Add a binding for several bit-banged I2C buses that share one SCL GPIO and have one SDA GPIO each, as on some Realtek RTL930x switches. Each child node is a bus with its own SDA line; the parent holds the shared SCL line and the i2c-gpio style timing properties.
Signed-off-by: Ross Cawston <[email protected]> --- .../bindings/i2c/i2c-gpio-shared-scl.yaml | 94 +++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gpio-shared-scl.yaml diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio-shared-scl.yaml b/Documentation/devicetree/bindings/i2c/i2c-gpio-shared-scl.yaml new file mode 100644 index 00000000000..e725120973a --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-gpio-shared-scl.yaml @@ -0,0 +1,94 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/i2c-gpio-shared-scl.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Bit-banged I2C buses sharing one SCL line + +maintainers: + - Ross Cawston <[email protected]> + +description: | + Several I2C buses bit-banged on GPIOs, with one SCL line common to all of + them and one SDA line per bus. Each child node is a separate I2C bus. + Transfers are serialized, so only one bus clocks SCL at a time. + +properties: + compatible: + const: i2c-gpio-shared-scl + + scl-gpios: + description: The shared SCL line, usually open drain. + maxItems: 1 + + i2c-gpio,delay-us: + description: Half the clock period in microseconds, as for i2c-gpio. + default: 5 + + i2c-gpio,timeout-ms: + description: Clock stretching timeout in milliseconds, as for i2c-gpio. + default: 100 + + "#address-cells": + const: 1 + + "#size-cells": + const: 0 + +patternProperties: + "^i2c@[0-9a-f]+$": + $ref: /schemas/i2c/i2c-controller.yaml# + unevaluatedProperties: false + + properties: + reg: + description: Index of the bus, for naming only. + maxItems: 1 + + sda-gpios: + description: The SDA line of this bus, usually open drain. + maxItems: 1 + + required: + - reg + - sda-gpios + +required: + - compatible + - scl-gpios + - "#address-cells" + - "#size-cells" + +additionalProperties: false + +examples: + - | + #include <dt-bindings/gpio/gpio.h> + + i2c-gpio-shared { + compatible = "i2c-gpio-shared-scl"; + scl-gpios = <&gpio0 8 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; + i2c-gpio,delay-us = <5>; + #address-cells = <1>; + #size-cells = <0>; + + i2c@0 { + reg = <0>; + sda-gpios = <&gpio0 9 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; + #address-cells = <1>; + #size-cells = <0>; + + fan-controller@2e { + compatible = "adi,adt7476"; + reg = <0x2e>; + }; + }; + + i2c@1 { + reg = <1>; + sda-gpios = <&gpio0 10 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; + #address-cells = <1>; + #size-cells = <0>; + }; + }; -- 2.55.0.windows.5
