[PATCH] rtc: ds1307: Enable battery backup on RX8130

[Marek Vasut <marex@denx.de>]

The battery backup can be disabled on this RTC, e.g. if populated right
out of production. Force the battery backup bit on to enable it.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Arnaud Ebalard <arno@natisbad.org>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
 drivers/rtc/rtc-ds1307.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 1f7e8aefc1eb..4af00cac1eff 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -121,6 +121,8 @@ enum ds_type {
 #define RX8130_REG_FLAG_AF		BIT(3)
 #define RX8130_REG_CONTROL0		0x1e
 #define RX8130_REG_CONTROL0_AIE		BIT(3)
+#define RX8130_REG_CONTROL1		0x0f
+#define RX8130_REG_CONTROL1_INIEN	BIT(4)
 
 #define MCP794XX_REG_CONTROL		0x07
 #	define MCP794XX_BIT_ALM0_EN	0x10
@@ -1750,6 +1752,11 @@ static int ds1307_probe(struct i2c_client *client,
 				     DS1307_REG_HOUR << 4 | 0x08, hour);
 		}
 		break;
+	case rx_8130:
+		/* make sure that the backup battery is enabled */
+		regmap_write(ds1307->regmap, chip->offset + RX8130_REG_CONTROL1,
+			     RX8130_REG_CONTROL1_INIEN);
+		break;
 	default:
 		break;
 	}
-- 
2.20.1