ethtool: allow custom interval for physical identification

When physical identification of an adapter is done by toggling the
mechanism on and off through software utilizing the set_phys_id operation,
it is done with a fixed duration for both on and off states.  Some drivers
may want to set a custom duration for the on/off intervals.  This patch
changes the API so the return code from the driver's entry point when it
is called with ETHTOOL_ID_ACTIVE can specify the frequency at which to
cycle the on/off states, and updates the drivers that have already been
converted to use the new set_phys_id and use the synchronous method for
identifying an adapter.

The physical identification frequency set in the updated drivers is based
on how it was done prior to the introduction of set_phys_id.

Compile tested only.  Also fixes a compiler warning in sfc.

v2: drivers do not return -EINVAL for ETHOOL_ID_ACTIVE
v3: fold patchset into single patch and cleanup per Ben's feedback

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Divy Le Ray <divy@chelsio.com>
Cc: Don Fry <pcnet32@frontier.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Solarflare linux maintainers <linux-net-drivers@solarflare.com>
Cc: Steve Hodgson <shodgson@solarflare.com>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Matt Carlson <mcarlson@broadcom.com>
Acked-by: Jon Mason <jdmason@kudzu.us>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index ad22a68c2e5d..9de31274341d 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -798,8 +798,10 @@ bool ethtool_invalid_flags(struct net_device *dev, u32 data, u32 supported);
  *      attached to it.  The implementation may update the indicator
  *      asynchronously or synchronously, but in either case it must return
  *      quickly.  It is initially called with the argument %ETHTOOL_ID_ACTIVE,
- *      and must either activate asynchronous updates or return -%EINVAL.
- *      If it returns -%EINVAL then it will be called again at intervals with
+ *      and must either activate asynchronous updates and return zero, return
+ *      a negative error or return a positive frequency for synchronous
+ *      indication (e.g. 1 for one on/off cycle per second).  If it returns
+ *      a frequency then it will be called again at intervals with the
  *      argument %ETHTOOL_ID_ON or %ETHTOOL_ID_OFF and should set the state of
  *      the indicator accordingly.  Finally, it is called with the argument
  *      %ETHTOOL_ID_INACTIVE and must deactivate the indicator.  Returns a