Re: [PATCH v4 1/2] dt-bindings: rng: timeriomem_rng: add reg-io-width and mask properties

[Krzysztof Kozlowski <krzk@kernel.org>]

On 17/06/2026 13:44, Jad Keskes wrote:
> Add optional reg-io-width (1, 2, or 4 bytes) and mask properties to the
> binding.  reg-io-width selects the bus access size,  mask is ANDed with
> the raw register value to allow only the entropy-bearing bits through.
> 
> Update the example to show a typical 1-byte configuration.
> Update SPDX to dual license to match kernel convention.

And did you Cc all of the copyright holders?

> Drop the misleading '32-bit aligned' constraint from the reg
> description since alignment now depends on the configured width.
> 
> Signed-off-by: Jad Keskes <inasj268@gmail.com>
> ---
>  .../bindings/rng/timeriomem_rng.yaml          | 48 +++++++++++++++----
>  1 file changed, 40 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/rng/timeriomem_rng.yaml b/Documentation/devicetree/bindings/rng/timeriomem_rng.yaml
> index 4754174e9849..740bc52bf474 100644
> --- a/Documentation/devicetree/bindings/rng/timeriomem_rng.yaml
> +++ b/Documentation/devicetree/bindings/rng/timeriomem_rng.yaml
> @@ -1,10 +1,16 @@
> -# SPDX-License-Identifier: GPL-2.0-only
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

Don't mix multiple changes into one commit.


>  %YAML 1.2
>  ---
>  $id: http://devicetree.org/schemas/rng/timeriomem_rng.yaml#
>  $schema: http://devicetree.org/meta-schemas/core.yaml#
>  
> -title: TimerIO Random Number Generator
> +title: Timer IOMEM Hardware Random Number Generator
> +
> +description: |
> +  This binding covers platforms that have a single IO memory address which

Do not describe the binding. Describe the hardware.

> +  provides periodic random data.  The driver reads from the address at a

Do not describe drivers. Describe the hardware.

> +  fixed interval, returning a configurable-width value masked to the desired
> +  bits.
>  
>  maintainers:
>    - Krzysztof Kozlowski <krzk@kernel.org>
> @@ -13,9 +19,17 @@ properties:
>    compatible:
>      const: timeriomem_rng
>  
> +  reg:
> +    maxItems: 1
> +    description:
> +      Base address to sample from.  Must be aligned to the configured access
> +      width (1, 2, or 4 bytes) and at least that wide.
> +
>    period:
>      $ref: /schemas/types.yaml#/definitions/uint32
> -    description: wait time in microseconds to use between samples
> +    description:
> +      Interval in microseconds between reads.  New random data is expected to
> +      be available at this rate.
>  
>    quality:
>      $ref: /schemas/types.yaml#/definitions/uint32
> @@ -26,16 +40,26 @@ properties:
>        instead.  Note that the default quality is usually zero which disables
>        using this rng to automatically fill the kernel's entropy pool.
>  
> -  reg:
> -    maxItems: 1
> +  reg-io-width:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    default: 4
> +    enum: [1, 2, 4]
>      description:
> -      Base address to sample from. Currently 'reg' must be at least four bytes
> -      wide and 32-bit aligned.
> +      Access width in bytes.  Determines whether the read is performed as
> +      an 8-bit, 16-bit, or 32-bit bus access.
> +
> +  mask:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    default: 0xFFFFFFFF
> +    description:
> +      Mask applied to the value read from the register.  Bits set to 0 in
> +      the mask are cleared in the output data.  Default (no mask) passes
> +      all bits through.
>  
>  required:
>    - compatible
> -  - period
>    - reg
> +  - period
>  
>  additionalProperties: false
>  
> @@ -46,3 +70,11 @@ examples:
>          reg = <0x44 0x04>;
>          period = <1000000>;
>      };
> +
> +    rng@64 {
> +        compatible = "timeriomem_rng";
> +        reg = <0x64 0x01>;
> +        period = <50000>;
> +        reg-io-width = <1>;
> +        mask = <0xFF>;
> +    };

Grow existing example. Or why can't it grow?


Best regards,
Krzysztof