ALSA: snd-es1968: Make hardware volume buttons an input device (rev2)

The hardware volume handling code in essence just detects key presses, and
then does some hardcoded modification of the master volume based on which key
is pressed.

Clearly the right thing to do here is just report these keypresses to
userspace and let userspace decide what to with them.

This patch adds a Kconfig option which when enabled reports the volume
buttons as keypresses using an input device. When enabled this option
also gets rid of the ugly direct ac97 writes from the tasklet, the ac97lock
and the need for using a tasklet in general.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/Kconfig b/sound/pci/Kconfig
index ebcf065..e7a8cd0 100644
--- a/sound/pci/Kconfig
+++ b/sound/pci/Kconfig
@@ -513,6 +513,16 @@
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-es1968.
 
+config SND_ES1968_INPUT
+	bool "Enable input device for es1968 volume buttons"
+	depends on SND_ES1968
+	depends on INPUT=y || INPUT=SND_ES1968
+	help
+	  If you say Y here, you will get an input device which reports
+	  keypresses for the volume buttons connected to the es1968 chip.
+	  If you say N the buttons will directly control the master volume.
+	  It is recommended to say Y.
+
 config SND_FM801
 	tristate "ForteMedia FM801"
 	select SND_OPL3_LIB