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 83BE9C7EE22 for ; Thu, 11 May 2023 23:29:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229654AbjEKX3b (ORCPT ); Thu, 11 May 2023 19:29:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239506AbjEKX3a (ORCPT ); Thu, 11 May 2023 19:29:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B920461BA for ; Thu, 11 May 2023 16:29:29 -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 dfw.source.kernel.org (Postfix) with ESMTPS id A38D265274 for ; Thu, 11 May 2023 23:29:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8179FC433EF; Thu, 11 May 2023 23:29:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683847768; bh=SLlcwEuE4JpFNFcPjNi/S0l6z/1UC6psRw1iRRUVsYs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=efUdlcXR/weB6qRSybLmpnKrQG4ctSZoORqH6nEZTv0i+nAPO4aErh3H652p78bhZ tVE+QXHCkMDO7gRC+eRJ7rKBpsXJZQ/l/knP+UPmqN5P4YyFLbvYLE/N+2mpU8jehw JDTysC+qkto2m3UoixYkCKVqqj2MKCiOiS0dSMR1lNHOnC6XTnUF1I9jWNYP4e6LhG h9d8bKTpoQq3YuR4xqlTf/GqOXvMYILRNsWv+evIyyp7FR/57/Fu6XvxYSnFYFbXoV M6uJbiFNqPHw4+XLoGIe9pJpTllMPFIVdCOcujeyDwvddeGva5nJ+dpAi7mfwoO6kW fb+AFD5Kkdh9g== Date: Thu, 11 May 2023 16:29:26 -0700 From: Jakub Kicinski To: "Kubalewski, Arkadiusz" Cc: Vadim Fedorenko , Jiri Pirko , Jonathan Lemon , Paolo Abeni , "Olech, Milena" , "Michalik, Michal" , "linux-arm-kernel@lists.infradead.org" , poros , mschmidt , "netdev@vger.kernel.org" , "linux-clk@vger.kernel.org" , Vadim Fedorenko Subject: Re: [RFC PATCH v7 1/8] dpll: spec: Add Netlink spec in YAML Message-ID: <20230511162926.009994bb@kernel.org> In-Reply-To: References: <20230428002009.2948020-1-vadfed@meta.com> <20230428002009.2948020-2-vadfed@meta.com> <20230504142451.4828bbb5@kernel.org> <20230511082053.7d2e57e3@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On Thu, 11 May 2023 20:53:40 +0000 Kubalewski, Arkadiusz wrote: > >Because I think that'd be done by an NCO, no? > > From docs I can also see that chip has additional designated dpll for NCO mode, > and this statement: > "Numerically controlled oscillator (NCO) behavior allows system software to steer > DPLL frequency or synthesizer frequency with resolution better than 0.005 ppt." > > I am certainly not an expert on this, but seems like the NCO mode for this chip > is better than FREERUN, since signal produced on output is somehow higher quality. Herm, this seems complicated. Do you have a use case for this? Maybe we can skip it :D My reading of the quote is that there is an NCO which SW can control precisely. But that does not answer the questions: - is the NCO driven by system clock or can it be used in locked mode? - what is the "system software"? FW which based on temperature information, and whatever else compensates drift of system clock? or there are exposed registers to control the NCO?