From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mail-yw1-f170.google.com (mail-yw1-f170.google.com [209.85.128.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0516C2705; Wed, 22 Nov 2023 07:41:53 -0800 (PST) Received: by mail-yw1-f170.google.com with SMTP id 00721157ae682-5cce5075bd6so2134947b3.0; Wed, 22 Nov 2023 07:41:53 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700667713; x=1701272513; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=QFZqsVfgRqiOD91xrpniJbD3hy+jg6Mb4nasXbDgGQI=; b=hL8USkXMMoGl/BNsfRPmuiSb5X37/LrA2kS1qgxDme4yDih5kP7vpR6wpsedlL57Fw 5UR4wEzTKaJZbG++rKyXl2Rm71ZoZFkqLyk907NnTxwVQmoqSgQYSi46FskQIyyU0cJo RcVA11Cz8vtL/zjeuw9B61gCnV7X11s6OJPW/H0mhn1SoVfSiXbUbayxu83BWhedp4yr 2yUzz0tSwwvHV0Sosk/pM+2CaiIDdUOJnFrdFUfbzlnHRP2NTC/1X+jHmvSTk/cnSNGW qd3Js8fKE1+ilTCWzBoEPTYaxMWnE7KmmIDDAdQbtgljjR2ZVR1vsPNxN3PquD3CwU/S zd+Q== X-Gm-Message-State: AOJu0YytUfbbnlWAq0BtmQtKsD+Iof55Bq5qA70DLYmXbnqvT+DIxHb/ K0ibS96lTrbRogyzjrF5FvvF+Q3xz1123w== X-Google-Smtp-Source: AGHT+IG/goYMXuUzgOytIxNuIDF0icJenMbqSH9fsdEuUXJt+OEKtqLJ8myE9MZf+UJCffzDczhPAA== X-Received: by 2002:a81:6c06:0:b0:5ca:4b7d:87e3 with SMTP id h6-20020a816c06000000b005ca4b7d87e3mr2258761ywc.3.1700667712806; Wed, 22 Nov 2023 07:41:52 -0800 (PST) Received: from mail-yw1-f179.google.com (mail-yw1-f179.google.com. [209.85.128.179]) by smtp.gmail.com with ESMTPSA id t19-20020a817813000000b005cb63f630bcsm1331801ywc.31.2023.11.22.07.41.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Nov 2023 07:41:50 -0800 (PST) Received: by mail-yw1-f179.google.com with SMTP id 00721157ae682-5ccf64439bdso1064937b3.0; Wed, 22 Nov 2023 07:41:50 -0800 (PST) X-Received: by 2002:a0d:d6cb:0:b0:5c9:b020:71b3 with SMTP id y194-20020a0dd6cb000000b005c9b02071b3mr2165932ywd.11.1700667710443; Wed, 22 Nov 2023 07:41:50 -0800 (PST) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20231120160740.3532848-1-niklas.soderlund+renesas@ragnatech.se> <2ab74479-f1fb-4faf-b223-ae750b4c08ce@linaro.org> <7fce3813-daa6-41ac-8167-21ccdd733fbc@lunn.ch> In-Reply-To: <7fce3813-daa6-41ac-8167-21ccdd733fbc@lunn.ch> From: Geert Uytterhoeven Date: Wed, 22 Nov 2023 16:41:37 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] dt-bindings: net: renesas,ethertsn: Add bindings for Ethernet TSN To: Andrew Lunn Cc: =?UTF-8?Q?Niklas_S=C3=B6derlund?= , Krzysztof Kozlowski , Rob Herring , Krzysztof Kozlowski , devicetree@vger.kernel.org, netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Andrew, On Wed, Nov 22, 2023 at 2:57=E2=80=AFPM Andrew Lunn wrote: > > > In general, we try to have the PHY add the delay, not the MAC. So i > > > would start with hard coding the delay to 0ns, and only implement > > > these properties if you have a board where the PHY cannot add the > > > delay. > > > > If I understand the KSZ9031 bindings correctly, that PHY is limited to > > a skew of up to 960 ps, not 1800 or 2000 ps. > > Reading ksz9031_config_rgmii_delay(), it implements the four > PHY_INTERFACE_MODE_RGMII* interface modes. So it should be able to > provide the 2ns delay. Sometimes the tuning ability is relative to the > base delay. So maybe it can do 2n +- 0.960/2 ? Oh, I do remember the regressions when the KSZ9031 driver started implementing that :-( See commit a6f51f2efa742df0 ("ravb: Add support for explicit internal clock delay configuration") and the commits it links to. > Anyway, try interface mode "rgmii_id" with the MAC not providing any > delay. That's more or less what we had before, cfr. commit 9b81018185965a30 ("arm64: dts: renesas: rcar-gen3: Convert EtherAVB to explicit delay handling")... Gr{oetje,eeting}s, Geert --=20 Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k= .org In personal conversations with technical people, I call myself a hacker. Bu= t when I'm talking to journalists I just say "programmer" or something like t= hat. -- Linus Torvalds