[U-Boot] [PATCH 10/33] rtc: mc146818: Set up RTC at start of day

[Simon Glass]

If the RTC needs to be cleared, write the U-Boot build date to it. In any
case make sure the settings are correct.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 drivers/rtc/mc146818.c | 49 +++++++++++++++++++++++++++++++++++++++++++++----
 include/rtc.h          |  7 +++++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/mc146818.c b/drivers/rtc/mc146818.c
index f7cf106..7528044 100644
--- a/drivers/rtc/mc146818.c
+++ b/drivers/rtc/mc146818.c
@@ -14,6 +14,7 @@
 #include <common.h>
 #include <command.h>
 #include <rtc.h>
+#include <version.h>
 
 #if defined(__I386__) || defined(CONFIG_MALTA)
 #include <asm/io.h>
@@ -42,6 +43,12 @@ static void  rtc_write (uchar reg, uchar val);
 #define RTC_CONFIG_C		0x0C
 #define RTC_CONFIG_D		0x0D
 
+#define RTC_CONFIG_A_REF_CLCK_32KHZ	(1 << 5)
+#define RTC_CONFIG_A_RATE_1024HZ	6
+
+#define RTC_CONFIG_B_24H		(1 << 1)
+
+#define RTC_CONFIG_D_VALID_RAM_AND_TIME	0x80
 
 /* ------------------------------------------------------------------------- */
 
@@ -128,25 +135,59 @@ void rtc_reset (void)
  */
 static uchar rtc_read (uchar reg)
 {
-	return(in8(CONFIG_SYS_RTC_REG_BASE_ADDR+reg));
+	return in8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg);
 }
 
 static void rtc_write (uchar reg, uchar val)
 {
-	out8(CONFIG_SYS_RTC_REG_BASE_ADDR+reg, val);
+	out8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg, val);
 }
 #else
 static uchar rtc_read (uchar reg)
 {
 	out8(RTC_PORT_MC146818,reg);
-	return(in8(RTC_PORT_MC146818+1));
+	return in8(RTC_PORT_MC146818 + 1);
 }
 
 static void rtc_write (uchar reg, uchar val)
 {
 	out8(RTC_PORT_MC146818,reg);
-	out8(RTC_PORT_MC146818+1,val);
+	out8(RTC_PORT_MC146818+1, val);
 }
 #endif
 
+void rtc_init(bool invalid)
+{
+	debug("RTC Init\n");
+
+#define CLEAR_CMOS 0
+#else
+#define CLEAR_CMOS 1
 #endif
+
+	if (invalid) {
+#if CLEAR_CMOS
+		int i;
+
+		rtc_write(0x01, 0);
+		rtc_write(0x03, 0);
+		rtc_write(0x05, 0);
+		for (i = 10; i < 128; i++)
+			rtc_write(i, 0);
+#endif
+		printf("RTC:%s%s\n",
+		       invalid ? " Clear requested" : "",
+		       CLEAR_CMOS ? " zeroing cmos" : "");
+	}
+
+	/* Setup the real time clock */
+	rtc_write(RTC_CONFIG_B, RTC_CONFIG_B_24H);
+	/* Setup the frequency it operates at */
+	rtc_write(RTC_CONFIG_A, RTC_CONFIG_A_REF_CLCK_32KHZ |
+		  RTC_CONFIG_A_RATE_1024HZ);
+	/* Ensure all reserved bits are 0 in register D */
+	rtc_write(RTC_CONFIG_D, RTC_CONFIG_D_VALID_RAM_AND_TIME);
+
+	/* Clear any pending interrupts */
+	rtc_read(RTC_CONFIG_C);
+}
diff --git a/include/rtc.h b/include/rtc.h
index c034966..8be06bb 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -50,4 +50,11 @@ void to_tm (int, struct rtc_time *);
 unsigned long mktime (unsigned int, unsigned int, unsigned int,
 		      unsigned int, unsigned int, unsigned int);
 
+/**
+ * rtc_init() - Set up the real time clock ready for use
+ *
+ * @rtc_failed:	true if time was lost (e.g. flat battery), else false
+ */
+void rtc_init(bool rtc_failed);
+
 #endif	/* _RTC_H_ */
-- 
2.1.0.rc2.206.gedb03e5