From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752280AbeA3OPY (ORCPT ); Tue, 30 Jan 2018 09:15:24 -0500 Received: from mail-pf0-f193.google.com ([209.85.192.193]:43381 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751711AbeA3OPW (ORCPT ); Tue, 30 Jan 2018 09:15:22 -0500 X-Google-Smtp-Source: AH8x226EyPscqNbcl64gq1iwUWV3l9C9yYYDY9RX1uh4riftWXeok4RURPiXGdzxNtkdCoI3xSvuzQ== Subject: Re: [PATCH 4/4] rtc: isl1208: add support for isl1219 with hwmon for tamper detection To: Denis OSTERLAND , "alexandre.belloni@free-electrons.com" Cc: "linux-rtc@vger.kernel.org" , "a.zummo@towertech.it" , "kernel@pengutronix.de" , "mgr@pengutronix.de" , "jdelvare@suse.com" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20180123121801.4214-1-m.grzeschik@pengutronix.de> <20180123121801.4214-5-m.grzeschik@pengutronix.de> <20180123182254.GA27379@roeck-us.net> <20180124090333.r5o2mzpm4q536w4r@pengutronix.de> <20180129215919.GA17988@roeck-us.net> <20180130102740.GD2809@piout.net> <1517312409.5307.22.camel@diehl.com> From: Guenter Roeck Message-ID: Date: Tue, 30 Jan 2018 06:15:18 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <1517312409.5307.22.camel@diehl.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/30/2018 03:40 AM, Denis OSTERLAND wrote: > Am Dienstag, den 30.01.2018, 11:27 +0100 schrieb Alexandre Belloni: >> On 29/01/2018 at 13:59:19 -0800, Guenter Roeck wrote: >>> >>> On Wed, Jan 24, 2018 at 10:03:33AM +0100, Michael Grzeschik wrote: >>> [ ... ] >>>> >>>>> >>>>>> >>>>>> + >>>>>> diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface >>>>>> index fc337c317c673..a12b3c2b2a18c 100644 >>>>>> --- a/Documentation/hwmon/sysfs-interface >>>>>> +++ b/Documentation/hwmon/sysfs-interface >>>>>> @@ -702,6 +702,13 @@ intrusion[0-*]_alarm >>>>>>   the user. This is done by writing 0 to the file. Writing >>>>>>   other values is unsupported. >>>>>> >>>>>> +intrusion[0-*]_timestamp >>>>>> + Chassis intrusion detection >>>>>> + YYYY-MM-DD HH:MM:SS UTC (ts.sec): intrusion detected >>>>>> + RO >>>>>> + The corresponding timestamp on which the intrustion >>>>>> + was detected. >>>>>> + >>>>> Sneaky. Nack. You don't just add attributes to the ABI because you want it, >>>>> without serious discussion, and much less so hidden in an RTC driver >>>>> (and even less as unparseable attribute). >>>> Right; but it was not meant to be sneaky. I should have stick to my first >>>> thought and label this patch RFC. Sorry for that. >>>> >>>>> >>>>> In addition to that, I consider the attribute unnecessary. The intrusion >>>>> already generates an event which should be sufficient for all practical >>>>> purposes. >>>> Would it make sense in between the other sysfs attributes of this driver? >>>> >>> I don't understand what you mean with that, sorry. >>> >>> From an ABI perspective, the attibute doesn't add value since it is >>> highly device specific (or at least it is the only chip I am aware of >>> which reports such a time stamp). Feel free to add the attribute to the >>> driver and document it, but not as part of the hwmon ABI. In that >>> case I would be inclined to accept it. However, keep in mind that >>> your version, reporting a human readable date/time, would effectively >>> preclude it from ever making it into the ABI. >>> >> Actually, there are many RTCs that are able to register one or more >> timestamps. My plan was to add support for that soon but I was not >> planning to do so in the hwmon ABI as this may be used for something >> that is not intrusion detection (interval timers for example). > What would you suggest? > I think about something like this: > event[0-*]_timestamp: timestamp in seconds since epoch or empty if not triggered > event[0-*]_alarm: 1 if event was triggered, else 0; write 0 to clear event Sure, that makes sense if the events are not specifically related to intrusion detection. Question is if there would ever be more than one or if event_timestamp and event_alarm would be sufficient. Guenter