dt-binding: pcf85063: add xtal load capacitance

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@skov.dk>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Urs Fässler <urs.fassler@bbv.ch>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
new file mode 100644 (file)
index 0000000..d3e380a
--- /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 27a7c1578f6e5ed58f8f867a7bfefaf540dd309b..d86e2850fe1c9da20953e3574fc079da59966f19 100644 (file)
--- a/Documentation/devicetree/bindings/rtc/rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc.txt
@@ -57,7 +57,6 @@ microcrystal,rv8523   Real Time Clock
 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