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

[Biju Das]

Hi Claudiu,

> -----Original Message-----
> From: Claudiu Beznea <claudiu.beznea@xxxxxxxxx>
> Sent: 15 June 2026 12:44
> Subject: Re: [PATCH 09/11] phy: renesas: phy-rcar-gen3-usb2: Fix devm action registration for disabled
> VBUS regulator
> 
> 
> 
> On 6/15/26 13:22, Biju Das wrote:
> > Hi Claudiu,
> >
> >> -----Original Message-----
> >> From: Claudiu Beznea <claudiu.beznea@xxxxxxxxx>
> >> 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@xxxxxxxxxxxxxx>
> >>>
> >>> 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@xxxxxxxxxxxxxx>
> >>
> >> 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/2f1bab20407dfe6031385819ff
> >> eabfc4eac772bd/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:

It is nothing related to stress, it is just enable_count issue.
Usb function increments the enable count of regulator, which it never decrement
Leading to WARN_ON(enable_count) during unbind.

> 
> 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.

I have identified the issue, it is USB function related.

I am investigating the fix, which will fix for all platforms.

Cgeers,
Biju