I2C driver for the Maxim DS1307 Real Time Clock chip.

The chip has been found on a Sun Fire V210 as a second RTC hooked up
to the SMU.  Setting the time there has the advantage that it remains
after a boot since the internal V210 RTC will be synced by the DS1307
at boot time.

Not linked to sparc64 yet since it will overwrite the internal RTC
handler.

ok deraadt

2 files changed, 301 insertions, 1 deletions

diff --git a/sys/dev/i2c/ds1307.c b/sys/dev/i2c/ds1307.c
new file mode 100644
index 00000000000..e5cbf1c9d4e
--- /dev/null
+++ b/sys/dev/i2c/ds1307.c
@@ -0,0 +1,295 @@
+/*	$OpenBSD: ds1307.c,v 1.1 2016/06/20 13:42:42 mglocker Exp $ */
+
+/*
+ * Copyright (c) 2016 Marcus Glocker <mglocker@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 <dev/clock_subr.h>
+#include <dev/i2c/i2cvar.h>
+
+/*
+ * Defines.
+ */
+/* RTC Registers */
+#define DS1307_SEC_REG		0x00
+#define DS1307_SEC_MASK		0x7f
+#define DS1307_SEC_MASK_CH	0x80	/* Clock Halt bit */
+#define DS1307_SEC_BIT_CH	7	/* 0 = osc enabled, 1 = osc disabled */
+#define DS1307_MIN_REG		0x01
+#define DS1307_MIN_MASK		0x7f
+#define DS1307_HOUR_REG		0x02
+#define DS1307_HOUR_MASK	0x3f
+#define DS1307_HOUR_MASK_MODE	0x40	/* Hour Mode bit */
+#define DS1307_HOUR_BIT_MODE	6	/* 0 = 24h mode, 1 = 12h mode */
+#define DS1307_WDAY_REG		0x03
+#define DS1307_WDAY_MASK	0x07
+#define DS1307_DATE_REG		0x04
+#define DS1307_DATE_MASK	0x3f
+#define DS1307_MONTH_REG	0x05
+#define DS1307_MONTH_MASK	0x1f
+#define DS1307_YEAR_REG		0x06
+#define DS1307_YEAR_MASK	0xff
+#define DS1307_CTRL_REG		0x07
+
+/* RAM Registers */
+#define DS1307_RAM_REG		0x08	/* RAM address space 0x08 - 0x3f */
+
+/*
+ * Driver structure.
+ */
+struct maxrtc_softc {
+	struct device		sc_dev;
+	i2c_tag_t		sc_tag;
+	int			sc_addr;
+	struct todr_chip_handle sc_todr;
+};
+
+/*
+ * Prototypes.
+ */
+int	maxrtc_match(struct device *, void *, void *);
+void	maxrtc_attach(struct device *, struct device *, void *);
+int	maxrtc_read(struct maxrtc_softc *, uint8_t *, uint8_t,
+	    uint8_t *, uint8_t);
+int	maxrtc_write(struct maxrtc_softc *, uint8_t *, uint8_t);
+int	maxrtc_enable_osc(struct maxrtc_softc *);
+int	maxrtc_set_24h_mode(struct maxrtc_softc *);
+int	maxrtc_gettime(struct todr_chip_handle *, struct timeval *);
+int	maxrtc_settime(struct todr_chip_handle *, struct timeval *);
+int	maxrtc_getcal(struct todr_chip_handle *, int *);
+int	maxrtc_setcal(struct todr_chip_handle *, int);
+
+/*
+ * Driver glue structures.
+ */
+struct cfattach maxrtc_ca = {
+	sizeof(struct maxrtc_softc), maxrtc_match, maxrtc_attach
+};
+
+struct cfdriver maxrtc_cd = {
+	NULL, "maxrtc", DV_DULL
+};
+
+extern todr_chip_handle_t todr_handle;
+
+/*
+ * Functions.
+ */
+int
+maxrtc_match(struct device *parent, void *v, void *arg)
+{
+	struct i2c_attach_args *ia = arg;
+
+	if (strcmp(ia->ia_name, "ds1307") == 0)
