[U-Boot-Users] [PATCH] Add CFG_RTC_DS1337_NOOSC to turn off OSC output

[Joakim Tjernlund]

The default settings for RTC DS1337 keeps the OSC
output, 32,768 Hz, on. This add CFG_RTC_DS1337_NOOSC to
turn it off.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
---

I don't want the square wave as it drains the battery needlessly
so I made it configurable.

 README               |    1 +
 drivers/rtc/ds1337.c |   11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/README b/README
index 491397a..9a55d35 100644
--- a/README
+++ b/README
@@ -670,6 +670,7 @@ The following options need to be configured:
 		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
 		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
 		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
+		CFG_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
 
 		Note that if the RTC uses I2C, then the I2C interface
 		must also be configured. See I2C Support, below.
diff --git a/drivers/rtc/ds1337.c b/drivers/rtc/ds1337.c
index c636ac5..56268e9 100644
--- a/drivers/rtc/ds1337.c
+++ b/drivers/rtc/ds1337.c
@@ -154,11 +154,18 @@ void rtc_set (struct rtc_time *tmp)
  * SQW/INTB* pin and program it for 32,768 Hz output. Note that
  * according to the datasheet, turning on the square wave output
  * increases the current drain on the backup battery from about
- * 600 nA to 2uA.
+ * 600 nA to 2uA. Define CFG_RTC_DS1337_NOOSC if you wish to turn
+ * off the OSC output.
  */
+#ifdef CFG_RTC_DS1337_NOOSC
+ #define RTC_DS1337_RESET_VAL \
+          (RTC_CTL_BIT_INTCN | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
+#else
+ #define RTC_DS1337_RESET_VAL (RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2)
+#endif
 void rtc_reset (void)
 {
-	rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
+	rtc_write (RTC_CTL_REG_ADDR, RTC_DS1337_RESET_VAL);
 }
 
 
-- 
1.5.4.3