[PATCH] dt-bindings: misc: add documentation for MediaLB DIM2 controller

[PATCH] dt-bindings: misc: add documentation for MediaLB DIM2 controller

[Kartik Nair]

Add device tree binding documentation for the MediaLB DIM2 hardware
dependent module. This documents the compatible strings used in
drivers/staging/most/dim2/dim2.c which were previously flagged as
undocumented by checkpatch.

Documented compatible strings:
- fsl,imx6q-mlb150 (Freescale i.MX6Q)
- renesas,mlp (Renesas Gen2)
- renesas,rcar-gen3-mlp (Renesas Gen3)
- xlnx,axi4-os62420_3pin-1.00.a (Xilinx 3-pin)
- xlnx,axi4-os62420_6pin-1.00.a (Xilinx 6-pin)

Signed-off-by: Kartik Nair <contact.kartikn@gmail.com>
---
 .../bindings/misc/microchip,most-dim2.yaml    | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml

diff --git a/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml b/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml
new file mode 100644
index 000000000..213078811
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/misc/microchip,most-dim2.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaLB DIM2 Hardware Dependent Module
+
+maintainers:
+  - Christian Gromm <christian.gromm@microchip.com>
+
+description:
+  The DIM2 is a MediaLB (Media Local Bus) interface controller that
+  provides high-speed communication between devices. It supports
+  synchronous, asynchronous, control, and isochronous data channels.
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx6q-mlb150
+      - renesas,mlp
+      - renesas,rcar-gen3-mlp
+      - xlnx,axi4-os62420_3pin-1.00.a
+      - xlnx,axi4-os62420_6pin-1.00.a
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 2
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: mediaLB_int
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    mlb: most@2b600000 {
+        compatible = "fsl,imx6q-mlb150";
+        reg = <0x2b600000 0x4000>;
+        interrupts = <0 53 4>, <0 117 4>;
+        clocks = <&clks 218>;
+        clock-names = "mediaLB_int";
+    };
-- 
2.50.0

Re: [PATCH] dt-bindings: misc: add documentation for MediaLB DIM2 controller

[Conor Dooley]

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Greg, Rob,

On Mon, May 11, 2026 at 12:14:19AM +0530, Kartik Nair wrote:
> Add device tree binding documentation for the MediaLB DIM2 hardware
> dependent module. This documents the compatible strings used in
> drivers/staging/most/dim2/dim2.c which were previously flagged as
> undocumented by checkpatch.

Are we actually meant to be taking bindings for things in staging?

I thought half the point of things being in staging that the state they
were in was poor at best, and that changing properties etc may be
required as part of destaging them.

Greg? Rob?

Cheers,
Conor.

> 
> Documented compatible strings:
> - fsl,imx6q-mlb150 (Freescale i.MX6Q)
> - renesas,mlp (Renesas Gen2)
> - renesas,rcar-gen3-mlp (Renesas Gen3)
> - xlnx,axi4-os62420_3pin-1.00.a (Xilinx 3-pin)
> - xlnx,axi4-os62420_6pin-1.00.a (Xilinx 6-pin)
> 
> Signed-off-by: Kartik Nair <contact.kartikn@gmail.com>
> ---
>  .../bindings/misc/microchip,most-dim2.yaml    | 54 +++++++++++++++++++
>  1 file changed, 54 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml
> 
> diff --git a/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml b/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml
> new file mode 100644
> index 000000000..213078811
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml
> @@ -0,0 +1,54 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/misc/microchip,most-dim2.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaLB DIM2 Hardware Dependent Module
> +
> +maintainers:
> +  - Christian Gromm <christian.gromm@microchip.com>
> +
> +description:
> +  The DIM2 is a MediaLB (Media Local Bus) interface controller that
> +  provides high-speed communication between devices. It supports
> +  synchronous, asynchronous, control, and isochronous data channels.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - fsl,imx6q-mlb150
> +      - renesas,mlp
> +      - renesas,rcar-gen3-mlp
> +      - xlnx,axi4-os62420_3pin-1.00.a
> +      - xlnx,axi4-os62420_6pin-1.00.a
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    maxItems: 2
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    const: mediaLB_int
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    mlb: most@2b600000 {
> +        compatible = "fsl,imx6q-mlb150";
> +        reg = <0x2b600000 0x4000>;
> +        interrupts = <0 53 4>, <0 117 4>;
> +        clocks = <&clks 218>;
> +        clock-names = "mediaLB_int";
> +    };
> -- 
> 2.50.0
> 

