Some devices provide support for detection of a small number of
buttons on their jacks. One common implementation provides a single
button, implemented by shorting the microphone to ground and detected
along with microphone presence detection by detecting varying current
draws on the microphone bias signal.

Provide support for up to three buttons via the jack interface. These
default to reporting BTN_n but an API is provided to allow these to
be remapped to other keys by the machine driver where it knows what
the keys are. More keys can be added with ease if required.

This is only intended to support simple accessory button designs. If
the interface is limiting then either creating a child device for the
accessory or accessing the input device in the jack directly is
recommended.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Added private_data and private_free fields to struct snd_jack so that
the caller can assign the data.  It'll be helpful for avoiding the
double-free of the jack instance.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Add support for reporting new jack types SND_JACK_VIDEOOUT and
SND_JACK_AVOUT (a combination of LINEOUT and VIDEOOUT) to the jack
reporting API.

Also add the corresponding SW_VIDEOOUT_INSERT switch to the input system
header.
Signed-off-by: NJani Nikula <ext-jani.1.nikula@nokia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Use a lookup table rather than explicit code to map input subsystem jack
types into ASoC ones, implemented as suggested by Takashi Iwai.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Some systems support both mechanical and electrical jack detection,
allowing them to report that a jack is physically present but does
not have any functioning connections. Add a new jack type for these,
allowing user space to report faulty connections.

Thanks to Guillem Jover for the suggestion.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

This patch introduces support for reporting SW_LINEOUT_INSERT detection events
via the jack abstraction layer.

Also adds a SND_JACK_LINEOUT define to the input system header.
Signed-off-by: NMatthew Ranostay <mranostay@embeddedalley.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Currently very few systems provide information about jack status to user
space, even though many have hardware facilities to do detection. Those
systems that do use an input device with the existing SW_HEADPHONE_INSERT
switch type to do so, often independently of ALSA.

This patch introduces a standard method for representing jacks to user
space into ALSA. It allows drivers to register jacks for a sound card with
the input subsystem, binding the input device to the card to help user
space associate the input devices with their sound cards. The created
input devices are named in the form "card longname jack" where jack is
provided by the driver when allocating a jack. By default the parent for
the input device is the sound card but this can be overridden by the
card driver.

The existing user space API with SW_HEADPHONE_INSERT is preserved.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>