--- /dev/null
+/* $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);
+}
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