From mboxrd@z Thu Jan 1 00:00:00 1970 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 DE375C433EF for ; Tue, 22 Mar 2022 09:08:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231408AbiCVJKL convert rfc822-to-8bit (ORCPT ); Tue, 22 Mar 2022 05:10:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230391AbiCVJKK (ORCPT ); Tue, 22 Mar 2022 05:10:10 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A5735F270 for ; Tue, 22 Mar 2022 02:08:42 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nWaV3-0002h8-Qv; Tue, 22 Mar 2022 10:08:21 +0100 Received: from [2a0a:edc0:0:900:1d::4e] (helo=lupine) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1nWaUn-002G5K-VH; Tue, 22 Mar 2022 10:08:08 +0100 Received: from pza by lupine with local (Exim 4.94.2) (envelope-from ) id 1nWaUq-00015B-0c; Tue, 22 Mar 2022 10:08:08 +0100 Message-ID: Subject: Re: [PATCH v2 3/3] ARM: dts: aspeed: add reset properties into MDIO nodes From: Philipp Zabel To: Dylan Hung , Andrew Lunn Cc: Krzysztof Kozlowski , "robh+dt@kernel.org" , "joel@jms.id.au" , "andrew@aj.id.au" , "hkallweit1@gmail.com" , "linux@armlinux.org.uk" , "davem@davemloft.net" , "kuba@kernel.org" , "pabeni@redhat.com" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-aspeed@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , BMC-SW , "stable@vger.kernel.org" Date: Tue, 22 Mar 2022 10:08:07 +0100 In-Reply-To: References: <20220321095648.4760-1-dylan_hung@aspeedtech.com> <20220321095648.4760-4-dylan_hung@aspeedtech.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Di, 2022-03-22 at 03:22 +0000, Dylan Hung wrote: > > -----Original Message----- > > From: Andrew Lunn [mailto:andrew@lunn.ch] > > Sent: 2022年3月22日 11:01 AM > > To: Dylan Hung > > Cc: Krzysztof Kozlowski ; robh+dt@kernel.org; > > joel@jms.id.au; andrew@aj.id.au; hkallweit1@gmail.com; > > linux@armlinux.org.uk; davem@davemloft.net; kuba@kernel.org; > > pabeni@redhat.com; p.zabel@pengutronix.de; > > devicetree@vger.kernel.org; > > linux-arm-kernel@lists.infradead.org; > > linux-aspeed@lists.ozlabs.org; > > linux-kernel@vger.kernel.org; netdev@vger.kernel.org; BMC-SW > > ; stable@vger.kernel.org > > Subject: Re: [PATCH v2 3/3] ARM: dts: aspeed: add reset properties > > into MDIO > > nodes > > > > On Tue, Mar 22, 2022 at 02:32:13AM +0000, Dylan Hung wrote: > > > > -----Original Message----- > > > > From: Krzysztof Kozlowski [mailto:krzk@kernel.org] > > > > Sent: 2022年3月21日 11:53 PM > > > > To: Dylan Hung ; robh+dt@kernel.org; > > > > joel@jms.id.au; andrew@aj.id.au; andrew@lunn.ch; > > > > hkallweit1@gmail.com; linux@armlinux.org.uk; > > > > davem@davemloft.net; > > > > kuba@kernel.org; pabeni@redhat.com; p.zabel@pengutronix.de; > > > > devicetree@vger.kernel.org; > > > > linux-arm-kernel@lists.infradead.org; > > > > linux-aspeed@lists.ozlabs.org; linux-kernel@vger.kernel.org; > > > > netdev@vger.kernel.org > > > > Cc: BMC-SW ; stable@vger.kernel.org > > > > Subject: Re: [PATCH v2 3/3] ARM: dts: aspeed: add reset > > > > properties > > > > into MDIO nodes > > > > > > > > On 21/03/2022 10:56, Dylan Hung wrote: > > > > > Add reset control properties into MDIO nodes.  The 4 MDIO > > > > > controllers in > > > > > AST2600 SOC share one reset control bit SCU50[3]. > > > > > > > > > > Signed-off-by: Dylan Hung > > > > > Cc: stable@vger.kernel.org > > > > > > > > Please describe the bug being fixed. See stable-kernel-rules. > > > > > > Thank you for your comment. > > > The reset deassertion of the MDIO device was usually done by the > > bootloader (u-boot). > > > However, one of our clients uses proprietary bootloader and > > > doesn't > > > deassert the MDIO reset so failed to access the HW in kernel > > > driver. > > > > So are you saying mainline u-boot releases the reset? > > > Yes, if the mdio devices are used in u-boot. > > > > The reset deassertion is missing in the kernel driver since it > > > was > > > created, should I add a BugFix for the first commit of this > > > driver? > > > > Yes, that is normal. Ideally the kernel should not depend on u- > > boot, because > > often people want to use other bootloaders, e.g. barebox. You > > should also > > consider kexec, where one kernel hands over to another kernel, > > without the > > bootloader being involved. In such a situation, you ideally want to > > assert and > > deassert the reset just to clean away any state the old kernel left > > around. > > > > But please do note, that the reset is optional, since you need to > > be able to > > work with old DT blobs which don't have the reset property in them. > > > > Thank you. I will let the reset property be optional and modify the > error-checking in the driver accordingly in V3. No need to change the error checking, just use devm_reset_control_get_optional_shared(). regards Philipp