The NXP pcf85063 supports two different xtal load capacitance
- 7000fF (7pF) HW default, Linux driver default
- 12500fF (12.5pF) Minimum power consumption
To obtain a precise RTC the pcf85063 must be configured
with the correct capacitance load of the xtal.
Add a property to specify the xtal capacitance load.
The default value matches that of the current Linux driver.
With a dedicated binding remove the entry in rtc.txt
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>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Urs Fässler <urs.fassler@xxxxxx>
---
Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt | 18 ++++++++++++++++++
Documentation/devicetree/bindings/rtc/rtc.txt | 1 -
2 files changed, 18 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
new file mode 100644
index 000000000000..d3e380ad712d
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
@@ -0,0 +1,18 @@
+* NXP PCF85063 Real Time Clock
+
+Required properties:
+- compatible: Should contain "nxp,pcf85063".
+- reg: I2C address for chip.
+
+Optional property:
+- quartz-load-femtofarads: The capacitive load of the quartz(x-tal),
+ expressed in femto Farad (fF). Valid values are 7000 and 12500.
+ Default value (if no value is specified) is 7000fF.
+
+Example:
+
+pcf85063: rtc@51 {
+ compatible = "nxp,pcf85063";
+ reg = <0x51>;
+ quartz-load-femtofarads = <12500>;
+};
diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt b/Documentation/devicetree/bindings/rtc/rtc.txt
index 6d726a801d21..460c503e86c6 100644
--- a/Documentation/devicetree/bindings/rtc/rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc.txt
@@ -56,7 +56,6 @@ microcrystal,rv3029 Real Time Clock Module with I2C-Bus
nxp,pcf2127 Real-time clock
nxp,pcf2129 Real-time clock
nxp,pcf8563 Real-time clock/calendar
-nxp,pcf85063 Tiny Real-Time Clock
pericom,pt7c4338 Real-time Clock Module
ricoh,r2025sd I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
ricoh,r2221tl I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
--
2.12.0
