rtc: Ramtron FM3130 RTC support

Ramtron FM3130 is a chip with two separate devices inside, RTC clock and
FRAM.  This driver provides only RTC functionality.

This chip is met in lots of custom boards with AT91SAMXXXX CPU I work
with, is cheap and in no way better or worse than any other RTC on market.
 While it is mostly met on much smaller devices, I think it is great to
have it supported in Linux.
Signed-off-by: Sergey Lapin <slapin@ossfans.org>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/Kconfig

@@ -256,6 +256,17 @@ config RTC_DRV_S35390A
 	  This driver can also be built as a module. If so the module
 	  will be called rtc-s35390a.
 
+config RTC_DRV_FM3130
+	tristate "Ramtron FM3130"
+	help
+	  If you say Y here you will get support for the
+	  Ramtron FM3130 RTC chips.
+	  Ramtron FM3130 is a chip with two separate devices inside,
+	  RTC clock and FRAM. This driver provides only RTC functionality.
+
+	  This driver can also be built as a module. If so the module
+	  will be called rtc-fm3130.
+
 endif # I2C
 
 comment "SPI RTC drivers"

drivers/rtc/Makefile

@@ -31,6 +31,7 @@ obj-$(CONFIG_RTC_DRV_DS1553)	+= rtc-ds1553.o
 obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o
 obj-$(CONFIG_RTC_DRV_DS1742)	+= rtc-ds1742.o
 obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
+obj-$(CONFIG_RTC_DRV_FM3130)	+= rtc-fm3130.o
 obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o
 obj-$(CONFIG_RTC_DRV_M41T80)	+= rtc-m41t80.o
 obj-$(CONFIG_RTC_DRV_M48T59)	+= rtc-m48t59.o
@@ -41,6 +42,7 @@ obj-$(CONFIG_RTC_DRV_OMAP)	+= rtc-omap.o
 obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)	+= rtc-pcf8583.o
 obj-$(CONFIG_RTC_DRV_PL031)	+= rtc-pl031.o
+obj-$(CONFIG_RTC_DRV_PPC)	+= rtc-ppc.o
 obj-$(CONFIG_RTC_DRV_R9701)	+= rtc-r9701.o
 obj-$(CONFIG_RTC_DRV_RS5C313)	+= rtc-rs5c313.o
 obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o
@@ -54,4 +56,3 @@ obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o
 obj-$(CONFIG_RTC_DRV_V3020)	+= rtc-v3020.o
 obj-$(CONFIG_RTC_DRV_VR41XX)	+= rtc-vr41xx.o
 obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o
-obj-$(CONFIG_RTC_DRV_PPC)	+= rtc-ppc.o

drivers/rtc/rtc-fm3130.c

+/*
+ * rtc-fm3130.c - RTC driver for Ramtron FM3130 I2C chip.
