Re: [PATCH v2 4/8] PCI: brcmstb: Fix error path upon call of regulator_bulk_get()

[Bjorn Helgaas <helgaas@kernel.org>]

On Fri, Feb 14, 2025 at 12:39:32PM -0500, Jim Quinlan wrote:
> If regulator_bulk_get() returns an error, no regulators are created and we
> need to set their number to zero.  If we do not do this and the PCIe
> link-up fails, regulator_bulk_free() will be invoked and effect a panic.
> 
> Also print out the error value, as we cannot return an error upwards as
> Linux will WARN on an error from add_bus().
> 
> Fixes: 9e6be018b263 ("PCI: brcmstb: Enable child bus device regulators from DT")
> Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
> ---
>  drivers/pci/controller/pcie-brcmstb.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index e0b20f58c604..56b49d3cae19 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -1416,7 +1416,8 @@ static int brcm_pcie_add_bus(struct pci_bus *bus)
>  
>  		ret = regulator_bulk_get(dev, sr->num_supplies, sr->supplies);
>  		if (ret) {
> -			dev_info(dev, "No regulators for downstream device\n");
> +			dev_info(dev, "Did not get regulators; err=%d\n", ret);
> +			pcie->sr = NULL;

Is alloc_subdev_regulators() buying us something useful?  It seems
like it would be simpler to have:

  struct brcm_pcie {
    ...
    struct regulator_bulk_data supplies[3];
    ...
  };

I think that's what most callers of devm_regulator_bulk_get() do.

>  			goto no_regulators;
>  		}
>  
> -- 
> 2.43.0
>