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SubjectRe: [PATCH v2 3/5] dt-binding: pcf85063: add xtal load capacitance
On Tue, Jan 08, 2019 at 07:54:12PM +0100, Sam Ravnborg wrote:
> The NXP pcf85063 supports two different xtal load capacitance
> - 7000fF (7pF) HW default, Linux driver default
> - 12500fF (12.5pF) Minimum power consumption
>
> To obtain a precise RTC the pcf85063 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>
> Cc: Urs Fässler <urs.fassler@bbv.ch>
> ---
> Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt | 18 ++++++++++++++++++
> Documentation/devicetree/bindings/rtc/rtc.txt | 1 -
> 2 files changed, 18 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
>
> diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
> new file mode 100644
> index 000000000000..ad5e8eaa370e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/nxp,pcf85063.txt
> @@ -0,0 +1,18 @@
> +* NXP PCF85063 Real Time Clock
> +
> +Required properties:
> +- compatible: Should contain "nxp,pcf85063".
> +- reg: I2C address for chip.
> +
> +Optional property:
> +- quartz-load-femtofarads: The capacitive load of the quartz(x-tal),

Probably should put this in rtc.txt so it can be shared.

> + expressed in femto Farad (fF). Valid values are 7000 and 12500.
> + Default value (if no value is specified) is 7000fF.
> +
> +Example:
> +
> +pcf85063: pcf85063@51 {

rtc@51

> + compatible = "nxp,pcf85063";
> + reg = <0x51>;
> + quartz-load-femtofarads = <12500>;
> +};
> diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt b/Documentation/devicetree/bindings/rtc/rtc.txt
> index e07b15d151ac..efac6dc5b914 100644
> --- a/Documentation/devicetree/bindings/rtc/rtc.txt
> +++ b/Documentation/devicetree/bindings/rtc/rtc.txt
> @@ -52,7 +52,6 @@ microcrystal,rv3029 Real Time Clock Module with I2C-Bus
> nxp,pcf2127 Real-time clock
> nxp,pcf2129 Real-time clock
> nxp,pcf8563 Real-time clock/calendar
> -nxp,pcf85063 Tiny Real-Time Clock
> pericom,pt7c4338 Real-time Clock Module
> ricoh,r2025sd I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> ricoh,r2221tl I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> --
> 2.12.0
>

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