mirror of https://gitee.com/openkylin/linux.git
47 lines
1.1 KiB
Plaintext
47 lines
1.1 KiB
Plaintext
* 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;
|
|
};
|
|
};
|