From: Søren Andersen <redacted>

Add support for specifying the quartz load in the DT node.
The pcf85063 may use either a 7 pF or an 12.5 pF xtal.
If the rtc has the wrong configuration the time will
drift several hours/week.

If nothing is specified in DT then the factory default of 7 pF is used.

Signed-off-by: Søren Andersen <redacted>
Signed-off-by: Sam Ravnborg <redacted>
Cc: Alessandro Zummo <redacted>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf85063.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 283c2335b01b..38163446664f 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c

@@ -27,6 +27,7 @@
 */
 
 #define PCF85063_REG_CTRL1		0x00 /* status */
+#define PCF85063_REG_CTRL1_CAP_SEL	BIT(0)
 #define PCF85063_REG_CTRL1_STOP		BIT(5)
 #define PCF85063_REG_CTRL2		0x01
 

@@ -180,6 +181,31 @@ static const struct rtc_class_ops pcf85063_rtc_ops = {
 	.set_time	= pcf85063_rtc_set_time
 };
 
+static int pcf85063_select_capacitance(struct i2c_client *client)
+{
+	int rc;
+	u8 reg;
+
+	rc = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
+	if (rc < 0) {
+		dev_err(&client->dev, "Failing to read Control1 reg\n");
+		return -EIO;
+	}
+
+	if (device_property_present(&client->dev, "nxp,quartz_load_12.5pf"))
+		reg = rc |= PCF85063_REG_CTRL1_CAP_SEL;
+	else
+		reg = rc &= ~PCF85063_REG_CTRL1_CAP_SEL;