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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2262DC433EF for ; Mon, 9 Sep 2019 08:20:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D51442086D for ; Mon, 9 Sep 2019 08:20:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568017233; bh=hUjMFYDt15aaG0KcZhtWuZvcPW21IIr+paV7LbXYOQk=; h=In-Reply-To:References:Cc:To:From:Subject:Date:List-ID:From; b=a4zZFUlUWe7zpA7hnIZ7ESWDdma8a4ykoMxo/qptt55bg0VQuTqeIJVzxQK3pWuzs Wbcbfpw8enafv9dP+m1rWdxr2bvXVSJlIlt/5hwgWZYqJW7zTz63YUG8ikWMoUG6F7 JFehohFQlp4fKtOlUXPmNrofbs5pFJFCbV6IJJf4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726971AbfIIIUd (ORCPT ); Mon, 9 Sep 2019 04:20:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:56320 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726924AbfIIIUd (ORCPT ); Mon, 9 Sep 2019 04:20:33 -0400 Received: from kernel.org (unknown [104.132.0.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B704D20678; Mon, 9 Sep 2019 08:20:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568017232; bh=hUjMFYDt15aaG0KcZhtWuZvcPW21IIr+paV7LbXYOQk=; h=In-Reply-To:References:Cc:To:From:Subject:Date:From; b=LXLYTbc0hnvTUjlZJEbqYjodBBHPV/b8iEKfS7UbLV2zb1p75QOnTkeUJhQRRxc6M 8GJWSw0+K+FqKPGS3JLrn1fTiPDdflA3APu33YlNsim7A72E9EarwUu2vCFbQheA93 YNiqaT/PfggdraDmM5l56vTOFLEUmUh794cM81Xc= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: References: <20190906172452.D1ED620838@mail.kernel.org> Cc: Jacky Bai , Michael Turquette , Abel Vesa , Viorel Suman , Aisheng Dong , Fabio Estevam , "kernel@pengutronix.de" , dl-linux-imx , "linux-clk@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" To: Daniel Baluta , Leonard Crestez , Peng Fan , Shawn Guo From: Stephen Boyd Subject: Re: [PATCH] clk: imx: pll14xx: Fix quick switch of S/K parameter User-Agent: alot/0.8.1 Date: Mon, 09 Sep 2019 01:20:31 -0700 Message-Id: <20190909082032.B704D20678@mail.kernel.org> Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Quoting Leonard Crestez (2019-09-06 12:36:47) > On 06.09.2019 20:24, Stephen Boyd wrote: > > Quoting Leonard Crestez (2019-09-04 02:49:18) > >> The PLL14xx on imx8m can change the S and K parameter without requiring > >> a reset and relock of the whole PLL. > >> > >> Fix clk_pll144xx_mp_change register reading and use it for pll1443 as > >> well since no reset+relock is required on K changes either. > >> > >> Signed-off-by: Leonard Crestez > >> --- > >> drivers/clk/imx/clk-pll14xx.c | 40 +++++++--------------------------= -- > >> 1 file changed, 8 insertions(+), 32 deletions(-) > >> > >> The PLLs are currently table-based and none of the entries differ only > >> in S/K so further work would be required to make use of this. The > >> prospective user is audio doing tiny freq adjustments and there is no > >> standard API for that. > >=20 > > sub-Hz adjustments? >=20 > Maybe at the audio level? The PLL itself runs at ~400Mhz so wouldn't=20 > need sub-hz adjustment. >=20 > My understanding is that adjustments would be made based on an external=20 > clock so if CLK framework rounds to 1hz then it would just take longer=20 > for adjustment to kick in. Ok. >=20 > >> Lacking users is not a good reason to carry broken code around. > >=20 > > Maybe add a Fixes tag so if anyone wants to use it in LTS kernels there > > might be a chance that they'll find this patch mention code they're > > using. >=20 > It doesn't meet stable kernel rules because it doesn't "fix a real bug=20 > that bothers people" but it's still technically a fix: >=20 > Fixes: 8646d4dcc7fb ("clk: imx: Add PLLs driver for imx8mm soc") >=20 Sure. Thanks! I assume Shawn will pick this up.