- Some of the upper bits of the time related (seconds, minutes, etc.)

  registers are control bits or depending on the model contain additional
  time bits with a different meaning than the lower ones. In order to
  only read the desired time bits and not change the upper bits on write
  use appropriate masks in the gettime and settime function respectively.
  Due to the polarity of the stop oscillator bit and the fact that the
  century bits aren't used on sparc64 not masking them didn't cause
  problems so far.
- Fix two off-by-one errors in the handling of the day of week. The
  genclock code represents the dow as 0 - 6 with 0 being Sunday but the
  mk48txx use 1 - 7 with 1 being Sunday. In the settime function when
  writing the dow to the clock the range wasn't adjusted accordingly but
  the clock apparently played along nicely otherwise the second bug in
  the gettime function which mapped 1 - 7 to 0 - 6 but with 0 meaning
  Saturday would have been triggered. Fixing these makes the date being
  stored in the same format Sun/Solaris uses and cures the "Invalid time
  in real time clock. Check and reset the date immediately!" when the
  date was set under Solaris prior to booting FreeBSD/sparc64. [1]
  Looking at other clock drivers/code e.g. FreeBSD/alpha the former "bug",
  i.e. storing the dow as 0 - 6 even when the clock uses 1 - 7, seems to
  be common but might be on purpose for compatibility when multi-booting
  with other OS which do the same. So it might make sense to add a flag
  to handle the dow off-by-one for use of this driver on platforms other
  than sparc64.
- Check the state of the battery on mk48txx that support this in the
  attach function.
- Add a note that use of the century bit should be implemented but isn't
  required at the moment because it isn't used on sparc64.

Problem noted by:	joerg [1]
MT5 candidate.

2 files changed, 131 insertions, 19 deletions

diff --git a/sys/dev/mk48txx/mk48txx.c b/sys/dev/mk48txx/mk48txx.c
index 9d28084..1cbb526 100644
--- a/sys/dev/mk48txx/mk48txx.c
+++ b/sys/dev/mk48txx/mk48txx.c
@@ -101,6 +101,13 @@ mk48txx_attach(device_t dev, bus_space_tag_t bt, bus_space_handle_t bh,
 	}
 	printf("\n");
 
+	if ((mk48txx_models[i].flags & MK48TXX_EXT_REGISTERS) &&
+	    (bus_space_read_1(bt, bh, clkoff + MK48TXX_FLAGS) &
+	    MK48TXX_FLAGS_BL)) {
+		device_printf(dev, "mk48txx_attach: battery low\n");
+		return (ENXIO);
+	}
+
 	sc = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT);
 	sc->mk_bt = bt;
 	sc->mk_bh = bh;
@@ -133,14 +140,33 @@ mk48txx_gettime(device_t dev, struct timespec *ts)
 	csr |= MK48TXX_CSR_READ;
 	bus_space_write_1(bt, bh, clkoff + MK48TXX_ICSR, csr);
 
+#define	FROMREG(reg, mask)						\
+	(bus_space_read_1(bt, bh, clkoff + (reg)) & (mask))
+
 	ct.nsec = 0;
-	ct.sec = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_ISEC));
-	ct.min = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_IMIN));
-	ct.hour = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_IHOUR));
-	ct.day = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_IDAY));
-	ct.dow = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_IWDAY)) % 7;
-	ct.mon = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_IMON));
-	year = FROMBCD(bus_space_read_1(bt, bh, clkoff + MK48TXX_IYEAR));
+	ct.sec = FROMBCD(FROMREG(MK48TXX_ISEC, MK48TXX_SEC_MASK));
+	ct.min = FROMBCD(FROMREG(MK48TXX_IMIN, MK48TXX_MIN_MASK));
+	ct.hour = FROMBCD(FROMREG(MK48TXX_IHOUR, MK48TXX_HOUR_MASK));
+	ct.day = FROMBCD(FROMREG(MK48TXX_IDAY, MK48TXX_DAY_MASK));
+	/* Map dow from 1 - 7 to 0 - 6; FROMBCD() isn't necessary here. */
+	ct.dow = FROMREG(MK48TXX_IWDAY, MK48TXX_WDAY_MASK) - 1;
+	ct.mon = FROMBCD(FROMREG(MK48TXX_IMON, MK48TXX_MON_MASK));
+	year = FROMBCD(FROMREG(MK48TXX_IYEAR, MK48TXX_YEAR_MASK));
+
+	/*
+	 * XXX:	At least the MK48T59 (probably all MK48Txx models with
+	 *	extended registers) has a century bit in the MK48TXX_IWDAY
+	 *	register which should be used here to make up the century
+	 *	when mk48txx_auto_century_adjust (which actually means
+	 *	manually adjust the century in the driver) is set to 0.
+	 *	Sun/Solaris doesn't use this bit (probably for backwards
+	 *	compatibility with Sun hardware equipped with older MK48Txx
+	 *	models) and at present this driver is only used on sparc64
+	 *	so not respecting the century bit doesn't really matter at
+	 *	the moment but generally this should be implemented.
+	 */
+
+#undef FROMREG
 
