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 8C8E0D5C0D0 for ; Fri, 8 Nov 2024 14:42:47 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hqyVZ/9viT/F74PJskLQVU+2qNAdTPQ6QUTRpJ7RymM=; b=LGwDgJduJY2G9kUASTnGAhGhgk qMOw96/XqD4GDniLmQtjl3m4rWn2B1S207n6VvDhZymLh2WV+kV1mcfnibsqPoSzAzyFRZs6OWjAW ope7yZK+cTbI+mEStuqoSy7EKc/X75S1UlHXvuZJORjWp96V1bB7RKTWChblGG80UibpxnNRSoUsd nO///YttimLhk93iyGwHhH5sCFDX7jNWt25Q1PuBabxVFKTlC3ZWsnDwid5Yig1Pl+3RoWA/ocvhT AHE5vGkpey3vaGABCJGEtXhmkCIdF2Cq03+pzqEX5HogBXEz5hp0Gg07TAAcVnaiYx/wMlp1aUHNX h7/tP3vg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t9QC5-0000000AtAy-1JS0; Fri, 08 Nov 2024 14:42:37 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t9Pha-0000000Ao4j-3fKd for linux-arm-kernel@lists.infradead.org; Fri, 08 Nov 2024 14:11:08 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 9DF7B5C5BCC; Fri, 8 Nov 2024 14:10:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D83A8C4CECD; Fri, 8 Nov 2024 14:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731075065; bh=cn9NWvkG2FmD8kESo4BHxEQQZk2BWVmfGCHOfHfEjEo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=CGXrjtMOWgqtA0TJAwGpybZurfjTSpW+4Y7zhVTkrcxOi666w38LvT0n0bw5WjLkq czYMxyfqDVdWVkHlLjRTwGavAIQAKP3mZXLw3t7dhxh5ZvlqBhw0Z1921RwSG1Yjht 96WuRZJkCv6WmSVw9JdeBJXIHO89DN6m1dchli/8d4FaviFfuEjAAiMqo0T+oTsdqy GqeJtkx+WBXIaI0aHqwW6960y84OIhKpo6r/vpizu8X1Fmd2JeXM43mxU27GgbCBl5 y0TXzXiob/mqHxXJDPGWAj2lf5m1qtSuVHU1W4IhObYb6DqVDr/latoCggXQnWV3/a JpHU8Tt/Ct9aA== Message-ID: <8c310eca-d695-418c-82cb-a89351d83887@kernel.org> Date: Fri, 8 Nov 2024 15:10:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/8] dt-bindings: clock: imx8m-clock: support spread spectrum clocking To: Peng Fan , Dario Binacchi Cc: "linux-kernel@vger.kernel.org" , "linux-amarula@amarulasolutions.com" , Abel Vesa , Conor Dooley , Fabio Estevam , Krzysztof Kozlowski , Michael Turquette , Pengutronix Kernel Team , Rob Herring , Sascha Hauer , Shawn Guo , Stephen Boyd , "devicetree@vger.kernel.org" , "imx@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , "linux-clk@vger.kernel.org" References: <20241106090549.3684963-1-dario.binacchi@amarulasolutions.com> <20241106090549.3684963-2-dario.binacchi@amarulasolutions.com> <4bix7me5vaoyhcuffyp4btajmhy7no6ltczoesopaz2fqupyaw@fensx4nn472u> <54dd6ae6-b992-451e-b1c6-8a1968955f4a@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241108_061107_043789_B98AF57D X-CRM114-Status: GOOD ( 16.48 ) 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 08/11/2024 13:50, Peng Fan wrote: >> Subject: Re: [PATCH v3 1/8] dt-bindings: clock: imx8m-clock: support >> spread spectrum clocking >> >> On 07/11/2024 15:57, Dario Binacchi wrote: >>> clocks = <&osc_32k>, <&osc_24m>, <&clk_ext1>, <&clk_ext2>, >>> <&clk_ext3>, <&clk_ext4>; >>> clock-names = "osc_32k", "osc_24m", "clk_ext1", "clk_ext2", >>> "clk_ext3", "clk_ext4"; >>> assigned-clocks = <&clk IMX8MN_CLK_A53_SRC>, >>> <&clk IMX8MN_CLK_A53_CORE>, >>> <&clk IMX8MN_CLK_NOC>, >>> <&clk IMX8MN_CLK_AUDIO_AHB>, >>> <&clk IMX8MN_CLK_IPG_AUDIO_ROOT>, >>> <&clk IMX8MN_SYS_PLL3>, >>> <&clk IMX8MN_AUDIO_PLL1>, >>> <&clk IMX8MN_AUDIO_PLL2>; >>> assigned-clock-parents = <&clk IMX8MN_SYS_PLL1_800M>, >>> <&clk IMX8MN_ARM_PLL_OUT>, >>> <&clk IMX8MN_SYS_PLL3_OUT>, >>> <&clk IMX8MN_SYS_PLL1_800M>; >>> assigned-clock-rates = <0>, <0>, <0>, >>> <400000000>, >>> <400000000>, >>> <600000000>, >>> <393216000>, >>> <361267200>; }; >>> >>> The spread spectrum is not configurable on these clocks or, more >>> generally, may not be configurable (only 4 PLLs have this capability). >>> Therefore, I need the "fsl,ssc-clocks" >> >> No. That's not true. You do not need it. >> > > i.MX8M clock hardware is similar as: > > OSC->ANATOP->CCM > > ANATOP will produce PLLs. > CCM use PLLs as input source. > > Currently there is no dedicated ANATOP driver in linux. > The CCM linux driver will parse the ANATOP node and > register clk_hw for the PLLs. I do not know what is CCM and how does it fit here. What's more, I don't get driver context here. We talk about bindings. > > >> First, the clock inputs for this device are listed in clocks *only*. >> What is no there, is not an input to the device. Including also Linux >> aspect (missing devlinks etc). Therefore how can you configure spread >> spectrum on clocks which are not connected to this device? > > I not understand this well, you mean > add clocks = in the ccm dtb node? Yes. Let me re-iterate and please respond to this exactly comment instead of ignoring it. How a device can care about spread spectrum of a clock which is not supplied to this device? Why would you care about spread spectrum of some clock which is not coming to this device? Please address these precisely because we talk about this for weeks in multiple places. I finish with this patchset if you do not provide such context. Best regards, Krzysztof