rtc: Add MCP79411 support to DS1307 rtc driver
The code is from Adrian Cox, and is patterned after similar
support in Linux (drivers/rtc/rtc-ds1307.c:1121-1135). This
chip is used on the Cyrus board from Varisys.
Signed-off-by: Andy Fleming <afleming@gmail.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 3092de1..fc38a3f 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -4,7 +4,6 @@
#
# SPDX-License-Identifier: GPL-2.0+
#
-
#ccflags-y += -DDEBUG
obj-$(CONFIG_DM_RTC) += rtc-uclass.o
@@ -37,6 +36,7 @@
obj-$(CONFIG_RTC_MAX6900) += max6900.o
obj-$(CONFIG_RTC_MC13XXX) += mc13xxx-rtc.o
obj-$(CONFIG_RTC_MC146818) += mc146818.o
+obj-$(CONFIG_RTC_MCP79411) += ds1307.o
obj-$(CONFIG_MCFRTC) += mcfrtc.o
obj-$(CONFIG_RTC_MK48T59) += mk48t59.o
obj-$(CONFIG_RTC_MPC5200) += mpc5xxx.o
diff --git a/drivers/rtc/ds1307.c b/drivers/rtc/ds1307.c
index 03ab1a8..3be1da6 100644
--- a/drivers/rtc/ds1307.c
+++ b/drivers/rtc/ds1307.c
@@ -58,6 +58,10 @@
#define RTC_CTL_BIT_SQWE 0x10 /* Square Wave Enable */
#define RTC_CTL_BIT_OUT 0x80 /* Output Control */
+/* MCP7941X-specific bits */
+#define MCP7941X_BIT_ST 0x80
+#define MCP7941X_BIT_VBATEN 0x08
+
static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);
@@ -69,6 +73,9 @@
int rel = 0;
uchar sec, min, hour, mday, wday, mon, year;
+#ifdef CONFIG_RTC_MCP79411
+read_rtc:
+#endif
sec = rtc_read (RTC_SEC_REG_ADDR);
min = rtc_read (RTC_MIN_REG_ADDR);
hour = rtc_read (RTC_HR_REG_ADDR);
@@ -81,6 +88,7 @@
"hr: %02x min: %02x sec: %02x\n",
year, mon, mday, wday, hour, min, sec);
+#ifdef CONFIG_RTC_DS1307
if (sec & RTC_SEC_BIT_CH) {
printf ("### Warning: RTC oscillator has stopped\n");
/* clear the CH flag */
@@ -88,6 +96,23 @@
rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH);
rel = -1;
}
+#endif
+
+#ifdef CONFIG_RTC_MCP79411
+ /* make sure that the backup battery is enabled */
+ if (!(wday & MCP7941X_BIT_VBATEN)) {
+ rtc_write(RTC_DAY_REG_ADDR,
+ wday | MCP7941X_BIT_VBATEN);
+ }
+
+ /* clock halted? turn it on, so clock can tick. */
+ if (!(sec & MCP7941X_BIT_ST)) {
+ rtc_write(RTC_SEC_REG_ADDR, MCP7941X_BIT_ST);
+ printf("Started RTC\n");
+ goto read_rtc;
+ }
+#endif
+
tmp->tm_sec = bcd2bin (sec & 0x7F);
tmp->tm_min = bcd2bin (min & 0x7F);
@@ -121,11 +146,20 @@
rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
+#ifdef CONFIG_RTC_MCP79411
+ rtc_write (RTC_DAY_REG_ADDR,
+ bin2bcd (tmp->tm_wday + 1) | MCP7941X_BIT_VBATEN);
+#else
rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
+#endif
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));
+#ifdef CONFIG_RTC_MCP79411
+ rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec) | MCP7941X_BIT_ST);
+#else
rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
+#endif
return 0;
}