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From: Rob Herring <robh@kernel.org>
To: "Kevin P. Fleming" <kevin+linux@km6g.us>
Cc: linux-rtc@vger.kernel.org, devicetree@vger.kernel.org,
	Alessandro Zummo <a.zummo@towertech.it>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: Re: [PATCH] rtc: abx80x: Add support for autocalibration filter capacitor
Date: Tue, 9 Jun 2020 16:14:01 -0600
Message-ID: <20200609221401.GA1492918@bogus> (raw)
In-Reply-To: <20200530123222.361104-1-kevin+linux@km6g.us>

On Sat, May 30, 2020 at 08:32:22AM -0400, Kevin P. Fleming wrote:
> All of the parts supported by this driver can make use of a
> small capacitor to improve the accuracy of the autocalibration
> process for their RC oscillators. If a capacitor is connected,
> a configuration register must be set to enable its use, so a
> new Device Tree property has been added for that purpose.
> 
> Signed-off-by: Kevin P. Fleming <kevin+linux@km6g.us>
> Cc: Alessandro Zummo <a.zummo@towertech.it>
> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> To: linux-rtc@vger.kernel.org
> To: devicetree@vger.kernel.org
> ---
>  .../bindings/rtc/abracon,abx80x.txt           |  6 ++++
>  drivers/rtc/rtc-abx80x.c                      | 34 +++++++++++++++++++
>  2 files changed, 40 insertions(+)

Binding should be a separate patch?

> 
> diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> index 2405e35a1bc0..ad5d59ed6f24 100644
> --- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> +++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt
> @@ -29,3 +29,9 @@ and valid to enable charging:
>   - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V)
>   - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output
>                            resistor, the other values are in kOhm.
> +
> +All of the devices can have a 47pf capacitor attached to increase the
> +autocalibration accuracy of their RC oscillators. To enable usage of the
> +capacitor the following property has to be defined:
> +
> + - "abracon,autocal-filter"

Can't the standard 'quartz-load-femtofarads' property be used here? You 
might not need to know the value, but presence of the property can 
enable the feature.

Rob

  parent reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-30 12:32 Kevin P. Fleming
2020-05-30 12:50 ` Kevin P. Fleming
2020-06-09 22:14 ` Rob Herring [this message]
2020-06-09 22:23   ` Kevin P. Fleming
2020-06-10 15:16     ` Alexandre Belloni
2020-06-12 11:48       ` Kevin P. Fleming
2020-06-12 14:23         ` Rob Herring

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