rtc: fixes and new functionality for fm3130

- add sanity check for alarm data in fm3130_probe

- fix fm3130_set_alarm.

According to the datasheet, setting match bit '0' indicates that the
corresponding alarm field will be used in the match process

- add operation alarm_irq_enable operation which is responsible for
handling RTC_AIE_ON, RTC_AIE_OFF ioctls

- remove clearing of AF bit after reading rtc/alarm control register:
according to datasheet this bit is cleared anyway when rtc/alarm control
register is read

[[e-mail]: make fm3130_alarm_irq_enable() static, fix comment layout]
Signed-off-by: Sergey Matyukevich <[e-mail]>
Acked-by: Wan ZongShun <[e-mail]>
Acked-by: Sergey Lapin <[e-mail]>
Cc: Alessandro Zummo <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/rtc/rtc-fm3130.c

···
 	struct i2c_msg		msg[4];
 	struct i2c_client	*client;
 	struct rtc_device	*rtc;
+	int			alarm_valid;
 	int			data_valid;
-	int			alarm;
 };
 static const struct i2c_device_id fm3130_id[] = {
 	{ "fm3130", 0 },
···
 		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]);
 }
···
 	struct fm3130 *fm3130 = dev_get_drvdata(dev);
 	int tmp;
 	struct rtc_time *tm = &alrm->time;
+
+	if (!fm3130->alarm_valid) {
+		/*
+		 * We have invalid alarm in RTC, probably due to battery faults
+		 * or other problems. Return EIO for now, it will allow us to
+		 * set alarm value later instead of error during probing which
+		 * disables device
+		 */
+		return -EIO;
+	}
+
 	/* read the RTC alarm registers all at once */
 	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
 			&fm3130->msg[2], 2);
···
 			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);
+
+	/* check if alarm enabled */
+	fm3130->regs[FM3130_RTC_CONTROL] =
+		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
+
+	if ((fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AEN) &&
+		(~fm3130->regs[FM3130_RTC_CONTROL] &
+			FM3130_RTC_CONTROL_BIT_CAL)) {
+		alrm->enabled = 1;
+	}
 
 	return 0;
 }
···
 		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;
+	fm3130->regs[FM3130_ALARM_SECONDS] =
+		(tm->tm_sec != -1) ? bin2bcd(tm->tm_sec) : 0x80;
 
-	if (tm->tm_min != -1)
-		fm3130->regs[FM3130_ALARM_MINUTES] =
-			bin2bcd(tm->tm_min) | 0x80;
+	fm3130->regs[FM3130_ALARM_MINUTES] =
+		(tm->tm_min != -1) ? bin2bcd(tm->tm_min) : 0x80;
 
-	if (tm->tm_hour != -1)
-		fm3130->regs[FM3130_ALARM_HOURS] =
-			bin2bcd(tm->tm_hour) | 0x80;
+	fm3130->regs[FM3130_ALARM_HOURS] =
+		(tm->tm_hour != -1) ? bin2bcd(tm->tm_hour) : 0x80;
 
-	if (tm->tm_mday != -1)
-		fm3130->regs[FM3130_ALARM_DATE] =
-			bin2bcd(tm->tm_mday) | 0x80;
+	fm3130->regs[FM3130_ALARM_DATE] =
+		(tm->tm_mday != -1) ? bin2bcd(tm->tm_mday) : 0x80;
 
-	if (tm->tm_mon != -1)
-		fm3130->regs[FM3130_ALARM_MONTHS] =
-			bin2bcd(tm->tm_mon + 1) | 0x80;
+	fm3130->regs[FM3130_ALARM_MONTHS] =
+		(tm->tm_mon != -1) ? 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_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;
-	}
+
+	/* enable or disable alarm */
 	if (alrm->enabled) {
 		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
 			(fm3130->regs[FM3130_RTC_CONTROL] &
···
 	} else {
 		i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
 			fm3130->regs[FM3130_RTC_CONTROL] &
-				~(FM3130_RTC_CONTROL_BIT_AEN));
+				~(FM3130_RTC_CONTROL_BIT_CAL) &
+					~(FM3130_RTC_CONTROL_BIT_AEN));
 	}
+
+	/* We assume here that data is valid once written */
+	if (!fm3130->alarm_valid)
+		fm3130->alarm_valid = 1;
+
 	return 0;
+}
+
+static int fm3130_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct fm3130 *fm3130 = dev_get_drvdata(dev);
+	int ret = 0;
+
+	fm3130->regs[FM3130_RTC_CONTROL] =
+		i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
+
+	dev_dbg(dev, "alarm_irq_enable: enable=%d, FM3130_RTC_CONTROL=%02x\n",
+		enabled, fm3130->regs[FM3130_RTC_CONTROL]);
+
+	switch (enabled) {
+	case 0:		/* alarm off */
+		ret = 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));
+		break;
+	case 1:		/* alarm on */
+		ret = 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);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
 }
 
 static const struct rtc_class_ops fm3130_rtc_ops = {
···
 	.set_time	= fm3130_set_time,
 	.read_alarm	= fm3130_read_alarm,
 	.set_alarm	= fm3130_set_alarm,
+	.alarm_irq_enable = fm3130_alarm_irq_enable,
 };
 
 static struct i2c_driver fm3130_driver;
···
 	fm3130->msg[3].len = FM3130_ALARM_REGS;
 	fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];
 
+	fm3130->alarm_valid = 0;
 	fm3130->data_valid = 0;
 
 	tmp = i2c_transfer(adapter, fm3130->msg, 4);
···
 		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) {
···
 			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)
+	/* low battery?  clear flag, and warn */
+	if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB) {
+		i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
+			fm3130->regs[FM3130_RTC_CONTROL] &
+				~(FM3130_RTC_CONTROL_BIT_LB));
 		dev_warn(&client->dev, "Low battery!\n");
+	}
 
-	/* oscillator fault?  clear flag, and warn */
+	/* check if Power On Reset bit is set */
 	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");
+		dev_dbg(&client->dev, "POR bit is set\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;
+	/* alarm registers sanity check */
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
+	if (tmp > 59)
+		goto bad_alarm;
+
 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
-	if (tmp > 60)
-		goto exit_bad;
+	if (tmp > 59)
+		goto bad_alarm;
+
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
+	if (tmp > 23)
+		goto bad_alarm;
 
 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
 	if (tmp == 0 || tmp > 31)
-		goto exit_bad;
+		goto bad_alarm;
 
 	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
 	if (tmp == 0 || tmp > 12)
-		goto exit_bad;
+		goto bad_alarm;
 
-	tmp = fm3130->regs[FM3130_RTC_HOURS];
+	fm3130->alarm_valid = 1;
+
+bad_alarm:
+
+	/* clock registers sanity chek */
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
+	if (tmp > 59)
+		goto bad_clock;
+
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
+	if (tmp > 59)
+		goto bad_clock;
+
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
+	if (tmp > 23)
+		goto bad_clock;
+
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x7);
+	if (tmp == 0 || tmp > 7)
+		goto bad_clock;
+
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
+	if (tmp == 0 || tmp > 31)
+		goto bad_clock;
+
+	tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
+	if (tmp == 0 || tmp > 12)
+		goto bad_clock;
 
 	fm3130->data_valid = 1;
 
-exit_bad:
-	if (!fm3130->data_valid)
+bad_clock:
+
+	if (!fm3130->data_valid || !fm3130->alarm_valid)
 		dev_dbg(&client->dev,
 				"%s: %02x %02x %02x %02x %02x %02x %02x %02x"
 				"%02x %02x %02x %02x %02x %02x %02x\n",