Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <db9b74f9-1f65-5b88-1c81-0a3fd6dcf9a6@linaro.org>
Date:   Thu, 11 Aug 2022 10:56:06 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.12.0
Subject: Re: [PATCH 1/3] dt-bindings: display/msm: Add binding for SC8280XP
 MDSS
Content-Language: en-US
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc:     Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>, linux-arm-msm@vger.kernel.org,
        dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20220811040121.3775613-1-bjorn.andersson@linaro.org>
 <20220811040121.3775613-2-bjorn.andersson@linaro.org>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20220811040121.3775613-2-bjorn.andersson@linaro.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 11/08/2022 07:01, Bjorn Andersson wrote:
> Add binding for the display subsystem and display processing unit in the
> Qualcomm SC8280XP platform.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  .../bindings/display/msm/dpu-sc8280xp.yaml    | 284 ++++++++++++++++++
>  1 file changed, 284 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/msm/dpu-sc8280xp.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/msm/dpu-sc8280xp.yaml b/Documentation/devicetree/bindings/display/msm/dpu-sc8280xp.yaml
> new file mode 100644
> index 000000000000..6c25943e639c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/msm/dpu-sc8280xp.yaml

qcom prefix is needed (also when file is in msm subdir)

The file name should be based on compatible, so "qcom,sc8280xp-mdss.yaml"

> @@ -0,0 +1,284 @@
> +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/msm/dpu-sc8280xp.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm Display Processing Unit for SC8280XP
> +
> +maintainers:
> +  - Bjorn Andersson <bjorn.andersson@linaro.org>
> +
> +description:
> +  Device tree bindings for MSM Mobile Display Subsystem (MDSS) that encapsulates
> +  sub-blocks like DPU display controller, DSI and DP interfaces etc. Device tree
> +  bindings of MDSS and DPU are mentioned for SC8280XP.

s/Device tree bindings//
so just:

SC8280XP MSM Mobile Display Subsystem (MDSS) that encapsulates
sub-blocks like DPU display controller, DSI and DP interfaces etc.

> +
> +properties:
> +  compatible:
> +    const: qcom,sc8280xp-mdss
> +
> +  reg:
> +    maxItems: 1
> +
> +  reg-names:
> +    const: mdss

You do not need reg names for one item, especially if the name is kind
of obvious... unless you re-use existing driver which needs it? Then
maybe let's change the driver to take first element?

> +
> +  power-domains:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: Display AHB clock from gcc
> +      - description: Display AHB clock from dispcc
> +      - description: Display core clock
> +
> +  clock-names:
> +    items:
> +      - const: iface
> +      - const: ahb
> +      - const: core
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  interrupt-controller: true
> +
> +  "#address-cells": true
> +
> +  "#size-cells": true

I see other DPU bindings also specify both as "true". Why not a fixed
number (const)?

> +
> +  "#interrupt-cells":
> +    const: 1
> +
> +  iommus:
> +    items:
> +      - description: Phandle to apps_smmu node with SID mask for Hard-Fail port0
> +
> +  ranges: true
> +
> +  interconnects:
> +    minItems: 2

No need for minItems in such case.

> +    maxItems: 2
> +
> +  interconnect-names:
> +    items:
> +      - const: mdp0-mem
> +      - const: mdp1-mem
> +
> +  resets:
> +    items:
> +      - description: MDSS_CORE reset
> +
> +patternProperties:
> +  "^display-controller@[0-9a-f]+$":
> +    type: object
> +    description: Node containing the properties of DPU.

additionalProperties:false on this level

which will point to missing properties (e.g. opp-table)

> +
> +    properties:
> +      compatible:
> +        const: qcom,sc8280xp-dpu
> +


Best regards,
Krzysztof