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From: Kurt Van Dijck <kurt.van.dijck@eia.be>
To: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
	linux-can@vger.kernel.org, linux-kernel@vger.kernel.org,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Wolfgang Grandegger <wg@grandegger.com>
Subject: Re: [PATCH can-next v6] can: add tx/rx LED trigger support
Date: Sat, 25 Aug 2012 22:25:56 +0200	[thread overview]
Message-ID: <20120825202556.GC413@vandijck-laurijssen.be> (raw)
In-Reply-To: <20120824220142.GA1470@gmail.com>

On Sat, Aug 25, 2012 at 12:01:42AM +0200, Fabio Baltieri wrote:
> Hello Kurt,
> 
> On Fri, Aug 24, 2012 at 02:42:48PM +0200, Kurt Van Dijck wrote:
> > On Fri, Aug 24, 2012 at 01:28:16PM +0200, Marc Kleine-Budde wrote:
> > > On 08/24/2012 07:10 AM, Kurt Van Dijck wrote:
> > > > Hello,
> > > > 
> > > > I find the CAN led triggers an interesting thing.
> > > > 
> > > > And then, this scenario fell crossed my mind:
> > > > Imagine I do:
> > > > [insert CAN device: can0]
> > > > $ ip link set can0 name helga
> > > > [insert another CAN device: again 'can0']
> > > > 
> > > > Registering 'can0-tx' led trigger will fail for the second CAN device,
> > > > since that led trigger name is already reserved for CAN device 'helga'.
> > > Good point.
> 
> Yep, thanks for pointing that out!
> 
> Interface renaming was something I considered when I first wrote the
> code and I had the mac80211-led driver in mind, as that driver uses the
> phy name and not the netdev one for its triggers.
> 
> The reason why I did not care that much in the end is that on SoC based
> systems trigger-led association is made at probe time, based on data
> either from platform_data or devicetree, so I imagined that once the
> kernel is ported to the board and default triggers are set correctly at
> boot time, the userspace is free to rename CAN interfaces and nobody
> should notice... :^)
> 
> The thing I did not consider are hot-plug interfaces mixed with
> renaming, such as in the case you pointed out - it's probably not really
> common but still possible.
> 
> > > > I'm not sure how to fix such.
> > > > If 'rx' & 'tx' may be combined, reusing the netdev name may be possible?
> > > > Just wild thinking ...
> > > 
> > > I think the device's name (not netdev) is unique in the system and
> > > cannot be changed.
> >
> > but may contain several netdev's ...
> 
> Ouch.
> 
> > 
> > > 
> > > On my device tree enabled mx28 I'm talking about the "80032000.can" in:
> > 
> > You idea triggered another thougt: since control is put in device drivers,
> > why putting the name in the generic can_dev struct?
> 
> Why not?  That makes the API easy.

The code is not next to the data?
Anyway, I said the above because I think the led names need a per-device approach,
but the data is in common parts. That's where things start being complicated.
I understand the common part now because you mainly addressed the SoC based drivers.

> 
> > A more flexible approach to assign names is the key to success here.
> > The correct 'works in all conditions' approach is not yet in my sight :-(
> 
> Agreed.
> 
> What about using a combination of device name + an optional port index
> specified in devm_can_led_init()? (something like to platform_device names)
> Of course that would require changing the API for libraries like
> register_sja1000dev(), to add a port index.
> 
> Fabio
> --
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-- 
Kurt Van Dijck
GRAMMER EiA ELECTRONICS
http://www.eia.be
kurt.van.dijck@eia.be
+32-38708534

