From nobody Sun Feb 8 18:10:46 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 217EDC7EE2C for ; Mon, 29 May 2023 19:33:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229560AbjE2Tdr (ORCPT ); Mon, 29 May 2023 15:33:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbjE2Tdq (ORCPT ); Mon, 29 May 2023 15:33:46 -0400 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BE56B7; Mon, 29 May 2023 12:33:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Cc:To :From:Sender:Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post: List-Owner:List-Archive; bh=LyKdt7bIuSLgYX3j/F+gzEFbzYlw1Pil8ehJHqfkgQE=; b=O V12uHWLprzyTdzNurAPHeByriz49zDuhyrfbUSbQxWIoGO5/4BnHzLRcsLvE21oVEvmz4QBIG1Zbw +vZAqhFtpIs4ObhoeHAABNkkwii2m7Nh+5qfmGzhHEbz6HjHXESmc14+gxTEvMki+hxcUnpf8Ymq6 P5MDzsv9V9KeuUik=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:42950 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1q3icZ-0000Ll-Ok; Mon, 29 May 2023 15:33:36 -0400 From: Hugo Villeneuve To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team Cc: hugo@hugovil.com, Hugo Villeneuve , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Date: Mon, 29 May 2023 15:33:12 -0400 Message-Id: <20230529193311.1033939-1-hugo@hugovil.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com Subject: [PATCH] arm64: dts: imx8mn-var-som: add 20ms delay to ethernet regulator enable X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Hugo Villeneuve This commit is taken from Variscite linux kernel public git repository. Original patch author: Nate Drude See: https://github.com/varigit/linux-imx/blob/5.15-2.0.x-imx_var01/drivers= /net/ethernet/freescale/fec_main.c#L3993-L4050 The ethernet phy reset was moved from the fec controller to the mdio bus, see for example: 0e825b32c033e1998d0ebaf247f5dab3c340e3bf When the fec driver managed the reset, the regulator had time to settle during the fec phy reset before calling of_mdiobus_register, which probes the mii bus for the phy id to match the correct driver. Now that the mdio bus controls the reset, the fec driver no longer has any delay between enabling the regulator and calling of_mdiobus_register. If the regulator voltage has not settled, the phy id will not be read correctly and the generic phy driver will be used. The following call tree explains in more detail: fec_probe fec_reset_phy <- no longer introduces delay= after migration to mdio reset fec_enet_mii_init of_mdiobus_register of_mdiobus_register_phy fwnode_mdiobus_register_phy get_phy_device <- mii probe for phy id to ma= tch driver happens here ... fwnode_mdiobus_phy_device_register phy_device_register mdiobus_register_device mdio_device_reset <- mdio reset assert / deasse= rt delay happens here Add a 20ms enable delay to the regulator to fix the issue. Signed-off-by: Hugo Villeneuve --- arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi b/arch/arm64= /boot/dts/freescale/imx8mn-var-som.dtsi index cbd9d124c80d..a502ef7394a3 100644 --- a/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi +++ b/arch/arm64/boot/dts/freescale/imx8mn-var-som.dtsi @@ -27,6 +27,7 @@ reg_eth_phy: regulator-eth-phy { regulator-name =3D "eth_phy_pwr"; regulator-min-microvolt =3D <3300000>; regulator-max-microvolt =3D <3300000>; + regulator-enable-ramp-delay =3D <20000>; gpio =3D <&gpio2 9 GPIO_ACTIVE_HIGH>; enable-active-high; }; base-commit: 8b817fded42d8fe3a0eb47b1149d907851a3c942 --=20 2.30.2