tree 8f46ddd276545b54013c2cb3bb83824def0f7465
parent 83abbd6fe404b52e81a3ac233258ab77b2fcc65f
author Brandon Wyman <bjwyman@gmail.com> 1506375825 -0500
committer Brandon Wyman <bjwyman@gmail.com> 1506969378 -0500

Add helper function to see if PMBus file exists

Due to some odd power supply behavior on some systems, certain PMBus
files in sysfs end up missing. Adding in a helper function to avoid
spurious tracing if an application so chooses to check for existence
before trying to read one of those files. See openbmc/openbmc#2364 issue
opened for this problem with the missing files.

Change-Id: Ib295beb7ff1733da6ecbcd6966b76b918ade7f54
Signed-off-by: Brandon Wyman <bjwyman@gmail.com>