Re: [PATCH] phy: renesas: rcar-gen3-usb2: Ignore missing VBUS regulator

From: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
To: Prabhakar <prabhakar.csengg@gmail.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	linux-renesas-soc@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Prabhakar <prabhakar.csengg+renesas@gmail.com>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH] phy: renesas: rcar-gen3-usb2: Ignore missing VBUS regulator
Date: Thu, 2 Jul 2026 17:45:28 +0200	[thread overview]
Message-ID: <akaHmCoG6d3bCher@tom-desktop> (raw)
In-Reply-To: <20260702125855.3157253-1-prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi Prabhakar,
Thanks for your patch.

On Thu, Jul 02, 2026 at 01:58:55PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Commit b6d7dd157763 ("phy: renesas: rcar-gen3-usb2: Add regulator for
> OTG VBUS control") introduced support for controlling OTG VBUS through
> the regulator framework.
> 
> As part of this change, the driver started requesting an exclusive "vbus"
> regulator for OTG-capable PHYs with no_adp_ctrl set. The lookup failure
> was propagated unconditionally, causing probe to fail on platforms where
> no VBUS regulator is described.
> 
> On RZ/V2H and RZ/V2N, which do not use a VBUS regulator, this results
> in the following error:
> 
>     phy_rcar_gen3_usb2 15800200.usb-phy:
>     dummy supplies not allowed for exclusive requests (id=vbus)
> 
> This failure completely prevents the USB 2.0 interface from initializing.
> 
> Fix this by allowing the probe to continue if an external VBUS regulator
> is missing. Only propagate the error if the internal vbus-regulator node
> is explicitly present, or if the lookup returns -EPROBE_DEFER. For all
> other missing regulator errors, gracefully assume no external VBUS
> regulator is available and return 0.
>

Patch LGTM, tested on RZ/G3E.

Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>

Thanks, Tommaso

> Fixes: b6d7dd157763 ("phy: renesas: rcar-gen3-usb2: Add regulator for OTG VBUS control")
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/phy/renesas/phy-rcar-gen3-usb2.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> index ef38c3b365d4..9ae9975d3255 100644
> --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> @@ -902,8 +902,17 @@ static int rcar_gen3_phy_usb2_vbus_regulator_get_exclusive_enable(struct rcar_ge
>  	int ret;
>  
>  	channel->vbus = devm_regulator_get_exclusive(dev, "vbus");
> -	if (IS_ERR(channel->vbus))
> -		return PTR_ERR(channel->vbus);
> +	if (IS_ERR(channel->vbus)) {
> +		ret = PTR_ERR(channel->vbus);
> +		/* If vbus-regulator node was present vbus regulator should be available */
> +		if (channel->otg_internal_reg)
> +			return ret;
> +
> +		if (ret == -EPROBE_DEFER)
> +			return ret;
> +
> +		return 0;
> +	}
>  
>  	if (enable) {
>  		ret = regulator_enable(channel->vbus);
> -- 
> 2.54.0
> 