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Commit 8c12af15 authored by Sam Ravnborg's avatar Sam Ravnborg Committed by Alexandre Belloni
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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: default avatarSøren Andersen <san@skov.dk>
Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
Reviewed-by: default avatarRob 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: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent d08fd7c1

Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt

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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>;

};

Documentation/devicetree/bindings/rtc/rtc.txt

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@@ -56,7 +56,6 @@ microcrystal,rv3029 Real Time Clock Module with I2C-Bus 
microcrystal,rv8523	Real Time Clock

nxp,pcf2127		Real-time clock

nxp,pcf2129		Real-time clock

nxp,pcf8523		Real-time Clock

nxp,pcf8563		Real-time clock/calendar

nxp,pcf85063		Tiny Real-Time Clock

pericom,pt7c4338	Real-time Clock Module