+ *
+ *  Copyright (C) 2008 Sergey Lapin
+ *  Based on ds1307 driver by James Chapman and David Brownell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+
+#define FM3130_RTC_CONTROL	(0x0)
+#define FM3130_CAL_CONTROL	(0x1)
+#define FM3130_RTC_SECONDS	(0x2)
+#define FM3130_RTC_MINUTES	(0x3)
+#define FM3130_RTC_HOURS	(0x4)
+#define FM3130_RTC_DAY		(0x5)
+#define FM3130_RTC_DATE		(0x6)
+#define FM3130_RTC_MONTHS	(0x7)
+#define FM3130_RTC_YEARS	(0x8)
+
+#define FM3130_ALARM_SECONDS	(0x9)
+#define FM3130_ALARM_MINUTES	(0xa)
+#define FM3130_ALARM_HOURS	(0xb)
+#define FM3130_ALARM_DATE	(0xc)
+#define FM3130_ALARM_MONTHS	(0xd)
+#define FM3130_ALARM_WP_CONTROL	(0xe)
+
+#define FM3130_CAL_CONTROL_BIT_nOSCEN (1 << 7) /* Osciallator enabled */
+#define FM3130_RTC_CONTROL_BIT_LB (1 << 7) /* Low battery */
+#define FM3130_RTC_CONTROL_BIT_AF (1 << 6) /* Alarm flag */
+#define FM3130_RTC_CONTROL_BIT_CF (1 << 5) /* Century overflow */
+#define FM3130_RTC_CONTROL_BIT_POR (1 << 4) /* Power on reset */
+#define FM3130_RTC_CONTROL_BIT_AEN (1 << 3) /* Alarm enable */
+#define FM3130_RTC_CONTROL_BIT_CAL (1 << 2) /* Calibration mode */
+#define FM3130_RTC_CONTROL_BIT_WRITE (1 << 1) /* W=1 -> write mode W=0 normal */
+#define FM3130_RTC_CONTROL_BIT_READ (1 << 0) /* R=1 -> read mode R=0 normal */
+
+#define FM3130_CLOCK_REGS 7
+#define FM3130_ALARM_REGS 5
+
+struct fm3130 {
+	u8			reg_addr_time;
+	u8 			reg_addr_alarm;
+	u8			regs[15];
+	struct i2c_msg		msg[4];
+	struct i2c_client	*client;
+	struct rtc_device	*rtc;
+	int			data_valid;
+	int			alarm;
+};
+static const struct i2c_device_id fm3130_id[] = {
+	{ "fm3130-rtc", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, fm3130_id);
+
+#define FM3130_MODE_NORMAL		0
+#define FM3130_MODE_WRITE		1
+#define FM3130_MODE_READ		2
+
+static void fm3130_rtc_mode(struct device *dev, int mode)
+{
+	struct fm3130 *fm3130 = dev_get_drvdata(dev);
+
+	fm3130->regs[FM3130_RTC_CONTROL] =
+		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
+	switch (mode) {
+	case FM3130_MODE_NORMAL:
+		fm3130->regs[FM3130_RTC_CONTROL] &=
+			~(FM3130_RTC_CONTROL_BIT_WRITE |
+			FM3130_RTC_CONTROL_BIT_READ);
+		break;
+	case FM3130_MODE_WRITE:
+		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_WRITE;
+		break;
+	case FM3130_MODE_READ:
+		fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_READ;
+		break;
+	default:
+		dev_dbg(dev, "invalid mode %d\n", mode);
+		break;
+	}
+	/* Checking for alarm */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AF) {
+		fm3130->alarm = 1;
+		fm3130->regs[FM3130_RTC_CONTROL] &= ~FM3130_RTC_CONTROL_BIT_AF;
+	}
+	i2c_smbus_write_byte_data(fm3130->client,
+		 FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL]);
+}
+
+static int fm3130_get_time(struct device *dev, struct rtc_time *t)
+{
+	struct fm3130 *fm3130 = dev_get_drvdata(dev);
+	int		tmp;
+
+	if (!fm3130->data_valid) {
+		/* We have invalid data in RTC, probably due
+		to battery faults or other problems. Return EIO
+		for now, it will allow us to set data later insted
