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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Zoltan Tamas Vajda <zoltan.tamas.vajda@gmail.com>,
        Jiri Kosina <jkosina@suse.cz>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 219/700] HID: hid-input: add Surface Go battery quirk
Date:   Mon, 12 Jul 2021 08:05:02 +0200
Message-Id: <20210712060957.835277227@linuxfoundation.org>
In-Reply-To: <20210712060924.797321836@linuxfoundation.org>
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From: Zoltan Tamas Vajda <zoltan.tamas.vajda@gmail.com>

[ Upstream commit b5539722eb832441f309642fe5102cc3536f92b8 ]

The Elantech touchscreen/digitizer in the Surface Go mistakenly reports
having a battery. This results in a low battery message every time you
try to use the pen.

This patch adds a quirk to ignore the non-existent battery and
gets rid of the false low battery messages.

Signed-off-by: Zoltan Tamas Vajda <zoltan.tamas.vajda@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 03978111d944..06168f485722 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -397,6 +397,7 @@
 #define USB_DEVICE_ID_HP_X2_10_COVER	0x0755
 #define I2C_DEVICE_ID_HP_SPECTRE_X360_15	0x2817
 #define USB_DEVICE_ID_ASUS_UX550_TOUCHSCREEN	0x2706
+#define I2C_DEVICE_ID_SURFACE_GO_TOUCHSCREEN	0x261A
 
 #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 e982d8173c9c..bf5e728258c1 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -326,6 +326,8 @@ static const struct hid_device_id hid_battery_quirks[] = {
 	  HID_BATTERY_QUIRK_IGNORE },
 	{ HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, I2C_DEVICE_ID_HP_SPECTRE_X360_15),
 	  HID_BATTERY_QUIRK_IGNORE },
+	{ HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, I2C_DEVICE_ID_SURFACE_GO_TOUCHSCREEN),
+	  HID_BATTERY_QUIRK_IGNORE },
 	{}
 };
 
-- 
2.30.2