 	year += mk->mk_year0;
 	if (year < POSIX_BASE_YEAR && mk48txx_auto_century_adjust != 0)
@@ -186,13 +212,26 @@ mk48txx_settime(device_t dev, struct timespec *ts)
 	csr |= MK48TXX_CSR_WRITE;
 	bus_space_write_1(bt, bh, clkoff + MK48TXX_ICSR, csr);
 
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_ISEC, TOBCD(ct.sec));
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_IMIN, TOBCD(ct.min));
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_IHOUR, TOBCD(ct.hour));
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_IWDAY, TOBCD(ct.dow));
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_IDAY, TOBCD(ct.day));
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_IMON, TOBCD(ct.mon));
-	bus_space_write_1(bt, bh, clkoff + MK48TXX_IYEAR, TOBCD(year));
+#define	TOREG(reg, mask, val)						\
+	(bus_space_write_1(bt, bh, clkoff + (reg),			\
+	(bus_space_read_1(bt, bh, clkoff + (reg)) & ~(mask)) |		\
+	((val) & (mask))))
+
+	TOREG(MK48TXX_ISEC, MK48TXX_SEC_MASK, TOBCD(ct.sec));
+	TOREG(MK48TXX_IMIN, MK48TXX_MIN_MASK, TOBCD(ct.min));
+	TOREG(MK48TXX_IHOUR, MK48TXX_HOUR_MASK, TOBCD(ct.hour));
+	/* Map dow from 0 - 6 to 1 - 7; TOBCD() isn't necessary here. */
+	TOREG(MK48TXX_IWDAY, MK48TXX_WDAY_MASK, ct.dow + 1);
+	TOREG(MK48TXX_IDAY, MK48TXX_DAY_MASK, TOBCD(ct.day));
+	TOREG(MK48TXX_IMON, MK48TXX_MON_MASK, TOBCD(ct.mon));
+	TOREG(MK48TXX_IYEAR, MK48TXX_YEAR_MASK, TOBCD(year));
+
+	/*
+	 * XXX:	Use the century bit for storing the century when
+	 *	mk48txx_auto_century_adjust is set to 0.
+	 */
+
+#undef TOREG
 
 	/* load them up */
 	csr = bus_space_read_1(bt, bh, clkoff + MK48TXX_ICSR);
diff --git a/sys/dev/mk48txx/mk48txxreg.h b/sys/dev/mk48txx/mk48txxreg.h
index 817f122..8bcadc2 100644
--- a/sys/dev/mk48txx/mk48txxreg.h
+++ b/sys/dev/mk48txx/mk48txxreg.h
@@ -59,22 +59,95 @@
  * The first bank of eight registers at offset (nvramsz - 16) is
  * available only on recenter (which?) MK48Txx models.
  */
-#define MK48TXX_X0	0	/* find out later */
-				/* ... */
-#define MK48TXX_X7	7	/* find out later */
+#define MK48TXX_FLAGS	0	/* flags register */
+#define MK48TXX_UNUSED	1	/* unused */
+#define MK48TXX_ASEC	2	/* alarm seconds (0..59; BCD) */
+#define MK48TXX_AMIN	3	/* alarm minutes (0..59; BCD) */
+#define MK48TXX_AHOUR	4	/* alarm hours (0..23; BCD) */
+#define MK48TXX_ADAY	5	/* alarm day in month (1..31; BCD) */
+#define MK48TXX_INTR	6	/* interrupts register */
+#define MK48TXX_WDOG	7	/* watchdog register */
+
 #define MK48TXX_ICSR	8	/* control register */
 #define MK48TXX_ISEC	9	/* seconds (0..59; BCD) */
 #define MK48TXX_IMIN	10	/* minutes (0..59; BCD) */
-#define MK48TXX_IHOUR	11	/* hour (0..23; BCD) */
+#define MK48TXX_IHOUR	11	/* hours (0..23; BCD) */
 #define MK48TXX_IWDAY	12	/* weekday (1..7) */
 #define MK48TXX_IDAY	13	/* day in month (1..31; BCD) */
 #define MK48TXX_IMON	14	/* month (1..12; BCD) */
 #define MK48TXX_IYEAR	15	/* year (0..99; BCD) */
 
