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: <8639e64d-c659-7090-2d0a-078fd96cfbd4@linaro.org>
Date:   Fri, 17 Jun 2022 18:25:17 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.10.0
Subject: Re: [PATCH 2/3] dt-bindings: usb: mtk-xhci: Allow middle optional
 clocks to be missing
Content-Language: en-US
To:     =?UTF-8?B?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= 
        <nfraprado@collabora.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Matthias Brugger <matthias.bgg@gmail.com>
Cc:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>, kernel@collabora.com,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org, linux-usb@vger.kernel.org
References: <20220617222916.2435618-1-nfraprado@collabora.com>
 <20220617222916.2435618-3-nfraprado@collabora.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20220617222916.2435618-3-nfraprado@collabora.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 17/06/2022 15:29, Nícolas F. R. A. Prado wrote:
> The current clock list in the binding doesn't allow for one of the
> optional clocks to be missing and a subsequent clock to be present. An
> example where this is an issue is in mt8192.dtsi, which has "sys_ck",
> "ref_ck", "xhci_ck" and would cause dtbs_check warnings.
> 
> Change the clock list in a way that allows the middle optional clocks to
> be missing, while still guaranteeing a fixed order. The "ref_ck" is kept
> as a const even though it is optional for simplicity, since it is
> present in all current dts files.
> 
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> ---
> 
>  .../devicetree/bindings/usb/mediatek,mtk-xhci.yaml       | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> index 63cbc2b62d18..99a1b233ec90 100644
> --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> @@ -80,8 +80,13 @@ properties:
>      items:
>        - const: sys_ck  # required, the following ones are optional
>        - const: ref_ck
> -      - const: mcu_ck
> -      - const: dma_ck
> +      - enum:
> +          - mcu_ck
> +          - dma_ck
> +          - xhci_ck
> +      - enum:
> +          - dma_ck
> +          - xhci_ck
>        - const: xhci_ck

You allow now almost any order here, including incorrect like
sys,ref,xhci,xhci,xhci.

The order of clocks has to be fixed and we cannot allow flexibility. Are
you sure that these clocks are actually optional (not wired to the device)?


Best regards,
Krzysztof