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 592CAC88E59 for ; Sat, 12 Sep 2026 14:16:38 +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:In-Reply-To:References:To: From:Subject:Cc:Message-Id:Date:Content-Type:Content-Transfer-Encoding: Mime-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Yoyqd/PyzlDo4VO4X/+8itOj92JfX8j1r4PXxYzmEhw=; b=iG6niIEy+HDCi3u/LsTaINvY53 6CvtmFVE0LHJDyIgACeOyN2riYXNRIa5wwr5bHAXKubY86CNZiC8rLqRxbECakAhUL3gyZNcnk/B0 WG5tmzRng/32QYVxcQYG6RSY02BvaExRdh+Q/9jACgFmuJ5aHpMuqCvays12jcaUl2qX/5KiP1oUj oxFwtGkXAZgIpd7kTcj98Hc5MmN74YN3D4uu5JK8u/7nv8iGod8Cv4lYYx6y2rCsZ1Fudyf18jOg/ MdDzsGW8NShEFeHD6zL5St3o/3AYoqLJC28j5kp/zPJli5Fni6Qzayqc0Yeef9y6bYIsoSfdIL4Rk BGUDJDFA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x5OWt-00000000vrf-1UHg; Sat, 12 Sep 2026 14:16:31 +0000 Received: from out-214.mta0.migadu.com ([2001:41d0:1004:224b::d6] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x5OWq-00000000vqT-09nY for linux-arm-kernel@lists.infradead.org; Sat, 12 Sep 2026 14:16:30 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=gWTv9m159o9tqPhsbO31jxi6b8U5wx9tbWutAlj+Ycc=; c=simple/simple; d=cknow-tech.com; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789222584; v=1; x=1789827384; b=Pf/FMT+szYm1C4slkIL1AF2TsUmqIYizkP1pOg5AzF9KLVjHmE53rDd5eygW2NYJLrvEyKpD S3afT/SP68ZH3YxA1LdSwrKLFEoVt5L4rTVTEtEt4TDTf5t6g1KuC9SxxhjdusU4HuIn87MGWxs pK7W/gzv8yFWrmLE2+m8kBqcNsJzTw7x0oR9xO1QEZAxA5WMsPYhumtrKtG38eNnEcsOGbWCn9Z NFszoRXJnx5n7aFkj+7NRDldtr2GxSCe1zBFFPLak1YbmlsiGz6ifWHr88tlb8JOEhnWfQybrUh ZgKR5VJKFwJhlDTxmNXarAdveD8147OvllSxL/VvDqLbQ== X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 771c737939bb75a4; Sat, 12 Sep 2026 14:16:24 +0000 X-Mizu-Trace-ID: 771c737939bb75a4 X-Migadu-Flow: FLOW_OUT Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Sat, 12 Sep 2026 16:16:22 +0200 Message-Id: Cc: "Ricardo Pardini" , , , , Subject: Re: [PATCH] arm64: dts: rockchip: Fix i2c6 clock-frequency on NanoPC-T6 From: "Diederik de Haas" To: "Heiko Stuebner" , "Rob Herring" , "Krzysztof Kozlowski" , "Conor Dooley" , "Diederik de Haas" X-Mailer: aerc 0.22.0-9-ge948bb7230f4 References: <20260911152911.2088363-1-diederik@cknow-tech.com> <2071782.usQuhbGJ8B@phil> In-Reply-To: <2071782.usQuhbGJ8B@phil> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260912_071628_725482_036989FA X-CRM114-Status: GOOD ( 11.37 ) 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 Sat Sep 12, 2026 at 2:41 PM CEST, Heiko Stuebner wrote: > Am Freitag, 11. September 2026, 17:28:33 Mitteleurop=C3=A4ische Sommerzei= t schrieb Diederik de Haas: >> The i2c6 bus needs to run at 200kHz, because at the default frequency of >> 100kHz it may fail to find the RTC resulting in warnings/errors like >>=20 >> rtc-hym8563 6-0051: no valid clock/calendar values available >> rtc-hym8563 6-0051: hctosys: unable to read the hardware clock >>=20 >> But only sometimes. This should not happen when there is a battery backi= ng >> the RTC, yet it does ... sometimes. > > I'm confused, shouldn't a slower clock always work? > Like I understand how a clock that is too fast can cause issues due > to hardware limitations, but running the bus slower somehow shouldn't > cause issues? Impeccable timing ... as I was just about to retract this patch. In all my testing I regularly got those error/warning on 100kHz and not once with 200kHz ... until just now. My reasoning was that it was too slow to respond making the system/driver think it wasn't there and thus causing those error/warning. In the downstream kernel it is set to 200kHz and in my testing the downstre= am image (with that kernel), I have not once seen those error/warning. So I figured that the 100kHz was the problem. But that's all null and void as I now did get the error/warning with 200kHz= . So please ignore/drop this and sorry for the noise. Diederik