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From:   Maximilian Luz <luzmaximilian@gmail.com>
To:     Jiri Kosina <jikos@kernel.org>
Cc:     Maximilian Luz <luzmaximilian@gmail.com>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: [PATCH] HID: hid-input: add Surface Go battery quirk
Date:   Thu, 26 May 2022 01:08:27 +0200
Message-Id: <20220525230827.1019662-1-luzmaximilian@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Similar to the Surface Go (1), the (Elantech) touchscreen/digitizer in
the Surface Go 2 mistakenly reports the battery of the stylus. Instead
of over the touchscreen device, battery information is provided via
bluetooth and the touchscreen device reports an empty battery.

Apply the HID_BATTERY_QUIRK_IGNORE quirk to ignore this battery and
prevent the erroneous low battery warnings.

Cc: stable@vger.kernel.org
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---
 drivers/hid/hid-ids.h   | 1 +
 drivers/hid/hid-input.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index d9eb676abe96..9c4e92a9c646 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -413,6 +413,7 @@
 #define USB_DEVICE_ID_ASUS_UX550VE_TOUCHSCREEN	0x2544
 #define USB_DEVICE_ID_ASUS_UX550_TOUCHSCREEN	0x2706
 #define I2C_DEVICE_ID_SURFACE_GO_TOUCHSCREEN	0x261A
+#define I2C_DEVICE_ID_SURFACE_GO2_TOUCHSCREEN	0x2A1C
 
 #define USB_VENDOR_ID_ELECOM		0x056e
 #define USB_DEVICE_ID_ELECOM_BM084	0x0061
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index c6b27aab9041..48c1c02c69f4 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -381,6 +381,8 @@ static const struct hid_device_id hid_battery_quirks[] = {
 	  HID_BATTERY_QUIRK_IGNORE },
 	{ HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, I2C_DEVICE_ID_SURFACE_GO_TOUCHSCREEN),
 	  HID_BATTERY_QUIRK_IGNORE },
+	{ HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, I2C_DEVICE_ID_SURFACE_GO2_TOUCHSCREEN),
+	  HID_BATTERY_QUIRK_IGNORE },
 	{}
 };
 
-- 
2.36.1