From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=uxIs=K4=lists.ozlabs.org=openbmc-bounces+openbmc=archiver.kernel.org@kernel.org>
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=-5.9 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,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 0D32AC4708F
	for <openbmc@archiver.kernel.org>; Wed,  2 Jun 2021 16:14:34 +0000 (UTC)
Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by mail.kernel.org (Postfix) with ESMTPS id 5AD956192E
	for <openbmc@archiver.kernel.org>; Wed,  2 Jun 2021 16:14:33 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5AD956192E
Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com
Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=openbmc-bounces+openbmc=archiver.kernel.org@lists.ozlabs.org
Received: from boromir.ozlabs.org (localhost [IPv6:::1])
	by lists.ozlabs.org (Postfix) with ESMTP id 4FwDcm3NYPz3049
	for <openbmc@archiver.kernel.org>; Thu,  3 Jun 2021 02:14:32 +1000 (AEST)
Authentication-Results: lists.ozlabs.org;
	dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=BH/dIcHR;
	dkim-atps=neutral
Authentication-Results: lists.ozlabs.org; spf=none (no SPF record)
 smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.156.1;
 helo=mx0a-001b2d01.pphosted.com;
 envelope-from=bruce.mitchell@linux.vnet.ibm.com; receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
 unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256
 header.s=pp1 header.b=BH/dIcHR; dkim-atps=neutral
Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com
 [148.163.156.1])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 4FwDcF4ZC2z2xb7
 for <openbmc@lists.ozlabs.org>; Thu,  3 Jun 2021 02:14:04 +1000 (AEST)
Received: from pps.filterd (m0098394.ppops.net [127.0.0.1])
 by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id
 152G4Apx139775; Wed, 2 Jun 2021 12:14:01 -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=coVFPW5yd5cQYHHWRtIqrzvLxhQNlVOFvbsZJX/szkw=;
 b=BH/dIcHRv9dg11WdDVK1pDD8JrbQgvM3KrQ+2xr/aydy0GbA64cEmfbQjwL+YE7J/idP
 QssNF1fGP+cTVv0NlsGiEYTzBQ3FoBmAsCjjb2M5r0Rsjqoia14wxqOHjdSy/8FHdKxD
 +OH/c521chKg64zjDGBTaW8n9F7eQ+rGws5+wmzmC90AWEJflBiUc21irxLU7yGE0vRo
 2ZC8jy4Q+2dd2omyM8VssaFtyZxzYHBIDphLlVF3tO1mQEgrvIH3mVIXfpU9od8V/1/+
 IdeMYwsPo3hd7QKlJIBTMJlQHoJgC7tmylOW/Oxw+vIp53JACzTBtdNWpZuQgBO1LfIw mQ== 
Received: from pps.reinject (localhost [127.0.0.1])
 by mx0a-001b2d01.pphosted.com with ESMTP id 38xb3u4mkc-1
 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT);
 Wed, 02 Jun 2021 12:14:01 -0400
Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1])
 by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 152G5VOT145008;
 Wed, 2 Jun 2021 12:14:01 -0400
Received: from ppma04wdc.us.ibm.com (1a.90.2fa9.ip4.static.sl-reverse.com
 [169.47.144.26])
 by mx0a-001b2d01.pphosted.com with ESMTP id 38xb3u4mjw-1
 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT);
 Wed, 02 Jun 2021 12:14:01 -0400
Received: from pps.filterd (ppma04wdc.us.ibm.com [127.0.0.1])
 by ppma04wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 152GDd9Y003415;
 Wed, 2 Jun 2021 16:13:59 GMT
Received: from b01cxnp23032.gho.pok.ibm.com (b01cxnp23032.gho.pok.ibm.com
 [9.57.198.27]) by ppma04wdc.us.ibm.com with ESMTP id 38ud89rv76-1
 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT);
 Wed, 02 Jun 2021 16:13:59 +0000
Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com
 [9.57.199.111])
 by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id
 152GDxLt26149328
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK);
 Wed, 2 Jun 2021 16:13:59 GMT
Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1])
 by IMSVA (Postfix) with ESMTP id 1A448AC066;
 Wed,  2 Jun 2021 16:13:59 +0000 (GMT)
Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1])
 by IMSVA (Postfix) with ESMTP id A927FAC05F;
 Wed,  2 Jun 2021 16:13:58 +0000 (GMT)
Received: from [9.211.138.111] (unknown [9.211.138.111])
 by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP;
 Wed,  2 Jun 2021 16:13:58 +0000 (GMT)
Subject: Re: Seeking your opinion on ways to report both Altitude and Pressure
 sensors for the DPS310 as well as Temperature from dbus-sensors.
To: Ed Tanous <edtanous@google.com>
References: <2e3016fe-2827-891b-07e3-0437a6038514@linux.vnet.ibm.com>
 <CAH2-KxA1VyhoUznEr-W5M83ZpVSqdx2c1oR3E1XdeU9fhTHN4Q@mail.gmail.com>
 <1bdf8842-2b53-0d51-40b6-6bf64f2bf315@linux.vnet.ibm.com>
 <CAH2-KxAjjefRFfirz0Gn9DTn-dCfqw_7ed2obk43wxevym3xPA@mail.gmail.com>
From: Bruce Mitchell <bruce.mitchell@linux.vnet.ibm.com>
Message-ID: <4746ede6-dea9-32c5-10e3-2fd6773e2033@linux.vnet.ibm.com>
Date: Wed, 2 Jun 2021 09:13:57 -0700
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.2
MIME-Version: 1.0
In-Reply-To: <CAH2-KxAjjefRFfirz0Gn9DTn-dCfqw_7ed2obk43wxevym3xPA@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
X-TM-AS-GCONF: 00
X-Proofpoint-GUID: 4yJo-55naRfsxTfNUS7GM16LDWOyc_UX
X-Proofpoint-ORIG-GUID: Puln8Xw1OCCKxpIW-t3aCibn44Evdn6m
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391, 18.0.761
 definitions=2021-06-02_08:2021-06-02,
 2021-06-02 signatures=0
X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0
 mlxscore=0 impostorscore=0
 clxscore=1015 adultscore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0
 phishscore=0 priorityscore=1501 mlxlogscore=999 malwarescore=0 spamscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000
 definitions=main-2106020101
X-BeenThere: openbmc@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Development list for OpenBMC <openbmc.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/openbmc>,
 <mailto:openbmc-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/openbmc/>
List-Post: <mailto:openbmc@lists.ozlabs.org>
List-Help: <mailto:openbmc-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/openbmc>,
 <mailto:openbmc-request@lists.ozlabs.org?subject=subscribe>
Cc: "openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>,
 Ed Tanous <ed@tanous.net>
Errors-To: openbmc-bounces+openbmc=archiver.kernel.org@lists.ozlabs.org
Sender: "openbmc"
 <openbmc-bounces+openbmc=archiver.kernel.org@lists.ozlabs.org>

