| Message ID | 20190108185414.26922-3-sam@ravnborg.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | add quartz load support to NXP rtc drivers | expand |
On Tue, 8 Jan 2019 19:54:11 +0100, Sam Ravnborg wrote: > 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> > 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> > --- > Documentation/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 > Reviewed-by: Rob Herring <robh@kernel.org>
diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt new file mode 100644 index 000000000000..214ac5d26df7 --- /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: pcf8523@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 7c8da6926095..e07b15d151ac 100644 --- a/Documentation/devicetree/bindings/rtc/rtc.txt +++ b/Documentation/devicetree/bindings/rtc/rtc.txt @@ -51,7 +51,6 @@ isil,isl12022 Intersil ISL12022 Real-time Clock microcrystal,rv3029 Real Time Clock Module with I2C-Bus 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