[PATCH v3 5/5] usb: typec: tcpm/tcpci_maxim: deprecate WAR for setting charger mode
Amit Sunil Dhamne
amitsd at google.com
Wed Jan 14 18:58:35 PST 2026
On 1/12/26 5:20 AM, Heikki Krogerus wrote:
> Fri, Jan 09, 2026 at 06:16:57PM -0800, Amit Sunil Dhamne kirjoitti:
>> Hi Heikki,
>>
>> Thanks for the review!
>>
>> On 1/9/26 5:14 AM, Heikki Krogerus wrote:
>>> Hi,
>>>
>>>> + if (source) {
>>>> + if (!regulator_is_enabled(chip->vbus_reg))
>>>> + ret = regulator_enable(chip->vbus_reg);
>>>> + } else {
>>>> + if (regulator_is_enabled(chip->vbus_reg))
>>>> + ret = regulator_disable(chip->vbus_reg);
>>>> + }
>>> It looks like you have to do one more round, so can drop the
>>> regulator_is_enabled() checks and just always enable/disable it
>>> unconditionally.
>>>
>>> if (source)
>>> ret = regulator_enable(chip->vbus_reg);
>>> else
>>> ret = regulator_disable(chip->vbus_reg);
>> The regulator framework uses refcounting on the number of enables. If
>> the number of times regulator is disabled > enabled, a warning will be
>> thrown. Also, I don't want to call regulator_enable more than once for
>> the same refcounting reason (will have to call disable those many number
>> of times to actually disable).
>>
>>> I don't think you need the check in any case, but if I've understood
>>> this correctly, you should not use that check when the regulator does
>>> not support that check because then the API claims it's always
>>> enabled. So I guess in that case "if (!regulator_is_enabled())" may
>>> not work as expected, and you may actually be left with a disabled
>>> regulator. This may not be a problem on current platforms, but who
>>> knows what happens in the future.
>> I don't think this should be an issue in the future as this driver is
>> specifically meant for max77759_tcpci device and should only be used
>> with max77759 charger (they both exist only in the same package). And
>> that the max77759_charger driver does implement the callback. However,
>> if you think that regulator_is_enabled() is unreliable, I could track
>> the state within the tcpci driver instead of calling
>> regulator_is_enabled() and call enable/disable regulator accordingly.
>>
>> Let me know wdyt and I'll update the next revision accordingly.
> Let's go with this then as is.
Sounds good. Thanks!
>
> thanks,
>
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