS_SHIFT;
error = ds3231_ctrl_write(sc);
if (error != 0)
return (error);
}
return (error);
}
static int
ds3231_str_sqw_mode(char *buf)
{
int len, rtrn;
rtrn = -1;
len = strlen(buf);
if ((len > 2 && strncasecmp("interrupt", buf, len) == 0) ||
(len > 2 && strncasecmp("int", buf, len) == 0)) {
rtrn = 1;
} else if ((len > 2 && strncasecmp("square-wave", buf, len) == 0) ||
(len > 2 && strncasecmp("sqw", buf, len) == 0)) {
rtrn = 0;
}
return (rtrn);
}
static int
ds3231_sqw_mode_sysctl(SYSCTL_HANDLER_ARGS)
{
char buf[16];
int error, mode, newm;
struct ds3231_softc *sc;
sc = (struct ds3231_softc *)arg1;
error = ds3231_ctrl_read(sc);
if (error != 0)
return (error);
if (sc->sc_ctrl & DS3231_CTRL_INTCN) {
mode = 1;
strlcpy(buf, "interrupt", sizeof(buf));
} else {
mode = 0;
strlcpy(buf, "square-wave", sizeof(buf));
}
error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
if (error != 0 || req->newptr == NULL)
return (error);
newm = ds3231_str_sqw_mode(buf);
if (newm != -1 && mode != newm) {
sc->sc_ctrl &= ~DS3231_CTRL_INTCN;
if (newm == 1)
sc->sc_ctrl |= DS3231_CTRL_INTCN;
error = ds3231_ctrl_write(sc);
if (error != 0)
return (error);
}
return (error);
}
static int
ds3231_en32khz_sysctl(SYSCTL_HANDLER_ARGS)
{
int error, en32khz, tmp;
struct ds3231_softc *sc;
sc = (struct ds3231_softc *)arg1;
error = ds3231_status_read(sc);
if (error != 0)
return (error);
tmp = en32khz = (sc->sc_status & DS3231_STATUS_EN32KHZ) ? 1 : 0;
error = sysctl_handle_int(oidp, &en32khz, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (en32khz != tmp) {
sc->sc_status &= ~DS3231_STATUS_EN32KHZ;
if (en32khz)
sc->sc_status |= DS3231_STATUS_EN32KHZ;
error = ds3231_status_write(sc, 0, 0);
if (error != 0)
return (error);
}
return (error);
}
static int
ds3231_probe(device_t dev)
{
#ifdef FDT
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (!ofw_bus_is_compatible(dev, "maxim,ds3231"))
return (ENXIO);
#endif
device_set_desc(dev, "Maxim DS3231 RTC");
return (BUS_PROBE_DEFAULT);
}
static int
ds3231_attach(device_t dev)
{
struct ds3231_softc *sc;
sc = device_get_softc(dev);
sc->sc_dev = dev;
sc->sc_addr = iicbus_get_addr(dev);
sc->sc_last_c = -1;
sc->sc_year0 = 1900;
sc->enum_hook.ich_func = ds3231_start;
sc->enum_hook.ich_arg = dev;
/*
* We have to wait until interrupts are enabled. Usually I2C read
* and write only works when the interrupts are available.
*/
if (config_intrhook_establish(&sc->enum_hook) != 0)
return (ENOMEM);
return (0);
}
static void
ds3231_start(void *xdev)
{
device_t dev;
struct ds3231_softc *sc;
struct sysctl_ctx_list *ctx;
struct sysctl_oid *tree_node;
struct sysctl_oid_list *tree;
dev = (device_t)xdev;
sc = device_get_softc(dev);
ctx = device_get_sysctl_ctx(dev);
tree_node = device_get_sysctl_tree(dev);
tree = SYSCTL_CHILDREN(tree_node);
config_intrhook_disestablish(&sc->enum_hook);
if (ds3231_ctrl_read(sc) != 0)
return;
if (ds3231_status_read(sc) != 0)
return;
/* Clear the OSF bit and ack any pending alarm interrupt. */
if (sc->sc_status & DS3231_STATUS_OSF) {
device_printf(sc->sc_dev,
"oscillator has stopped, check the battery.\n");
sc->sc_status &= ~DS3231_STATUS_OSF;
}
if (ds3231_status_write(sc, 1, 1) != 0)
return;
/* Always enable the oscillator. */
if (ds3231_ctrl_write(sc) != 0)
return;
/* Set the 24 hours mode. */
if (ds3231_set_24hrs_mode(sc) != 0)
return;
/* Temperature. */
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "temperature",
CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, sc, 0,
