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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 EDB6CC433E0 for ; Wed, 20 Jan 2021 15:18:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD4902336D for ; Wed, 20 Jan 2021 15:18:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390941AbhATPSS (ORCPT ); Wed, 20 Jan 2021 10:18:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390747AbhATPPL (ORCPT ); Wed, 20 Jan 2021 10:15:11 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36628C061786 for ; Wed, 20 Jan 2021 07:13:18 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1l2FAQ-00006V-Iw; Wed, 20 Jan 2021 16:13:06 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1l2FAP-0003uY-Cr; Wed, 20 Jan 2021 16:13:05 +0100 Date: Wed, 20 Jan 2021 16:13:05 +0100 From: Sascha Hauer To: Abel Vesa Cc: Adam Ford , arm-soc , Adam Ford-BE , Aisheng Dong , Michael Turquette , Stephen Boyd , Shawn Guo , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Linus Walleij , Jerome Brunet , linux-clk , Linux Kernel Mailing List Subject: Re: [PATCH V3] clk: imx: Fix reparenting of UARTs not associated with sdout Message-ID: <20210120151305.GC19063@pengutronix.de> References: <20210115182909.314756-1-aford173@gmail.com> <20210118125204.hxsanoohwvdtdvym@fsr-ub1664-175> <20210120144454.f6b72lnasw4q3bde@fsr-ub1664-175> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210120144454.f6b72lnasw4q3bde@fsr-ub1664-175> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 16:11:27 up 49 days, 3:38, 84 users, load average: 0.30, 0.19, 0.12 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Abel, On Wed, Jan 20, 2021 at 04:44:54PM +0200, Abel Vesa wrote: > On 21-01-18 08:00:43, Adam Ford wrote: > > On Mon, Jan 18, 2021 at 6:52 AM Abel Vesa wrote: > > > > > > On 21-01-15 12:29:08, Adam Ford wrote: > > > > > > ... > > > > > > > diff --git a/drivers/clk/imx/clk-imx25.c b/drivers/clk/imx/clk-imx25.c > > > > index a66cabfbf94f..66192fe0a898 100644 > > > > --- a/drivers/clk/imx/clk-imx25.c > > > > +++ b/drivers/clk/imx/clk-imx25.c > > > > @@ -73,16 +73,6 @@ enum mx25_clks { > > > > > > > > static struct clk *clk[clk_max]; > > > > > > > > -static struct clk ** const uart_clks[] __initconst = { > > > > - &clk[uart_ipg_per], > > > > - &clk[uart1_ipg], > > > > - &clk[uart2_ipg], > > > > - &clk[uart3_ipg], > > > > - &clk[uart4_ipg], > > > > - &clk[uart5_ipg], > > > > - NULL > > > > -}; > > > > - > > > > > > I'm assuming there is another patch that updates the dts files. Right ? > > > > I have only been able to test this on an i.MX8M Mini. I need to set > > the parent clock of the i.MX8M Mini to an 80 MHz clock in order to run > > the UART at 4Mbps. With this patch, I can stop enabling the all the > > UART clocks early and allow the clock parent configuration to occur. > > From what I can tell, the remaining clocks should get activated as > > they are needed, because I was able to use Bluetooth connected to > > UART1 running at 4MBps using a 80MHz clock source with this patch, and > > the clk_summary shows the clock is running at the proper speed. > > Without this patch, the UART fails to re-parent, so I'm stuck at lower > > speeds and that means choppy Bluetooth audio. > > > > The Kernel that NXP hosts on Code Aurora that they use for Yocto > > attempts scan through stdout to only enable those clocks [1]. I > > attempted to push it upstream, but it was rejected [2]. Sascha > > suggested creating an array which could be filled when the clocks are > > enabled and that array would be used to deactivate the clocks at > > shutdown. That's what I attempted to do here. > > > > I don't have older imx boards to know if their device trees are > > configured in such a way without modifications to the device tree or > > not, but since it appears to work for NXP in [2], I assumed it would > > work here. > > > > [1] - https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsource.codeaurora.org%2Fexternal%2Fimx%2Flinux-imx%2Fcommit%2Fdrivers%2Fclk%2Fimx%2Fclk.c%3Fh%3Dimx_5.4.47_2.2.0%26id%3D754ae82cc55b7445545fc2f092a70e0f490e9c1b&data=04%7C01%7Cabel.vesa%40nxp.com%7Cf8922e76fa85485b86c508d8bbb97c47%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637465752633257569%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=bVmPaM1nN7Sm%2BISVvlIBoWYozfJE96fHpw431IEuggk%3D&reserved=0 > > [2] - https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Flinux-arm-kernel%2Fpatch%2F20201229145130.2680442-1-aford173%40gmail.com%2F&data=04%7C01%7Cabel.vesa%40nxp.com%7Cf8922e76fa85485b86c508d8bbb97c47%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637465752633257569%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=226HwbeVhZUW%2FJ3hsCSaVIxghOsPBH9EWeF8vFxaTWE%3D&reserved=0 > > > > > > > > TBH, I'm against the idea of having to call consumer API from a clock provider driver. > > > I'm still investigating a way of moving the uart clock control calls in drivers/serial/imx, > > > where they belong. > > > > That makes sense. > > > > Just a thought. The uart clock used for console remains on from u-boot, > so maybe it's enough to just add the CLK_IGNORE_UNUSED flag to all the > uart root clocks and remove the prepare/enable calls for uart clocks > for good. I don't really have a way to test it right now, but maybe > you could give it a try. That would mean that UART clocks will never be disabled, regardless of whether they are used for console or not. That doesn't sound very appealing. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |