trivial: sysfs.c: fixes in comments

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
trivial: sysfs: simplify zobj_store_enable

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
trivial: chardev.c: rename local variables

Two different functions use the "can_read" and "can_write" names in
different ways: integer flags or function pointers. This is confusing.
So now flags are called "ret_ok", leavning can_read as the name of
a function pointer and nothing else.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
chardev: return POLLERR if user disables the trigger

Unfortunately, we sometimes have threads that block in the I/O
operation (the use case is input), and need to be notified when
another thread aborts the scheduled operation.  This sometimes applies
to a user-requested reconfiguration of the trigger.

This commit awakes processes sleeping on a cset when the trigger is
disabled by a sysfs store, and the chardev interface returns POLLERR
in the poll/select functions for control devices.

We chose not to affect the data device nor read and write. This means
all simple code (scripts, simple demos etc) is not affected.  But
full-featured applications, which rely on poll, have this additional
notification if they check the POLLERR bit.

Note: select(2) reports files both readable and writable when the drive
returns POLLERR, so applications should really use poll(2) instead.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
build: add git describe info as modinfo

For traceability purposes, we include commit descriptions
as MODULE_VERSION information in drivers that are deployed
in CERN control system.

Ideally, the commit description should be added to all the
binary blobs installed, but the kernel module is critical
in this connection, as it is crucial to trace back quickly
the whereabouts of installed .ko sources.

Signed-off-by: Juan David Gonzalez Cobas <dcobas@cern.ch>
Acked-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>
zio-vmk8055: add MODULE_VERSION using git revision

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com
Merge branch 'pollerr'

This branche adds POLLERR support (see commit messages).
Federico gave his acked-by, but the original commit is already in
production, so I am not changing the commit messages.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>