From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- .../bindings/spi/icpdas-lp8841-spi-rtc.txt | 54 ++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt (limited to 'Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt') diff --git a/Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt b/Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt new file mode 100644 index 000000000..852b651f3 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/icpdas-lp8841-spi-rtc.txt @@ -0,0 +1,54 @@ +* ICP DAS LP-8841 SPI Controller for RTC + +ICP DAS LP-8841 contains a DS-1302 RTC. RTC is connected to an IO +memory register, which acts as an SPI master device. + +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: + +- #address-cells: should be 1 + +- #size-cells: should be 0 + +- compatible: should be "icpdas,lp8841-spi-rtc" + +- reg: should provide IO memory address + +Requirements to SPI slave nodes: + +- There can be only one slave device. + +- The spi slave node should claim the following flags which are + required by the spi controller. + + - spi-3wire: The master itself has only 3 wire. It cannor work in + full duplex mode. + + - spi-cs-high: DS-1302 has active high chip select line. The master + doesn't support active low. + + - spi-lsb-first: DS-1302 requires least significant bit first + transfers. The master only support this type of bit ordering. + + +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; + }; +}; -- cgit v1.2.3