linux-kernel - Re: [PATCH v3 1/5] dt-bindings: bus: add documentation for the IMX AIPSTZ bridge

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Message-ID: <20250326102522.rtsffb37wvolhwd4@pengutronix.de>
Date: Wed, 26 Mar 2025 11:25:22 +0100
From: Marco Felsch <m.felsch@...gutronix.de>
To: Rob Herring <robh@...nel.org>
Cc: Laurentiu Mihalcea <laurentiumihalcea111@...il.com>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Daniel Baluta <daniel.baluta@....com>,
	Shengjiu Wang <shengjiu.wang@....com>, Frank Li <Frank.li@....com>,
	Marc Kleine-Budde <mkl@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	devicetree@...r.kernel.org, imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/5] dt-bindings: bus: add documentation for the IMX
 AIPSTZ bridge

Hi Laurentiu,

On 25-03-24, Rob Herring wrote:
> On Mon, Mar 24, 2025 at 12:25:52PM -0400, Laurentiu Mihalcea wrote:
> > From: Laurentiu Mihalcea <laurentiu.mihalcea@....com>
> > 
> > Add documentation for IMX AIPSTZ bridge.
> > 
> > Co-developed-by: Daniel Baluta <daniel.baluta@....com>
> > Signed-off-by: Daniel Baluta <daniel.baluta@....com>
> > Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@....com>
> > ---
> >  .../bindings/bus/fsl,imx8mp-aipstz.yaml       | 107 ++++++++++++++++++
> >  1 file changed, 107 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/bus/fsl,imx8mp-aipstz.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/bus/fsl,imx8mp-aipstz.yaml b/Documentation/devicetree/bindings/bus/fsl,imx8mp-aipstz.yaml
> > new file mode 100644
> > index 000000000000..c0427dfcdaca
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/bus/fsl,imx8mp-aipstz.yaml
> > @@ -0,0 +1,107 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/bus/fsl,imx8mp-aipstz.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Secure AHB to IP Slave bus (AIPSTZ) bridge
> > +
> > +description:
> > +  The secure AIPS bridge (AIPSTZ) acts as a bridge for AHB masters
> > +  issuing transactions to IP Slave peripherals. Additionally, this module
> > +  offers access control configurations meant to restrict which peripherals
> > +  a master can access.
> 
> Wrap at 80 chars.
> 
> > +
> > +maintainers:
> > +  - Laurentiu Mihalcea <laurentiu.mihalcea@....com>
> > +
> > +properties:
> > +  compatible:
> > +    const: fsl,imx8mp-aipstz
> > +
> > +  reg:
> > +    maxItems: 2
> > +
> > +  reg-names:
> > +    items:
> > +      - const: bus
> > +      - const: ac
> > +
> > +  power-domains:
> > +    maxItems: 1
> > +
> > +  "#address-cells":
> > +    const: 1
> > +
> > +  "#size-cells":
> > +    const: 1
> > +
> > +  "#access-controller-cells":
> > +    const: 0
> 
> With 0 cells, how do you identify which device it is?
> 
> > +
> > +  ranges: true
> > +
> > +# borrowed from simple-bus.yaml, no additional requirements for children
> > +patternProperties:
> > +  "@(0|[1-9a-f][0-9a-f]*)$":
> > +    type: object
> > +    additionalProperties: true
> > +    properties:
> > +      reg:
> > +        items:
> > +          minItems: 2
> > +          maxItems: 4
> > +        minItems: 1
> > +        maxItems: 1024
> > +      ranges:
> > +        oneOf:
> > +          - items:
> > +              minItems: 3
> > +              maxItems: 7
> > +            minItems: 1
> > +            maxItems: 1024
> > +          - $ref: /schemas/types.yaml#/definitions/flag
> > +    anyOf:
> > +      - required:
> > +          - reg
> > +      - required:
> > +          - ranges
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - reg-names
> > +  - power-domains
> > +  - "#address-cells"
> > +  - "#size-cells"
> > +  - "#access-controller-cells"
> > +  - ranges
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/clock/imx8mp-clock.h>
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +
> > +    bus@...00000 {
> > +        compatible = "fsl,imx8mp-aipstz";
> > +        reg = <0x30c00000 0x400000>, <0x30df0000 0x10000>;
> 
> It doesn't look like you have any registers in the 1st entry, but they 
> are child devices? Then you should use ranges and drop it here:
> 
> ranges = <0x0 0x30c00000 0x400000>;
> 
> 
> > +        reg-names = "bus", "ac";

Thanks for picking up my suggestion :) IMHO it does look more logical
now. I wasn't aware of the 'ranges' property else I would have suggested
you to use this property instead of having two regs, sorry. Once you
changed it to ranges we can drop the 'reg-names' as well since you only
need to supply the 'ac' register space.

Regards,
  Marco

> > +        power-domains = <&pgc_audio>;
> > +        #address-cells = <1>;
> > +        #size-cells = <1>;
> > +        #access-controller-cells = <0>;
> > +        ranges;
> > +
> > +        dma-controller@...00000 {
> > +            compatible = "fsl,imx8mp-sdma", "fsl,imx8mq-sdma";
> > +            reg = <0x30e00000 0x10000>;
> > +            #dma-cells = <3>;
> > +            clocks = <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_SDMA3_ROOT>,
> > +                     <&clk IMX8MP_CLK_AUDIO_ROOT>;
> > +            clock-names = "ipg", "ahb";
> > +            interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
> > +            fsl,sdma-ram-script-name = "imx/sdma/sdma-imx7d.bin";
> 
> No 'access-controllers' here?
> 
> > +        };
> > +    };
> > -- 
> > 2.34.1
> > 
>