From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH 06/14] net: dsa: Add support for hardware monitoring Date: Fri, 24 Oct 2014 09:19:19 -0700 Message-ID: <20141024161919.GA29600@roeck-us.net> References: <1414037002-25528-7-git-send-email-linux@roeck-us.net> <54488CE1.2000106@roeck-us.net> <20141023134706.GB25190@lunn.ch> <20141023162754.GA21343@roeck-us.net> <20141023165459.GE25190@lunn.ch> <20141023173847.GA22988@roeck-us.net> <20141023180357.GG25190@lunn.ch> <20141023184322.GA24281@roeck-us.net> <20141023195526.GH25190@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Florian Fainelli , netdev , "David S. Miller" , "linux-kernel@vger.kernel.org" To: Andrew Lunn Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:48739 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247AbaJXQTb (ORCPT ); Fri, 24 Oct 2014 12:19:31 -0400 Received: from mailnull by bh-25.webhostbox.net with sa-checked (Exim 4.82) (envelope-from ) id 1XhhaM-002iRD-Hc for netdev@vger.kernel.org; Fri, 24 Oct 2014 16:19:30 +0000 Content-Disposition: inline In-Reply-To: <20141023195526.GH25190@lunn.ch> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Oct 23, 2014 at 09:55:26PM +0200, Andrew Lunn wrote: > On Thu, Oct 23, 2014 at 11:43:22AM -0700, Guenter Roeck wrote: > > On Thu, Oct 23, 2014 at 08:03:57PM +0200, Andrew Lunn wrote: > > > > No, I am not saying that. The hwmon device's parent device will= tell, > > > > which is how it works for all other hwmon devices. > > >=20 > > > O.K, so parent is important. > > >=20 > > > > Not really. Again, the parent device provides that information.= libsensors, > > > > which is the preferred way of accessing sensors information fro= m user space, > > > > provides the parent device instance as part of the logical sens= or device > > > > name. In this case, the names will end up being dsa-isa-0000, d= sa-isa-0001, > > > > and so on. With your added tags it would be dsa.0.0-isa-0000, d= sa.0.1-isa-0001, > > > > and so on. I don't see how this would add any value. > > >=20 > > > isa is the name of the ethernet device? Why is it not eth0? Most > >=20 > > isa is just an internal name made up by libsensors, and pretty much= just > > indicates something like "neither i2c nor spi". It is mostly histor= ic, > > but nowadays almost part of the ABI. It is made up by user space, > > based on the parent device type, not by the kernel. >=20 > So for DSA, since it is not i2c or spi, the parent is actually > irrelevant, because libsensor ignores it and says "IsSomethingAlien". > So the name alone needs to identify it. >=20 > > You have convinced me that 'dsa' as hwmon attribute name is insuff= icient, > > so let's see what we have. > >=20 > > - the parent network device in dst->master_netdev > > - the dsa device in 'parent' > > - the host device in host_dev > > - the switch index in 'index' > >=20 > > First question is what should be the parent device. >=20 > Does it even matter, given the observation above? I would probably g= o > for dsa, since as you said, the Ethernet device may have a temperatur= e > sensor of its own. DSA is a virtual device... >=20 > > Second is what to choose for the hwmon device 'name' attribute. > > 'dsa' is not sufficient, but what to choose instead ? dsa.X or dsa_= X, > > where X is the switch index ? At this point I am open to suggestion= s. > > Note that we can not use the name returned from the switch probe > > functions as it may contain spaces and other invalid characters. > > Including the ethernet device name (eg as in eth0_dsa_0) may also b= e > > problematic if it can contain '-', which is illegal for hwmon devic= es. >=20 > Does hwmon offer a function to sanitise a string? >=20 > The switch index definitely should be used and i would probably > combine that with a sanitised version of the ethernet device name and > "dsa". >=20 Here is another naming option: em1dsa0-virtual-0 Adapter: Virtual device temp1: +52.0=B0C (high =3D +100.0=B0C) I think I'll go with that one. I get it by not specifying a parent device when registering with the hwmon subsystem. It is kind of similar to the thermal sensor data reported through acpi. acpitz-virtual-0 Adapter: Virtual device temp1: +52.0=B0C (crit =3D +111.0=B0C) temp2: +52.0=B0C (crit =3D +111.0=B0C) Guenter