[v8,9/9] HID: nintendo: patch hw version for userspace HID mappings

Commit Message

Daniel Ogorchock Oct. 14, 2019, 12:22 a.m. UTC

This patch sets the most significant bit of the hid hw version to allow
userspace to distinguish between this driver's input mappings vs. the
default hid mappings. This prevents breaking userspace applications that
use SDL2 for gamepad input, allowing them to distinguish the mappings
based on the version.

Signed-off-by: Daniel J. Ogorchock <[e-mail]>
---
 drivers/hid/hid-nintendo.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Patch

diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c
index 333d1e0d07d6..2992a0d6831c 100644
--- a/drivers/hid/hid-nintendo.c
+++ b/drivers/hid/hid-nintendo.c
@@ -1361,6 +1361,15 @@  static int nintendo_hid_probe(struct hid_device *hdev,
 		goto err_wq;
 	}
 
+	/*
+	 * Patch the hw version of pro controller/joycons, so applications can
+	 * distinguish between the default HID mappings and the mappings defined
+	 * by the Linux game controller spec. This is important for the SDL2
+	 * library, which has a game controller database, which uses device ids
+	 * in combination with version as a key.
+	 */
+	hdev->version |= 0x8000;
+
 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
 	if (ret) {
 		hid_err(hdev, "HW start failed\n");