Default driver did not consider battery supported
use cases, which DTS and probe did not control
the charge switch and strength. As such battery
could be dried out and possible dmanage.

Signed-off-by: Brian Sune <briansune@gmail.com>
---
 drivers/rtc/rtc-sd3078.c | 47 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-sd3078.c b/drivers/rtc/rtc-sd3078.c
index 10cc1dcfc774..871e6d9acd86 100644
--- a/drivers/rtc/rtc-sd3078.c
+++ b/drivers/rtc/rtc-sd3078.c
@@ -22,11 +22,17 @@
 #define SD3078_REG_CTRL1		0x0f
 #define SD3078_REG_CTRL2		0x10
 #define SD3078_REG_CTRL3		0x11
+#define SD3078_REG_AGTC			0x17
+#define SD3078_REG_CHARGE		0x18
 
 #define KEY_WRITE1		0x80
 #define KEY_WRITE2		0x04
 #define KEY_WRITE3		0x80
 
+#define CLK_F32K		0x40
+
+#define BAT_IIC			0x80
+
 #define NUM_TIME_REGS   (SD3078_REG_YR - SD3078_REG_SC + 1)
 
 /*
@@ -36,6 +42,13 @@
  */
 #define WRITE_PROTECT_EN	0
 
+static const char * const sd3078_charge_names[] = {
+	"10k", /* 0x00 */
+	"5k",  /* 0x01 */
+	"2k",  /* 0x02 */
+	"inf", /* 0x03 */
+};
+
 /*
  * In order to prevent arbitrary modification of the time register,
  * when modification of the register,
@@ -148,13 +161,15 @@ static const struct rtc_class_ops sd3078_rtc_ops = {
 static const struct regmap_config regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
-	.max_register = 0x11,
+	.max_register = 0x18,
 };
 
 static int sd3078_probe(struct i2c_client *client)
 {
 	int ret;
+	unsigned int val;
 	struct regmap *regmap;
+	bool f32k_out, bat_iic;
 	struct rtc_device *rtc;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
@@ -182,6 +197,36 @@ static int sd3078_probe(struct i2c_client *client)
 
 	sd3078_enable_reg_write(regmap);
 
+	f32k_out = device_property_read_bool(&client->dev, "CLOCK_F32K");
+	regmap_update_bits(regmap, SD3078_REG_CTRL3,
+			   CLK_F32K, !f32k_out);
+
+	bat_iic = device_property_read_bool(&client->dev, "IIC_ON_BAT");
+	regmap_update_bits(regmap, SD3078_REG_AGTC,
+			   BAT_IIC, bat_iic);
+
+	ret = regmap_read(regmap, SD3078_REG_CHARGE, &val);
+	if (!ret) {
+		dev_info(&client->dev, "RTC BAT Charge: %s",
+			 (val & 0x80) ? "ON" : "OFF");
+	}
+
+	ret = device_property_read_u32(&client->dev, "BAT_CHARGE", &val);
+	if (!ret) {
+		// 0: 10k, 1: 5k, 2: 2k, 3: inf
+		dev_info(&client->dev, "Enable Battery Charge.\n");
+		regmap_write(regmap, SD3078_REG_CHARGE,
+			     (val < 3) ? (u8)(val|0x80) : 0x03);
+	}
+
+	ret = regmap_read(regmap, SD3078_REG_CHARGE, &val);
+	if (!ret) {
+		dev_info(&client->dev, "RTC BAT charge: %s",
+			 (val & 0x80) ? "ON" : "OFF");
+		dev_info(&client->dev, "RTC BAT Charge Strength: %s",
+			 sd3078_charge_names[val & 0x03]);
+	}
+
 	return 0;
 }
 
-- 
2.34.1