Re: [PATCH 4/5] PCI: histb: Properly handle optional regulators

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

On Wed, Aug 28, 2019 at 06:36:35PM +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: Shawn Guo <shawn.guo@linaro.org>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/pci/controller/dwc/pcie-histb.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-histb.c b/drivers/pci/controller/dwc/pcie-histb.c
> index 954bc2b74bbc..811b5c6d62ea 100644
> --- a/drivers/pci/controller/dwc/pcie-histb.c
> +++ b/drivers/pci/controller/dwc/pcie-histb.c
> @@ -340,8 +340,8 @@ static int histb_pcie_probe(struct platform_device *pdev)
>  
>  	hipcie->vpcie = devm_regulator_get_optional(dev, "vpcie");
>  	if (IS_ERR(hipcie->vpcie)) {
> -		if (PTR_ERR(hipcie->vpcie) == -EPROBE_DEFER)
> -			return -EPROBE_DEFER;
> +		if (PTR_ERR(hipcie->vpcie) != -ENODEV)
> +			return PTR_ERR(hipcie->vpcie);

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

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

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