[PATCH v2] HID: sigmamicro: Fix modifier keys for SiGma Micro based keyboards

[Desmond Lim <peckishrine@gmail.com>]

SIGMACHIP USB Keyboard (1c4f:0059) has a problem where all the
modifier keys mapped to Shift_L.

Fix the report descriptor to make modifier keys work as expected.

Co-developed-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Desmond Lim <peckishrine@gmail.com>
---
Changes since v1:
 - Update commit message
 - Correct Kconfig dependency
---
 drivers/hid/Kconfig          | 10 ++++++++
 drivers/hid/Makefile         |  1 +
 drivers/hid/hid-ids.h        |  1 +
 drivers/hid/hid-sigmamicro.c | 45 ++++++++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+)
 create mode 100644 drivers/hid/hid-sigmamicro.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 9f5435b55949..5b76c56bf9a4 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -970,6 +970,16 @@ config HID_SEMITEK
 	- Woo-dy
 	- X-Bows Nature/Knight
 
+config HID_SIGMAMICRO
+	tristate "SiGma Micro based keyboards"
+	depends on USB_HID
+	help
+	  Support for keyboards that use the SiGma Micro (a.k.a SigmaChip) IC.
+
+	  Supported devices:
+	  - Landslides KR-700
+	  - Rapoo V500
+
 config HID_SONY
 	tristate "Sony PS2/3/4 accessories"
 	depends on USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 55a6fa3eca5a..89ea7fafb66b 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -108,6 +108,7 @@ obj-$(CONFIG_HID_RMI)		+= hid-rmi.o
 obj-$(CONFIG_HID_SAITEK)	+= hid-saitek.o
 obj-$(CONFIG_HID_SAMSUNG)	+= hid-samsung.o
 obj-$(CONFIG_HID_SEMITEK)	+= hid-semitek.o
+obj-$(CONFIG_HID_SIGMAMICRO)	+= hid-sigmamicro.o
 obj-$(CONFIG_HID_SMARTJOYPLUS)	+= hid-sjoy.o
 obj-$(CONFIG_HID_SONY)		+= hid-sony.o
 obj-$(CONFIG_HID_SPEEDLINK)	+= hid-speedlink.o
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 96a455921c67..279410bc8fce 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -1083,6 +1083,7 @@
 
 #define USB_VENDOR_ID_SIGMA_MICRO	0x1c4f
 #define USB_DEVICE_ID_SIGMA_MICRO_KEYBOARD	0x0002
+#define USB_DEVICE_ID_SIGMA_MICRO_KEYBOARD2	0x0059
 
 #define USB_VENDOR_ID_SIGMATEL		0x066F
 #define USB_DEVICE_ID_SIGMATEL_STMP3780	0x3780
diff --git a/drivers/hid/hid-sigmamicro.c b/drivers/hid/hid-sigmamicro.c
new file mode 100644
index 000000000000..eb34d6198083
--- /dev/null
+++ b/drivers/hid/hid-sigmamicro.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HID driver for SiGma Micro based keyboards
+ *
+ * Copyright (c) 2016 Kinglong Mee
+ * Copyright (c) 2021 Desmond Lim
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+static __u8 *sm_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+			     unsigned int *rsize)
+{
+	switch (hdev->product) {
+	case USB_DEVICE_ID_SIGMA_MICRO_KEYBOARD2:
+		if (*rsize == 167 && rdesc[98] == 0x81 && rdesc[99] == 0x00) {
+			hid_info(hdev, "Fixing up SiGma Micro report descriptor\n");
+			rdesc[99] = 0x02;
+		}
+		break;
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id sm_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SIGMA_MICRO, USB_DEVICE_ID_SIGMA_MICRO_KEYBOARD2) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, sm_devices);
+
+static struct hid_driver sm_driver = {
+	.name = "sigmamicro",
+	.id_table = sm_devices,
+	.report_fixup = sm_report_fixup,
+};
+module_hid_driver(sm_driver);
+
+MODULE_AUTHOR("Kinglong Mee <kinglongmee@gmail.com>");
+MODULE_AUTHOR("Desmond Lim <peckishrine@gmail.com>");
+MODULE_DESCRIPTION("SiGma Micro HID driver");
+MODULE_LICENSE("GPL");

base-commit: 740bebf42104d2f082514b1545a14056f3b1b56c
-- 
2.30.2