Re: [PATCH v10 6/6] usb: typec: tcpm/tcpci_maxim: deprecate WAR for setting charger mode

[Amit Sunil Dhamne <amitsd@google.com>]

Hi Heikki,

On 4/2/26 7:33 AM, Heikki Krogerus wrote:
> Hi Amit,
>
>> +static int get_vbus_regulator_handle(struct max_tcpci_chip *chip)
>> +{
>> +	if (IS_ERR_OR_NULL(chip->vbus_reg)) {
>> +		chip->vbus_reg = devm_regulator_get_exclusive(chip->dev,
>> +							      "vbus");
> Sorry to go back to this, but why can't you just get the regulator in
> max_tcpci_probe()?

Thanks for calling this out. This was an intentional design decision to 
break a circular dependency.

The charger driver is guaranteed to probe after the TCPC driver due to a 
power supply dependency (the TCPC is a supplier of power for the Battery 
Charger). However, the charger driver is also the regulator provider for 
VBUS out (when Type-C goes into source mode).

Because of this, the regulator handle will not be available during the 
TCPC driver's probe. If we tried to fetch it in max_tcpci_probe() and 
returned -EPROBE_DEFER, it would create a probe deadlock, as the charger 
would then never probe. Therefore, I made the decision to get the 
regulator handle lazily and on-demand.

Thanks,
Amit

>
> thanks,
>
>> +		if (IS_ERR_OR_NULL(chip->vbus_reg)) {
>> +			dev_err(chip->dev,
>> +				"Failed to get vbus regulator handle\n");
>> +			return -ENODEV;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}