linux-kernel - Re: [PATCH 8/8] PCI: qcom: Add support to PCIe slot power supplies

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Message-ID: <0c3347a5-85a0-4f28-a393-58f9653d80c6@quicinc.com>
Date: Fri, 13 Sep 2024 16:41:00 +0800
From: Qiang Yu <quic_qianyu@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Manivannan Sadhasivam
	<manivannan.sadhasivam@...aro.org>
CC: Konrad Dybcio <konradybcio@...nel.org>, <vkoul@...nel.org>,
        <kishon@...nel.org>, <robh@...nel.org>, <andersson@...nel.org>,
        <krzk+dt@...nel.org>, <conor+dt@...nel.org>, <mturquette@...libre.com>,
        <sboyd@...nel.org>, <abel.vesa@...aro.org>, <quic_msarkar@...cinc.com>,
        <quic_devipriy@...cinc.com>, <kw@...ux.com>, <lpieralisi@...nel.org>,
        <neil.armstrong@...aro.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-phy@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-clk@...r.kernel.org>
Subject: Re: [PATCH 8/8] PCI: qcom: Add support to PCIe slot power supplies


On 9/12/2024 10:49 PM, Dmitry Baryshkov wrote:
> On Thu, 12 Sept 2024 at 17:45, Manivannan Sadhasivam
> <manivannan.sadhasivam@...aro.org> wrote:
>> On Thu, Sep 12, 2024 at 04:15:56PM +0200, Konrad Dybcio wrote:
>>> On 12.09.2024 3:39 PM, Qiang Yu wrote:
>>>> On 9/11/2024 11:32 PM, Manivannan Sadhasivam wrote:
>>>>> On Wed, Sep 11, 2024 at 04:17:41PM +0800, Qiang Yu wrote:
>>>>>> On 8/28/2024 12:58 AM, Manivannan Sadhasivam wrote:
>>>>>>> On Tue, Aug 27, 2024 at 02:44:09PM +0300, Dmitry Baryshkov wrote:
>>>>>>>> On Tue, 27 Aug 2024 at 09:36, Qiang Yu <quic_qianyu@...cinc.com> wrote:
>>>>>>>>> On platform x1e80100 QCP, PCIe3 is a standard x8 form factor. Hence, add
>>>>>>>>> support to use 3.3v, 3.3v aux and 12v regulators.
>>>>>>>> First of all, I don't see corresponding bindings change.
>>>>>>>>
>>>>>>>> Second, these supplies power up the slot, not the host controller
>>>>>>>> itself. As such these supplies do not belong to the host controller
>>>>>>>> entry. Please consider using the pwrseq framework instead.
>>>>>>>>
>>>>>>> Indeed. For legacy reasons, slot power supplies were populated in the host
>>>>>>> bridge node itself until recently Rob started objecting it [1]. And it makes
>>>>>>> real sense to put these supplies in the root port node and handle them in the
>>>>>>> relevant driver.
>>>>>>>
>>>>>>> I'm still evaluating whether the handling should be done in the portdrv or
>>>>>>> pwrctl driver, but haven't reached the conclusion. Pwrctl seems to be the ideal
>>>>>>> choice, but I see a few issues related to handling the OF node for the root
>>>>>>> port.
>>>>>>>
>>>>>>> Hope I'll come to a conclusion in the next few days and will update this thread.
>>>>>>>
>>>>>>> - Mani
>>>>>>>
>>>>>>> [1] https://lore.kernel.org/lkml/20240604235806.GA1903493-robh@kernel.org/
>>>>>> Hi Mani, do you have any updates?
>>>>>>
>>>>> I'm working with Bartosz to add a new pwrctl driver for rootports. And we are
>>>>> debugging an issue currently. Unfortunately, the progress is very slow as I'm on
>>>>> vacation still.
>>>>>
>>>>> Will post the patches once it got resolved.
>>>>>
>>>>> - Mani
>>>> OK, thanks for your update.
>>> Qiang, you can still resubmit the rest of the patches without having
>>> to wait on that to be resolved
>>>
>> In that case, the slot supplies should be described in the PCIe bridge.
> Patches 1-6 don't seem to depend on slot supplies, so they can be
> submitted separately.
OK, let me send v2 patch. Hi Mani, if you need any supports, please let 
me know.

Thanks,
Qiang
>
>> - Mani
>>
>>> Konrad
>> --
>> மணிவண்ணன் சதாசிவம்
>
>