| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 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 | }; |