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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 93D9CC3A5A5 for ; Mon, 26 Aug 2019 09:17:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7159922D6D for ; Mon, 26 Aug 2019 09:17:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730712AbfHZJRW (ORCPT ); Mon, 26 Aug 2019 05:17:22 -0400 Received: from hel-mailgw-01.vaisala.com ([193.143.230.17]:7153 "EHLO hel-mailgw-01.vaisala.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726401AbfHZJRW (ORCPT ); Mon, 26 Aug 2019 05:17:22 -0400 IronPort-SDR: keSo3pUeqXFCZW8fIW6SNCibYA8NYiuCD4DNXcAC9RPWbr/LnrjqNVazqQfoPQOKISrd4Hx98N 3OaKAlT+yDBivYslmu6IQ8Ijq2S0yq8DhqOX2KJ7MSpkN9k6JlrkzIe1MskxWU2l8ABxDJsS/v MRSxIIEyCSfh6KOB9AgVEcPon4oL1EYw3voA0SzColcqlXyGWqlBwWwVmn8qezVu9Z2t3ZdW2j SCZq+bmCVZL3Ly9lltMuqTQI31psRkRWha1Mk5xQLUYUIbeqZiho3AACW8bIQtzPKpUknf9Osx FUY= X-IronPort-AV: E=Sophos;i="5.64,431,1559509200"; d="scan'208";a="229615643" Subject: Re: [EXT] Re: [v2] rtc: pcf85363/pcf85263: fix error that failed to run hwclock -w To: Biwen Li , Leo Li , Alexandre Belloni , Mark Brown Cc: "a.zummo@towertech.it" , "linux-rtc@vger.kernel.org" , lkml References: <20190816024636.34738-1-biwen.li@nxp.com> <20190816080417.GB3545@piout.net> <20190816162825.GE3545@piout.net> From: Nandor Han Message-ID: <21f417e3-db50-5930-ddc9-eed54f5d5893@vaisala.com> Date: Mon, 26 Aug 2019 12:17:11 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 26 Aug 2019 09:17:16.0573 (UTC) FILETIME=[0DE524D0:01D55BEF] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/26/19 7:29 AM, Biwen Li wrote: >> >> On 8/16/19 10:40 PM, Li Yang wrote: >>> On Fri, Aug 16, 2019 at 11:30 AM Alexandre Belloni >>> wrote: >>>> >>>> On 16/08/2019 10:50:49-0500, Li Yang wrote: >>>>> On Fri, Aug 16, 2019 at 3:05 AM Alexandre Belloni >>>>> wrote: >>>>>> >>>>>> On 16/08/2019 10:46:36+0800, Biwen Li wrote: >>>>>>> Issue: >>>>>>> - # hwclock -w >>>>>>> hwclock: RTC_SET_TIME: Invalid argument >>>>>>> >>>>>>> Why: >>>>>>> - Relative patch: >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.org >> %2Flkml%2F2019%2F4%2F3%2F55&data=02%7C01%7Cbiwen.li%40nxp. >> com%7Cff8cebc3f1034ae3fa9608d725ff9e5e%7C686ea1d3bc2b4c6fa92cd99 >> c5c301635%7C0%7C0%7C637019652111923736&sdata=spY6e22YOkOF >> 3%2BF7crSM0M6xPmOhgULDqMZLQw%2BAmdI%3D&reserved=0 , this >> patch >>>>>>> will always check for unwritable registers, it will compare reg >>>>>>> with max_register in regmap_writeable. >>>>>>> >>>>>>> - In drivers/rtc/rtc-pcf85363.c, CTRL_STOP_EN is 0x2e, but >> DT_100THS >>>>>>> is 0, max_regiter is 0x2f, then reg will be equal to 0x30, >>>>>>> '0x30 < 0x2f' is false,so regmap_writeable will return false. >>>>>>> >>>>>>> - Root cause: the buf[] was written to a wrong place in the file >>>>>>> drivers/rtc/rtc-pcf85363.c >>>>>>> >>>>>> >>>>>> This is not true, the RTC wraps the register accesses properly and >>>>>> this >>>>> >>>>> This performance hack probably deserve some explanation in the code >>>>> comment. :) >>>>> >>>>>> is probably something that should be handled by regmap_writable. >>>>> >>>>> The address wrapping is specific to this RTC chip. Is it also >>>>> commonly used by other I2C devices? I'm not sure if regmap_writable >>>>> should handle the wrapping case if it is too special. >>>>> >>>> >>>> Most of the i2c RTCs do address wrapping which is sometimes the only >>>> way to properly set the time. >>> >>> Adding Mark and Nandor to the loop. >>> >>> Regards, >>> Leo >>> >> >> Hi, >> `regmap` provides couple of ways to validate the registers: >> max_register, callback function and write table. All of these are optional, so it >> gives you the freedom to customize it as needed. >> >> In this situation probably you could: >> 1. Avoid using the wrapping feature of pcf85363 (you can just provide >> separate calls for stop, reset and time confguration). In this way the >> `max_register` validation method will work fine. > Yes, I use this way. Path as follows: > Stop and reset - > set time > stop > Some of the concerns regarding this method was that it might not be precise enough. That because you need 2 I2C operations (one for stop and one for time configuration). Not sure about your case if this is a problem or not. >> 2. Replace `max_register` method validation with `callback function` >> validation method, were you could make your own validation. > It is not work, show the code in as follows: > > bool regmap_writeable(struct regmap *map, unsigned int reg) > { > if (map->max_register && reg > map->max_register) > return false; > Callback function (writeable_reg) will not be called. > if (map->writeable_reg) > return map->writeable_reg(map->dev, reg); Hi Li, If you *replace* the `max_register` method with `callback function` it should work. The code above will use every method *if provided*. In other words if `map->max_register` is 0 will go to the next step and check `map->writeable_reg`. Right? Regards, Nandor