On Thu, Sep 13, 2018 at 09:05:16PM +0200, Alexandre Belloni wrote: > Hi, > > You can remove 'rtci-' from the subject. > > On 07/09/2018 21:35:04+0200, Sam Ravnborg wrote: > > From: Søren Andersen <san@xxxxxxx> > > > > The NXP pcf8523 supports two different quartz loads. > > - 7 pF (default) > > - 12.5 pF (minimum power consumption) > > > > The pcf8523 needs to know the size of the quartz load, > > otherwise the the RTC will have a bad precision. > > > > The default for the rtc (after power-on) is 7 pF. > > Add a property that tells if the external capacitor is 12.5 pF. > > > > Signed-off-by: Søren Andersen <san@xxxxxxx> > > Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx> > > Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx> > > Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> > > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > --- > > Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt | 19 +++++++++++++++++++ > > Documentation/devicetree/bindings/trivial-devices.txt | 1 - > > 2 files changed, 19 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..7c5e93f5077c > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt > > @@ -0,0 +1,19 @@ > > +* NXP PCF8523 Real Time Clock > > + > > +NXP PCF8523 Real Time Clock > > + > > +Required properties: > > +- compatible: Should contain "nxp,pcf8523". > > +- reg: I2C address for chip. > > + > > +Optional property: > > +- nxp,quartz_load_12.5pF: The capacitive load on the quartz is 12.5 pF, > > + which differ from the default value of 7 pF > > + > > The boolean properties usually don't work well for RTCs because people > usually want to keep any previous configuration that may have been done > at the factory or in the bootloader so I would use: > > nxp,quartz_load_fF and this would be either 7000 or 12500. Use '-' rather than '_'. There's already a defined unit suffix of '-picofarads'. If you need '-femtofarads', then please add to property-units.txt. Though I'd prefer not as wouldn't a value of 12 (or 13) be close enough for the needs here? Rob
