spi-controller.yaml (4030B)
1# SPDX-License-Identifier: GPL-2.0 2%YAML 1.2 3--- 4$id: http://devicetree.org/schemas/spi/spi-controller.yaml# 5$schema: http://devicetree.org/meta-schemas/core.yaml# 6 7title: SPI Controller Generic Binding 8 9maintainers: 10 - Mark Brown <broonie@kernel.org> 11 12description: | 13 SPI busses can be described with a node for the SPI controller device 14 and a set of child nodes for each SPI slave on the bus. The system SPI 15 controller may be described for use in SPI master mode or in SPI slave mode, 16 but not for both at the same time. 17 18properties: 19 $nodename: 20 pattern: "^spi(@.*|-[0-9a-f])*$" 21 22 "#address-cells": 23 enum: [0, 1] 24 25 "#size-cells": 26 const: 0 27 28 cs-gpios: 29 description: | 30 GPIOs used as chip selects. 31 If that property is used, the number of chip selects will be 32 increased automatically with max(cs-gpios, hardware chip selects). 33 34 So if, for example, the controller has 4 CS lines, and the 35 cs-gpios looks like this 36 cs-gpios = <&gpio1 0 0>, <0>, <&gpio1 1 0>, <&gpio1 2 0>; 37 38 Then it should be configured so that num_chipselect = 4, with 39 the following mapping 40 cs0 : &gpio1 0 0 41 cs1 : native 42 cs2 : &gpio1 1 0 43 cs3 : &gpio1 2 0 44 45 The second flag of a gpio descriptor can be GPIO_ACTIVE_HIGH (0) 46 or GPIO_ACTIVE_LOW(1). Legacy device trees often use 0. 47 48 There is a special rule set for combining the second flag of an 49 cs-gpio with the optional spi-cs-high flag for SPI slaves. 50 51 Each table entry defines how the CS pin is to be physically 52 driven (not considering potential gpio inversions by pinmux): 53 54 device node | cs-gpio | CS pin state active | Note 55 ================+===============+=====================+===== 56 spi-cs-high | - | H | 57 - | - | L | 58 spi-cs-high | ACTIVE_HIGH | H | 59 - | ACTIVE_HIGH | L | 1 60 spi-cs-high | ACTIVE_LOW | H | 2 61 - | ACTIVE_LOW | L | 62 63 Notes: 64 1) Should print a warning about polarity inversion. 65 Here it would be wise to avoid and define the gpio as 66 ACTIVE_LOW. 67 2) Should print a warning about polarity inversion 68 because ACTIVE_LOW is overridden by spi-cs-high. 69 Should be generally avoided and be replaced by 70 spi-cs-high + ACTIVE_HIGH. 71 72 num-cs: 73 $ref: /schemas/types.yaml#/definitions/uint32 74 description: 75 Total number of chip selects. 76 77 spi-slave: 78 $ref: /schemas/types.yaml#/definitions/flag 79 description: 80 The SPI controller acts as a slave, instead of a master. 81 82 slave: 83 type: object 84 85 properties: 86 compatible: 87 description: 88 Compatible of the SPI device. 89 90 required: 91 - compatible 92 93patternProperties: 94 "^.*@[0-9a-f]+$": 95 type: object 96 $ref: spi-peripheral-props.yaml 97 98 required: 99 - compatible 100 - reg 101 102allOf: 103 - if: 104 not: 105 required: 106 - spi-slave 107 then: 108 properties: 109 "#address-cells": 110 const: 1 111 else: 112 properties: 113 "#address-cells": 114 const: 0 115 116additionalProperties: true 117 118examples: 119 - | 120 spi@80010000 { 121 #address-cells = <1>; 122 #size-cells = <0>; 123 compatible = "fsl,imx28-spi"; 124 reg = <0x80010000 0x2000>; 125 interrupts = <96>; 126 dmas = <&dma_apbh 0>; 127 dma-names = "rx-tx"; 128 129 display@0 { 130 compatible = "lg,lg4573"; 131 spi-max-frequency = <1000000>; 132 reg = <0>; 133 }; 134 135 sensor@1 { 136 compatible = "bosch,bme680"; 137 spi-max-frequency = <100000>; 138 reg = <1>; 139 }; 140 141 flash@2 { 142 compatible = "jedec,spi-nor"; 143 spi-max-frequency = <50000000>; 144 reg = <2>, <3>; 145 stacked-memories = /bits/ 64 <0x10000000 0x10000000>; 146 }; 147 };