+		of error during probing which disables device */
+		return -EIO;
+	}
+	fm3130_rtc_mode(dev, FM3130_MODE_READ);
+
+	/* read the RTC date and time registers all at once */
+	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
+			fm3130->msg, 2);
+	if (tmp != 2) {
+		dev_err(dev, "%s error %d\n", "read", tmp);
+		return -EIO;
+	}
+
+	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
+
+	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x %02x"
+			"%02x %02x %02x %02x %02x %02x %02x\n",
+			"read",
+			fm3130->regs[0], fm3130->regs[1],
+			fm3130->regs[2], fm3130->regs[3],
+			fm3130->regs[4], fm3130->regs[5],
+			fm3130->regs[6], fm3130->regs[7],
+			fm3130->regs[8], fm3130->regs[9],
+			fm3130->regs[0xa], fm3130->regs[0xb],
+			fm3130->regs[0xc], fm3130->regs[0xd],
+			fm3130->regs[0xe]);
+
+	t->tm_sec = BCD2BIN(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
+	t->tm_min = BCD2BIN(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
+	tmp = fm3130->regs[FM3130_RTC_HOURS] & 0x3f;
+	t->tm_hour = BCD2BIN(tmp);
+	t->tm_wday = BCD2BIN(fm3130->regs[FM3130_RTC_DAY] & 0x07) - 1;
+	t->tm_mday = BCD2BIN(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
+	tmp = fm3130->regs[FM3130_RTC_MONTHS] & 0x1f;
+	t->tm_mon = BCD2BIN(tmp) - 1;
+
+	/* assume 20YY not 19YY, and ignore CF bit */
+	t->tm_year = BCD2BIN(fm3130->regs[FM3130_RTC_YEARS]) + 100;
+
+	dev_dbg(dev, "%s secs=%d, mins=%d, "
+		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+		"read", t->tm_sec, t->tm_min,
+		t->tm_hour, t->tm_mday,
+		t->tm_mon, t->tm_year, t->tm_wday);
+
+	/* initial clock setting can be undefined */
+	return rtc_valid_tm(t);
+}
+
+
+static int fm3130_set_time(struct device *dev, struct rtc_time *t)
+{
+	struct fm3130 *fm3130 = dev_get_drvdata(dev);
+	int		tmp, i;
+	u8		*buf = fm3130->regs;
+
+	dev_dbg(dev, "%s secs=%d, mins=%d, "
+		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+		"write", t->tm_sec, t->tm_min,
+		t->tm_hour, t->tm_mday,
+		t->tm_mon, t->tm_year, t->tm_wday);
+
+	/* first register addr */
+	buf[FM3130_RTC_SECONDS] = BIN2BCD(t->tm_sec);
+	buf[FM3130_RTC_MINUTES] = BIN2BCD(t->tm_min);
+	buf[FM3130_RTC_HOURS] = BIN2BCD(t->tm_hour);
+	buf[FM3130_RTC_DAY] = BIN2BCD(t->tm_wday + 1);
+	buf[FM3130_RTC_DATE] = BIN2BCD(t->tm_mday);
+	buf[FM3130_RTC_MONTHS] = BIN2BCD(t->tm_mon + 1);
+
+	/* assume 20YY not 19YY */
+	tmp = t->tm_year - 100;
+	buf[FM3130_RTC_YEARS] = BIN2BCD(tmp);
+
+	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x"
+		"%02x %02x %02x %02x %02x %02x %02x %02x\n",
+		"write", buf[0], buf[1], buf[2], buf[3],
+		buf[4], buf[5], buf[6], buf[7],
+		buf[8], buf[9], buf[0xa], buf[0xb],
+		buf[0xc], buf[0xd], buf[0xe]);
+
+	fm3130_rtc_mode(dev, FM3130_MODE_WRITE);
+
+	/* Writing time registers, we don't support multibyte transfers */
+	for (i = 0; i < FM3130_CLOCK_REGS; i++) {
+		i2c_smbus_write_byte_data(fm3130->client,
+					FM3130_RTC_SECONDS + i,
+					fm3130->regs[FM3130_RTC_SECONDS + i]);
+	}
+
+	fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
+
+	/* We assume here that data are valid once written */
