From: Søren Andersen <san@xxxxxxx>
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 <san@xxxxxxx>
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
---
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;
+
+ rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, reg);
+ if (rc < 0) {
+ dev_err(&client->dev, "Failing to configure device\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
static int pcf85063_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -197,6 +223,11 @@ static int pcf85063_probe(struct i2c_client *client,
return err;
}
+ err = pcf85063_select_capacitance(client);
+ if (err < 0)
+ dev_warn(&client->dev,
+ "Capacitance setup failed. Trying to continue\n");
+
rtc = devm_rtc_device_register(&client->dev,
pcf85063_driver.driver.name,
&pcf85063_rtc_ops, THIS_MODULE);
--
2.12.0
