Add a netdev LED trigger for all Blinkenlights lovers...
Originally taken from https://dev.openwrt.org/ticket/2776
Slightly updated for 2.6.24 by Mickey Lauer <mickey@openmoko.org>
and for 2.6.36 by Eric Cooper <ecc@cmu.edu>

Signed-off-by: Eric Cooper <ecc@cmu.edu>
---
Changes in v2:
- Use individual entries for link, transmit, and receive;
  each can be "enabled" or "disabled"
- Use strict_strtoul instead of simple_strtoul
- Add descriptions to Documentation/ABI/testing/sysfs-class-led

 Documentation/ABI/testing/sysfs-class-led |   64 ++++
 drivers/leds/Kconfig                      |    7 +
 drivers/leds/Makefile                     |    1 +
 drivers/leds/ledtrig-netdev.c             |  475 +++++++++++++++++++++++++++++
 4 files changed, 547 insertions(+), 0 deletions(-)
 create mode 100644 drivers/leds/ledtrig-netdev.c

diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 9e4541d..0b03863 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -26,3 +26,67 @@ Description:
 		scheduler is chosen. Trigger specific parameters can appear in
 		/sys/class/leds/<led> once a given trigger is selected.
 
+What:		/sys/class/leds/<led>/device_name
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@cmu.edu>
+Description:
+		Network device name to monitor when trigger is set to "netdev".
+
+What:		/sys/class/leds/<led>/interval
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@cmu.edu>
+Description:
+		Duration of LED blink in milliseconds when trigger is set to
+		"netdev".
+
+What:		/sys/class/leds/<led>/link
+Date:		November 2010
+KernelVersion:	2.6.37
+Contact:	Eric Cooper <ecc@cmu.edu>
+Description:
+		When trigger is set to "netdev", this value is either "enabled"
+		or "disabled". If enabled, this LED's normal state reflects
+		whether or not the link for the corresponding network device
+		is up (has ...
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You should really send this to netdev too.

Some comments:

The timer seems power unfriendly -- it will always tick even if nothing 
happens.

Using the device name as an identifier is not reliable, they may 
not be unique.

rwlocks are deprecated.

your store code has a off by one I think, it's possible to put 
not 0 terminated data in the string.


-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.
--

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I'm confused about this -- how else can the user specify the desired network

In favor of what?  Should I use a spinlock?

Thanks for the feedback.

-- 
Eric Cooper             e c c @ c m u . e d u
--

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For presenting the user the name is probably still the best, but internally

spinlocks or mutexes.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.
--

[ message continues ]

Hi

Looks like most of the comments I had on v1 are still valid:
https://lkml.org/lkml/2010/11/15/506


--

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