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Date:   Thu, 16 Sep 2021 23:22:34 +0300
From:   Ilya Skriblovsky <ilyaskriblovsky@gmail.com>
To:     Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org
Subject: [PATCH v2] Support for side buttons of Xiaomi Mi Dual Mode Wireless
 Mouse Silent Edition
Message-ID: <YUOninNA2UMADRVt@ilya-330s>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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This patch enables side-buttons of Xiaomi Bluetooth mouse (specifically
Xiaomi Mi Dual Mode Wireless Mouse Silent Edition).

The mouse sends invalid button count in its HID Report Descriptor and
this patch just replaces its descriptor with corrected one. With this
driver side buttons work as expected acting like Back/Forward buttons.

Signed-off-by: Ilya Skriblovsky <ilyaskriblovsky@gmail.com>
---
Changes since v1:
 - Fixed syntax of Kconfig
---
 drivers/hid/Kconfig      |   7 +++
 drivers/hid/Makefile     |   1 +
 drivers/hid/hid-xiaomi.c | 103 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 111 insertions(+)
 create mode 100644 drivers/hid/hid-xiaomi.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 76937f716fbe..cc0d3169fe75 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -467,6 +467,13 @@ config HID_VIEWSONIC
 	help
 	  Support for ViewSonic/Signotec PD1011 signature pad.
 
+config HID_XIAOMI
+	tristate "Xiaomi"
+	depends on HID
+	help
+	  Adds support for side buttons of Xiaomi Mi Dual Mode Wireless
+	  Mouse Silent Edition.
+
 config HID_GYRATION
 	tristate "Gyration remote control"
 	depends on HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 1ea1a7c0b20f..c89a25b9c4b9 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -126,6 +126,7 @@ hid-uclogic-objs		:= hid-uclogic-core.o \
 obj-$(CONFIG_HID_UCLOGIC)	+= hid-uclogic.o
 obj-$(CONFIG_HID_UDRAW_PS3)	+= hid-udraw-ps3.o
 obj-$(CONFIG_HID_LED)		+= hid-led.o
+obj-$(CONFIG_HID_XIAOMI)	+= hid-xiaomi.o
 obj-$(CONFIG_HID_XINMO)		+= hid-xinmo.o
 obj-$(CONFIG_HID_ZEROPLUS)	+= hid-zpff.o
 obj-$(CONFIG_HID_ZYDACRON)	+= hid-zydacron.o
diff --git a/drivers/hid/hid-xiaomi.c b/drivers/hid/hid-xiaomi.c
new file mode 100644
index 000000000000..56e8edd3d62f
--- /dev/null
+++ b/drivers/hid/hid-xiaomi.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * HID driver for Xiaomi Mi Dual Mode Wireless Mouse Silent Edition
+ *
+ * Copyright (c) 2021 Ilya Skriblovsky
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/hid.h>
+
+#define USB_VENDOR_ID_XIAOMI    0x2717
+#define USB_DEVICE_ID_MI_SILENT_MOUSE   0x5014
+
+/* Fixed Mi Silent Mouse report descriptor */
+/* Button's Usage Maximum changed from 3 to 5 to make side buttons work */
+#define MI_SILENT_MOUSE_ORIG_RDESC_LENGTH   87
+static __u8 mi_silent_mouse_rdesc_fixed[] = {
+	0x05, 0x01,         /*  Usage Page (Desktop),               */
+	0x09, 0x02,         /*  Usage (Mouse),                      */
+	0xA1, 0x01,         /*  Collection (Application),           */
+	0x85, 0x03,         /*      Report ID (3),                  */
+	0x09, 0x01,         /*      Usage (Pointer),                */
+	0xA1, 0x00,         /*      Collection (Physical),          */
+	0x05, 0x09,         /*          Usage Page (Button),        */
+	0x19, 0x01,         /*          Usage Minimum (01h),        */
+	0x29, 0x05, /* X */ /*          Usage Maximum (05h),        */
+	0x15, 0x00,         /*          Logical Minimum (0),        */
+	0x25, 0x01,         /*          Logical Maximum (1),        */
+	0x75, 0x01,         /*          Report Size (1),            */
+	0x95, 0x05,         /*          Report Count (5),           */
+	0x81, 0x02,         /*          Input (Variable),           */
+	0x75, 0x03,         /*          Report Size (3),            */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0x81, 0x01,         /*          Input (Constant),           */
+	0x05, 0x01,         /*          Usage Page (Desktop),       */
+	0x09, 0x30,         /*          Usage (X),                  */
+	0x09, 0x31,         /*          Usage (Y),                  */
+	0x15, 0x81,         /*          Logical Minimum (-127),     */
+	0x25, 0x7F,         /*          Logical Maximum (127),      */
+	0x75, 0x08,         /*          Report Size (8),            */
+	0x95, 0x02,         /*          Report Count (2),           */
+	0x81, 0x06,         /*          Input (Variable, Relative), */
+	0x09, 0x38,         /*          Usage (Wheel),              */
+	0x15, 0x81,         /*          Logical Minimum (-127),     */
+	0x25, 0x7F,         /*          Logical Maximum (127),      */
+	0x75, 0x08,         /*          Report Size (8),            */
+	0x95, 0x01,         /*          Report Count (1),           */
+	0x81, 0x06,         /*          Input (Variable, Relative), */
+	0xC0,               /*      End Collection,                 */
+	0xC0,               /*  End Collection,                     */
+	0x06, 0x01, 0xFF,   /*  Usage Page (FF01h),                 */
+	0x09, 0x01,         /*  Usage (01h),                        */
+	0xA1, 0x01,         /*  Collection (Application),           */
+	0x85, 0x05,         /*      Report ID (5),                  */
+	0x09, 0x05,         /*      Usage (05h),                    */
+	0x15, 0x00,         /*      Logical Minimum (0),            */
+	0x26, 0xFF, 0x00,   /*      Logical Maximum (255),          */
+	0x75, 0x08,         /*      Report Size (8),                */
+	0x95, 0x04,         /*      Report Count (4),               */
+	0xB1, 0x02,         /*      Feature (Variable),             */
+	0xC0                /*  End Collection                      */
+};
+
+static __u8 *xiaomi_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+				 unsigned int *rsize)
+{
+	switch (hdev->product) {
+	case USB_DEVICE_ID_MI_SILENT_MOUSE:
+		if (*rsize == MI_SILENT_MOUSE_ORIG_RDESC_LENGTH) {
+			hid_info(hdev, "fixing up Mi Silent Mouse report descriptor\n");
+			rdesc = mi_silent_mouse_rdesc_fixed;
+			*rsize = sizeof(mi_silent_mouse_rdesc_fixed);
+		}
+		break;
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id xiaomi_devices[] = {
+	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_XIAOMI, USB_DEVICE_ID_MI_SILENT_MOUSE) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, xiaomi_devices);
+
+static struct hid_driver xiaomi_driver = {
+	.name = "xiaomi",
+	.id_table = xiaomi_devices,
+	.report_fixup = xiaomi_report_fixup,
+};
+module_hid_driver(xiaomi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ilya Skriblovsky <IlyaSkriblovsky@gmail.com>");
+MODULE_DESCRIPTION("Fixing side buttons of Xiaomi Mi Silent Mouse");
-- 
2.30.2