Subject: Re: [RFC 01/13] dt-bindings: remoteproc: Add PRU consumer bindings

From: Rob Herring <[email-masked]>
Date: Thu, 7 Apr 2022 10:09:53 -0500

On Wed, Apr 06, 2022 at 03:13:46PM +0530, Puranjay Mohan wrote:
> From: Suman Anna <[email-masked]>
> 
> Add a YAML binding document 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.
> 
> Co-developed-by: Tero Kristo <[email-masked]>
> Signed-off-by: Tero Kristo <[email-masked]>
> Signed-off-by: Suman Anna <[email-masked]>
> Co-developed-by: Grzegorz Jaszczyk <[email-masked]>
> Signed-off-by: Grzegorz Jaszczyk <[email-masked]>
> Signed-off-by: Puranjay Mohan <[email-masked]>
> ---
>  .../bindings/remoteproc/ti,pru-consumer.yaml  | 66 +++++++++++++++++++
>  1 file changed, 66 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/remoteproc/ti,pru-consumer.yaml
> 
> diff --git a/Documentation/devicetree/bindings/remoteproc/ti,pru-consumer.yaml b/Documentation/devicetree/bindings/remoteproc/ti,pru-consumer.yaml
> new file mode 100644
> index 000000000000..c245fe1de656
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/remoteproc/ti,pru-consumer.yaml
> @@ -0,0 +1,66 @@
> +# 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 <[email-masked]>
> +
> +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

Needs contraints. A phandle-array is really a matrix of phandles and 
args. If no args, something like this:

minItems: ??
maxItems: ??
items:
  maxItems: 1

> +    description: phandles to the PRU, RTU or Tx_PRU nodes used
> +
> +  firmware-name:
> +    $ref: /schemas/types.yaml#/definitions/string-array
> +    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
> +    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
> +
> +dependencies:
> +  firmware-name: [ 'ti,prus' ]
> +  ti,pruss-gp-mux-sel: [ 'ti,prus' ]
> +
> +additionalProperties: true

This must be false unless it is a common, shared schema.

> +
> +examples:
> +  - |
> +    /* PRU application node example */
> +    pru-app {
> +        ti,prus = <&pru0>, <&pru1>;
> +        firmware-name = "pruss-app-fw0", "pruss-app-fw1";
> +        ti,pruss-gp-mux-sel = <2>, <1>;
> +    };
> -- 
> 2.17.1
> 
>