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drivers/rtc/rtc-r9701.c: reset registers if invalid values are detected

Message ID 1330680999-4434-1-git-send-email-agust@denx.de
State Accepted
Headers show

Commit Message

Anatolij Gustschin March 2, 2012, 9:36 a.m. UTC 
From: Andreas Dumberger <andreas.dumberger@tqs.de>

hwclock refuses to set date/time if RTC registers contain invalid
valies. Check the date/time register values at probe time and pre-
initialize them to make hwclock happy.

Signed-off-by: Andreas Dumberger <andreas.dumberger@tqs.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
---
 drivers/rtc/rtc-r9701.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)
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Patch

diff --git a/drivers/rtc/rtc-r9701.c b/drivers/rtc/rtc-r9701.c
index 2853c2a..3b911b3 100644
--- a/drivers/rtc/rtc-r9701.c
+++ b/drivers/rtc/rtc-r9701.c
@@ -122,6 +122,7 @@  static const struct rtc_class_ops r9701_rtc_ops = {
 static int __devinit r9701_probe(struct spi_device *spi)
 {
 	struct rtc_device *rtc;
+	struct rtc_time dt;
 	unsigned char tmp;
 	int res;
 
@@ -132,6 +133,27 @@  static int __devinit r9701_probe(struct spi_device *spi)
 		return -ENODEV;
 	}
 
+	/*
+	 * The device seems to be present. Now check if the registers
+	 * contain invalid values. If so, try to write a default date:
+	 * 2000/1/1 00:00:00
+	 */
+	r9701_get_datetime(&spi->dev, &dt);
+	if (rtc_valid_tm(&dt)) {
+		dev_info(&spi->dev, "trying to repair invalid date/time\n");
+		dt.tm_sec  = 0;
+		dt.tm_min  = 0;
+		dt.tm_hour = 0;
+		dt.tm_mday = 1;
+		dt.tm_mon  = 0;
+		dt.tm_year = 100;
+
+		if (r9701_set_datetime(&spi->dev, &dt)) {
+			dev_err(&spi->dev, "cannot repair RTC register\n");
+			return -ENODEV;
+		}
+	}
+
 	rtc = rtc_device_register("r9701",
 				&spi->dev, &r9701_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rtc))