linux/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt
Sam Ravnborg 8c12af15e7 dt-binding: pcf8523: add xtal load capacitance
The NXP pcf8523 supports two different xtal load capacitance
- 7000fF  (7pF)    HW default
- 12500fF (12.5pF) Minimum power consumption, driver default

To obtain a precise RTC the pcf8523 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>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2019-01-22 18:56:52 +01:00

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* NXP PCF8523 Real Time Clock
Required properties:
- compatible: Should contain "nxp,pcf8523".
- 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 12500fF.
Example:
pcf8523: rtc@68 {
compatible = "nxp,pcf8523";
reg = <0x68>;
quartz-load-femtofarads = <7000>;
};