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 7DED5C433EF for ; Thu, 12 May 2022 19:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357928AbiELTLf (ORCPT ); Thu, 12 May 2022 15:11:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357922AbiELTLb (ORCPT ); Thu, 12 May 2022 15:11:31 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCFA83E0C8; Thu, 12 May 2022 12:11:30 -0700 (PDT) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24CIRWY9013204; Thu, 12 May 2022 19:11:09 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=erGBUJ07wNUJV+sPUuGngCGtTCXo+k3qkrV4vWOiECc=; b=NtTZRFqZFca0PWldtWwrZnnw6PSKA6IeSJWa5WxaOL29cn+bfUtYAWlPNhb187G9rzkw Y1twkCN3GyuH/qcxWx4MZfZsbruRaW5smW/+pJ/iIRfjevjhIMMC5lmsacw05HQVlPSH LiVuR0KlcroJg5R0dRjTKrn0AljJYOWUjaBIK0XOTFN1aTMy0lUHHR0Iaf85r/PnIrWH R6WZFN+y8Ubxm4hVXT2/Fg45s7kEkwR+JzUPm+A7kNg/hYFqk/nJTYEdp0cH++C2t0Ze ruuvdKioG75HVKv1AK19Nvm/apP0cNHEb5Nhmdn50TDpYlSRcAQNG8Y7ePc/nIc0Oq+m 9g== Received: from ppma01dal.us.ibm.com (83.d6.3fa9.ip4.static.sl-reverse.com [169.63.214.131]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3g173b9f2a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 12 May 2022 19:11:09 +0000 Received: from pps.filterd (ppma01dal.us.ibm.com [127.0.0.1]) by ppma01dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 24CIvDkX019581; Thu, 12 May 2022 19:11:08 GMT Received: from b01cxnp23034.gho.pok.ibm.com (b01cxnp23034.gho.pok.ibm.com [9.57.198.29]) by ppma01dal.us.ibm.com with ESMTP id 3fwgdb6jqv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 12 May 2022 19:11:08 +0000 Received: from b01ledav001.gho.pok.ibm.com (b01ledav001.gho.pok.ibm.com [9.57.199.106]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 24CJB7wr23920930 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 May 2022 19:11:07 GMT Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9BD8E2805E; Thu, 12 May 2022 19:11:07 +0000 (GMT) Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C72CF28059; Thu, 12 May 2022 19:11:06 +0000 (GMT) Received: from [9.211.56.168] (unknown [9.211.56.168]) by b01ledav001.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 12 May 2022 19:11:06 +0000 (GMT) Message-ID: Date: Thu, 12 May 2022 14:11:06 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v2 0/2] iio: humidity: si7020: Check device property for skipping reset in probe Content-Language: en-US To: Jonathan Cameron Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org, lars@metafoo.de, jic23@kernel.org, miltonm@us.ibm.com References: <20220512162020.33450-1-eajames@linux.ibm.com> <20220512174859.000042b6@Huawei.com> From: Eddie James In-Reply-To: <20220512174859.000042b6@Huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: h0MVSw3yJcPGbeM8LBRXqFnnQ43eC3Tx X-Proofpoint-GUID: h0MVSw3yJcPGbeM8LBRXqFnnQ43eC3Tx X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-12_16,2022-05-12_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 mlxlogscore=999 priorityscore=1501 clxscore=1015 impostorscore=0 spamscore=0 bulkscore=0 suspectscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205120083 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/12/22 11:48, Jonathan Cameron wrote: > On Thu, 12 May 2022 11:20:18 -0500 > Eddie James wrote: > >> I2C commands issued after the SI7020 is starting up or after reset >> can potentially upset the startup sequence. Therefore, the host >> needs to wait for the startup sequence to finish before issuing >> further i2c commands. This is impractical in cases where the SI7020 >> is on a shared bus or behind a mux, which may switch channels at >> any time (generating I2C traffic). Therefore, check for a device >> property that indicates that the driver should skip resetting the >> device when probing. > Why not lock the bus? It's not ideal, but then not resetting and hence > potentially ending up in an unknown state isn't great either. Also, I should mention that in our case we can rely on the power on reset, so the device should be in a known state. Eddie > > Jonathan > >> Changes since v1: >> - Fix dt binding document >> >> Eddie James (2): >> dt-bindings: iio: humidity: Add si7020 bindings >> iio: humidity: si7020: Check device property for skipping reset in probe >> >> .../bindings/iio/humidity/silabs,si7020.yaml | 47 +++++++++++++++++++ >> .../devicetree/bindings/trivial-devices.yaml | 2 - >> drivers/iio/humidity/si7020.c | 14 +++--- >> 3 files changed, 55 insertions(+), 8 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/iio/humidity/silabs,si7020.yaml >>