freebsd-dev/sys/dev/iicbus/pcf8563.c

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/*-
* Copyright (c) 2012 Marius Strobl <marius@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 NXP PCF8563 real-time clock/calendar
*/
#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 <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/pcf8563reg.h>
#include "clock_if.h"
#include "iicbus_if.h"
#define PCF8563_NCLOCKREGS (PCF8563_R_YEAR - PCF8563_R_CS1 + 1)
struct pcf8563_softc {
uint32_t sc_flags;
#define PCF8563_CPOL (1 << 0) /* PCF8563_R_MONTH_C means 19xx */
uint16_t sc_addr; /* PCF8563 slave address */
uint16_t sc_year0; /* TOD clock year 0 */
};
static device_attach_t pcf8563_attach;
static device_probe_t pcf8563_probe;
static clock_gettime_t pcf8563_gettime;
static clock_settime_t pcf8563_settime;
static int
pcf8563_probe(device_t dev)
{
device_set_desc(dev, "NXP PCF8563 RTC");
return (BUS_PROBE_NOWILDCARD);
}
static int
pcf8563_attach(device_t dev)
{
uint8_t reg = PCF8563_R_SECOND, val;
struct iic_msg msgs[] = {
{ 0, IIC_M_WR, sizeof(reg), &reg },
{ 0, IIC_M_RD, sizeof(val), &val }
};
struct pcf8563_softc *sc;
int error;
sc = device_get_softc(dev);
sc->sc_addr = iicbus_get_addr(dev);
if (sc->sc_addr == 0)
sc->sc_addr = PCF8563_ADDR;
/*
* NB: PCF8563_R_SECOND_VL doesn't automatically clear when VDD
* rises above Vlow again and needs to be cleared manually.
* However, apparently this needs all of the time registers to be
* set, i.e. pcf8563_settime(), and not just PCF8563_R_SECOND in
* order for PCF8563_R_SECOND_VL to stick. Thus, we just issue a
* warning here rather than failing with ENXIO in case it is set.
* Note that pcf8563_settime() will also clear PCF8563_R_SECOND_VL
* as a side-effect.
*/
msgs[0].slave = msgs[1].slave = sc->sc_addr;
error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
sizeof(*msgs));
if (error != 0) {
device_printf(dev, "%s: cannot read RTC\n", __func__);
return (error);
}
if ((val & PCF8563_R_SECOND_VL) != 0)
device_printf(dev, "%s: battery low\n", __func__);
sc->sc_year0 = 1900;
clock_register(dev, 1000000); /* 1 second resolution */
return (0);
}
static int
pcf8563_gettime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
uint8_t reg = PCF8563_R_SECOND, val[PCF8563_NCLOCKREGS];
struct iic_msg msgs[] = {
{ 0, IIC_M_WR, sizeof(reg), &reg },
{ 0, IIC_M_RD, PCF8563_NCLOCKREGS, &val[PCF8563_R_SECOND] }
};
struct pcf8563_softc *sc;
int error;
sc = device_get_softc(dev);
msgs[0].slave = msgs[1].slave = sc->sc_addr;
error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
sizeof(*msgs));
if (error != 0) {
device_printf(dev, "%s: cannot read RTC\n", __func__);
return (error);
}
ct.nsec = 0;
ct.sec = FROMBCD(val[PCF8563_R_SECOND] & PCF8563_M_SECOND);
ct.min = FROMBCD(val[PCF8563_R_MINUTE] & PCF8563_M_MINUTE);
ct.hour = FROMBCD(val[PCF8563_R_HOUR] & PCF8563_M_HOUR);
ct.day = FROMBCD(val[PCF8563_R_DAY] & PCF8563_M_DAY);
ct.dow = val[PCF8563_R_WEEKDAY] & PCF8563_M_WEEKDAY;
ct.mon = FROMBCD(val[PCF8563_R_MONTH] & PCF8563_M_MONTH);
ct.year = FROMBCD(val[PCF8563_R_YEAR] & PCF8563_M_YEAR);
ct.year += sc->sc_year0;
if (ct.year < POSIX_BASE_YEAR)
ct.year += 100; /* assume [1970, 2069] */
if ((val[PCF8563_R_MONTH] & PCF8563_R_MONTH_C) != 0) {
if (ct.year >= 100 + sc->sc_year0)
sc->sc_flags |= PCF8563_CPOL;
} else if (ct.year < 100 + sc->sc_year0)
sc->sc_flags |= PCF8563_CPOL;
return (clock_ct_to_ts(&ct, ts));
}
static int
pcf8563_settime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
uint8_t val[PCF8563_NCLOCKREGS];
struct iic_msg msgs[] = {
{ 0, IIC_M_WR, PCF8563_NCLOCKREGS - 1, &val[PCF8563_R_CS2] }
};
struct pcf8563_softc *sc;
int error;
sc = device_get_softc(dev);
val[PCF8563_R_CS2] = PCF8563_R_SECOND; /* abuse */
/* Accuracy is only one second. */
if (ts->tv_nsec >= 500000000)
ts->tv_sec++;
ts->tv_nsec = 0;
clock_ts_to_ct(ts, &ct);
val[PCF8563_R_SECOND] = TOBCD(ct.sec);
val[PCF8563_R_MINUTE] = TOBCD(ct.min);
val[PCF8563_R_HOUR] = TOBCD(ct.hour);
val[PCF8563_R_DAY] = TOBCD(ct.day);
val[PCF8563_R_WEEKDAY] = ct.dow;
val[PCF8563_R_MONTH] = TOBCD(ct.mon);
val[PCF8563_R_YEAR] = TOBCD(ct.year % 100);
if ((sc->sc_flags & PCF8563_CPOL) != 0) {
if (ct.year >= 100 + sc->sc_year0)
val[PCF8563_R_MONTH] |= PCF8563_R_MONTH_C;
} else if (ct.year < 100 + sc->sc_year0)
val[PCF8563_R_MONTH] |= PCF8563_R_MONTH_C;
msgs[0].slave = sc->sc_addr;
error = iicbus_transfer(device_get_parent(dev), msgs, sizeof(msgs) /
sizeof(*msgs));
if (error != 0)
device_printf(dev, "%s: cannot write RTC\n", __func__);
return (error);
}
static device_method_t pcf8563_methods[] = {
DEVMETHOD(device_probe, pcf8563_probe),
DEVMETHOD(device_attach, pcf8563_attach),
DEVMETHOD(clock_gettime, pcf8563_gettime),
DEVMETHOD(clock_settime, pcf8563_settime),
DEVMETHOD_END
};
static driver_t pcf8563_driver = {
"pcf8563_rtc",
pcf8563_methods,
sizeof(struct pcf8563_softc),
};
static devclass_t pcf8563_devclass;
DRIVER_MODULE(pcf8563, iicbus, pcf8563_driver, pcf8563_devclass, NULL, NULL);
MODULE_VERSION(pcf8563, 1);
MODULE_DEPEND(pcf8563, iicbus, 1, 1, 1);