From f8b6a74719b5e003e28b2deb7ef91d7158333cbf Mon Sep 17 00:00:00 2001
From: Aaron Armstrong Skomra <skomra@gmail.com>
Date: Tue, 6 Mar 2018 10:48:34 -0800
Subject: [PATCH] HID: wacom: generic: Support multiple tools per report
Git-commit: f8b6a74719b5e003e28b2deb7ef91d7158333cbf
Patch-mainline: v4.17-rc1
References: bsc#1051510

Some Wacom devices contain contain Pen and Pad usages in
the same report. Future devices of this type may utilize
HID Descriptors.

The generic code path of the Wacom driver previously
assumed pen, touch, and pad reports were delivered in
separate reports. This patch adds support for processing
each collection of a report separately, in order to support
reports with multiple tools.

Signed-off-by: Aaron Armstrong Skomra <skomra@gmail.com>
Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
Reviewed-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/hid/wacom_wac.c | 94 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 68 insertions(+), 26 deletions(-)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index d532c1ebf2ee..7a0a7f67e7ed 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -2072,7 +2072,7 @@ static void wacom_wac_pad_pre_report(struct hid_device *hdev,
 }
 
 static void wacom_wac_pad_report(struct hid_device *hdev,
-		struct hid_report *report)
+		struct hid_report *report, struct hid_field *field)
 {
 	struct wacom *wacom = hid_get_drvdata(hdev);
 	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
@@ -2080,7 +2080,7 @@ static void wacom_wac_pad_report(struct hid_device *hdev,
 	bool active = wacom_wac->hid_data.inrange_state != 0;
 
 	/* report prox for expresskey events */
-	if ((wacom_equivalent_usage(report->field[0]->physical) == HID_DG_TABLETFUNCTIONKEY) &&
+	if ((wacom_equivalent_usage(field->physical) == HID_DG_TABLETFUNCTIONKEY) &&
 	    wacom_wac->hid_data.pad_input_event_flag) {
 		input_event(input, EV_ABS, ABS_MISC, active ? PAD_DEVICE_ID : 0);
 		input_sync(input);
@@ -2627,11 +2627,13 @@ void wacom_wac_event(struct hid_device *hdev, struct hid_field *field,
 		wacom_wac_finger_event(hdev, field, usage, value);
 }
 
-static void wacom_report_events(struct hid_device *hdev, struct hid_report *report)
+static void wacom_report_events(struct hid_device *hdev,
+				struct hid_report *report, int collection_index,
+				int field_index)
 {
 	int r;
 
-	for (r = 0; r < report->maxfield; r++) {
+	for (r = field_index; r < report->maxfield; r++) {
 		struct hid_field *field;
 		unsigned count, n;
 
@@ -2641,30 +2643,23 @@ static void wacom_report_events(struct hid_device *hdev, struct hid_report *repo
 		if (!(HID_MAIN_ITEM_VARIABLE & field->flags))
 			continue;
 
-		for (n = 0; n < count; n++)
-			wacom_wac_event(hdev, field, &field->usage[n], field->value[n]);
+		for (n = 0 ; n < count; n++) {
+			if (field->usage[n].collection_index == collection_index)
+				wacom_wac_event(hdev, field, &field->usage[n],
+						field->value[n]);
+			else
+				return;
+		}
 	}
 }
 
-void wacom_wac_report(struct hid_device *hdev, struct hid_report *report)
+int wacom_wac_collection(struct hid_device *hdev, struct hid_report *report,
+			 int collection_index, struct hid_field *field,
+			 int field_index)
 {
 	struct wacom *wacom = hid_get_drvdata(hdev);
-	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
-	struct hid_field *field = report->field[0];
-
-	if (wacom_wac->features.type != HID_GENERIC)
-		return;
-
-	wacom_wac_battery_pre_report(hdev, report);
-
-	if (WACOM_PAD_FIELD(field) && wacom->wacom_wac.pad_input)
-		wacom_wac_pad_pre_report(hdev, report);
-	else if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input)
-		wacom_wac_pen_pre_report(hdev, report);
-	else if (WACOM_FINGER_FIELD(field) && wacom->wacom_wac.touch_input)
-		wacom_wac_finger_pre_report(hdev, report);
 
-	wacom_report_events(hdev, report);
+	wacom_report_events(hdev, report, collection_index, field_index);
 
 	/*
 	 * Non-input reports may be sent prior to the device being
@@ -2674,16 +2669,63 @@ void wacom_wac_report(struct hid_device *hdev, struct hid_report *report)
 	 * processing functions.
 	 */
 	if (report->type != HID_INPUT_REPORT)
-		return;
-
-	wacom_wac_battery_report(hdev, report);
+		return -1;
 
 	if (WACOM_PAD_FIELD(field) && wacom->wacom_wac.pad_input)
-		wacom_wac_pad_report(hdev, report);
+		wacom_wac_pad_report(hdev, report, field);
 	else if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input)
 		wacom_wac_pen_report(hdev, report);
 	else if (WACOM_FINGER_FIELD(field) && wacom->wacom_wac.touch_input)
 		wacom_wac_finger_report(hdev, report);
+
+	return 0;
+}
+
+void wacom_wac_report(struct hid_device *hdev, struct hid_report *report)
+{
+	struct wacom *wacom = hid_get_drvdata(hdev);
+	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
+	struct hid_field *field;
+	bool pad_in_hid_field = false, pen_in_hid_field = false,
+		finger_in_hid_field = false;
+	int r;
+	int prev_collection = -1;
+
+	if (wacom_wac->features.type != HID_GENERIC)
+		return;
+
+	for (r = 0; r < report->maxfield; r++) {
+		field = report->field[r];
+
+		if (WACOM_PAD_FIELD(field))
+			pad_in_hid_field = true;
+		if (WACOM_PEN_FIELD(field))
+			pen_in_hid_field = true;
+		if (WACOM_FINGER_FIELD(field))
+			finger_in_hid_field = true;
+	}
+
+	wacom_wac_battery_pre_report(hdev, report);
+
+	if (pad_in_hid_field && wacom->wacom_wac.pad_input)
+		wacom_wac_pad_pre_report(hdev, report);
+	if (pen_in_hid_field && wacom->wacom_wac.pen_input)
+		wacom_wac_pen_pre_report(hdev, report);
+	if (finger_in_hid_field && wacom->wacom_wac.touch_input)
+		wacom_wac_finger_pre_report(hdev, report);
+
+	for (r = 0; r < report->maxfield; r++) {
+		field = report->field[r];
+
+		if (field->usage[0].collection_index != prev_collection) {
+			if (wacom_wac_collection(hdev, report,
+				field->usage[0].collection_index, field, r) < 0)
+				return;
+			prev_collection = field->usage[0].collection_index;
+		}
+	}
+
+	wacom_wac_battery_report(hdev, report);
 }
 
 static int wacom_bpt_touch(struct wacom_wac *wacom)
-- 
2.16.4