dt-bindings: remoteproc: Add PRU consumer bindings

Add DT schema binding for PRU consumers. The binding includes
all the common properties that can be used by different PRU consumer
or application nodes and supported by the PRU remoteproc driver.
These are used to configure the PRU hardware for specific user
applications.

The application nodes themselves should define their own bindings.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230106121046.886863-2-danishanwar@ti.comSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Documentation/devicetree/bindings/remoteproc/ti,pru-consumer.yaml

+# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/remoteproc/ti,pru-consumer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Common TI PRU Consumer Binding
+
+maintainers:
+  - Suman Anna <s-anna@ti.com>
+
+description: |
+  A PRU application/consumer/user node typically uses one or more PRU device
+  nodes to implement a PRU application/functionality. Each application/client
+  node would need a reference to at least a PRU node, and optionally define
+  some properties needed for hardware/firmware configuration. The below
+  properties are a list of common properties supported by the PRU remoteproc
+  infrastructure.
+
+  The application nodes shall define their own bindings like regular platform
+  devices, so below are in addition to each node's bindings.
+
+properties:
+  ti,prus:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description: phandles to the PRU, RTU or Tx_PRU nodes used
+    minItems: 1
+    maxItems: 6
+    items:
+      maxItems: 1
+
+  firmware-name:
+    $ref: /schemas/types.yaml#/definitions/string-array
+    minItems: 1
+    maxItems: 6
+    description: |
+      firmwares for the PRU cores, the default firmware for the core from
+      the PRU node will be used if not provided. The firmware names should
+      correspond to the PRU cores listed in the 'ti,prus' property
+
+  ti,pruss-gp-mux-sel:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 1
+    maxItems: 6
+    items:
+      enum: [0, 1, 2, 3, 4]
+    description: |
+      array of values for the GP_MUX_SEL under PRUSS_GPCFG register for a PRU.
+      This selects the internal muxing scheme for the PRU instance. Values
+      should correspond to the PRU cores listed in the 'ti,prus' property. The
+      GP_MUX_SEL setting is a per-slice setting (one setting for PRU0, RTU0,
+      and Tx_PRU0 on K3 SoCs). Use the same value for all cores within the
+      same slice in the associative array. If the array size is smaller than
+      the size of 'ti,prus' property, the default out-of-reset value (0) for the
+      PRU core is used.
+
+required:
+  - ti,prus
+
+additionalProperties: true