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authorSergey Yanovich <ynvich@gmail.com>2016-02-23 13:54:57 +0300
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2016-05-20 12:33:51 +0200
commitd25a5ed37d5fdd25f3cfbffc2f9a0f62e58f884c (patch)
treeab7921d55bcb2c297b7ee375ceef35da9ebd26ac /Documentation/devicetree
parent2dcd0af568b0cf583645c8a317dd12e344b1c72a (diff)
downloadlinux-d25a5ed37d5fdd25f3cfbffc2f9a0f62e58f884c.tar.gz
rtc: ds1302: rewrite using SPI
DS1302 is an half-duplex SPI device. The driver respects this fact now. Pin configurations should be implemented using SPI subsystem. Signed-off-by: Sergei Ianovich <ynvich@gmail.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'Documentation/devicetree')
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+* Maxim/Dallas Semiconductor DS-1302 RTC
+
+Simple device which could be used to store date/time between reboots.
+
+The device uses the standard MicroWire half-duplex transfer timing.
+Master output is set on low clock and sensed by the RTC on the rising
+edge. Master input is set by the RTC on the trailing edge and is sensed
+by the master on low clock.
+
+Required properties:
+
+- compatible : Should be "maxim,ds1302"
+
+Required SPI properties:
+
+- reg : Should be address of the device chip select within
+ the controller.
+
+- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V,
+ and 2MHz if powered at 5V.
+
+- spi-3wire : The device has a shared signal IN/OUT line.
+
+- spi-lsb-first : DS-1302 requires least significant bit first
+ transfers.
+
+- spi-cs-high: DS-1302 has active high chip select line. This is
+ required unless inverted in hardware.
+
+Example:
+
+spi@901c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "icpdas,lp8841-spi-rtc";
+ reg = <0x901c 0x1>;
+
+ rtc@0 {
+ compatible = "maxim,ds1302";
+ reg = <0>;
+ spi-max-frequency = <500000>;
+ spi-3wire;
+ spi-lsb-first;
+ spi-cs-high;
+ };
+};