[PATCH v2] phy: renesas: rcar-gen3-usb2: Keep OTG VBUS disabled until role is known

[Manivannan Sadhasivam]

On 2026-10-07 20:06 +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
> 
> On OTG channels of SoCs without ADP control, the VBUS regulator is
> acquired with devm_regulator_get_exclusive() and its output is switched
> by rcar_gen3_enable_vbus_ctrl() using regulator_hardware_enable() once
> the port role is known.
> 
> The helper acquiring the regulator has the following problems:
> 
> - The internal regulator is unconditionally enabled at probe, so VBUS
>   is driven before the port role is known. If the port is connected to
>   an external host this can back-power it.
> 
> - regulator_get_exclusive() hands the consumer an enable reference if
>   the regulator is already enabled, for example by the bootloader. The
>   unconditional regulator_enable() then takes a second reference while
>   only one is released on unbind, leaving the regulator enabled and
>   triggering the WARN_ON() in _regulator_put().
> 
> Fix this by making sure the driver always holds exactly one reference
> to the regulator: reuse the reference handed over by the exclusive get
> if the regulator is already enabled, and call regulator_enable()
> otherwise. Register the disable action in both cases, then turn off the
> physical VBUS output with regulator_hardware_enable() until the port
> role is established. Enabling a disabled regulator to take the
> reference may briefly drive VBUS during probe; this cannot be avoided
> with the regulator API.
> 
> Rename the regulator helper to reflect that it acquires the regulator
> without directly enabling its physical VBUS output.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>

Mising Fixes tag. With that added,

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam at oss.qualcomm.com>

- Mani