From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-197.mta0.migadu.com [91.218.175.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 45DC12DB7B8 for ; Sat, 12 Sep 2026 14:16:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789222590; cv=none; b=IGISOyBLz9F5r44+yLN3CkK+9vRZcXCKLpqHVAaqhid7/+nGSozV2+W1qsFOvWoPg8yBC+NODJPzLPf0zLPdozk0QGHMAl5/YFsa5O37TGgIxHYLizu0XGzDzVGt0eFzNeUXjRzku9QnVrxjEemoVwpcanr56IZ4QE3YTYr0+vg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789222590; c=relaxed/simple; bh=gWTv9m159o9tqPhsbO31jxi6b8U5wx9tbWutAlj+Ycc=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=YUzgW5h4MyALzlcOomMG3Z7x1A+28gjR8ugEZmzDf4lzhaGXP1QQ41yYn0pND1nNDO/cjV3/v6sxqzbxB2X/sy+D4aHe54TDSXN74NxgjKns8lLa02EYNv9ofx6M+9RYHje9PnSxMJe+0GUseBtZpV/t+HknCUuhdHBa1+NAMt0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=cknow-tech.com; spf=pass smtp.mailfrom=cknow-tech.com; dkim=pass (2048-bit key) header.d=cknow-tech.com header.i=@cknow-tech.com header.b=Pf/FMT+s; arc=none smtp.client-ip=91.218.175.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=cknow-tech.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cknow-tech.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cknow-tech.com header.i=@cknow-tech.com header.b="Pf/FMT+s" X-Envelope-To: linux-kernel@vger.kernel.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-kernel@vger.kernel.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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> 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