+		return (1);
+
+	return (0);
+}
+
+void
+maxrtc_attach(struct device *parent, struct device *self, void *arg)
+{
+	struct maxrtc_softc *sc = (struct maxrtc_softc *)self;
+	struct i2c_attach_args *ia = arg;
+
+	sc->sc_tag = ia->ia_tag;
+	sc->sc_addr = ia->ia_addr;
+	sc->sc_todr.cookie = sc;
+	sc->sc_todr.todr_gettime = maxrtc_gettime;
+	sc->sc_todr.todr_settime = maxrtc_settime;
+	sc->sc_todr.todr_getcal = maxrtc_getcal;
+	sc->sc_todr.todr_setcal = maxrtc_setcal;
+	sc->sc_todr.todr_setwen = NULL;
+
+	if (maxrtc_enable_osc(sc) == -1)
+		return;
+
+	if (maxrtc_set_24h_mode(sc) == -1)
+		return;
+
+	/* register our time handlers */
+	if (todr_handle != NULL) {
+		printf("%s: overwriting existing rtc handler\n",
+		    sc->sc_dev.dv_xname);
+	}
+	/* XXX just overwrite existing rtc handler? */
+	todr_handle = &sc->sc_todr;
+}
+
+int
+maxrtc_read(struct maxrtc_softc *sc, uint8_t *cmd, uint8_t cmd_len,
+    uint8_t *data, uint8_t data_len)
+{
+	int r;
+
+	iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
+	if ((r = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
+	    cmd, cmd_len, data, data_len, I2C_F_POLL)))
+		printf("%s: maxrtc_read failed\n", sc->sc_dev.dv_xname);
+	iic_release_bus(sc->sc_tag, I2C_F_POLL);
+
+	return (r);
+}
+
+int
+maxrtc_write(struct maxrtc_softc *sc, uint8_t *data, uint8_t data_len)
+{
+	int r;
+
+	/*
+	 * On write operation the DS1307 requires the target address to be
+	 * stored in the first byte of the data packet.  Therefore we don't
+	 * fill up the command packet here.
+	 */
+	iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
+	if ((r = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
+	    NULL, 0, data, data_len, I2C_F_POLL)))
+		printf("%s: maxrtc_write failed\n", sc->sc_dev.dv_xname);
+	iic_release_bus(sc->sc_tag, I2C_F_POLL);
+
+	return (r);
+}
+
+int
+maxrtc_enable_osc(struct maxrtc_softc *sc)
+{
+	uint8_t cmd;
+	uint8_t data_r;
+	uint8_t data_w[2];
+
+	cmd = DS1307_SEC_REG;
+	data_r = 0;
+	if (maxrtc_read(sc, &cmd, sizeof(cmd), &data_r, sizeof(data_r))) {
+		printf("%s: maxrtc_enable_osc failed\n", sc->sc_dev.dv_xname);
+		return (-1);
+	}
+	if ((data_r & DS1307_SEC_MASK_CH) == 0) {
+		/* oscilliator is already enabled */
+		printf(": rtc is ok\n");
+		return (0);
+	}
+	printf(": rtc was halted, check battery\n");
+
+	/* enable the oscillator */
+	data_r |= 0 << DS1307_SEC_BIT_CH;
+	data_w[0] = DS1307_SEC_REG;
+	data_w[1] = data_r;
+	if (maxrtc_write(sc, data_w, sizeof(data_w))) {
+		printf("%s: maxrtc_enable_osc failed\n", sc->sc_dev.dv_xname);
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+maxrtc_set_24h_mode(struct maxrtc_softc *sc)
+{
+	uint8_t cmd;
+	uint8_t data_r;
+	uint8_t data_w[2];
+
+	cmd = DS1307_HOUR_REG;
+	data_r = 0;
+	if (maxrtc_read(sc, &cmd, sizeof(cmd), &data_r, sizeof(data_r))) {
+		printf("%s: maxrtc_set_24h_mode failed\n", sc->sc_dev.dv_xname);
