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

[Jan Kiszka]

On 08.08.24 16:27, Caleb Connolly wrote:
> 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?
> 

Possible. Would that be the only case where a stub should not return
ENOSYS? All do so far.

> Somewhat confusing to check for -ENOSYS here imo, since it isn't really
> obvious when that would be the case.

But that would still leave is a with a misleading message, even if it is
just a debug output. The absence of a regulator is not per se a bug to
my understanding.

Jan

>>           return rc;
>>         hccr = (struct xhci_hccr *)priv->gen_priv.base;
> 

-- 
Siemens AG, Technology
Linux Expert Center