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Re: [PATCH] dt-bindings: misc: add documentation for MediaLB DIM2 controller

[Greg KH]

On Mon, May 11, 2026 at 05:14:21PM +0100, Conor Dooley wrote:
> Greg, Rob,
> 
> On Mon, May 11, 2026 at 12:14:19AM +0530, Kartik Nair wrote:
> > Add device tree binding documentation for the MediaLB DIM2 hardware
> > dependent module. This documents the compatible strings used in
> > drivers/staging/most/dim2/dim2.c which were previously flagged as
> > undocumented by checkpatch.
> 
> Are we actually meant to be taking bindings for things in staging?

Nope!

> I thought half the point of things being in staging that the state they
> were in was poor at best, and that changing properties etc may be
> required as part of destaging them.
> 
> Greg? Rob?

Staging drivers need to be self-contained, without bindings outside of
drivers/staging/

thanks,

greg k-h

Re: [PATCH] dt-bindings: misc: add documentation for MediaLB DIM2 controller

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
- [High] The `microchip,clock-speed` property is required by the driver but omitted from the schema.
- [High] The clock properties restrict definitions to a single clock named "mediaLB_int", which is incompatible with the Freescale driver.
- [High] The `interrupts` property permits 1 interrupt, but the driver unconditionally requires 2.
- [Medium] Missing conditional constraints to enforce hardware-specific clock requirements.
--

commit ed9d7ddf4fb03364e5365e6ea5d84fa84fa267e6
Author: Kartik Nair <contact.kartikn@gmail.com>

dt-bindings: misc: add documentation for MediaLB DIM2 controller

Add device tree binding documentation for the MediaLB DIM2 hardware
dependent module. This documents the compatible strings used in
drivers/staging/most/dim2/dim2.c which were previously flagged as
undocumented by checkpatch.

> diff --git a/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml b/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml
> new file mode 100644
> index 0000000000000..213078811f820
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/microchip,most-dim2.yaml

[ ... ]

> +properties:
> +  compatible:
> +    enum:
> +      - fsl,imx6q-mlb150
> +      - renesas,mlp
> +      - renesas,rcar-gen3-mlp
> +      - xlnx,axi4-os62420_3pin-1.00.a
> +      - xlnx,axi4-os62420_6pin-1.00.a

Should we add conditional constraints for the clocks property based on the
compatible string?

The Freescale and Renesas variants strictly require clocks in their driver
implementations, while Xilinx variants do not. Since clocks is omitted
from the global required list, incomplete device tree nodes for Freescale
and Renesas platforms will pass validation.

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    maxItems: 2

Does the driver support a single interrupt?

The driver implementation in dim2_probe() unconditionally requests two
distinct interrupts by index (index 1 and index 0). If a device tree
specifies only 1 interrupt as permitted here, the driver's attempt to
retrieve index 1 will return an error and abort the probe.

> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    const: mediaLB_int

Are these clock constraints compatible with the Freescale driver?

The fsl_mx6_enable() implementation explicitly requests up to two clocks by
name ("mlb" and optionally "pll8_mlb"). A device tree adhering to this
schema will provide a single clock named "mediaLB_int", causing the
Freescale driver to fail its clock lookup.

> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +additionalProperties: false

Is there a missing definition for the microchip,clock-speed property?

The driver dim2_probe() explicitly calls of_property_read_string() for
microchip,clock-speed and aborts if it is missing. With
additionalProperties set to false, a device tree including this required
property will fail schema validation, while one conforming strictly to the
schema will omit it and cause the driver to fail at runtime.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260510184419.98043-1-contact.kartikn@gmail.com?part=1