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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>,
	"Urs Fässler" <urs.fassler@bbv.ch>,
	"Shawn Guo" <shawnguo@kernel.org>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-rtc@vger.kernel.org, "Sam Ravnborg" <sam@ravnborg.org>,
	"Søren Andersen" <san@skov.dk>
Subject: [PATCH v3 4/6] dt-binding: pcf85063: add xtal load capacitance
Date: Sat, 19 Jan 2019 10:00:29 +0100	[thread overview]
Message-ID: <20190119090031.29147-5-sam@ravnborg.org> (raw)
In-Reply-To: <20190119090031.29147-1-sam@ravnborg.org>

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..d3e380ad712d
--- /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),
+  expressed in femto Farad (fF). Valid values are 7000 and 12500.
+  Default value (if no value is specified) is 7000fF.
+
+Example:
+
+pcf85063: 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 6d726a801d21..460c503e86c6 100644
--- a/Documentation/devicetree/bindings/rtc/rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc.txt
@@ -56,7 +56,6 @@ 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


  parent reply	other threads:[~2019-01-19  9:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-19  9:00 [PATCH v3 0/6] add quartz load support to NXP rtc drivers Sam Ravnborg
2019-01-19  9:00 ` [PATCH v3 1/6] devicetree: property-units: Add femtofarads unit Sam Ravnborg
2019-01-19  9:00 ` [PATCH v3 2/6] dt-bindings: rtc: Add quartz-load-femtofarads property Sam Ravnborg
2019-01-21 15:24   ` Rob Herring
2019-01-19  9:00 ` [PATCH v3 3/6] dt-binding: pcf8523: add xtal load capacitance Sam Ravnborg
2019-01-19  9:00 ` Sam Ravnborg [this message]
2019-01-21 15:25   ` [PATCH v3 4/6] dt-binding: pcf85063: " Rob Herring
2019-01-19  9:00 ` [PATCH v3 5/6] rtc: pcf8523: set xtal load capacitance from DT Sam Ravnborg
2019-01-19  9:00 ` [PATCH v3 6/6] rtc: pcf85063: " Sam Ravnborg
2019-01-22 17:57 ` [PATCH v3 0/6] add quartz load support to NXP rtc drivers Alexandre Belloni

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