Re: [PATCH 2/5] PCI: imx6: Properly handle optional regulators

[Andrew Murray <andrew.murray@arm.com>]

On Wed, Aug 28, 2019 at 06:36:33PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> regulator_get_optional() can fail for a number of reasons besides probe
> deferral. It can for example return -ENOMEM if it runs out of memory as
> it tries to allocate data structures. Propagating only -EPROBE_DEFER is
> problematic because it results in these legitimately fatal errors being
> treated as "regulator not specified in DT".
> 
> What we really want is to ignore the optional regulators only if they
> have not been specified in DT. regulator_get_optional() returns -ENODEV
> in this case, so that's the special case that we need to handle. So we
> propagate all errors, except -ENODEV, so that real failures will still
> cause the driver to fail probe.
> 
> Cc: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: Sascha Hauer <s.hauer@pengutronix.de>
> Cc: Fabio Estevam <festevam@gmail.com>
> Cc: kernel@pengutronix.de
> Cc: linux-imx@nxp.com
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 8b8efa3063f5..acfbd34032a8 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1174,8 +1174,8 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  
>  	imx6_pcie->vpcie = devm_regulator_get_optional(&pdev->dev, "vpcie");
>  	if (IS_ERR(imx6_pcie->vpcie)) {
> -		if (PTR_ERR(imx6_pcie->vpcie) == -EPROBE_DEFER)
> -			return -EPROBE_DEFER;
> +		if (PTR_ERR(imx6_pcie->vpcie) != -ENODEV)
> +			return PTR_ERR(imx6_pcie->vpcie);

Once you've applied Bjorn's feedback you can add:

Reviewed-by: Andrew Murray <andrew.murray@arm.com>

>  		imx6_pcie->vpcie = NULL;
>  	}
>  
> -- 
> 2.22.0
>