ds3231_temp_sysctl, "IK", "Current temperature");
/* Configuration parameters. */
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "temp_conv",
CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
ds3231_conv_sysctl, "IU",
"DS3231 start a new temperature converstion");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "bbsqw",
CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
ds3231_bbsqw_sysctl, "IU",
"DS3231 battery-backed square-wave output enable");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "sqw_freq",
CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
ds3231_sqw_freq_sysctl, "IU",
"DS3231 square-wave output frequency");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "sqw_mode",
CTLFLAG_RW | CTLTYPE_STRING | CTLFLAG_MPSAFE, sc, 0,
ds3231_sqw_mode_sysctl, "A", "DS3231 SQW output mode control");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "32khz_enable",
CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
ds3231_en32khz_sysctl, "IU", "DS3231 enable the 32kHz output");
/* 1 second resolution. */
clock_register(dev, 1000000);
}
static int
ds3231_gettime(device_t dev, struct timespec *ts)
{
int c, error;
struct clocktime ct;
struct ds3231_softc *sc;
uint8_t data[7];
sc = device_get_softc(dev);
memset(data, 0, sizeof(data));
error = ds3231_read(sc->sc_dev, sc->sc_addr, DS3231_SECS,
data, sizeof(data));
if (error != 0) {
device_printf(dev, "cannot read from RTC.\n");
return (error);
}
ct.nsec = 0;
ct.sec = FROMBCD(data[DS3231_SECS] & DS3231_SECS_MASK);
ct.min = FROMBCD(data[DS3231_MINS] & DS3231_MINS_MASK);
ct.hour = FROMBCD(data[DS3231_HOUR] & DS3231_HOUR_MASK);
ct.day = FROMBCD(data[DS3231_DATE] & DS3231_DATE_MASK);
ct.dow = data[DS3231_WEEKDAY] & DS3231_WEEKDAY_MASK;
ct.mon = FROMBCD(data[DS3231_MONTH] & DS3231_MONTH_MASK);
ct.year = FROMBCD(data[DS3231_YEAR] & DS3231_YEAR_MASK);
c = (data[DS3231_MONTH] & DS3231_C_MASK) ? 1 : 0;
if (sc->sc_last_c == -1)
sc->sc_last_c = c;
else if (c != sc->sc_last_c) {
sc->sc_year0 += 100;
sc->sc_last_c = c;
}
ct.year += sc->sc_year0;
if (ct.year < POSIX_BASE_YEAR)
ct.year += 100; /* assume [1970, 2069] */
return (clock_ct_to_ts(&ct, ts));
}
static int
ds3231_settime(device_t dev, struct timespec *ts)
{
int error;
struct clocktime ct;
struct ds3231_softc *sc;
uint8_t data[8];
sc = device_get_softc(dev);
/* Accuracy is only one second. */
if (ts->tv_nsec >= 500000000)
ts->tv_sec++;
ts->tv_nsec = 0;
clock_ts_to_ct(ts, &ct);
memset(data, 0, sizeof(data));
data[0] = DS3231_SECS;
data[DS3231_SECS + 1] = TOBCD(ct.sec);
data[DS3231_MINS + 1] = TOBCD(ct.min);
data[DS3231_HOUR + 1] = TOBCD(ct.hour);
data[DS3231_DATE + 1] = TOBCD(ct.day);
data[DS3231_WEEKDAY + 1] = ct.dow;
data[DS3231_MONTH + 1] = TOBCD(ct.mon);
data[DS3231_YEAR + 1] = TOBCD(ct.year % 100);
if (sc->sc_last_c)
data[DS3231_MONTH] |= DS3231_C_MASK;
/* Write the time back to RTC. */
error = ds3231_write(dev, sc->sc_addr, data, sizeof(data));
if (error != 0)
device_printf(dev, "cannot write to RTC.\n");
return (error);
}
static device_method_t ds3231_methods[] = {
DEVMETHOD(device_probe, ds3231_probe),
DEVMETHOD(device_attach, ds3231_attach),
DEVMETHOD(clock_gettime, ds3231_gettime),
DEVMETHOD(clock_settime, ds3231_settime),
DEVMETHOD_END
};
static driver_t ds3231_driver = {
"ds3231",
ds3231_methods,
sizeof(struct ds3231_softc),
};
static devclass_t ds3231_devclass;
DRIVER_MODULE(ds3231, iicbus, ds3231_driver, ds3231_devclass, NULL, NULL);
MODULE_VERSION(ds3231, 1);
MODULE_DEPEND(ds3231, iicbus, 1, 1, 1);