+	if (!fm3130->data_valid)
+		fm3130->data_valid = 1;
+	return 0;
+}
+
+static int fm3130_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct fm3130 *fm3130 = dev_get_drvdata(dev);
+	int tmp;
+	struct rtc_time *tm = &alrm->time;
+	/* read the RTC alarm registers all at once */
+	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
+			&fm3130->msg[2], 2);
+	if (tmp != 2) {
+		dev_err(dev, "%s error %d\n", "read", tmp);
+		return -EIO;
+	}
+	dev_dbg(dev, "alarm read %02x %02x %02x %02x %02x\n",
+			fm3130->regs[FM3130_ALARM_SECONDS],
+			fm3130->regs[FM3130_ALARM_MINUTES],
+			fm3130->regs[FM3130_ALARM_HOURS],
+			fm3130->regs[FM3130_ALARM_DATE],
+			fm3130->regs[FM3130_ALARM_MONTHS]);
+
+
+	tm->tm_sec	= BCD2BIN(fm3130->regs[FM3130_ALARM_SECONDS] & 0x7F);
+	tm->tm_min	= BCD2BIN(fm3130->regs[FM3130_ALARM_MINUTES] & 0x7F);
+	tm->tm_hour	= BCD2BIN(fm3130->regs[FM3130_ALARM_HOURS] & 0x3F);
+	tm->tm_mday	= BCD2BIN(fm3130->regs[FM3130_ALARM_DATE] & 0x3F);
+	tm->tm_mon	= BCD2BIN(fm3130->regs[FM3130_ALARM_MONTHS] & 0x1F);
+	if (tm->tm_mon > 0)
+		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
+	dev_dbg(dev, "%s secs=%d, mins=%d, "
+		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+		"read alarm", tm->tm_sec, tm->tm_min,
+		tm->tm_hour, tm->tm_mday,
+		tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+	return 0;
+}
+
+static int fm3130_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct fm3130 *fm3130 = dev_get_drvdata(dev);
+	struct rtc_time *tm = &alrm->time;
+	int i;
+
+	dev_dbg(dev, "%s secs=%d, mins=%d, "
+		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+		"write alarm", tm->tm_sec, tm->tm_min,
+		tm->tm_hour, tm->tm_mday,
+		tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+	if (tm->tm_sec != -1)
+		fm3130->regs[FM3130_ALARM_SECONDS] =
+			BIN2BCD(tm->tm_sec) | 0x80;
+
+	if (tm->tm_min != -1)
+		fm3130->regs[FM3130_ALARM_MINUTES] =
+			BIN2BCD(tm->tm_min) | 0x80;
+
+	if (tm->tm_hour != -1)
+		fm3130->regs[FM3130_ALARM_HOURS] =
+			BIN2BCD(tm->tm_hour) | 0x80;
+
+	if (tm->tm_mday != -1)
+		fm3130->regs[FM3130_ALARM_DATE] =
+			BIN2BCD(tm->tm_mday) | 0x80;
+
+	if (tm->tm_mon != -1)
+		fm3130->regs[FM3130_ALARM_MONTHS] =
+			BIN2BCD(tm->tm_mon + 1) | 0x80;
+
+	dev_dbg(dev, "alarm write %02x %02x %02x %02x %02x\n",
+			fm3130->regs[FM3130_ALARM_SECONDS],
+			fm3130->regs[FM3130_ALARM_MINUTES],
+			fm3130->regs[FM3130_ALARM_HOURS],
+			fm3130->regs[FM3130_ALARM_DATE],
+			fm3130->regs[FM3130_ALARM_MONTHS]);
+	/* Writing time registers, we don't support multibyte transfers */
+	for (i = 0; i < FM3130_ALARM_REGS; i++) {
+		i2c_smbus_write_byte_data(fm3130->client,
+					FM3130_ALARM_SECONDS + i,
+					fm3130->regs[FM3130_ALARM_SECONDS + i]);
+	}
+	fm3130->regs[FM3130_RTC_CONTROL] =
+		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
+	/* Checking for alarm */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AF) {
+		fm3130->alarm = 1;
+		fm3130->regs[FM3130_RTC_CONTROL] &= ~FM3130_RTC_CONTROL_BIT_AF;
+	}
+	if (alrm->enabled) {
+		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
