From 0aba665489c8f16ebb96c17f619211c0f43337a1 Mon Sep 17 00:00:00 2001
From: Arne Keller <arne.keller@posteo.de>
Date: Mon, 13 Sep 2021 09:53:24 +0200
Subject: [PATCH] Initial commit

---
 Makefile                  |   1 +
 hid-microsoft-ergonomic.c | 109 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 Makefile
 create mode 100644 hid-microsoft-ergonomic.c

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..4c76df6
--- /dev/null
+++ b/Makefile
@@ -0,0 +1 @@
+obj-m += hid-microsoft-ergonomic.o
diff --git a/hid-microsoft-ergonomic.c b/hid-microsoft-ergonomic.c
new file mode 100644
index 0000000..4308512
--- /dev/null
+++ b/hid-microsoft-ergonomic.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for the microsoft ergonomic keyboard
+ *
+ *  Copyright (c) 2021 Arne Keller
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#define USB_VENDOR_ID_MICROSOFT 0x045e
+#define USB_DEVICE_ID_MS_ERGONOMIC_KEYBOARD 0x082c
+#define MS_ERGONOMY2	BIT(8)
+
+struct ms_data {
+	unsigned long quirks;
+	struct hid_device *hdev;
+	__u8 strong;
+	__u8 weak;
+	void *output_report_dmabuf;
+};
+
+
+static int ms_raw_event(struct hid_device *hdev, struct hid_report *report,
+			u8 *data, int size)
+{
+	struct ms_data *ms = hid_get_drvdata(hdev);
+	unsigned long quirks = ms->quirks;
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT))
+		return 0;
+
+	if (quirks & MS_ERGONOMY2) {
+		if (size == 8 && ((data[1] & 0x0f) == 0x0f)) {
+			hid_info(hdev, "remapped button %x :)", data[1]);
+			// weird Office button just simulates Left Shift + Ctrl + Alt + Super!
+			data[1] |= 0x80; // other combination keys might also be pressed!
+			data[1] &= 0xf0; // clear the 4 key mess
+		}
+		/*
+		hid_info(hdev, "event of size %d", size);
+		int size2 = size;
+		while (size2 > 0) {
+			printk(KERN_CONT " %x", *data);
+			size2--;
+			data++;
+		}
+		printk(KERN_CONT "\n");
+		*/
+	}
+	return 0;
+}
+
+static int ms_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	unsigned long quirks = id->driver_data;
+	struct ms_data *ms;
+	int ret;
+
+	ms = devm_kzalloc(&hdev->dev, sizeof(*ms), GFP_KERNEL);
+	if (ms == NULL)
+		return -ENOMEM;
+
+	ms->quirks = quirks;
+
+	hid_set_drvdata(hdev, ms);
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		goto err_free;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		goto err_free;
+	}
+
+	return 0;
+err_free:
+	return ret;
+}
+
+static void ms_remove(struct hid_device *hdev)
+{
+	hid_hw_stop(hdev);
+}
+
+static const struct hid_device_id ms_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROSOFT, USB_DEVICE_ID_MS_ERGONOMIC_KEYBOARD),
+	 	.driver_data = MS_ERGONOMY2},
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ms_devices);
+
+static struct hid_driver ms_driver = {
+	.name = "microsoft_ergonomic",
+	.id_table = ms_devices,
+	.raw_event = ms_raw_event,
+	.probe = ms_probe,
+	.remove = ms_remove,
+};
+module_hid_driver(ms_driver);
+
+MODULE_LICENSE("GPL");
+