linux-kernel - Re: [PATCH v6 5/8] PCI: imx6: Refine the regulator usage

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Date:   Fri, 11 Feb 2022 17:27:58 +0100
From:   Francesco Dolcini <francesco.dolcini@...adex.com>
To:     Richard Zhu <hongxing.zhu@....com>
Cc:     l.stach@...gutronix.de, bhelgaas@...gle.com, broonie@...nel.org,
        lorenzo.pieralisi@....com, jingoohan1@...il.com,
        festevam@...il.com, linux-pci@...r.kernel.org, linux-imx@....com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel@...gutronix.de
Subject: Re: [PATCH v6 5/8] PCI: imx6: Refine the regulator usage

Hello Richard,

On Tue, Feb 08, 2022 at 11:25:32AM +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().
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@....com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 0aca762d88a3..e165ad00989c 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -369,8 +369,6 @@ static int imx6_pcie_attach_pd(struct device *dev)
>  
>  static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
>  {
> -	struct device *dev = imx6_pcie->pci->dev;
> -
>  	switch (imx6_pcie->drvdata->variant) {
>  	case IMX7D:
>  	case IMX8MQ:
> @@ -400,14 +398,6 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
>  				   IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
>  		break;
>  	}
> -
> -	if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> -		int ret = regulator_disable(imx6_pcie->vpcie);
> -
> -		if (ret)
> -			dev_err(dev, "failed to disable vpcie regulator: %d\n",
> -				ret);
> -	}

This commit is not just cleaning up the regulator usage as you state in
the commit message, this is removing the vpcie regulator_disable
from imx6_pcie_assert_core_reset().

I would not do it, this is called for example on the shutdown callback
where it makes sense.

Francesco