0001 * Maxim/Dallas Semiconductor DS-1302 RTC
0002
0003 Simple device which could be used to store date/time between reboots.
0004
0005 The device uses the standard MicroWire half-duplex transfer timing.
0006 Master output is set on low clock and sensed by the RTC on the rising
0007 edge. Master input is set by the RTC on the trailing edge and is sensed
0008 by the master on low clock.
0009
0010 Required properties:
0011
0012 - compatible : Should be "maxim,ds1302"
0013
0014 Required SPI properties:
0015
0016 - reg : Should be address of the device chip select within
0017 the controller.
0018
0019 - spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V,
0020 and 2MHz if powered at 5V.
0021
0022 - spi-3wire : The device has a shared signal IN/OUT line.
0023
0024 - spi-lsb-first : DS-1302 requires least significant bit first
0025 transfers.
0026
0027 - spi-cs-high: DS-1302 has active high chip select line. This is
0028 required unless inverted in hardware.
0029
0030 Example:
0031
0032 spi@901c {
0033 #address-cells = <1>;
0034 #size-cells = <0>;
0035 compatible = "icpdas,lp8841-spi-rtc";
0036 reg = <0x901c 0x1>;
0037
0038 rtc@0 {
0039 compatible = "maxim,ds1302";
0040 reg = <0>;
0041 spi-max-frequency = <500000>;
0042 spi-3wire;
0043 spi-lsb-first;
0044 spi-cs-high;
0045 };
0046 };
