From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: [PATCH 4/4] rtc: isl1208: add support for isl1219 with hwmon for tamper detection Date: Tue, 30 Jan 2018 11:27:40 +0100 Message-ID: <20180130102740.GD2809@piout.net> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180129215919.GA17988@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org To: Guenter Roeck Cc: Michael Grzeschik , a.zummo@towertech.it, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jdelvare@suse.com, kernel@pengutronix.de, Denis.Osterland@diehl.com List-Id: devicetree@vger.kernel.org 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). -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com