linux-t2-patches/1011-HID-apple-ibridge-rely-on-hid-core-s-parsing.patch

From 1076dfa2cb823cf51f3843583957fbcb20c2678c Mon Sep 17 00:00:00 2001
From: Kerem Karabay <kekrby@gmail.com>
Date: Tue, 8 Nov 2022 20:48:46 +0300
Subject: [PATCH 08/13] HID: apple-ibridge: rely on hid-core's parsing

This commit addresses the issues raised in
https://lore.kernel.org/lkml/CAO-hwJLXAHvjYKxu8pyqMPCNgMrN-H8bGWudVqCaRFnWODHPVQ@mail.gmail.com/.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
---
 drivers/hid/apple-ibridge.c | 69 ++++---------------------------------
 1 file changed, 6 insertions(+), 63 deletions(-)

diff --git a/drivers/hid/apple-ibridge.c b/drivers/hid/apple-ibridge.c
index 4caa7820fcf6..bc070ab034dd 100644
--- a/drivers/hid/apple-ibridge.c
+++ b/drivers/hid/apple-ibridge.c
@@ -328,43 +328,6 @@ static struct hid_ll_driver appleib_ll_driver = {
 	.output_report = appleib_ll_output_report,
 };
 
-static __u8 *appleib_find_collection(__u8 *start, __u8 *end,
-				     unsigned int *usage)
-{
-	struct hid_item item;
-	int depth = 0;
-
-	*usage = 0;
-
-	while ((start = hid_fetch_item(start, end, &item)) != NULL) {
-		if (item.type == HID_ITEM_TYPE_MAIN) {
-			switch (item.tag) {
-			case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
-				depth++;
-				break;
-
-			case HID_MAIN_ITEM_TAG_END_COLLECTION:
-				depth--;
-				if (depth <= 0)
-					return start;
-				break;
-			}
-		} else if (item.type == HID_ITEM_TYPE_GLOBAL &&
-			   item.tag == HID_GLOBAL_ITEM_TAG_USAGE_PAGE &&
-			   depth == 0) {
-			*usage = (*usage & 0x0000FFFF) |
-				 ((hid_item_udata(&item) & 0xFFFF) << 16);
-		} else if (item.type == HID_ITEM_TYPE_LOCAL &&
-			   item.tag == HID_LOCAL_ITEM_TAG_USAGE &&
-			   depth == 0) {
-			*usage = (*usage & 0xFFFF0000) |
-				 (hid_item_udata(&item) & 0xFFFF);
-		}
-	}
-
-	return end;
-}
-
 static struct hid_device_id *appleib_find_dev_id_for_usage(unsigned int usage)
 {
 	int i;
@@ -379,7 +342,7 @@ static struct hid_device_id *appleib_find_dev_id_for_usage(unsigned int usage)
 
 static struct hid_device *
 appleib_add_sub_dev(struct appleib_hid_dev_info *hdev_info,
-		    struct hid_device_id *dev_id, u8 *rdesc, size_t rsize)
+		    struct hid_device_id *dev_id)
 {
 	struct hid_device *sub_hdev;
 	int rc;
@@ -404,12 +367,6 @@ appleib_add_sub_dev(struct appleib_hid_dev_info *hdev_info,
 
 	sub_hdev->driver_data = hdev_info;
 
-	rc = hid_parse_report(sub_hdev, rdesc, rsize);
-	if (rc) {
-		hid_destroy_device(sub_hdev);
-		return ERR_PTR(rc);
-	}
-
 	rc = hid_add_device(sub_hdev);
 	if (rc) {
 		hid_destroy_device(sub_hdev);
@@ -422,9 +379,6 @@ appleib_add_sub_dev(struct appleib_hid_dev_info *hdev_info,
 static struct appleib_hid_dev_info *appleib_add_device(struct hid_device *hdev)
 {
 	struct appleib_hid_dev_info *hdev_info;
-	__u8 *start = hdev->dev_rdesc;
-	__u8 *end = start + hdev->dev_rsize;
-	__u8 *pos;
 	struct hid_device_id *dev_id;
 	unsigned int usage;
 	int i;
@@ -435,33 +389,22 @@ static struct appleib_hid_dev_info *appleib_add_device(struct hid_device *hdev)
 
 	hdev_info->hdev = hdev;
 
-	for (i = 0; ; ) {
-		pos = appleib_find_collection(start, end, &usage);
-
+	for (i = 0; i < hdev->maxcollection; i++) {
+		usage = hdev->collection[i].usage;
 		dev_id = appleib_find_dev_id_for_usage(usage);
+
 		if (!dev_id) {
 			hid_warn(hdev, "Unknown collection encountered with usage %x\n",
 				 usage);
-
-		} else if (i >= ARRAY_SIZE(hdev_info->sub_hdevs)) {
-			hid_warn(hdev, "Too many collections encountered - ignoring for usage %x\n",
-				 usage);
 		} else {
-			hdev_info->sub_hdevs[i] =
-				appleib_add_sub_dev(hdev_info, dev_id, start,
-						    pos - start);
+			hdev_info->sub_hdevs[i] = appleib_add_sub_dev(hdev_info, dev_id);
+
 			if (IS_ERR(hdev_info->sub_hdevs[i])) {
 				while (i-- > 0)
 					hid_destroy_device(hdev_info->sub_hdevs[i]);
 				return (void *)hdev_info->sub_hdevs[i];
 			}
-
-			i++;
 		}
-
-		start = pos;
-		if (start >= end)
-			break;
 	}
 
 	return hdev_info;
-- 
2.38.1