[PATCH] usb: dwc3-generic: fix CONFIG_DM_REGULATOR-off case

[Caleb Connolly]

Hi Jan,

On 08/08/2024 10:51, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka at siemens.com>
> 
> When DM_REGULATOR is disabled, all calls will return -ENOSYS. Account
> for that so that targets like the IOT2050 will work again.
> 
> Fixes: de451d5d5b6f ("usb: dwc3-generic: support external vbus regulator")
> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
> ---
>   drivers/usb/dwc3/dwc3-generic.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
> index a9ba315463c..2ab41cbae45 100644
> --- a/drivers/usb/dwc3/dwc3-generic.c
> +++ b/drivers/usb/dwc3/dwc3-generic.c
> @@ -246,12 +246,12 @@ static int dwc3_generic_host_probe(struct udevice *dev)
>   		return rc;
>   
>   	rc = device_get_supply_regulator(dev, "vbus-supply", &priv->vbus_supply);
> -	if (rc)
> +	if (rc && rc != -ENOSYS)
>   		debug("%s: No vbus regulator found: %d\n", dev->name, rc);
>   
> -	/* Only returns an error if regulator is valid and failed to enable due to a driver issue */
> +	/* Does not return an error if regulator is invalid - but does so when DM_REGULATOR is disabled */
>   	rc = regulator_set_enable_if_allowed(priv->vbus_supply, true);
> -	if (rc)
> +	if (rc && rc != -ENOSYS)

regulator_set_enable_if_allowed() will return 0 if the call to 
regulator_set_enable() returns -ENOSYS

Maybe it would make sense to have the stub implementation of 
regulator_set_enable_if_allowed() return 0?

Somewhat confusing to check for -ENOSYS here imo, since it isn't really 
obvious when that would be the case.
>   		return rc;
>   
>   	hccr = (struct xhci_hccr *)priv->gen_priv.base;

-- 
// Caleb (they/them)