In some cases, it is required to provide the state to which the mux
controller has be set to, from the consumer device tree node. Document the
property mux-states that can be used for adding this support.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
---
 .../devicetree/bindings/mux/gpio-mux.yaml     | 11 ++++++--
 .../devicetree/bindings/mux/mux-consumer.yaml | 14 ++++++++++
 .../bindings/mux/mux-controller.yaml          | 26 ++++++++++++++++++-
 3 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/mux/gpio-mux.yaml b/Documentation/devicetree/bindings/mux/gpio-mux.yaml
index 0a7c8d64981a..ee4de9fbaf4d 100644
--- a/Documentation/devicetree/bindings/mux/gpio-mux.yaml
+++ b/Documentation/devicetree/bindings/mux/gpio-mux.yaml
@@ -26,7 +26,10 @@ properties:
       List of gpios used to control the multiplexer, least significant bit first.
 
   '#mux-control-cells':
-    const: 0
+    enum: [ 0, 1 ]
+
+  '#mux-state-cells':
+    enum: [ 1, 2 ]
 
   idle-state:
     default: -1
@@ -34,7 +37,11 @@ properties:
 required:
   - compatible
   - mux-gpios
-  - "#mux-control-cells"
+anyOf:
+  - required:
+      - "#mux-control-cells"
+  - required:
+      - "#mux-state-cells"
 
 additionalProperties: false
 
diff --git a/Documentation/devicetree/bindings/mux/mux-consumer.yaml b/Documentation/devicetree/bindings/mux/mux-consumer.yaml
index 7af93298ab5c..64f353714227 100644
--- a/Documentation/devicetree/bindings/mux/mux-consumer.yaml
+++ b/Documentation/devicetree/bindings/mux/mux-consumer.yaml
@@ -25,6 +25,11 @@ description: |
   strings to label each of the mux controllers listed in the "mux-controls"
   property.
 
+  If it is required to provide the state that the mux controller needs to
+  be set to, the property "mux-states" must be used. An optional property
+  "mux-state-names" can be used to provide a list of strings, to label
+  each of the mux controllers listed in the "mux-states" property.
+
   mux-ctrl-specifier typically encodes the chip-relative mux controller number.
   If the mux controller chip only provides a single mux controller, the
   mux-ctrl-specifier can typically be left out.
@@ -35,12 +40,21 @@ properties:
   mux-controls:
     $ref: /schemas/types.yaml#/definitions/phandle-array
 
+  mux-states:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+
   mux-control-names:
     description:
       Devices that use more than a single mux controller can use the
       "mux-control-names" property to map the name of the requested mux
       controller to an index into the list given by the "mux-controls" property.
 
+  mux-state-names:
+    description:
+      Devices that use more than a single mux controller can use the
+      "mux-state-names" property to map the name of the requested mux
+      controller to an index into the list given by the "mux-states" property.
+
 additionalProperties: true
 
 ...
diff --git a/Documentation/devicetree/bindings/mux/mux-controller.yaml b/Documentation/devicetree/bindings/mux/mux-controller.yaml
index 736a84c3b6a5..b29dbf521f01 100644
--- a/Documentation/devicetree/bindings/mux/mux-controller.yaml
+++ b/Documentation/devicetree/bindings/mux/mux-controller.yaml
@@ -25,7 +25,9 @@ description: |
   --------------------
 
   Mux controller nodes must specify the number of cells used for the
-  specifier using the '#mux-control-cells' property.
+  specifier using the '#mux-control-cells' or 'mux-state-cells'
+  property. Value of '#mux-state-cells' will always be one greater then
+  the value of '#mux-control-cells'.
 
   Optionally, mux controller nodes can also specify the state the mux should
   have when it is idle. The idle-state property is used for this. If the
@@ -67,6 +69,8 @@ select:
           pattern: '^mux-controller'
     - required:
         - '#mux-control-cells'
+    - required:
+        - '#mux-state-cells'
 
 properties:
   $nodename:
@@ -75,6 +79,9 @@ properties:
   '#mux-control-cells':
     enum: [ 0, 1 ]
 
+  '#mux-state-cells':
+    enum: [ 1, 2 ]
+
   idle-state:
     $ref: /schemas/types.yaml#/definitions/int32
     minimum: -2
@@ -179,4 +186,21 @@ examples:
             };
         };
     };
+
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    mux1: mux-controller {
+        compatible = "gpio-mux";
+        #mux-state-cells = <1>;
+        mux-gpios = <&exp_som 2 GPIO_ACTIVE_HIGH>;
+    };
+
+    transceiver4: can-phy4 {
+        compatible = "ti,tcan1042";
+        #phy-cells = <0>;
+        max-bitrate = <5000000>;
+        standby-gpios = <&exp_som 7 GPIO_ACTIVE_HIGH>;
+        mux-states = <&mux1 1>;
+    };
 ...
-- 
2.17.1