+/*
+ * Note that some of the bits below that are not in the first eight
+ * registers are also only available on models with an extended
+ * register set.
+ */
+
+/* Bits in the flags register (extended only) */
+#define MK48TXX_FLAGS_BL	0x10	/* battery low (read only) */
+#define MK48TXX_FLAGS_AF	0x40	/* alarm flag (read only) */
+#define MK48TXX_FLAGS_WDF	0x80	/* watchdog flag (read only) */
+
+/* Bits in the alarm seconds register (extended only) */
+#define MK48TXX_ASEC_MASK	0x7f	/* mask for alarm seconds */
+#define MK48TXX_ASEC_RPT1	0x80	/* alarm repeat mode bit 1 */
+
+/* Bits in the alarm minutes register (extended only) */
+#define MK48TXX_AMIN_MASK	0x7f	/* mask for alarm minutes */
+#define MK48TXX_AMIN_RPT2	0x80	/* alarm repeat mode bit 2 */
+
+/* Bits in the alarm hours register (extended only) */
+#define MK48TXX_AHOUR_MASK	0x3f	/* mask for alarm hours */
+#define MK48TXX_AHOUR_RPT3	0x80	/* alarm repeat mode bit 3 */
+
+/* Bits in the alarm day in month register (extended only) */
+#define MK48TXX_ADAY_MASK	0x3f	/* mask for alarm day in month */
+#define MK48TXX_ADAY_RPT4	0x80	/* alarm repeat mode bit 4 */
+
+/* Bits in the interrupts register (extended only) */
+#define MK48TXX_INTR_ABE	0x20	/* alarm in battery back-up mode */
+#define MK48TXX_INTR_AFE	0x80	/* alarm flag enable */
+
+/* Bits in the watchdog register (extended only) */
+#define MK48TXX_WDOG_RB_1_16	0x00	/* watchdog resolution 1/16 second */
+#define MK48TXX_WDOG_RB_1_4	0x01	/* watchdog resolution 1/4 second */
+#define MK48TXX_WDOG_RB_1	0x02	/* watchdog resolution 1 second */
+#define MK48TXX_WDOG_RB_4	0x03	/* watchdog resolution 4 seconds */
+#define MK48TXX_WDOG_BMB_MASK	0x7c	/* mask for watchdog multiplier */
+#define MK48TXX_WDOG_WDS	0x80	/* watchdog steering bit */
+
 /* Bits in the control register */
-#define MK48TXX_CSR_WRITE	0x80	/* want to write */
+#define MK48TXX_CSR_CALIB_MASK	0x1f	/* mask for calibration step width */
+#define MK48TXX_CSR_SIGN	0x20	/* sign of above calibration witdh */
 #define MK48TXX_CSR_READ	0x40	/* want to read (freeze clock) */
+#define MK48TXX_CSR_WRITE	0x80	/* want to write */
+
+/* Bits in the seconds register */
+#define MK48TXX_SEC_MASK	0x7f	/* mask for seconds */
+#define MK48TXX_SEC_ST		0x80	/* stop oscillator */
+
+/* Bits in the minutes register */
+#define MK48TXX_MIN_MASK	0x7f	/* mask for minutes */
+
+/* Bits in the hours register */
+#define MK48TXX_HOUR_MASK	0x3f	/* mask for hours */
+
+/* Bits in the century/weekday register */
+#define MK48TXX_WDAY_MASK	0x07	/* mask for weekday */
+#define MK48TXX_WDAY_CB		0x10	/* century bit (extended only) */
+#define MK48TXX_WDAY_CEB	0x20	/* century enable bit (extended only) */
+#define MK48TXX_WDAY_FT		0x30	/* frequency bit */
+
+/* Bits in the day in month register */
+#define MK48TXX_DAY_MASK	0x3f	/* mask for day in month */
+
+/* Bits in the month register */
+#define MK48TXX_MON_MASK	0x1f	/* mask for month */
+
+/* Bits in the year register */
+#define MK48TXX_YEAR_MASK	0xff	/* mask for year */
 
+/* Model specific NVRAM sizes and clock offsets */
 #define MK48T02_CLKSZ		2048
 #define MK48T02_CLKOFF		0x7f0