On 6/2/2021 09:03, Ed Tanous wrote:
> On Wed, Jun 2, 2021 at 8:58 AM Bruce Mitchell
> <bruce.mitchell@linux.vnet.ibm.com> wrote:
>>
>> On 6/2/2021 08:39, Ed Tanous wrote:
>>> On Tue, Jun 1, 2021 at 8:43 AM Bruce Mitchell
>>> <bruce.mitchell@linux.vnet.ibm.com> wrote:
>>>>
>>>> Hello Ed,
>>>>
>>>> It has been suggest I seeking your opinion on ways to report both
>>>> Altitude and Pressure sensors for the DPS310 as well as Temperature from
>>>> dbus-sensors before going to far down the road.  Thus that is what I am
>>>> attempting to do in the email, others on the mailing list input is
>>>> desirable as well.
>>>
>>> Thanks for discussing this before getting too far along.  I haven't
>>> worked on any systems with physical pressure sensors, but I'm excited
>>> to see new things get added.
>>>
>>>>
>>>> As I see it, Altitude and Pressure are different in that
>>>>        1) Altitude is computed base off of essentially a policy
>>>
>>> I have no idea what this means.....   In what way is altitude a
>>> "policy"?  Can you elaborate a little?
>>>
>>
>> I view a mechanism is something like update a FLASH part with
>> an image provided.
>>
>> I view a policy is what decides if the the update of the FLASH part
>> with the specific image is allowed.
>>
>> I the case if Pressure and Temperature I view them as mechanism,
>> merely a simple reading and possibly some well defined computations
>> that are universal.
>>
>> With Altitude computed from Pressure there are several ways to
>> compute the Altitude and they are not universal.  So I see it as
>> a policy of which Pressure to Altitude model is chosen and why.
> 
> Sounds like I interpreted your intention correctly. (I think).

I believe you did.

> 
>>
>>>>        2) Pressures is a read measurement which is a mechanism
>>>>        3) Temperature is a read measurement which is also a mechanism
>>>
>>> I'm really struggling with the above to understand what you're getting
>>> after, so if I go down the wrong path, please forgive me.
>>>
>>> I think what you're saying is that altitude is calculated based on
>>> pressure + some transfer function to determine an altitude?  And that
>>> transfer function might be fungible depending on the platform?
>>>
>>> If I got the above right (big if) I would probably expect a new
>>> pressure sensor type to be added that reports a pressure sensor, then
>>> we'd put the transform code in something that looks a lot like CFM
>>> sensor (which oddly enough has a hardcoded 0 for altitude in its
>>> algorithm for systems without pressure sensors).  Considering how
>>> related a pressure sensor is to altitude, I could see putting them in
>>> the same application if you wanted;  It might simplify the code some.
>>>
>>>
>>> I think overall a better picture of what you're wanting to accomplish
>>> would be a good place to start, then we can iterate from there on what
>>> pieces we need that are new.
>>
>> I have Temperature, Pressure, possibly Humidity sensors all which are
>> variables to different models to compute Altitude from.  I do not have a
>> true Altitude sensor.
> 
> This sounds exactly like the CFM sensor, and Exit air temp sensor;
> Most systems don't have exit air temp sensors, but they have input
> power and individual fan speeds, which can be put into models to
> determine CFM and ultimately exit air temperature.  I would expect
> Altitude to do something very similar in code (although with a
> completely different algorithm).
> 

So the DPS310 has 2 sensors in it a Pressure and a Temperature sensor.
Do I create a Pressure reading and a Temperature reading for the DPS310
and then add Altitude to it as well?

Or do I create 3 separate things,  one for each Pressure, Temperature,
and Altitude?

Also I believe I should be looking to the CFM sensor and Exit air 
temperature sensor as reference examples.

>>
>> I am being asked to provide Altitude.
>>
>> Personally I believe the desired feature is how much cooling a parcel of
>> air per unit of time.  Thus I would think air Temperature, Humidity, and
>> Density (probably compute-able from Pressure, but I have not checked on
>> the specifics) would be the important factors.