+		return (-1);
+	}
+	if ((data_r & DS1307_HOUR_MASK_MODE) == 0) {
+		/* 24h mode is already set */
+		return (0);
+	}
+
+	/* set 24h mode */
+	data_r |= 0 << DS1307_HOUR_BIT_MODE;
+	data_w[0] = DS1307_HOUR_REG;
+	data_w[1] = data_r;
+	if (maxrtc_write(sc, data_w, sizeof(data_w))) {
+		printf("%s: maxrtc_set_24h_mode failed\n", sc->sc_dev.dv_xname);
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+maxrtc_gettime(struct todr_chip_handle *ch, struct timeval *tv)
+{
+	struct maxrtc_softc *sc = ch->cookie;
+	struct clock_ymdhms dt;
+	uint8_t cmd;
+	uint8_t data[7];
+
+	cmd = DS1307_SEC_REG;
+	memset(data, 0, sizeof(data));
+	if (maxrtc_read(sc, &cmd, sizeof(cmd), data, sizeof(data))) {
+		printf("%s: maxrtc_gettime failed\n", sc->sc_dev.dv_xname);
+		return (-1);
+	}
+
+	dt.dt_sec = FROMBCD(data[DS1307_SEC_REG] & DS1307_SEC_MASK);
+	dt.dt_min = FROMBCD(data[DS1307_MIN_REG] & DS1307_MIN_MASK);
+	dt.dt_hour = FROMBCD(data[DS1307_HOUR_REG] & DS1307_HOUR_MASK);
+	dt.dt_wday = FROMBCD(data[DS1307_WDAY_REG] & DS1307_WDAY_MASK);
+	dt.dt_day = FROMBCD(data[DS1307_DATE_REG] & DS1307_DATE_MASK);
+	dt.dt_mon = FROMBCD(data[DS1307_MONTH_REG] & DS1307_MONTH_MASK);
+	dt.dt_year = FROMBCD(data[DS1307_YEAR_REG] & DS1307_YEAR_MASK) + 2000;
+
+	tv->tv_sec = clock_ymdhms_to_secs(&dt);
+	tv->tv_usec = 0;
+
+	return (0);
+}
+
+int
+maxrtc_settime(struct todr_chip_handle *ch, struct timeval *tv)
+{
+	struct maxrtc_softc *sc = ch->cookie;
+	struct clock_ymdhms dt;
+	uint8_t data[8];
+
+	clock_secs_to_ymdhms(tv->tv_sec, &dt);
+
+	data[0] = DS1307_SEC_REG;
+	data[1] = TOBCD(dt.dt_sec);	/* this will also enable the osc */
+	data[2] = TOBCD(dt.dt_min);
+	data[3] = TOBCD(dt.dt_hour);	/* this will also set 24h mode */
+	data[4] = TOBCD(dt.dt_wday);
+	data[5] = TOBCD(dt.dt_day);
+	data[6] = TOBCD(dt.dt_mon);
+	data[7] = TOBCD(dt.dt_year - 2000);
+	if (maxrtc_write(sc, data, sizeof(data))) {
+		printf("%s: maxrtc_settime failed\n", sc->sc_dev.dv_xname);
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+maxrtc_getcal(struct todr_chip_handle *ch, int *cal)
+{
+	return (EOPNOTSUPP);
+}
+
+int
+maxrtc_setcal(struct todr_chip_handle *ch, int cal)
+{
+	return (EOPNOTSUPP);
+}
diff --git a/sys/dev/i2c/files.i2c b/sys/dev/i2c/files.i2c
index afc58215e4c..c9103c79f1d 100644
--- a/sys/dev/i2c/files.i2c
+++ b/sys/dev/i2c/files.i2c
@@ -1,4 +1,4 @@
-# $OpenBSD: files.i2c,v 1.55 2016/05/16 22:05:36 kettenis Exp $
+# $OpenBSD: files.i2c,v 1.56 2016/06/20 13:42:42 mglocker Exp $
 #	$NetBSD: files.i2c,v 1.3 2003/10/20 16:24:10 briggs Exp $
 
 define	i2c {[addr = -1], [size = -1]}
@@ -74,6 +74,11 @@ device	pcagpio: gpiobus
 attach	pcagpio at i2c
 file	dev/i2c/pca9554.c			pcagpio
 
+# Maxim DS1307
+device	maxrtc
+attach	maxrtc at i2c
+file	dev/i2c/ds1307.c			maxrtc
+
 # Maxim DS1631
 device	maxds
 attach	maxds at i2c