[PATCH] usb: dwc3-generic: fix support without DM_REGULATOR

[Caleb Connolly]

On 15/04/2024 11:53, Robert Marko wrote:
> Recent addition of vbus-supply support has broke platform which dont use
> controllable regulators for USB.
> 
> Issue is that even withou DM_REGULATOR being enabled regulator related
> functions will still build as there is a stub in regulator.h but they will
> simply return -ENOSYS which will then make dwc3_generic_host_probe()
> return the same error thus breaking probe.

Rather than stubbing out the code, could you check for -ENOSYS and
ignore the error in that case? I believe there's only one place where
this matters (marked below).
> 
> Fixes: de451d5d5b6f ("usb: dwc3-generic: support external vbus regulator")
> Signed-off-by: Robert Marko <robert.marko at sartura.hr>
> ---
>  drivers/usb/dwc3/dwc3-generic.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
> index 7a00529a2a..784d3ec2ed 100644
> --- a/drivers/usb/dwc3/dwc3-generic.c
> +++ b/drivers/usb/dwc3/dwc3-generic.c
> @@ -242,6 +242,7 @@ static int dwc3_generic_host_probe(struct udevice *dev)
>  	if (rc)
>  		return rc;
>  
> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
>  	rc = device_get_supply_regulator(dev, "vbus-supply", &priv->vbus_supply);
>  	if (rc)
>  		debug("%s: No vbus regulator found: %d\n", dev->name, rc);
> @@ -250,14 +251,17 @@ static int dwc3_generic_host_probe(struct udevice *dev)
>  	rc = regulator_set_enable_if_allowed(priv->vbus_supply, true);
>  	if (rc)
>  		return rc;

Here, if (rc && rc != -ENOSYS)
or even if (CONFIG_IS_ENABLED(DM_REGULATOR) && rc) to be verbose (maybe
not the preferred style though).

All the other regulator_* calls either ignore the result or only print a
debug message.
> +#endif
>  
>  	hccr = (struct xhci_hccr *)priv->gen_priv.base;
>  	hcor = (struct xhci_hcor *)(priv->gen_priv.base +
>  			HC_LENGTH(xhci_readl(&(hccr)->cr_capbase)));
>  
>  	rc = xhci_register(dev, hccr, hcor);
> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
>  	if (rc)
>  		regulator_set_enable_if_allowed(priv->vbus_supply, false);
> +#endif
>  
>  	return rc;
>  }
> @@ -265,14 +269,18 @@ static int dwc3_generic_host_probe(struct udevice *dev)
>  static int dwc3_generic_host_remove(struct udevice *dev)
>  {
>  	struct dwc3_generic_host_priv *priv = dev_get_priv(dev);
> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
>  	int rc;
> +#endif
>  
>  	/* This function always returns 0 */
>  	xhci_deregister(dev);
>  
> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
>  	rc = regulator_set_enable_if_allowed(priv->vbus_supply, false);
>  	if (rc)
>  		debug("%s: Failed to disable vbus regulator: %d\n", dev->name, rc);
> +#endif
>  
>  	return dwc3_generic_remove(dev, &priv->gen_priv);
>  }

-- 
// Caleb (they/them)