From patchwork Thu Jul 1 00:53:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 469653 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DFE7C11F66 for ; Thu, 1 Jul 2021 00:53:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDBAF61474 for ; Thu, 1 Jul 2021 00:53:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235557AbhGAA4V (ORCPT ); Wed, 30 Jun 2021 20:56:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:57952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232066AbhGAA4V (ORCPT ); Wed, 30 Jun 2021 20:56:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6FC196124B; Thu, 1 Jul 2021 00:53:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625100831; bh=X1Yit87ebjU7Q0XF7mRkUpCYj5/wowh8TWqrZoeyU4Y=; h=From:To:Cc:Subject:Date:From; b=SKl4Fpadc7lo6ehwAu0BJ1KKR2gfNrh+iGLFwYrT4deSd1kJtk7bf7870Z7vavLdU fTXJWecinMaBCmyaNQRZHFfBh9PfEZXuphZ1FIlIX76ebVgO7O06P2R+323DKiXLeA KAj2VQG8mSZQGBoh6jr1Kg0lOKc8LTw6qzGyeL9im84FyVlHcAqhIKK9FVx0x8dzIt JbYVT+irzZulaA45GEkkBmE7tfHqnXrdi5FU0n06HR33wSG1y7balaRDRDjvzGyCb6 ZNvdNew/IIayHwGsRUN/dIXSjcprzzqXO+7AEa65Vo7ulMBxmDVVgQcmBhaUv/NdzY +YXgAXKVMu9TQ== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: Peter Rosin , Andrew Lunn , netdev@vger.kernel.org, Russell King Cc: Rob Herring , devicetree@vger.kernel.org, =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH RFC net-next] dt-bindings: ethernet-controller: document signal multiplexer Date: Thu, 1 Jul 2021 02:53:47 +0200 Message-Id: <20210701005347.8280-1-kabel@kernel.org> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org There are devices where the MAC signals from the ethernet controller are not directly connected to an ethernet PHY or a SFP cage, but to a multiplexer, so that the device can switch between the endpoints. For example on Turris Omnia the WAN controller is connected to a SerDes switch, which multiplexes the SerDes lanes between SFP cage and ethernet PHY, depending on whether a SFP module is present (MOD_DEF0 GPIO from the SFP cage). Document how to describe such a situation for an ethernet controller in the device tree bindings. Example usage could then look like: ð2 { status = "okay"; phys = <&comphy5 2>; buffer-manager = <&bm>; bm,pool-long = <2>; bm,pool-short = <3>; signal-multiplexer { compatible = "gpio-signal-multiplexer"; gpios = <&pcawan 4 GPIO_ACTIVE_LOW>; endpoint@0 { phy-mode = "sgmii"; phy-handle = <&phy1>; }; endpoint@1 { sfp = <&sfp>; phy-mode = "sgmii"; managed = "in-band-status"; }; }; }; Signed-off-by: Marek Behún --- I wonder if this is the proper way to do this. We already have framework for multiplexers in Linux, in drivers/mux. But as I understand it, that framework is meant to be used when the multiplexer state is to be set by kernel, while here it is possible that the multiplexer state can be (and on Turris Omnia is) set by the user plugging a SFP module into the SFP cage. We theoretically could add a method for getting mux state into the mux framework and state notification support. But using the mux framework to solve this case in phylink would be rather complicated, especially since mux framework is abstract, and if the multiplexer state is determined by the MOD_DEF0 GPIO, which is also used by SFP code, the implementation would get rather complicate in phylink... I wonder whether driver implementation complexity should play a role when proposing device tree bindings :-) Some thoughts? --- .../bindings/net/ethernet-controller.yaml | 60 +++++++++++++++++++ 1 file changed, 60 insertions(+) diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml index b0933a8c295a..a7770edaec2b 100644 --- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml +++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml @@ -226,6 +226,66 @@ properties: required: - speed + signal-multiplexer: + type: object + description: + Specifies that the signal pins (for example SerDes lanes) are connected + to a multiplexer from which they can be multiplexed to several different + endpoints, depending on the multiplexer configuration. (For example SerDes + lanes can be switched between an ethernet PHY and a SFP cage.) + + properties: + compatible: + const: gpio-signal-multiplexer + + gpios: + maxItems: 1 + description: + GPIO to determine which endpoint the multiplexer is switched to. + + patternProperties: + "^endpoint@[01]$": + type: object + description: + Specifies a multiplexer endpoint settings. Each endpoint can have + different settings. (For example in the case when multiplexing between + an ethernet PHY and a SFP cage, the SFP cage endpoint should specify + SFP phandle, while the PHY endpoint should specify PHY handle.) + + properties: + reg: + enum: [ 0, 1 ] + + phy-connection-type: + $ref: #/properties/phy-connection-type + + phy-mode: + $ref: #/properties/phy-mode + + phy-handle: + $ref: #/properties/phy-handle + + phy: + $ref: #/properties/phy + + phy-device: + $ref: #/properties/phy-device + + sfp: + $ref: #/properties/sfp + + managed: + $ref: #/properties/managed + + fixed-link: + $ref: #/properties/fixed-link + + required: + - reg + + required: + - gpios + additionalProperties: true ...