linux-kernel - Re: [PATCH v10 5/7] PCI: imx6: Turn off regulator when the system is in suspend mode

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Message-ID: <20220613101712.GA20538@francesco-nb.int.toradex.com>
Date:   Mon, 13 Jun 2022 12:17:12 +0200
From:   Francesco Dolcini <francesco.dolcini@...adex.com>
To:     Richard Zhu <hongxing.zhu@....com>, l.stach@...gutronix.de,
        bhelgaas@...gle.com, robh@...nel.org
Cc:     broonie@...nel.org, lorenzo.pieralisi@....com, festevam@...il.com,
        francesco.dolcini@...adex.com, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel@...gutronix.de, linux-imx@....com
Subject: Re: [PATCH v10 5/7] PCI: imx6: Turn off regulator when the system is
 in suspend mode

On Mon, Jun 13, 2022 at 04:55:36PM +0800, Richard Zhu wrote:
> The driver should undo any enables it did itself. The regulator disable
> shouldn't be basing decisions on regulator_is_enabled().
> 
> Move the regulator_disable to the suspend function, turn off regulator
> when the system is in suspend mode.

According to the documentation:

  vpcie-supply:
    description: Should specify the regulator in charge of PCIe port power.
      The regulator will be enabled when initializing the PCIe host and
      disabled either as part of the init process or when shutting down
      the host (optional required).

Is this really what we want to do (remove power in suspend, enable
it on resume)? On our boards this powers a PCIe device connected to the host
port, that sound fair according to the binding documentation for it.
Am I wrong?

We do have issues with PCIe not working anymore after suspend/resume,
wondering (I did not have time to properly dig into it) if this is the
root cause.

Francesco