--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pirelli/volume-ctrl	Sat Jul 31 07:00:26 2021 +0000
@@ -0,0 +1,55 @@
+Pirelli's fw offers 10 audio output volume levels selectable via volume up/down
+keys.  Cycling through these volume levels on the idle screen and reading out
+Iota VBDCTRL register (fc-tmsh abbr 0 6) at each level yields the following
+table:
+
+Volume level	VBDCTRL		Vol	PGA	Total
+-----------------------------------------------------
+1		047		-18	+1	-17
+2		04A		-18	+4	-14
+3		006		-12	0	-12
+4		008		-12	+2	-10
+5		00A		-12	+4	-8
+6		067		-6	+1	-5
+7		06A		-6	+4	-2
+8		026		0	0	0
+9		028		0	+2	+2
+10		02A		0	+4	+4
+
+In an active call in handheld (earpiece output) mode, the above relation of
+selectable volume level to VBDCTRL remains the same.  However, when the
+loudspeaker is turned on in a call, the mapping changes to the following:
+
+Volume level	VBDCTRL		Vol	PGA	Total
+-----------------------------------------------------
+1		046		-18	0	-18
+2		049		-18	+3	-15
+3		005		-12	-1	-13
+4		007		-12	+1	-11
+5		009		-12	+3	-9
+6		066		-6	0	-6
+7		069		-6	+3	-3
+8		025		0	-1	-1
+9		027		0	+1	+1
+10		029		0	+3	+3
+
+Plugging in Pirelli's wired headset and cycling through volume levels on the
+idle screen, we get this:
+
+Volume level	VBDCTRL		Vol	PGA	Total
+-----------------------------------------------------
+1		045		-18	-1	-19
+2		048		-18	+2	-16
+3		004		-12	-2	-14
+4		006		-12	0	-12
+5		008		-12	+2	-10
+6		065		-6	-1	-7
+7		068		-6	+2	-4
+8		024		0	-2	-2
+9		026		0	0	0
+10		028		0	+2	+2
+
+In-call state in headset mode follows the same mapping as headset mode idle
+screen.  If the user turns on the loudspeaker while in a call with the headset
+inserted, the volume table becomes that of the loudspeaker mode, not the
+headset mode.