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Date:   Thu, 8 Jun 2023 21:22:14 +0530
From:   Manivannan Sadhasivam <mani@kernel.org>
To:     Rob Herring <robh@kernel.org>
Cc:     Krishna chaitanya chundru <quic_krichai@quicinc.com>,
        manivannan.sadhasivam@linaro.org, quic_vbadigan@quicinc.com,
        quic_ramkri@quicinc.com, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@vger.kernel.org>,
        "open list:PCIE ENDPOINT DRIVER FOR QUALCOMM" 
        <linux-pci@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/3] dt-bindings: PCI: qcom: ep: Add interconnects path
Message-ID: <20230608155214.GA8632@thinkpad>
References: <1686154687-29356-1-git-send-email-quic_krichai@quicinc.com>
 <1686154687-29356-2-git-send-email-quic_krichai@quicinc.com>
 <20230608152759.GA2721945-robh@kernel.org>
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On Thu, Jun 08, 2023 at 09:27:59AM -0600, Rob Herring wrote:
> On Wed, Jun 07, 2023 at 09:48:05PM +0530, Krishna chaitanya chundru wrote:
> > Add the "pcie-mem" interconnect path to the bindings.
> > 
> > Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> > ---
> >  Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
> > index b3c22eb..6fc5440 100644
> > --- a/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
> > +++ b/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
> > @@ -70,6 +70,13 @@ properties:
> >      description: GPIO used as WAKE# output signal
> >      maxItems: 1
> >  
> > +  interconnects:
> > +    maxItems: 1
> > +
> > +  interconnect-names:
> > +    items:
> > +      - const: pcie-mem
> > +
> >    resets:
> >      maxItems: 1
> >  
> > @@ -97,6 +104,8 @@ required:
> >    - interrupts
> >    - interrupt-names
> >    - reset-gpios
> > +  - interconnects
> > +  - interconnect-names
> 
> You can't add required properties. That's an ABI break. Up to the 
> platform whether that's acceptible, but you have to explain all this in 
> the commmit msg.
> 

Some platforms may not boot if a device driver doesn't initialize the
interconnect path. Mostly it is all handled by the bootloader but we have
starting to see cases where bootloader simply ignores them.

So I'd say that these need to be made required (should've been from the start
but I take the blame). And yes, this info should be part of the commit message.

- Mani

> >    - resets
> >    - reset-names
> >    - power-domains
> > -- 
> > 2.7.4
> > 

-- 
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