Commit | Line | Data |
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d25a5ed3 SY |
1 | * Maxim/Dallas Semiconductor DS-1302 RTC |
2 | ||
3 | Simple device which could be used to store date/time between reboots. | |
4 | ||
5 | The device uses the standard MicroWire half-duplex transfer timing. | |
6 | Master output is set on low clock and sensed by the RTC on the rising | |
7 | edge. Master input is set by the RTC on the trailing edge and is sensed | |
8 | by the master on low clock. | |
9 | ||
10 | Required properties: | |
11 | ||
12 | - compatible : Should be "maxim,ds1302" | |
13 | ||
14 | Required SPI properties: | |
15 | ||
16 | - reg : Should be address of the device chip select within | |
17 | the controller. | |
18 | ||
19 | - spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V, | |
20 | and 2MHz if powered at 5V. | |
21 | ||
22 | - spi-3wire : The device has a shared signal IN/OUT line. | |
23 | ||
24 | - spi-lsb-first : DS-1302 requires least significant bit first | |
25 | transfers. | |
26 | ||
27 | - spi-cs-high: DS-1302 has active high chip select line. This is | |
28 | required unless inverted in hardware. | |
29 | ||
30 | Example: | |
31 | ||
32 | spi@901c { | |
33 | #address-cells = <1>; | |
34 | #size-cells = <0>; | |
35 | compatible = "icpdas,lp8841-spi-rtc"; | |
36 | reg = <0x901c 0x1>; | |
37 | ||
38 | rtc@0 { | |
39 | compatible = "maxim,ds1302"; | |
40 | reg = <0>; | |
41 | spi-max-frequency = <500000>; | |
42 | spi-3wire; | |
43 | spi-lsb-first; | |
44 | spi-cs-high; | |
45 | }; | |
46 | }; |