From 8c12af15e7340a14e2978814ef28df58962283d6 Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Sat, 19 Jan 2019 10:00:28 +0100 Subject: [PATCH] dt-binding: pcf8523: add xtal load capacitance MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Sam Ravnborg Reviewed-by: Rob Herring Cc: Alessandro Zummo Cc: Alexandre Belloni Cc: Mark Rutland Signed-off-by: Alexandre Belloni --- .../devicetree/bindings/rtc/nxp,pcf8523.txt | 18 ++++++++++++++++++ Documentation/devicetree/bindings/rtc/rtc.txt | 1 - 2 files changed, 18 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt new file mode 100644 index 000000000000..0b1080c60f63 --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt @@ -0,0 +1,18 @@ +* 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>; +}; diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt b/Documentation/devicetree/bindings/rtc/rtc.txt index 0cacbc0edd20..27a7c1578f6e 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 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 -- 2.45.2