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 B67EAC433F5 for ; Mon, 11 Apr 2022 21:33:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233040AbiDKVff (ORCPT ); Mon, 11 Apr 2022 17:35:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231789AbiDKVfe (ORCPT ); Mon, 11 Apr 2022 17:35:34 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 781CEB7EE for ; Mon, 11 Apr 2022 14:33:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1E993B818C4 for ; Mon, 11 Apr 2022 21:33:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B0A9C385A3; Mon, 11 Apr 2022 21:33:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649712796; bh=lEYz4+ERIjZyTTLkGjkRDmNUp6uVkmGZIVZ/FkmwMEY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tzEuM2scRaNRnLZH5XnCszne4cBhexTFKyC5R7hBuDspiTe93+tYKUZ3z1M8VyS9e +J9k/o/42dRN1VlNRBkim1RNfl6/ERLFNjXWuGmpQe0esBXL/p//WRfJMvu1yywK8h LSlf+QzQSLuhF7nP1bIYoAHw9fcusn6sQJl2TYK7EGb+nZ3pg1N/EXp00WjpVIEWOR WVx65ablWaAl7SN3QZMvQ2NSO+LSwRs3Q0p5mvYXdTT+WcRnOmGeKRuCQXIdGir8da gaLEzbOSpCoIxM93jeY3ybR2d1s0O2/LXnFxFhfN8a5wdtXB5HoOXaeLUNYs4b7Sqw 0RLTrawyeTidA== Date: Mon, 11 Apr 2022 14:33:15 -0700 From: Jakub Kicinski To: Andrew Lunn Cc: Josua Mayer , Krzysztof Kozlowski , netdev@vger.kernel.org, alvaro.karsz@solid-run.com, Michael Hennerich , "David S. Miller" , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Alexandru Ardelean Subject: Re: [PATCH 1/3] dt: adin: document clk-out property Message-ID: <20220411143315.6cd5484e@kernel.org> In-Reply-To: References: <20220410104626.11517-1-josua@solid-run.com> <20220410104626.11517-2-josua@solid-run.com> <20220411130715.516fc5cc@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 11 Apr 2022 22:59:59 +0200 Andrew Lunn wrote: > > Noob question - can you explain how this property describes HW? > > I thought we had a framework for clock config, and did not require > > vendor specific properties of this sort. > > > > The recovered vs free running makes the entire thing sound like > > a SyncE related knob, irrelevant to normal HW operation. > > It is not necessarily SyncE. Fast Ethernet is based around a 25MHz > clock. Something needs to provide that clock. Sometimes the SoC/MAC > provides it, and passes it to the PHY. Sometimes the PHY provides it, > and passes it to the SoC/MAC. > > There are a couple of PHYs which make use of the common clock > framework, when the SoC is the clock source. However, i don't think > there are any PHYs which provide a clock to the common clock framework > when they are the source. We do however have a number of vendor > properties to control the PHY clock output, disable the PHY clock > output, select the PHY clock output, etc. There is not too much > standardisation here, and it is made worse by some PHYs needing a > reset once the clock is ticking, some MACs stop the clock when the > link is administrative down, some PHYs stop the clock a short time > after the link goes down which can be bad for the MAC etc. I see. Why would the MAC/SoC care if the clock is recovered or free running, tho?