ALSA: Build jack detection

Since jack detection requires the input subsystem which may not be
desired on small systems it is not built unless required by a driver
that is being built. Drivers using jack detection should use a pattern
like this:

config SND_FOO
        tristate "..."
        ...
        select SND_JACK if INPUT=y || INPUT=SND

to ensure that the jack detection API is enabled if the input subsystem
is.  If the input subsystem is not enabled then a stub version of the
API is provided.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

1 files changed, 6 insertions, 0 deletions

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index 335d45ecde6a..9c4da1cd4a6b 100644
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -12,6 +12,12 @@ config SND_HWDEP
 config SND_RAWMIDI
         tristate
 
+# To be effective this also requires INPUT - users should say:
+#    select SND_JACK if INPUT=y || INPUT=SND
+# to avoid having to force INPUT on.
+config SND_JACK
+        bool
+
 config SND_SEQUENCER
         tristate "Sequencer support"
         select SND_TIMER