From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752571AbbAVAuQ (ORCPT ); Wed, 21 Jan 2015 19:50:16 -0500 Received: from mail-out.m-online.net ([212.18.0.9]:43915 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751531AbbAVAuL (ORCPT ); Wed, 21 Jan 2015 19:50:11 -0500 X-Auth-Info: ZUQepINkS+00IfcXJquKKQ6GSIbuCkqL88UQtAGpSrg= From: Marek Vasut To: Zhi Li Subject: Re: [PATCH V2] clk: mxs: Fix invalid 32-bit access to frac registers Date: Thu, 22 Jan 2015 00:39:01 +0100 User-Agent: KMail/1.13.7 (Linux/3.13-trunk-amd64; KDE/4.13.1; x86_64; ; ) Cc: Stefan Wahren , mturquette@linaro.org, kernel list , Sascha Hauer , harald@ccbib.org, Shawn Guo , Fabio Estevam , "linux-arm-kernel@lists.infradead.org" References: <1419762402-4548-1-git-send-email-stefan.wahren@i2se.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201501220039.02073.marex@denx.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, January 21, 2015 at 05:16:03 PM, Zhi Li wrote: > On Sun, Dec 28, 2014 at 4:26 AM, Stefan Wahren wrote: > > According to i.MX23 and i.MX28 reference manual the fractional > > clock control registers must be addressed by byte instructions. > > I don't think mx23 and mx28 have such limitation. I will double check > with IC team about this. > RTL is generated from a xml file. All registers implement is unified. > I don't think only clock control register have such limitation and > other registers not. Hi, Section 10.8.24 in the MX28 datasheet (Fractional Clock Control Register 0) states otherwise, but maybe the documentation is simply not matching the silicon. Here's a quote: " This register controls the 9-phase fractional clock dividers. The fractional clock frequencies are a product of the values in these registers. NOTE: This register can only be addressed by byte instructions. Addressing word or half- word are not allowed. " I also recall seeing weird behavior when these registers were accessed by word access in U-Boot, so I believe the datasheet is correct. Best regards, Marek Vasut