Re: [PATCH can-next v6] can: add tx/rx LED trigger support
From: Fabio Baltieri <hidden>
Date: 2012-09-04 20:15:07
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On Tue, Sep 04, 2012 at 09:11:28AM +0200, Kurt Van Dijck wrote:
On Mon, Sep 03, 2012 at 10:54:49PM +0200, Oliver Hartkopp wrote:quoted
On 03.09.2012 20:29, Fabio Baltieri wrote:quoted
On Mon, Sep 03, 2012 at 08:13:35PM +0200, Kurt Van Dijck wrote:quoted
On Mon, Sep 03, 2012 at 02:40:39PM +0200, Marc Kleine-Budde wrote:quoted
The net->ifindex is unique. But it's only an integer. Usually can0 has a ifindex != 0, so a simple can%d is contra productive here. Some pointers to related code: http://lxr.free-electrons.com/source/drivers/base/core.c#L1847 http://lxr.free-electrons.com/source/drivers/base/core.c#L73 http://lxr.free-electrons.com/source/include/linux/device.h#L695 comments?That would probabily makes really hard to choose the right default_trigger for led devices to get to the appropriate CAN LED in embedded systems, as trigger name would depend from other network devices and probing order (correct me if I'm wrong). Something with device name would probaily be more appropriate here.quoted
a very recent idea: something with netdevice notifiers and NETDEV_CHANGENAME ... http://lxr.free-electrons.com/source/net/core/dev.c#L1030 you could: rename the trigger, or if we think it's usefull, block the netdev rename when its triggers are in use.Blocking the rename looks overkill to me,renaming a netdev _after_ first attaching led triggers looks stupid to me anyway.quoted
quoted
what about using device name with an optional "port id" appended to it? Sounds simpler...The name of the device can only be changed when the interface is down. Is it possible to put some scripting around it to detach and attach the leds to the interfaces on ifup/ifdown triggers?Are the led triggers available for using while the netdev is down then?
Sure! On embedded systems triggers are usually attached to actual LEDs at probe time using default_trigger field of struct led_classdev, and that can be specified both in machine files or in device tree. See http://lxr.free-electrons.com/source/arch/powerpc/boot/dts/mpc8315erdb.dts#L477 http://lxr.free-electrons.com/source/arch/arm/mach-pxa/tosa.c#L576 that's why the trigger name should be predictable, at least at boot/probe time. The actual CAN LED trigger also reflects the actual state of the interface (off if down, on if up, blink on activity). Fabio