Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220428114049.1456382-1-michael@walle.cc> <20220428114049.1456382-2-michael@walle.cc>
In-Reply-To: <20220428114049.1456382-2-michael@walle.cc>
From:   Rob Herring <robh+dt@kernel.org>
Date:   Tue, 3 May 2022 08:04:23 -0500
Message-ID: <CAL_JsqKmgsErk41D8MBsQxLfmk16UYVu8+Z5SkwJ6W-obhtysQ@mail.gmail.com>
Subject: Re: [PATCH net-next 1/2] dt-bindings: net: lan966x: remove PHY reset
To:     Michael Walle <michael@walle.cc>
Cc:     "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        netdev <netdev@vger.kernel.org>, devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, Apr 28, 2022 at 6:40 AM Michael Walle <michael@walle.cc> wrote:
>
> The PHY reset was intended to be a phandle for a special PHY reset
> driver for the integrated PHYs as well as any external PHYs. It turns
> out, that the culprit is how the reset of the switch device is done.
> In particular, the switch reset also affects other subsystems like
> the GPIO and the SGPIO block and it happens to be the case that the
> reset lines of the external PHYs are connected to a common GPIO line.
> Thus as soon as the switch issues a reset during probe time, all the
> external PHYs will go into reset because all the GPIO lines will
> switch to input and the pull-down on that signal will take effect.
>
> So even if there was a special PHY reset driver, it (1) won't fix
> the root cause of the problem and (2) it won't fix all the other
> consumers of GPIO lines which will also be reset.
>
> It turns out, the Ocelot SoC has the same weird behavior (or the
> lack of a dedicated switch reset) and there the problem is already
> solved and all the bits and pieces are already there and this PHY
> reset property isn't not needed at all.
>
> There are no users of this binding. Just remove it.

Seems there was 1 user:

/builds/robherring/linux-dt/Documentation/devicetree/bindings/net/microchip,lan966x-switch.example.dtb:
switch@e0000000: resets: [[4294967295, 0], [4294967295, 0]] is too
long
 From schema: /builds/robherring/linux-dt/Documentation/devicetree/bindings/net/microchip,lan966x-switch.yaml
/builds/robherring/linux-dt/Documentation/devicetree/bindings/net/microchip,lan966x-switch.example.dtb:
switch@e0000000: reset-names: ['switch', 'phy'] is too long
 From schema: /builds/robherring/linux-dt/Documentation/devicetree/bindings/net/microchip,lan966x-switch.yaml

Please fix as this is now failing in linux-next.

Rob