summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml')
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml123
1 files changed, 123 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml
new file mode 100644
index 000000000..b6af924de
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpmux.yaml
@@ -0,0 +1,123 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/i2c-mux-gpmux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: General Purpose I2C Bus Mux
+
+maintainers:
+ - Peter Rosin <peda@axentia.se>
+
+description: |+
+ This binding describes an I2C bus multiplexer that uses a mux controller
+ from the mux subsystem to route the I2C signals.
+
+ .-----. .-----.
+ | dev | | dev |
+ .------------. '-----' '-----'
+ | SoC | | |
+ | | .--------+--------'
+ | .------. | .------+ child bus A, on MUX value set to 0
+ | | I2C |-|--| Mux |
+ | '------' | '--+---+ child bus B, on MUX value set to 1
+ | .------. | | '----------+--------+--------.
+ | | MUX- | | | | | |
+ | | Ctrl |-|-----+ .-----. .-----. .-----.
+ | '------' | | dev | | dev | | dev |
+ '------------' '-----' '-----' '-----'
+
+
+allOf:
+ - $ref: /schemas/i2c/i2c-mux.yaml#
+
+properties:
+ compatible:
+ const: i2c-mux
+
+ i2c-parent:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description:
+ The phandle of the I2C bus that this multiplexer's master-side port is
+ connected to.
+
+ mux-controls:
+ maxItems: 1
+ description:
+ The mux-controller states are the I2C sub-bus numbers.
+
+ mux-locked:
+ type: boolean
+ description: |
+ Explicitly allow unrelated I2C transactions on the parent I2C adapter at
+ these times:
+ - during setup of the multiplexer
+ - between setup of the multiplexer and the child bus I2C transaction
+ - between the child bus I2C transaction and releasing of the multiplexer
+ - during releasing of the multiplexer
+
+ However, I2C transactions to devices behind all I2C multiplexers connected
+ to the same parent adapter that this multiplexer is connected to are blocked
+ for the full duration of the complete multiplexed I2C transaction (i.e.
+ including the times covered by the above list).
+ If mux-locked is not present, the multiplexer is assumed to be parent-locked.
+ This means that no unrelated I2C transactions are allowed on the parent I2C
+ adapter for the complete multiplexed I2C transaction.
+ The properties of mux-locked and parent-locked multiplexers are discussed
+ in more detail in Documentation/i2c/i2c-topology.rst.
+
+required:
+ - compatible
+ - i2c-parent
+ - mux-controls
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ mux: mux-controller {
+ compatible = "gpio-mux";
+ #mux-control-cells = <0>;
+
+ mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
+ <&pioA 1 GPIO_ACTIVE_HIGH>;
+ };
+
+ i2c-mux {
+ compatible = "i2c-mux";
+ mux-locked;
+ i2c-parent = <&i2c1>;
+
+ mux-controls = <&mux>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ i2c@1 {
+ reg = <1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ gpio@20 {
+ compatible = "nxp,pca9555";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x20>;
+ };
+ };
+
+ i2c@3 {
+ reg = <3>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ gpio@20 {
+ compatible = "nxp,pca9555";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x20>;
+ };
+ };
+ };
+...