Re: [PATCH 1/4] dt-bindings: reset: add schema for imx8ulp SIM reset

From: Laurentiu Mihalcea <laurentiumihalcea111@gmail.com>
To: Rob Herring <robh@kernel.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>, Lee Jones <lee@kernel.org>,
	Shawn Guo <shawnguo@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Liu Ying <victor.liu@nxp.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	laurentiu.mihalcea@nxp.com, devicetree@vger.kernel.org,
	imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] dt-bindings: reset: add schema for imx8ulp SIM reset
Date: Wed, 22 May 2024 21:43:37 +0300	[thread overview]
Message-ID: <6b9b959e-9a03-420c-9f61-adaae05bc5eb@gmail.com> (raw)
In-Reply-To: <20240517195943.GA2854624-robh@kernel.org>


On 5/17/2024 10:59 PM, Rob Herring wrote:
> On Thu, May 16, 2024 at 11:40:28PM +0300, Laurentiu Mihalcea wrote:
>> From: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
>>
>> Add schema for imx8ulp's SIM reset controller.
>>
>> Signed-off-by: Liu Ying <victor.liu@nxp.com>
>> Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
>> ---
>>  .../bindings/reset/nxp,imx8ulp-sim-reset.yaml | 43 +++++++++++++++++++
>>  1 file changed, 43 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/reset/nxp,imx8ulp-sim-reset.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/reset/nxp,imx8ulp-sim-reset.yaml b/Documentation/devicetree/bindings/reset/nxp,imx8ulp-sim-reset.yaml
>> new file mode 100644
>> index 000000000000..ec9a5c73e83c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/reset/nxp,imx8ulp-sim-reset.yaml
>> @@ -0,0 +1,43 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/reset/nxp,imx8ulp-sim-reset.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: NXP i.MX8ULP System Integration Module Reset Controller
>> +
>> +maintainers:
>> +  - Liu Ying <victor.liu@nxp.com>
>> +
>> +description: |
>> +  Some instances of i.MX8ULP's SIM may offer control over the
>> +  reset of some components of a certain domain (e.g: AVD-SIM).
>> +  As far as the DT is concerned, this means that the reset
>> +  controller needs to be a child of the SIM node.
>> +
>> +properties:
>> +  compatible:
>> +    const: nxp,imx8ulp-avd-sim-reset
>> +
>> +  '#reset-cells':
>> +    const: 1
>> +
>> +required:
>> +  - compatible
>> +  - '#reset-cells'
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/clock/imx8ulp-clock.h>
>> +    syscon@2da50000 {
>> +      compatible = "nxp,imx8ulp-avd-sim", "syscon";
>> +      reg = <0x2da50000 0x38>;
>> +      clocks = <&pcc5 IMX8ULP_CLK_AVD_SIM>;
>> +
>> +      reset-controller {
>> +        compatible = "nxp,imx8ulp-avd-sim-reset";
>> +        #reset-cells = <1>;
>> +      };
>> +    };
> Why do you need a child node here? No DT resources or anything for this 
> 'sub-block'. Just put "#reset-cells" in the parent node.
You're right, we don't need the child here. In fact, the reset controller will never
get probed anyways since "simple-mfd" was removed from the compatible
list of the parent. Will remove it and turn the parent into a syscon + reset controller
in V2.
>
> (Note that examples for MFDs like this go in the MFD binding rather than 
> having incomplete examples here.)
>
> Rob
Noted, thank you!

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