+			(fm3130->regs[FM3130_RTC_CONTROL] &
+				~(FM3130_RTC_CONTROL_BIT_CAL)) |
+					FM3130_RTC_CONTROL_BIT_AEN);
+	} else {
+		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
+			fm3130->regs[FM3130_RTC_CONTROL] &
+				~(FM3130_RTC_CONTROL_BIT_AEN));
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops fm3130_rtc_ops = {
+	.read_time	= fm3130_get_time,
+	.set_time	= fm3130_set_time,
+	.read_alarm	= fm3130_read_alarm,
+	.set_alarm	= fm3130_set_alarm,
+};
+
+static struct i2c_driver fm3130_driver;
+
+static int __devinit fm3130_probe(struct i2c_client *client,
+				  const struct i2c_device_id *id)
+{
+	struct fm3130		*fm3130;
+	int			err = -ENODEV;
+	int			tmp;
+	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
+
+	if (!i2c_check_functionality(adapter,
+			I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+		return -EIO;
+
+	fm3130 = kzalloc(sizeof(struct fm3130), GFP_KERNEL);
+
+	if (!fm3130)
+		return -ENOMEM;
+
+	fm3130->client = client;
+	i2c_set_clientdata(client, fm3130);
+	fm3130->reg_addr_time = FM3130_RTC_SECONDS;
+	fm3130->reg_addr_alarm = FM3130_ALARM_SECONDS;
+
+	/* Messages to read time */
+	fm3130->msg[0].addr = client->addr;
+	fm3130->msg[0].flags = 0;
+	fm3130->msg[0].len = 1;
+	fm3130->msg[0].buf = &fm3130->reg_addr_time;
+
+	fm3130->msg[1].addr = client->addr;
+	fm3130->msg[1].flags = I2C_M_RD;
+	fm3130->msg[1].len = FM3130_CLOCK_REGS;
+	fm3130->msg[1].buf = &fm3130->regs[FM3130_RTC_SECONDS];
+
+	/* Messages to read alarm */
+	fm3130->msg[2].addr = client->addr;
+	fm3130->msg[2].flags = 0;
+	fm3130->msg[2].len = 1;
+	fm3130->msg[2].buf = &fm3130->reg_addr_alarm;
+
+	fm3130->msg[3].addr = client->addr;
+	fm3130->msg[3].flags = I2C_M_RD;
+	fm3130->msg[3].len = FM3130_ALARM_REGS;
+	fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];
+
+	fm3130->data_valid = 0;
+
+	tmp = i2c_transfer(adapter, fm3130->msg, 4);
+	if (tmp != 4) {
+		pr_debug("read error %d\n", tmp);
+		err = -EIO;
+		goto exit_free;
+	}
+
+	fm3130->regs[FM3130_RTC_CONTROL] =
+		i2c_smbus_read_byte_data(client, FM3130_RTC_CONTROL);
+	fm3130->regs[FM3130_CAL_CONTROL] =
+		i2c_smbus_read_byte_data(client, FM3130_CAL_CONTROL);
+
+	/* Checking for alarm */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AF) {
+		fm3130->alarm = 1;
+		fm3130->regs[FM3130_RTC_CONTROL] &= ~FM3130_RTC_CONTROL_BIT_AF;
+	}
+
+	/* Disabling calibration mode */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_CAL)
+		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
+			fm3130->regs[FM3130_RTC_CONTROL] &
+				~(FM3130_RTC_CONTROL_BIT_CAL));
+		dev_warn(&client->dev, "Disabling calibration mode!\n");
+
+	/* Disabling read and write modes */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_WRITE ||
+	    fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_READ)
+		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
+			fm3130->regs[FM3130_RTC_CONTROL] &
+				~(FM3130_RTC_CONTROL_BIT_READ |
+					FM3130_RTC_CONTROL_BIT_WRITE));
+		dev_warn(&client->dev, "Disabling READ or WRITE mode!\n");
