Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Add new types for TLV dB scale specified with min/max values instead
of min/step since the resolution can't match always with the one
a device provides.  For example, usb audio devices give 1/256 dB
resolution while ALSA TLV is based on 1/100 dB resolution.
The new min/max types have less problems because the possible
rounding error happens only at min/max.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Signed-off-by: NJaroslav Kysela <perex@perex.cz>

Added the definition of TLV dB range compound.  It contains one or
more dB-range or linear-volume TLV entries with min/max ranges.
Used for volume controls with non-linear curves.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>

Added the definition of linear volume TLV type.
Some DSP chips and codecs (e.g. AK codec) use linear volume control.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>

This patch implements a TLV mechanism to transfer an additional information
like dB scale to the user space. The types might be extended in future.
Acked-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>