Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

Add the basic ALSA mixer functionality.  The mixer is event-driven,
and will work fine on IBM ThinkPads.  I expect Lenovo ThinkPads will
cause some trouble with the event interface.

Heavily based on work by Lorne Applebaum <lorne.applebaum@gmail.com>
and ideas from Matthew Garrett <mjg@redhat.com>.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Lorne Applebaum <lorne.applebaum@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Disable volume control by default.  It can be enabled at module load
time by a module parameter (volume_control=1).

The audio control mixer that thinkpad-acpi interacts with is fully
functional without any drivers, and operated by hotkeys.

The idea behind the console audio control is that the human operator
is the only one that can interact with it.  The ThinkVantage suite in
Windows does not allow any software-based overrides, and only does OSD
(on-screen-display) functions.

The Linux driver will, with the addition of the ALSA interface, try to
follow and enforce the ThinkVantage UI design:

The user is supposed to use the keyboard hotkeys to interact with the
console audio control.  The kernel and the desktop environment is
supposed to cooperate to provide proper user feedback through
on-screen-display functions.

Distros are urged to not to enable volume control by default.
Enabling this must be a local admin's decision.  This is the reason
why there is no Kconfig option.

Keep in mind that all ThinkPads have a normal, main mixer (AC97 or
HDA) for regular software-based audio control.  We are not talking
about that mixer here.

Advanced users are, of course, free to enable volume control and do as
they please.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Lorne Applebaum <lorne.applebaum@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Lenovo removed the extra mixer since the T61 and thereabouts.
Newer Lenovo models only have the mute gate function, and leave
the volume control to the HDA mixer.

Until a way to automatically query the firmware about its audio
control capabilities is discovered (there might not be any), use a
white/black list.

We will likely need to ask T60 (old and new model) and Z60/Z61 users
whether they have volume control to populate the black/white list.
Meanwhile, provide a volume_capabilities parameter that can be used to
override the defaults.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Lorne Applebaum <lorne.applebaum@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

I don't trust the coupled EC writes and SMI calls the current volume
control code does very much, although it is exactly what the IBM DSDTs
seem to do (they never do more than a single step though).

Change the driver to stop issuing SMIs, and just drive the EC directly
to the desired level (DSDTs seem to confirm this will work even on
very old models like the 570 and 600e/x).

We checkpoint directly to NVRAM (this can be turned off) at
suspend/shutdown/driver unload, which from what I can see in tbp,
should also work on every ThinkPad.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Lorne Applebaum <lorne.applebaum@gmail.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Take advantage of the new events capabilities of the backlight class to
notify userspace of backlight changes.

This depends on "backlight: Allow drivers to update the core, and
generate events on changes", by Matthew Garrett.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Update the HKEY event driver to:

1. Handle better the second-gen firmware, which has no HKEY mask
   support but does report FN+F3, FN+F4 and FN+F12 without the need
   for NVRAM polling.

   a) always make the mask-related attributes available in sysfs;
   b) use DMI quirks to detect the second-gen firmware;
   c) properly report that FN+F3, FN+F4 and FN+F12 are enabled,
      and available even on mask-less second-gen firmware;

2. Decouple the issuing of hotkey events towards userspace from
   their reception from the firmware.  ALSA mixer and brightness
   event reporting support will need this feature.

3. Clean up the mess in the hotkey driver a great deal.  It is
   still very convoluted, and wants a full refactoring into a
   proper event API interface, but that is not going to happen
   today.

4. Fully reset firmware interface on resume (restore hotkey
   mask and status).

5. Stop losing polled events for no good reason when changing the
   mask and poll frequencies.  We will still lose them when the
   hotkey_source_mask is changed, as well as any that happened
   between driver suspend and driver resume.

The hotkey subdriver now has the notion of user-space-visible hotkey
event mask, as well as of the set of "hotkey" events the driver needs
(because brightness/volume change reports are not just keypress
reports in most ThinkPad models).

With this rewrite, the ABI level is bumped to 0x020500 should
userspace need to know it is dealing with the updated hotkey
subdriver.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

HKEY event 0x5010 is useless to us: old ThinkPads don't issue it.  Newer
ThinkPads won't issue it anymore.  And all ThinkPads issue 0x1010 and
0x1011 events.

Just silently drop it instead of sending it to userspace.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>