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Diffstat (limited to 'Documentation/devicetree/bindings/spi/spi-controller.yaml')
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1 files changed, 164 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml new file mode 100644 index 0000000000..524f6fe8c2 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml @@ -0,0 +1,164 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/spi/spi-controller.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: SPI Controller Common Properties + +maintainers: + - Mark Brown <broonie@kernel.org> + +description: | + SPI busses can be described with a node for the SPI controller device + and a set of child nodes for each SPI slave on the bus. The system SPI + controller may be described for use in SPI master mode or in SPI slave mode, + but not for both at the same time. + +properties: + $nodename: + pattern: "^spi(@.*|-([0-9]|[1-9][0-9]+))?$" + + "#address-cells": + enum: [0, 1] + + "#size-cells": + const: 0 + + cs-gpios: + description: | + GPIOs used as chip selects. + If that property is used, the number of chip selects will be + increased automatically with max(cs-gpios, hardware chip selects). + + So if, for example, the controller has 4 CS lines, and the + cs-gpios looks like this + cs-gpios = <&gpio1 0 0>, <0>, <&gpio1 1 0>, <&gpio1 2 0>; + + Then it should be configured so that num_chipselect = 4, with + the following mapping + cs0 : &gpio1 0 0 + cs1 : native + cs2 : &gpio1 1 0 + cs3 : &gpio1 2 0 + + The second flag of a gpio descriptor can be GPIO_ACTIVE_HIGH (0) + or GPIO_ACTIVE_LOW(1). Legacy device trees often use 0. + + There is a special rule set for combining the second flag of an + cs-gpio with the optional spi-cs-high flag for SPI slaves. + + Each table entry defines how the CS pin is to be physically + driven (not considering potential gpio inversions by pinmux): + + device node | cs-gpio | CS pin state active | Note + ================+===============+=====================+===== + spi-cs-high | - | H | + - | - | L | + spi-cs-high | ACTIVE_HIGH | H | + - | ACTIVE_HIGH | L | 1 + spi-cs-high | ACTIVE_LOW | H | 2 + - | ACTIVE_LOW | L | + + Notes: + 1) Should print a warning about polarity inversion. + Here it would be wise to avoid and define the gpio as + ACTIVE_LOW. + 2) Should print a warning about polarity inversion + because ACTIVE_LOW is overridden by spi-cs-high. + Should be generally avoided and be replaced by + spi-cs-high + ACTIVE_HIGH. + + num-cs: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + Total number of chip selects. + + spi-slave: + $ref: /schemas/types.yaml#/definitions/flag + description: + The SPI controller acts as a slave, instead of a master. + + slave: + type: object + + properties: + compatible: + description: + Compatible of the SPI device. + + required: + - compatible + +patternProperties: + "^.*@[0-9a-f]+$": + type: object + $ref: spi-peripheral-props.yaml + additionalProperties: true + + properties: + spi-3wire: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires 3-wire mode. + + spi-cpha: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires shifted clock phase (CPHA) mode. + + spi-cpol: + $ref: /schemas/types.yaml#/definitions/flag + description: + The device requires inverse clock polarity (CPOL) mode. + + required: + - compatible + - reg + +allOf: + - if: + not: + required: + - spi-slave + then: + properties: + "#address-cells": + const: 1 + else: + properties: + "#address-cells": + const: 0 + +additionalProperties: true + +examples: + - | + spi@80010000 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "fsl,imx28-spi"; + reg = <0x80010000 0x2000>; + interrupts = <96>; + dmas = <&dma_apbh 0>; + dma-names = "rx-tx"; + + display@0 { + compatible = "lg,lg4573"; + spi-max-frequency = <1000000>; + reg = <0>; + }; + + sensor@1 { + compatible = "bosch,bme680"; + spi-max-frequency = <100000>; + reg = <1>; + }; + + flash@2 { + compatible = "jedec,spi-nor"; + spi-max-frequency = <50000000>; + reg = <2>, <3>; + stacked-memories = /bits/ 64 <0x10000000 0x10000000>; + }; + }; |