[PATCH 09/11] phy: renesas: phy-rcar-gen3-usb2: Fix devm action registration for disabled VBUS regulator

[Claudiu Beznea]

On 6/15/26 13:22, Biju Das wrote:
> Hi Claudiu,
> 
>> -----Original Message-----
>> From: Claudiu Beznea <claudiu.beznea at tuxon.dev>
>> Sent: 15 June 2026 10:37
>> Subject: Re: [PATCH 09/11] phy: renesas: phy-rcar-gen3-usb2: Fix devm action registration for disabled
>> VBUS regulator
>>
>> Hi, Biju,
>>
>> On 6/12/26 17:30, Biju wrote:
>>> From: Biju Das <biju.das.jz at bp.renesas.com>
>>>
>>> devm_regulator_get_exclusive() initialises the regulator with
>>> enable_count = 1, requiring the consumer to disable it before release.
>>>
>>> Previously, the devm disable action was only registered when the
>>> regulator was explicitly enabled, causing the cleanup path to skip
>>> decrementing enable_count on device removal when the regulator was
>>> left disabled.
>>>
>>> Fix this by always registering the devm disable action when the
>>> regulator is enabled (checked via regulator_is_enabled()), covering
>>> both the explicitly-enabled case and the initial state set by
>>> devm_regulator_get_exclusive().
>>>
>>> This fixes WARN_ON enable count during regulator release.
>>>
>>> Fixes: 24843404efe4 ("phy: renesas: phy-rcar-gen3-usb2: Control VBUS
>>> for RZ/G2L SoCs")
>>> Signed-off-by: Biju Das <biju.das.jz at bp.renesas.com>
>>
>> The approach in this patch don't solve the problem, at least on RZ/G3S. See [1] for logs.
>>
>> I applied this patch on next-20260610:
>>
>> git log --oneline -2
>> afe09f11d549 (HEAD) phy: renesas: phy-rcar-gen3-usb2: Fix devm action registration for disabled VBUS
>> regulator
>> abe651837cb3 (tag: next-20260610, linux-next/master) Add linux-next specific files for 20260610
>>
>> [1]
>> https://github.com/claudiubeznea/logs/blob/2f1bab20407dfe6031385819ffeabfc4eac772bd/logs
> 
> I have tested only with RZ/G3L host and I don't see the issue.
> How can the issue be reproduced? It could be related to RZ/G3S.

It's reproducible with this patch on G2L as well, please see 
https://github.com/claudiubeznea/logs/blob/0601044903b5ae714592db9770bc4ed31fd8bf84/logs.

> I have executed the following tests and don't see any issue.
> Can you please try the same tests on RZ/G3S?

Try stressing it a bit, e.g. the following command trigger it on both G3S and G2L:

cnt=300; while [ $cnt -ge 0 ]; do echo 11c40000.usbphy-ctrl > unbind ; echo 
11c40000.usbphy-ctrl > bind ; cnt=$((cnt-1)); done

Same command could be executed for other USB drivers.

> Is unbind/bind ever worked on RZ?G3S previously?

In the same way it works on G2L: functionality is OK, these stack traces are 
displayed as on any other RZ/G2L based SoCs.

Thank you,
Claudiu