  reply	other threads:[~2012-08-25 20:26 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-30 19:20 [PATCH can-next v3 1/2] can: add tx/rx LED trigger support Fabio Baltieri
2012-07-30 19:20 ` [PATCH can-next v3 2/2] can: flexcan: add " Fabio Baltieri
2012-07-30 21:17 ` [PATCH can-next v3 1/2] can: add tx/rx " Marc Kleine-Budde
2012-07-31  6:57   ` Fabio Baltieri
2012-07-31  7:10     ` Marc Kleine-Budde
2012-07-31 11:57       ` Fabio Baltieri
2012-07-31 12:00         ` Marc Kleine-Budde
2012-07-31 22:05           ` [PATCH can-next v4] " Fabio Baltieri
2012-08-01  9:36             ` Marc Kleine-Budde
2012-08-01 10:07               ` Marc Kleine-Budde
2012-08-01 10:30               ` Fabio Baltieri
2012-08-01 11:37                 ` Marc Kleine-Budde
2012-08-01 11:49               ` [PATCH can-next v5 1/2] " Fabio Baltieri
2012-08-01 11:49                 ` [PATCH can-next v5 2/2] can: flexcan: add " Fabio Baltieri
2012-08-01 11:53                   ` Marc Kleine-Budde
2012-08-01 12:24                     ` Fabio Baltieri
2012-08-01 12:30                       ` Marc Kleine-Budde
2012-08-01 21:02                   ` Marc Kleine-Budde
2012-08-01 11:59                 ` [PATCH can-next v5 1/2] can: add tx/rx " Marc Kleine-Budde
2012-08-01 12:06                 ` Oliver Hartkopp
2012-08-01 12:18                   ` Marc Kleine-Budde
2012-08-01 18:21                     ` [PATCH can-next v6] " Fabio Baltieri
2012-08-01 21:00                       ` Marc Kleine-Budde
2012-08-01 22:38                         ` Fabio Baltieri
2012-08-01 21:05                       ` Oliver Hartkopp
2012-08-24  5:10                       ` Kurt Van Dijck
2012-08-24 11:28                         ` Marc Kleine-Budde
2012-08-24 12:42                           ` Kurt Van Dijck
2012-08-24 22:01                             ` Fabio Baltieri
2012-08-25 20:25                               ` Kurt Van Dijck [this message]
2012-09-03 12:40                               ` Marc Kleine-Budde
2012-09-03 18:13                                 ` Kurt Van Dijck
2012-09-03 18:29                                   ` Fabio Baltieri
2012-09-03 20:54                                     ` Oliver Hartkopp
2012-09-04  7:11                                       ` Kurt Van Dijck
2012-09-04  9:29                                         ` [PATCH] can: rename LED trigger name on netdev renames Kurt Van Dijck
2012-09-06 18:59                                           ` Fabio Baltieri
2012-09-06 19:31                                             ` Oliver Hartkopp
2012-09-06 20:46                                               ` Fabio Baltieri
2012-09-07  7:19                                                 ` Kurt Van Dijck
2012-09-09 16:17                                                   ` [PATCH v2] " Fabio Baltieri
2012-09-10 14:25                                                     ` [PATCH] can: export a safe netdev_priv wrapper for candev Kurt Van Dijck
2012-09-10 18:22                                                       ` Oliver Hartkopp
2012-09-10 18:29                                                       ` Fabio Baltieri
2012-09-10 19:55                                                         ` [PATCH v2] " Kurt Van Dijck
2012-09-10 14:28                                                     ` [PATCH v3] can: rename LED trigger name on netdev renames Kurt Van Dijck
2012-09-10 18:25                                                       ` Oliver Hartkopp
2012-09-10 18:40                                                         ` Fabio Baltieri
2012-09-10 19:01                                                           ` Oliver Hartkopp
2012-09-10 20:08                                                             ` Kurt Van Dijck
2012-09-11  5:42                                                               ` Oliver Hartkopp
2012-09-11  7:13                                                                 ` Fabio Baltieri
2012-09-12  7:22                                                                   ` Kurt Van Dijck
2012-09-11  8:05                                                               ` Kurt Van Dijck
2012-09-10 20:06                                                           ` [PATCH v4] " Kurt Van Dijck
2012-09-11 21:04                                                             ` Fabio Baltieri
2012-09-04 20:15                                         ` [PATCH can-next v6] can: add tx/rx LED trigger support Fabio Baltieri
2012-09-06 10:33                                           ` Kurt Van Dijck
2012-09-06 11:17                                             ` Fabio Baltieri
2012-09-06 15:11                                               ` Kurt Van Dijck
2012-09-06 20:57                                                 ` Fabio Baltieri
2012-09-07  7:04                                                   ` Kurt Van Dijck
2012-09-07 18:59                                                     ` Fabio Baltieri
2012-07-31  8:46 ` [PATCH can-next v3 1/2] " Wolfgang Grandegger
2012-07-31 10:12   ` Marc Kleine-Budde
2012-07-31 11:55     ` Fabio Baltieri
2012-07-31 12:14   ` Fabio Baltieri

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