psm(4): Add natural scrolling support to sysmouse protocol

This change enables natural scrolling with two finger scroll enabled
and when user is using a trackpad (mouse and trackpoint are not affected).
Depending on trackpad model it can be activated with setting of
hw.psm.synaptics.natural_scroll or hw.psm.elantech.natural_scroll sysctl
values to 1.

Evdev protocol is not affected by this change too. Tune userland client
e.g. libinput to enable natural scrolling in that case.

Submitted by:	nyan_myuji.xyz
Reviewed by:	wulf
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D20447

1 files changed, 32 insertions, 7 deletions

diff --git a/sys/dev/atkbdc/psm.c b/sys/dev/atkbdc/psm.c
index f51621dfb5b1..6c4947aeeeef 100644
--- a/sys/dev/atkbdc/psm.c
+++ b/sys/dev/atkbdc/psm.c
@@ -236,6 +236,7 @@ typedef struct synapticsinfo {
 	int			 softbutton3_x;
 	int			 max_x;
 	int			 max_y;
+	int			 natural_scroll;
 } synapticsinfo_t;
 
 typedef struct synapticspacket {
@@ -571,6 +572,8 @@ enum {
 	SYNAPTICS_SYSCTL_SOFTBUTTONS_Y =	SYN_OFFSET(softbuttons_y),
 	SYNAPTICS_SYSCTL_SOFTBUTTON2_X =	SYN_OFFSET(softbutton2_x),
 	SYNAPTICS_SYSCTL_SOFTBUTTON3_X =	SYN_OFFSET(softbutton3_x),
+	SYNAPTICS_SYSCTL_NATURAL_SCROLL =	SYN_OFFSET(natural_scroll),
+#define	SYNAPTICS_SYSCTL_LAST	SYNAPTICS_SYSCTL_NATURAL_SCROLL
 };
 
 /* packet formatting function */
@@ -4134,6 +4137,7 @@ psmsmoother(struct psm_softc *sc, finger_t *f, int smoother_id,
 		int len, weight_prev_x, weight_prev_y;
 		int div_max_x, div_max_y, div_x, div_y;
 		int is_fuzzy;
+		int natural_scroll;
 
 		/* Read sysctl. */
 		/* XXX Verify values? */
@@ -4161,6 +4165,7 @@ psmsmoother(struct psm_softc *sc, finger_t *f, int smoother_id,
 		two_finger_scroll = sc->syninfo.two_finger_scroll;
 		max_x = sc->syninfo.max_x;
 		max_y = sc->syninfo.max_y;
+		natural_scroll = sc->syninfo.natural_scroll;
 
 		is_fuzzy = (f->flags & PSM_FINGER_FUZZY) != 0;
 
@@ -4322,14 +4327,24 @@ psmsmoother(struct psm_softc *sc, finger_t *f, int smoother_id,
 			    smoother_id, dx, dy, dxp, dyp));
 			break;
 		case 1: /* Vertical scrolling. */
-			if (dyp != 0)
-				ms->button |= (dyp > 0) ?
-				    MOUSE_BUTTON4DOWN : MOUSE_BUTTON5DOWN;
+			if (dyp != 0) {
+				if (two_finger_scroll && natural_scroll)
+					ms->button |= (dyp > 0) ?
+					    MOUSE_BUTTON5DOWN : MOUSE_BUTTON4DOWN;
+				else
+					ms->button |= (dyp > 0) ?
+					    MOUSE_BUTTON4DOWN : MOUSE_BUTTON5DOWN;
+			}
 			break;
 		case 2: /* Horizontal scrolling. */
-			if (dxp != 0)
-				ms->button |= (dxp > 0) ?
-				    MOUSE_BUTTON7DOWN : MOUSE_BUTTON6DOWN;
+			if (dxp != 0) {
+				if (two_finger_scroll && natural_scroll)
+					ms->button |= (dxp > 0) ?
+					    MOUSE_BUTTON6DOWN : MOUSE_BUTTON7DOWN;
+				else
+					ms->button |= (dxp > 0) ?
+					    MOUSE_BUTTON7DOWN : MOUSE_BUTTON6DOWN;
+			}
 			break;
 		}
 
@@ -5641,7 +5656,7 @@ synaptics_sysctl(SYSCTL_HANDLER_ARGS)
 	int error, arg;
 
 	if (oidp->oid_arg1 == NULL || oidp->oid_arg2 < 0 ||
-	    oidp->oid_arg2 > SYNAPTICS_SYSCTL_SOFTBUTTON3_X)
+	    oidp->oid_arg2 > SYNAPTICS_SYSCTL_LAST)
 		return (EINVAL);
 
 	sc = oidp->oid_arg1;
@@ -5730,6 +5745,7 @@ synaptics_sysctl(SYSCTL_HANDLER_ARGS)
 			return (EINVAL);
 		break;
         case SYNAPTICS_SYSCTL_TOUCHPAD_OFF:
+	case SYNAPTICS_SYSCTL_NATURAL_SCROLL:
 		if (arg < 0 || arg > 1)
 			return (EINVAL);
 		break;
@@ -6122,6 +6138,15 @@ synaptics_sysctl_create_tree(struct psm_softc *sc, const char *name,
 	    synaptics_sysctl, "I",
 	    "Turn off touchpad");
 
+	/* hw.psm.synaptics.natural_scroll. */
+	sc->syninfo.natural_scroll = 0;
+	SYSCTL_ADD_PROC(&sc->syninfo.sysctl_ctx,
+	    SYSCTL_CHILDREN(sc->syninfo.sysctl_tree), OID_AUTO,
+	    "natural_scroll", CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_ANYBODY,
+	    sc, SYNAPTICS_SYSCTL_NATURAL_SCROLL,
+	    synaptics_sysctl, "I",
+	    "Enable natural scrolling");
+
 	sc->syninfo.softbuttons_y = 0;
 	sc->syninfo.softbutton2_x = 0;
 	sc->syninfo.softbutton3_x = 0;