From: Sam Ravnborg <sam@ravnborg.org>
To: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: "Alessandro Zummo" <a.zummo@towertech.it>,
"Andrew Jeffery" <andrew@aj.id.au>,
"Fabio Estevam" <fabio.estevam@nxp.com>,
"Joel Stanley" <joel@jms.id.au>,
"Mark Rutland" <mark.rutland@arm.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Russell King" <linux@armlinux.org.uk>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Shawn Guo" <shawnguo@kernel.org>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-rtc@vger.kernel.org, "Søren Andersen" <san@skov.dk>
Subject: Re: [PATCH v1 1/5] dt-binding: rtci-pcf8523: add quartz_load property
Date: Thu, 13 Sep 2018 22:44:12 +0200 [thread overview]
Message-ID: <20180913204412.GA30987@ravnborg.org> (raw)
In-Reply-To: <20180913190516.GG14988@piout.net>
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
next prev parent reply other threads:[~2018-09-13 20:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180822183555.GA24084@ravnborg.org>
2018-09-07 19:35 ` [PATCH v1 0/5] add quartz load support to NXP rtc drivers Sam Ravnborg
2018-09-07 19:35 ` [PATCH v1 1/5] dt-binding: rtci-pcf8523: add quartz_load property Sam Ravnborg
2018-09-07 21:43 ` Sam Ravnborg
2018-09-13 19:05 ` Alexandre Belloni
2018-09-13 20:44 ` Sam Ravnborg [this message]
2018-09-13 20:51 ` Alexandre Belloni
2018-09-26 15:47 ` Rob Herring
2018-09-26 18:51 ` Alexandre Belloni
2018-09-26 20:42 ` Sam Ravnborg
2018-09-07 19:35 ` [PATCH v1 2/5] dt-binding: rtc-pcf85063: add quartz load property Sam Ravnborg
2018-09-13 19:11 ` Alexandre Belloni
2018-09-07 19:35 ` [PATCH v1 3/5] dts: add nxp,quartz_load_12.5pf to all pcf8523 nodes Sam Ravnborg
2018-09-13 19:14 ` Alexandre Belloni
2018-09-07 19:35 ` [PATCH v1 4/5] rtc: pcf8523: external capacitor configuration Sam Ravnborg
2018-09-13 19:27 ` Alexandre Belloni
2018-09-07 19:35 ` [PATCH v1 5/5] rtc: pcf85063: " Sam Ravnborg
2018-09-13 19:29 ` Alexandre Belloni
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