wmt(4): Add support for hybrid mode

In Hybrid mode, the number of contacts that can be reported in one
report is less than the maximum number of contacts that the device
supports.  For example, a device that supports a maximum of 4
concurrent physical contacts, can set up its top-level collection to
deliver a maximum of two contacts in one report.  If four contact
points are present, the device can break these up into two serial
reports that deliver two contacts each.

Obtained from:	sysutils/iichid

1 files changed, 40 insertions, 13 deletions

diff --git a/sys/dev/usb/input/wmt.c b/sys/dev/usb/input/wmt.c
index 14733dc48209..3d4663693f5f 100644
--- a/sys/dev/usb/input/wmt.c
+++ b/sys/dev/usb/input/wmt.c
@@ -191,7 +191,7 @@ struct wmt_softc
 	struct mtx		mtx;
 	struct wmt_absinfo	ai[WMT_N_USAGES];
 	struct hid_location	locs[MAX_MT_SLOTS][WMT_N_USAGES];
-	struct hid_location	nconts_loc;
+	struct hid_location	cont_count_loc;
 
 	struct usb_xfer		*xfer[WMT_N_TRANSFER];
 	struct evdev_dev	*evdev;
@@ -199,7 +199,8 @@ struct wmt_softc
 	uint32_t		slot_data[WMT_N_USAGES];
 	uint32_t		caps;
 	uint32_t		isize;
-	uint32_t		nconts_max;
+	uint32_t		nconts_per_report;
+	uint32_t		nconts_todo;
 	uint32_t		report_len;
 	uint8_t			report_id;
 
@@ -396,15 +397,40 @@ wmt_process_report(struct wmt_softc *sc, uint8_t *buf, int len)
 	size_t usage;
 	uint32_t *slot_data = sc->slot_data;
 	uint32_t cont;
-	uint32_t nconts;
+	uint32_t cont_count;
 	uint32_t width;
 	uint32_t height;
 	int32_t slot;
 
-	nconts = hid_get_data_unsigned(buf, len, &sc->nconts_loc);
+	/*
+	 * "In Parallel mode, devices report all contact information in a
+	 * single packet. Each physical contact is represented by a logical
+	 * collection that is embedded in the top-level collection."
+	 *
+	 * Since additional contacts that were not present will still be in the
+	 * report with contactid=0 but contactids are zero-based, find
+	 * contactcount first.
+	 */
+	cont_count = hid_get_data_unsigned(buf, len, &sc->cont_count_loc);
+	/*
+	 * "In Hybrid mode, the number of contacts that can be reported in one
+	 * report is less than the maximum number of contacts that the device
+	 * supports. For example, a device that supports a maximum of
+	 * 4 concurrent physical contacts, can set up its top-level collection
+	 * to deliver a maximum of two contacts in one report. If four contact
+	 * points are present, the device can break these up into two serial
+	 * reports that deliver two contacts each.
+	 *
+	 * "When a device delivers data in this manner, the Contact Count usage
+	 * value in the first report should reflect the total number of
+	 * contacts that are being delivered in the hybrid reports. The other
+	 * serial reports should have a contact count of zero (0)."
+	 */
+	if (cont_count != 0)
+		sc->nconts_todo = cont_count;
 
 #ifdef USB_DEBUG
-	DPRINTFN(6, "nconts = %u   ", (unsigned)nconts);
+	DPRINTFN(6, "cont_count:%2u", (unsigned)cont_count);
 	if (wmt_debug >= 6) {
 		WMT_FOREACH_USAGE(sc->caps, usage) {
 			if (wmt_hid_map[usage].usage != WMT_NO_USAGE)
@@ -414,13 +440,11 @@ wmt_process_report(struct wmt_softc *sc, uint8_t *buf, int len)
 	}
 #endif
 
-	if (nconts > sc->nconts_max) {
-		DPRINTF("Contact count overflow %u\n", (unsigned)nconts);
-		nconts = sc->nconts_max;
-	}
+	/* Find the number of contacts reported in current report */
+	cont_count = MIN(sc->nconts_todo, sc->nconts_per_report);
 
 	/* Use protocol Type B for reporting events */
-	for (cont = 0; cont < nconts; cont++) {
+	for (cont = 0; cont < cont_count; cont++) {
 		bzero(slot_data, sizeof(sc->slot_data));
 		WMT_FOREACH_USAGE(sc->caps, usage) {
 			if (sc->locs[cont][usage].size > 0)
@@ -471,7 +495,10 @@ wmt_process_report(struct wmt_softc *sc, uint8_t *buf, int len)
 			evdev_push_abs(sc->evdev, ABS_MT_TRACKING_ID, -1);
 		}
 	}
-	evdev_sync(sc->evdev);
+
+	sc->nconts_todo -= cont_count;
+	if (sc->nconts_todo == 0)
+		evdev_sync(sc->evdev);
 }
 
 static void
@@ -709,7 +736,7 @@ wmt_hid_parse(struct wmt_softc *sc, const void *d_ptr, uint16_t d_len)
 			    HID_USAGE2(HUP_DIGITIZERS, HUD_CONTACTCOUNT)) {
 				cont_count_found = true;
 				if (sc != NULL)
-					sc->nconts_loc = hi.loc;
+					sc->cont_count_loc = hi.loc;
 				break;
 			}
 			/* Scan time is required but clobbered by evdev */
@@ -817,7 +844,7 @@ wmt_hid_parse(struct wmt_softc *sc, const void *d_ptr, uint16_t d_len)
 
 	sc->report_id = report_id;
 	sc->caps = caps;
-	sc->nconts_max = cont;
+	sc->nconts_per_report = cont;
 	sc->cont_max_rid = cont_max_rid;
 	sc->thqa_cert_rid = thqa_cert_rid;