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dt-bindings: gpio: add gpio-line-mux controller

Add dt-schema for a gpio-line-mux controller which exposes virtual
GPIOs for a shared GPIO controlled by a multiplexer, e.g. a gpio-mux.

The gpio-line-mux controller is a gpio-controller, thus has mostly the
same semantics. However, it requires a mux-control to be specified upon
which it will operate.

Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20251227180134.1262138-2-jelonek.jonas@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

authored by

Jonas Jelonek and committed by
Bartosz Golaszewski 2a7618ba 48befae0

+107
+107
Documentation/devicetree/bindings/gpio/gpio-line-mux.yaml
··· 1 + # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 + %YAML 1.2 3 + --- 4 + $id: http://devicetree.org/schemas/gpio/gpio-line-mux.yaml# 5 + $schema: http://devicetree.org/meta-schemas/core.yaml# 6 + 7 + title: GPIO line mux 8 + 9 + maintainers: 10 + - Jonas Jelonek <jelonek.jonas@gmail.com> 11 + 12 + description: | 13 + A GPIO controller to provide virtual GPIOs for a 1-to-many input-only mapping 14 + backed by a single shared GPIO and a multiplexer. A simple illustrated 15 + example is: 16 + 17 + +----- A 18 + IN / 19 + <-----o------- B 20 + / |\ 21 + | | +----- C 22 + | | \ 23 + | | +--- D 24 + | | 25 + M1 M0 26 + 27 + MUX CONTROL 28 + 29 + M1 M0 IN 30 + 0 0 A 31 + 0 1 B 32 + 1 0 C 33 + 1 1 D 34 + 35 + This can be used in case a real GPIO is connected to multiple inputs and 36 + controlled by a multiplexer, and another subsystem/driver does not work 37 + directly with the multiplexer subsystem. 38 + 39 + properties: 40 + compatible: 41 + const: gpio-line-mux 42 + 43 + gpio-controller: true 44 + 45 + "#gpio-cells": 46 + const: 2 47 + 48 + gpio-line-mux-states: 49 + description: Mux states corresponding to the virtual GPIOs. 50 + $ref: /schemas/types.yaml#/definitions/uint32-array 51 + 52 + gpio-line-names: true 53 + 54 + mux-controls: 55 + maxItems: 1 56 + description: 57 + Phandle to the multiplexer to control access to the GPIOs. 58 + 59 + ngpios: false 60 + 61 + muxed-gpios: 62 + maxItems: 1 63 + description: 64 + GPIO which is the '1' in 1-to-many and is shared by the virtual GPIOs 65 + and controlled via the mux. 66 + 67 + required: 68 + - compatible 69 + - gpio-controller 70 + - gpio-line-mux-states 71 + - mux-controls 72 + - muxed-gpios 73 + 74 + additionalProperties: false 75 + 76 + examples: 77 + - | 78 + #include <dt-bindings/gpio/gpio.h> 79 + #include <dt-bindings/mux/mux.h> 80 + 81 + sfp_gpio_mux: mux-controller-1 { 82 + compatible = "gpio-mux"; 83 + mux-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>, 84 + <&gpio0 1 GPIO_ACTIVE_HIGH>; 85 + #mux-control-cells = <0>; 86 + idle-state = <MUX_IDLE_AS_IS>; 87 + }; 88 + 89 + sfp1_gpio: sfp-gpio-1 { 90 + compatible = "gpio-line-mux"; 91 + gpio-controller; 92 + #gpio-cells = <2>; 93 + 94 + mux-controls = <&sfp_gpio_mux>; 95 + muxed-gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>; 96 + 97 + gpio-line-mux-states = <0>, <1>, <3>; 98 + }; 99 + 100 + sfp1: sfp-p1 { 101 + compatible = "sff,sfp"; 102 + 103 + i2c-bus = <&sfp1_i2c>; 104 + los-gpios = <&sfp1_gpio 0 GPIO_ACTIVE_HIGH>; 105 + mod-def0-gpios = <&sfp1_gpio 1 GPIO_ACTIVE_LOW>; 106 + tx-fault-gpios = <&sfp1_gpio 2 GPIO_ACTIVE_HIGH>; 107 + };