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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EF749D2CE05 for ; Tue, 22 Oct 2024 17:01:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qhSKd2J3l8RyLoipAAMrIXHuHA0SVPJOKCKGMnKgPYA=; b=RDYXXHyM4egq4hiD3ajs6L94Ic PbzcQVl+smYzRy5iHx2E80/MBlg3h5J88D+vJlUQBnoIiWCCm/A1z3ApXlGEzCGjNQYshNsOPOXwo 58k/+FCC/T2FXnLUAAS63rkLZH9Euc8MOvxMYVfxggfkzT3G+dy5DsVVLHMJwO0/xwCPOHAVO6BUI fOh6bQxUGh/iLRQOWV9lf3kunUK0HQ8Flnvvw+6GruYL4rLiyfm2Mgv3Z0hZ/qUCPM1FItthcHy9A tImLiofkYkM/A9yB42qk1LZssau63LG6eUhl+80ATpOHOeKRyfVr8CVUilfMpR0mVml/s64lkIUsX IPTBbmfA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t3IFw-0000000BZuj-0jvu; Tue, 22 Oct 2024 17:01:16 +0000 Received: from mail-pl1-x62c.google.com ([2607:f8b0:4864:20::62c]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t3Hu0-0000000BUlT-1Gd5 for linux-arm-kernel@lists.infradead.org; Tue, 22 Oct 2024 16:38:37 +0000 Received: by mail-pl1-x62c.google.com with SMTP id d9443c01a7336-20cdb889222so56720555ad.3 for ; Tue, 22 Oct 2024 09:38:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1729615115; x=1730219915; darn=lists.infradead.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=qhSKd2J3l8RyLoipAAMrIXHuHA0SVPJOKCKGMnKgPYA=; b=qZO8OKp4olRdxVSd/aOSugWjvTynQL6NBj/QGSNm/sl902HQnpJZAJNAK/vAawC/ts NWN3BOMgWpD5/15txSOrKrEbT0qdGn1sL0/+NORF8HG7IRyV6ne82NgPB26kYQuTtAJ1 5UjjEnVFP+Q2vRd9Frr8GsKnbodfKiSYwKUvMz4aIQ3xHSaD9eZqyj89NxRMQF1NOJdJ Fc3oyzkHIPazIOEeb5DBvMieNPvL5Qq/ELqx3HW+O0TlgxN2wtNf5lhKFtuTwfvqAJjn 8oiYpqkwINa3qXM+FOOHedy5uCxQ71C7RPxyfsvdrs4g6uY/z1dHfs6dpweP92wwTwQW b4qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729615115; x=1730219915; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=qhSKd2J3l8RyLoipAAMrIXHuHA0SVPJOKCKGMnKgPYA=; b=A4HYJ1Kitu/S7G+ET48ewJo4o0qtvAMLhZcwBZEtSkXoWhEzJnJb4GFEPD60SDADsr xt7v5ch9/jQPMKKZMrtHW1Ciex/duJ/LujV8R90XnwcH9cBvfFazb3CCEVDg3vtt9KO9 oJJG1FuIbQhzfiSGhOMj+o4wms3DND9oMbqsfXMQ0wlqlKRoTYP7Fvx75i7Ad/rYi2nI bGq/0A7bKjyFhg6WEF+NU/ygWlatLfbVhAc/U+NV3kZ5kRjlEvGuMKREW06Vlid6psyX HgmAKFE0G/ZN8NnQTaBLWmoP9NomW0DIpkkBrVdVEub1C9DUx66W+dRsLlFWD6mEJZd8 GGfA== X-Forwarded-Encrypted: i=1; AJvYcCUBtcNyXHWI4CekZUG4sE6OqwjR09NFFNjBH7kEp4hvaVsmf+lYYIUmCt0pWN+yFZ12xmmCj0yxtGvl8ALHOSxp@lists.infradead.org X-Gm-Message-State: AOJu0Yw+qEJa64SD27NDJ0UbIlOflRz9jJzCp/+yQn6iChDdkahrf0WG s6MGZbaIFyUsGbAu9HZpvNnJ/b1cyOHInCP0zDI4scS72z+VKTX9KBoCfOsNWA== X-Google-Smtp-Source: AGHT+IENmUY9fziUvs63gVSy652sJwbamPCQ2VYyNU8dTskEqduYXYWzphnoXxB4WhyxD1leELQILw== X-Received: by 2002:a17:90a:f518:b0:2e2:a3aa:6509 with SMTP id 98e67ed59e1d1-2e5ddb758c5mr3458449a91.14.1729615115179; Tue, 22 Oct 2024 09:38:35 -0700 (PDT) Received: from thinkpad ([36.255.17.224]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e5ad4ed825sm6422503a91.35.2024.10.22.09.38.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Oct 2024 09:38:34 -0700 (PDT) Date: Tue, 22 Oct 2024 22:08:26 +0530 From: Manivannan Sadhasivam To: Bjorn Helgaas Cc: Richard Zhu , kw@linux.com, bhelgaas@google.com, lpieralisi@kernel.org, frank.li@nxp.com, l.stach@pengutronix.de, robh+dt@kernel.org, conor+dt@kernel.org, shawnguo@kernel.org, krzysztof.kozlowski+dt@linaro.org, festevam@gmail.com, s.hauer@pengutronix.de, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, kernel@pengutronix.de, imx@lists.linux.dev Subject: Re: [PATCH v4 1/9] dt-bindings: imx6q-pcie: Add ref clock for i.MX95 PCIe RC Message-ID: <20241022163826.6w3it42o7kbp6ydp@thinkpad> References: <1728981213-8771-2-git-send-email-hongxing.zhu@nxp.com> <20241018231305.GA768070@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241018231305.GA768070@bhelgaas> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241022_093836_366110_D7296720 X-CRM114-Status: GOOD ( 21.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Oct 18, 2024 at 06:13:05PM -0500, Bjorn Helgaas wrote: > On Tue, Oct 15, 2024 at 04:33:25PM +0800, Richard Zhu wrote: > > Previous reference clock of i.MX95 PCIe RC is on when system boot to > > kernel. But boot firmware change the behavor, it is off when boot. So it > > needs be turn on when it is used. Also it needs be turn off/on when suspend > > and resume. > > I think this background would make more sense in patch 2. IIUC, > that's where the driver behavior changes to do something with the > "ref" clock. > > I'm not sure how to interpret "Previous reference clock of i.MX95 PCIe > RC is on when system boot to kernel. But boot firmware change the > behavor, it is off when boot." > > Does that mean a previous version of the boot firmware left the ref > clock on at handoff to the OS, and newer firmware turns it off? If > so, I think it would be useful to include information about the > relevant firmware versions. > Most likely that the bootloader *used to* turn on the reference clock and now it decides not to do so (for whatever reason). But ideally, the clock should be voted/enabled by the kernel irrespective of that. So the reference of 'boot firmware' is not relevant here. - Mani -- மணிவண்ணன் சதாசிவம்