rtc: Add M41T62 support

This patch add support for the STM M41T62 RTC. It is used and tested
on the AMCC Canyonlands 406EX platform.

Signed-off-by: Stefan Roese <sr@denx.de>

2 files changed, 136 insertions, 0 deletions

diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 2af2bf4..56847d2 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -41,6 +41,7 @@ COBJS-y += ds174x.o
 COBJS-y += ds3231.o
 COBJS-y += m41t11.o
 COBJS-y += m41t60.o
+COBJS-$(CONFIG_RTC_M41T62) += m41t62.o
 COBJS-y += max6900.o
 COBJS-y += m48t35ax.o
 COBJS-y += mc146818.o
diff --git a/drivers/rtc/m41t62.c b/drivers/rtc/m41t62.c
new file mode 100644
index 0000000..2bdca3b
--- /dev/null
+++ b/drivers/rtc/m41t62.c
@@ -0,0 +1,135 @@
+/*
+ * (C) Copyright 2008
+ * Stefan Roese, DENX Software Engineering, sr@denx.de.
+ *
+ * based on a the Linux rtc-m41t80.c driver which is:
+ *   Alexander Bigga <ab@mycable.de>, 2006 (c) mycable GmbH
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Date & Time support for STMicroelectronics M41T62
+ */
+
+/* #define	DEBUG	*/
+
+#include <common.h>
+#include <command.h>
+#include <rtc.h>
+#include <i2c.h>
+#include <bcd.h>
+
+#if defined(CONFIG_CMD_DATE)
+
+#define M41T62_REG_SSEC	0
+#define M41T62_REG_SEC	1
+#define M41T62_REG_MIN	2
+#define M41T62_REG_HOUR	3
+#define M41T62_REG_WDAY	4
+#define M41T62_REG_DAY	5
+#define M41T62_REG_MON	6
+#define M41T62_REG_YEAR	7
+#define M41T62_REG_ALARM_MON	0xa
+#define M41T62_REG_ALARM_DAY	0xb
+#define M41T62_REG_ALARM_HOUR	0xc
+#define M41T62_REG_ALARM_MIN	0xd
+#define M41T62_REG_ALARM_SEC	0xe
+#define M41T62_REG_FLAGS	0xf
+
+#define M41T62_DATETIME_REG_SIZE	(M41T62_REG_YEAR + 1)
+#define M41T62_ALARM_REG_SIZE	\
+	(M41T62_REG_ALARM_SEC + 1 - M41T62_REG_ALARM_MON)
+
+#define M41T62_SEC_ST		(1 << 7)	/* ST: Stop Bit */
+#define M41T62_ALMON_AFE	(1 << 7)	/* AFE: AF Enable Bit */
+#define M41T62_ALMON_SQWE	(1 << 6)	/* SQWE: SQW Enable Bit */
+#define M41T62_ALHOUR_HT	(1 << 6)	/* HT: Halt Update Bit */
+#define M41T62_FLAGS_AF		(1 << 6)	/* AF: Alarm Flag Bit */
+#define M41T62_FLAGS_BATT_LOW	(1 << 4)	/* BL: Battery Low Bit */
+
+#define M41T62_FEATURE_HT	(1 << 0)
+#define M41T62_FEATURE_BL	(1 << 1)
+
+void rtc_get(struct rtc_time *tm)
+{
+	u8 buf[M41T62_DATETIME_REG_SIZE];
+
+	i2c_read(CFG_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
+
+	debug("%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
+	      "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
+	      __FUNCTION__,
+	      buf[0], buf[1], buf[2], buf[3],
+	      buf[4], buf[5], buf[6], buf[7]);
+
+	tm->tm_sec = BCD2BIN(buf[M41T62_REG_SEC] & 0x7f);
+	tm->tm_min = BCD2BIN(buf[M41T62_REG_MIN] & 0x7f);
+	tm->tm_hour = BCD2BIN(buf[M41T62_REG_HOUR] & 0x3f);
+	tm->tm_mday = BCD2BIN(buf[M41T62_REG_DAY] & 0x3f);
+	tm->tm_wday = buf[M41T62_REG_WDAY] & 0x07;
+	tm->tm_mon = BCD2BIN(buf[M41T62_REG_MON] & 0x1f) - 1;
+
+	/* assume 20YY not 19YY, and ignore the Century Bit */
+	/* U-Boot needs to add 1900 here */
+	tm->tm_year = BCD2BIN(buf[M41T62_REG_YEAR]) + 100 + 1900;
+
+	debug("%s: tm is secs=%d, mins=%d, hours=%d, "
+	      "mday=%d, mon=%d, year=%d, wday=%d\n",
+	      __FUNCTION__,
+	      tm->tm_sec, tm->tm_min, tm->tm_hour,
+	      tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+}
+
+void rtc_set(struct rtc_time *tm)
+{
+	u8 buf[M41T62_DATETIME_REG_SIZE];
+
+	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+	      tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	i2c_read(CFG_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
+
+	/* Merge time-data and register flags into buf[0..7] */
+	buf[M41T62_REG_SSEC] = 0;
+	buf[M41T62_REG_SEC] =
+		BIN2BCD(tm->tm_sec) | (buf[M41T62_REG_SEC] & ~0x7f);
+	buf[M41T62_REG_MIN] =
+		BIN2BCD(tm->tm_min) | (buf[M41T62_REG_MIN] & ~0x7f);
+	buf[M41T62_REG_HOUR] =
+		BIN2BCD(tm->tm_hour) | (buf[M41T62_REG_HOUR] & ~0x3f) ;
+	buf[M41T62_REG_WDAY] =
+		(tm->tm_wday & 0x07) | (buf[M41T62_REG_WDAY] & ~0x07);
+	buf[M41T62_REG_DAY] =
+		BIN2BCD(tm->tm_mday) | (buf[M41T62_REG_DAY] & ~0x3f);
+	buf[M41T62_REG_MON] =
+		BIN2BCD(tm->tm_mon + 1) | (buf[M41T62_REG_MON] & ~0x1f);
+	/* assume 20YY not 19YY */
+	buf[M41T62_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
+
+	if (i2c_write(CFG_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE))
+		printf("I2C write failed in %s()\n", __func__);
+}
+
+void rtc_reset(void)
+{
+	/*
+	 * Nothing to do
+	 */
+}
+
+#endif