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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB16CC433EF for ; Thu, 9 Jun 2022 14:53:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245282AbiFIOxz (ORCPT ); Thu, 9 Jun 2022 10:53:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244857AbiFIOxx (ORCPT ); Thu, 9 Jun 2022 10:53:53 -0400 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0DA4B236869; Thu, 9 Jun 2022 07:53:50 -0700 (PDT) Received: (Authenticated sender: alexandre.belloni@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 1F844E000B; Thu, 9 Jun 2022 14:53:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1654786429; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=f976Phy9dbyp8PfTdJv/r4/TWKmZetB6K2N29VZ68bs=; b=oMlNSPZmrZnLNnhi2KkImi3VKLojeIwiLpBjpjbDiyOQVtdONpj0Q5u9R/z5x7F728VbNN bwU5IiAqaPTTUJ0l3WnliDh6Q5OcXZ1ABl+3ZAuvnA2gOJBtvvRpmmlD5QVmLhP9oOPHmw kE/E1kC4odTMFH1BEnozW2b3pdFcqyE9/C4QaSZC02auE6yyOF+XpIqapyZoE4YgkHBsEf 0SQOC2Bj3R22/Qgkp6MCXP94TUzzqzHzQqQRy8pOK/RHjowU6WuKvLJI309cRyaLvGnpb3 DXEiBOoH+9tNbmY7/uuJlhdPoeH8Y69+vbrOTJXCeh2PTwkhLs2Mx1XESKUPdw== Date: Thu, 9 Jun 2022 16:53:46 +0200 From: Alexandre Belloni To: Peter Korsgaard Cc: Srinivas Neeli , a.zummo@towertech.it, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, michal.simek@xilinx.com, sgoud@xilinx.com, shubhraj@xilinx.com, srinivas.neeli@amd.com, neelisrinivas18@gmail.com, devicetree@vger.kernel.org, linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, git@xilinx.com Subject: Re: [PATCH V6 2/2] rtc: zynqmp: Add calibration set and get support Message-ID: References: <20220609140833.1784738-1-srinivas.neeli@xilinx.com> <20220609140833.1784738-2-srinivas.neeli@xilinx.com> <87r13x28o4.fsf@dell.be.48ers.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87r13x28o4.fsf@dell.be.48ers.dk> Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org On 09/06/2022 16:50:03+0200, Peter Korsgaard wrote: > >>>>> "Srinivas" == Srinivas Neeli writes: > > > Zynqmp RTC controller has a calibration feature to compensate > > time deviation due to input clock inaccuracy. > > Set and get calibration API's are used for setting and getting > > calibration value from the controller calibration register. > > As per RTC spec default calibration value is 0x7FFF. > > Where do you see that? ug1085 rev2.2 still lists: > > Programming Sequences > init rtc > 1. Write the value 0019_8231h into the calibration register, CALIB_WRITE. > This is a very weird value. Last time I had a look, I couldn't find an explanation for it. -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com