Messages in this thread | | | Date | Thu, 13 Sep 2018 22:44:12 +0200 | From | Sam Ravnborg <> | Subject | Re: [PATCH v1 1/5] dt-binding: rtci-pcf8523: add quartz_load property |
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Hi Alexandre.
On Thu, Sep 13, 2018 at 09:05:16PM +0200, Alexandre Belloni wrote: > Hi, > > You can remove 'rtci-' from the subject.
The 'i' part was me fooling around in vi. After submitting this serie I read the proper subject would be: (from bindings/submitting-patches.txt)
dt-bindings: rtc: <short description>
I will use this in next submission so it is clear this is rtc related.
> > On 07/09/2018 21:35:04+0200, Sam Ravnborg wrote: > > From: Søren Andersen <san@skov.dk> > > > > 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@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 | 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. We had is implmented like this (using pF) in the beginning but then went for the simpler property. Will add a fF property as you suggest and avoid breaking the existing drivers. We will check a few of the boards to see if the current configuration of the pcf8523 driver looks wrong, and if so we will print the warnings as suggested.
I think the above covers feedback on all patches. And thanks for the feedback!
Sam
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