Re: [PATCH 2/7] arm64: dts: allwinner: a523: add third usb2 phy

From: Krzysztof Kozlowski <krzk@kernel.org>
To: iuncuim <iuncuim@gmail.com>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Samuel Holland <samuel@sholland.org>,
	Andre Przywara <andre.przywara@arm.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>
Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-phy@lists.infradead.org, linux-clk@vger.kernel.org,
	linux-sunxi@lists.linux.dev
Subject: Re: [PATCH 2/7] arm64: dts: allwinner: a523: add third usb2 phy
Date: Sat, 16 Aug 2025 11:31:12 +0200	[thread overview]
Message-ID: <c7468189-deee-449f-b7d0-fa1830ca88fc@kernel.org> (raw)
In-Reply-To: <20250816084700.569524-3-iuncuim@gmail.com>

On 16/08/2025 10:46, iuncuim wrote:
> From: Mikhail Kalashnikov <iuncuim@gmail.com>
> 
> It seems that there are actually three usb2 phys in the processor, which
> makes it incompatible with D1.
> The third phy is used together with USB3/PCIe combophy with DWC3
> controller. In the BSP code, the third PHY requires a separate glue
> driver, but it seems that it is not needed.
> According to the BSP code, the third phy does not have a reset line; the
> only reset is declared in the DWC3 node, but none of this is documented.
> Since sun4i-usb-phy driver requires a reset, I added RST_BUS_3 here.
> 
> Signed-off-by: Mikhail Kalashnikov <iuncuim@gmail.com>
> ---
>  .../arm64/boot/dts/allwinner/sun55i-a523.dtsi | 21 ++++++++++++-------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/allwinner/sun55i-a523.dtsi b/arch/arm64/boot/dts/allwinner/sun55i-a523.dtsi
> index 6b6f2296b..e4ed4fa82 100644
> --- a/arch/arm64/boot/dts/allwinner/sun55i-a523.dtsi
> +++ b/arch/arm64/boot/dts/allwinner/sun55i-a523.dtsi
> @@ -503,22 +503,27 @@ usb_otg: usb@4100000 {
>  		};
>  
>  		usbphy: phy@4100400 {
> -			compatible = "allwinner,sun55i-a523-usb-phy",
> -				     "allwinner,sun20i-d1-usb-phy";
> +			compatible = "allwinner,sun55i-a523-usb-phy";

That's potential break of all users. Also, having third phy (so
additional piece) is not making things incompatible.

Best regards,
Krzysztof