Re: [PATCH 4/4] rtc: isl1208: add support for isl1219 with hwmon for tamper detection

[Denis OSTERLAND <denis.osterland@diehl.com>]

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
> 
> 
Diehl AKO Stiftung & Co. KG, Pfannerstraße 75-83, 88239 Wangen im Allgäu
Bereichsvorstand: Dr.-Ing. Michael Siedentop (Sprecher), Josef Fellner (Mitglied)
Sitz der Gesellschaft: Wangen i.A. – Registergericht: Amtsgericht Ulm HRA 620609 – Persönlich haftende Gesellschafterin: Diehl Verwaltungs-Stiftung – Sitz: Nürnberg – Registergericht: Amtsgericht Nürnberg HRA 11756 –
Vorstand: Dr.-Ing. E.h. Thomas Diehl (†) (Vorsitzender), Herr Dipl.-Wirtsch.-Ing. Wolfgang Weggen (stellvertretender Vorsitzender), Dipl.-Kfm. Claus Günther, Dipl.-Kfm. Frank Gutzeit, Dr.-Ing. Heinrich Schunk, Dr.-Ing. Michael Siedentop , Dipl.-Kfm. Dr.-Ing. Martin Sommer, Dipl.-Ing. (FH) Rainer von Borstel, Vorsitzender des Aufsichtsrates: Dr. Klaus Maier
___________________________________________________________________________________________________
Der Inhalt der vorstehenden E-Mail ist nicht rechtlich bindend. Diese E-Mail enthaelt vertrauliche und/oder rechtlich geschuetzte Informationen.
Informieren Sie uns bitte, wenn Sie diese E-Mail faelschlicherweise erhalten haben. Bitte loeschen Sie in diesem Fall die Nachricht. Jede unerlaubte Form der Reproduktion, Bekanntgabe, Aenderung, Verteilung und/oder Publikation dieser E-Mail ist strengstens untersagt.
The contents of the above mentioned e-mail is not legally binding. This e-mail contains confidential and/or legally protected information. Please inform us if you have received this e-mail by mistake and delete it in such a case. Each unauthorized reproduction, disclosure, alteration, distribution and/or publication of this e-mail is strictly prohibited.