+
+	/* oscillator off?  turn it on, so clock can tick. */
+	if (fm3130->regs[FM3130_CAL_CONTROL] & FM3130_CAL_CONTROL_BIT_nOSCEN)
+		i2c_smbus_write_byte_data(client, FM3130_CAL_CONTROL,
+			fm3130->regs[FM3130_CAL_CONTROL] &
+				~(FM3130_CAL_CONTROL_BIT_nOSCEN));
+
+	/* oscillator fault?  clear flag, and warn */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB)
+		dev_warn(&client->dev, "Low battery!\n");
+
+	/* oscillator fault?  clear flag, and warn */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_POR) {
+		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
+			fm3130->regs[FM3130_RTC_CONTROL] &
+				~FM3130_RTC_CONTROL_BIT_POR);
+		dev_warn(&client->dev, "SET TIME!\n");
+	}
+	/* ACS is controlled by alarm */
+	i2c_smbus_write_byte_data(client, FM3130_ALARM_WP_CONTROL, 0x80);
+
+	/* TODO */
+	/* TODO need to sanity check alarm */
+	tmp = fm3130->regs[FM3130_RTC_SECONDS];
+	tmp = BCD2BIN(tmp & 0x7f);
+	if (tmp > 60)
+		goto exit_bad;
+	tmp = BCD2BIN(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
+	if (tmp > 60)
+		goto exit_bad;
+
+	tmp = BCD2BIN(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
+	if (tmp == 0 || tmp > 31)
+		goto exit_bad;
+
+	tmp = BCD2BIN(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
+	if (tmp == 0 || tmp > 12)
+		goto exit_bad;
+
+	tmp = fm3130->regs[FM3130_RTC_HOURS];
+
+	fm3130->data_valid = 1;
+
+exit_bad:
+	if (!fm3130->data_valid)
+		dev_dbg(&client->dev,
+				"%s: %02x %02x %02x %02x %02x %02x %02x %02x"
+				"%02x %02x %02x %02x %02x %02x %02x\n",
+			"bogus registers",
+			fm3130->regs[0], fm3130->regs[1],
+			fm3130->regs[2], fm3130->regs[3],
+			fm3130->regs[4], fm3130->regs[5],
+			fm3130->regs[6], fm3130->regs[7],
+			fm3130->regs[8], fm3130->regs[9],
+			fm3130->regs[0xa], fm3130->regs[0xb],
+			fm3130->regs[0xc], fm3130->regs[0xd],
+			fm3130->regs[0xe]);
+
+	/* We won't bail out here because we just got invalid data.
+	   Time setting from u-boot doesn't work anyway */
+	fm3130->rtc = rtc_device_register(client->name, &client->dev,
+				&fm3130_rtc_ops, THIS_MODULE);
+	if (IS_ERR(fm3130->rtc)) {
+		err = PTR_ERR(fm3130->rtc);
+		dev_err(&client->dev,
+			"unable to register the class device\n");
+		goto exit_free;
+	}
+	return 0;
+exit_free:
+	kfree(fm3130);
+	return err;
+}
+
+static int __devexit fm3130_remove(struct i2c_client *client)
+{
+	struct fm3130 *fm3130 = i2c_get_clientdata(client);
+
+	rtc_device_unregister(fm3130->rtc);
+	kfree(fm3130);
+	return 0;
+}
+
+static struct i2c_driver fm3130_driver = {
+	.driver = {
+		.name	= "rtc-fm3130",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= fm3130_probe,
+	.remove		= __devexit_p(fm3130_remove),
+	.id_table	= fm3130_id,
+};
+
+static int __init fm3130_init(void)
+{
+	return i2c_add_driver(&fm3130_driver);
+}
+module_init(fm3130_init);
+
+static void __exit fm3130_exit(void)
+{
+	i2c_del_driver(&fm3130_driver);
+}
+module_exit(fm3130_exit);
+
+MODULE_DESCRIPTION("RTC driver for FM3130");
+MODULE_AUTHOR("Sergey Lapin <slapin@ossfans.org>");
+MODULE_LICENSE("GPL");
+