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=-6.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 494F4C433E4 for ; Thu, 20 Aug 2020 21:06:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FB4920FC3 for ; Thu, 20 Aug 2020 21:06:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="eTm5DueW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728638AbgHTVGU (ORCPT ); Thu, 20 Aug 2020 17:06:20 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:21402 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726716AbgHTVGS (ORCPT ); Thu, 20 Aug 2020 17:06:18 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 07KL3F9P132149; Thu, 20 Aug 2020 17:06:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=+wFKt5gOp2qKwt78X+GCUmMn4fQpqMO/fSREOF3d7cI=; b=eTm5DueWgcdzE/MxP/QLZbDxQdAHm6yNArQ/Ahc3YFmHdwRCy89fP6fkDvuSdjRmTauH 8S9VIJG0EwtyXJ77raWjJ0WT/EKCvAidSdSt+M0Ro5KTq2uPi52tA2tyDAQmF4CM0s8J YE1PRJbYmA46O5MJL09QWAN8CXv0+6/7d/xMKkZiCiHHmWjSyc3XFtwdD1zIE0N0eDMd 6AAFY1KKZi5EVbUll5G3Il42/yCetNYECWmjFWfUMerANjRLc74bOOgjUXAgUd4N3zrf DBxRc/1Cipd3VeQsu58gXwOhm5cuZ3mWTpa7ewlx+60ayrMKe1bavQ2jW1tZAT8u7qjy zA== Received: from ppma05wdc.us.ibm.com (1b.90.2fa9.ip4.static.sl-reverse.com [169.47.144.27]) by mx0a-001b2d01.pphosted.com with ESMTP id 331w97wwch-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Aug 2020 17:06:10 -0400 Received: from pps.filterd (ppma05wdc.us.ibm.com [127.0.0.1]) by ppma05wdc.us.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 07KL4aZR010256; Thu, 20 Aug 2020 21:06:09 GMT Received: from b03cxnp08028.gho.boulder.ibm.com (b03cxnp08028.gho.boulder.ibm.com [9.17.130.20]) by ppma05wdc.us.ibm.com with ESMTP id 3304th737g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Aug 2020 21:06:09 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 07KL68sb61145526 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Aug 2020 21:06:08 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 612B7C6063; Thu, 20 Aug 2020 21:06:08 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 01ACCC605D; Thu, 20 Aug 2020 21:06:07 +0000 (GMT) Received: from [9.163.70.74] (unknown [9.163.70.74]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Thu, 20 Aug 2020 21:06:07 +0000 (GMT) Subject: Re: [PATCH 2/7] spi: fsi: Fix clock running too fast To: Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, joel@jms.id.au, bradleyb@fuzziesquirrel.com, robh+dt@kernel.org, arnd@arndb.de References: <20200820170228.42053-1-eajames@linux.ibm.com> <20200820170228.42053-3-eajames@linux.ibm.com> <20200820171257.GG5854@sirena.org.uk> From: Eddie James Message-ID: <660034d2-c808-3a4b-6ecc-be1769e8a017@linux.ibm.com> Date: Thu, 20 Aug 2020 16:06:07 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200820171257.GG5854@sirena.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-08-20_07:2020-08-19,2020-08-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 bulkscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 priorityscore=1501 spamscore=0 malwarescore=0 mlxlogscore=813 suspectscore=0 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008200170 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/20/20 12:12 PM, Mark Brown wrote: > On Thu, Aug 20, 2020 at 12:02:23PM -0500, Eddie James wrote: >> From: Brad Bishop >> >> Use a clock divider tuned to a 200MHz FSI clock. Use of the previous >> divider at 200MHz results in corrupt data from endpoint devices. Ideally >> the clock divider would be calculated from the FSI clock, but that >> would require some significant work on the FSI driver. > Presumably this divider was chosen for FSI clocks that aren't 200MHz - > how will those be handled? They aren't handled at the moment, but 200MHz FSI represents the worst case, as it's the maximum. Slower FSI clocks will simply result in slower SPI clocks. Thanks, Eddie