MCP7941x RTCs are very similar to ds1307. So add support in the ds1307 driver,
as it is done in the linux kernel

Signed-off-by: Soeren Moch <sm...@web.de>
---
Cc: Tom Rini <tr...@ti.com>
---
 drivers/rtc/ds1307.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/ds1307.c b/drivers/rtc/ds1307.c
index 03ab1a8..20da43a 100644
--- a/drivers/rtc/ds1307.c
+++ b/drivers/rtc/ds1307.c
@@ -10,6 +10,10 @@
 /*
  * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
  * DS1307 and DS1338/9 Real Time Clock (RTC).
+ * i2c address 0x68
+ *
+ * Date & Time support (no alarms) for MCP7941x  Real Time Clock (RTC).
+ * i2c address 0x6f
  *
  * based on ds1337.c
  */
@@ -52,12 +56,24 @@
 #define RTC_CTL_REG_ADDR       0x07
 
 #define RTC_SEC_BIT_CH         0x80    /* Clock Halt (in Register 0)   */
+#define RTC_SEC_CH             0x80    /* Clock Halt (in Register 0)   */
+
+#define RTC_DAY_VBATEN         0x00    /* Battery EN (in Register 3)   */
 
 #define RTC_CTL_BIT_RS0                0x01    /* Rate select 0                
*/
 #define RTC_CTL_BIT_RS1                0x02    /* Rate select 1                
*/
 #define RTC_CTL_BIT_SQWE       0x10    /* Square Wave Enable           */
 #define RTC_CTL_BIT_OUT                0x80    /* Output Control               
*/
 
+#if CONFIG_SYS_I2C_RTC_ADDR == 0x6f
+#undef RTC_SEC_CH
+#undef RTC_DAY_VBATEN
+#undef RTC_CTL_BIT_SQWE
+#define RTC_SEC_CH             0x00    /* Clock Halt (in Register 0)   */
+#define RTC_DAY_VBATEN         0x08    /* Battery EN (in Register 3)   */
+#define RTC_CTL_BIT_SQWE       0x40    /* Square Wave Enable           */
+#endif
+
 static uchar rtc_read (uchar reg);
 static void rtc_write (uchar reg, uchar val);
 
@@ -81,11 +97,11 @@ int rtc_get (struct rtc_time *tmp)
                "hr: %02x min: %02x sec: %02x\n",
                year, mon, mday, wday, hour, min, sec);
 
-       if (sec & RTC_SEC_BIT_CH) {
+       if ((sec & RTC_SEC_BIT_CH) == RTC_SEC_CH) {
                printf ("### Warning: RTC oscillator has stopped\n");
-               /* clear the CH flag */
+               /* start clock */
                rtc_write (RTC_SEC_REG_ADDR,
-                          rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH);
+                          rtc_read (RTC_SEC_REG_ADDR) ^ RTC_SEC_BIT_CH);
                rel = -1;
        }
 
@@ -112,6 +128,9 @@ int rtc_get (struct rtc_time *tmp)
  */
 int rtc_set (struct rtc_time *tmp)
 {
+       uchar clk_en = RTC_SEC_BIT_CH & ~RTC_SEC_CH;
+       uchar bat_en = RTC_DAY_VBATEN;
+
        DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
@@ -121,11 +140,11 @@ int rtc_set (struct rtc_time *tmp)
 
        rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
        rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
-       rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
+       rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1) | bat_en);
        rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
        rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
        rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
-       rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
+       rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec) | clk_en);
 
        return 0;
 }
@@ -142,7 +161,6 @@ void rtc_reset (void)
 {
        struct rtc_time tmp;
 
-       rtc_write (RTC_SEC_REG_ADDR, 0x00);     /* clearing Clock Halt  */
        rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 | 
RTC_CTL_BIT_RS0);
 
        tmp.tm_year = 1970;
-- 
1.9.1

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