HID: cougar: Add support for the Cougar 500k Gaming Keyboard

Cougar 500k Gaming Keyboard have some special function keys that
make the keyboard stop responding once pressed. Implement the custom
vendor interface that deals with the extended keypresses to fix.

The bug can be reproduced by plugging in the keyboard, then pressing the
rightmost part of the spacebar.

Signed-off-by: Daniel M. Lambea <dmlambea@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

4 files changed, 326 insertions, 0 deletions

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index a49a10437c40..61e1953ff921 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -207,6 +207,16 @@ config HID_CORSAIR
 	- Vengeance K90
 	- Scimitar PRO RGB
 
+config HID_COUGAR
+	tristate "Cougar devices"
+	depends on HID
+	help
+	Support for Cougar devices that are not fully compliant with the
+	HID standard.
+
+	Supported devices:
+	- Cougar 500k Gaming Keyboard
+
 config HID_PRODIKEYS
 	tristate "Prodikeys PC-MIDI Keyboard support"
 	depends on HID && SND
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 511e1cbff768..bd7ac53b75c5 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_HID_CHERRY)	+= hid-cherry.o
 obj-$(CONFIG_HID_CHICONY)	+= hid-chicony.o
 obj-$(CONFIG_HID_CMEDIA)	+= hid-cmedia.o
 obj-$(CONFIG_HID_CORSAIR)	+= hid-corsair.o
+obj-$(CONFIG_HID_COUGAR)	+= hid-cougar.o
 obj-$(CONFIG_HID_CP2112)	+= hid-cp2112.o
 obj-$(CONFIG_HID_CYPRESS)	+= hid-cypress.o
 obj-$(CONFIG_HID_DRAGONRISE)	+= hid-dr.o
diff --git a/drivers/hid/hid-cougar.c b/drivers/hid/hid-cougar.c
new file mode 100644
index 000000000000..ad2e87de7dc5
--- /dev/null
+++ b/drivers/hid/hid-cougar.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  HID driver for Cougar 500k Gaming Keyboard
+ *
+ *  Copyright (c) 2018 Daniel M. Lambea <dmlambea@gmail.com>
+ */
+
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+MODULE_AUTHOR("Daniel M. Lambea <dmlambea@gmail.com>");
+MODULE_DESCRIPTION("Cougar 500k Gaming Keyboard");
+MODULE_LICENSE("GPL");
+MODULE_INFO(key_mappings, "G1-G6 are mapped to F13-F18");
+
+static int cougar_g6_is_space = 1;
+module_param_named(g6_is_space, cougar_g6_is_space, int, 0600);
+MODULE_PARM_DESC(g6_is_space,
+	"If set, G6 programmable key sends SPACE instead of F18 (0=off, 1=on) (default=1)");
+
+
+#define COUGAR_VENDOR_USAGE	0xff00ff00
+
+#define COUGAR_FIELD_CODE	1
+#define COUGAR_FIELD_ACTION	2
+
+#define COUGAR_KEY_G1		0x83
+#define COUGAR_KEY_G2		0x84
+#define COUGAR_KEY_G3		0x85
+#define COUGAR_KEY_G4		0x86
+#define COUGAR_KEY_G5		0x87
+#define COUGAR_KEY_G6		0x78
+#define COUGAR_KEY_FN		0x0d
+#define COUGAR_KEY_MR		0x6f
+#define COUGAR_KEY_M1		0x80
+#define COUGAR_KEY_M2		0x81
+#define COUGAR_KEY_M3		0x82
+#define COUGAR_KEY_LEDS		0x67
+#define COUGAR_KEY_LOCK		0x6e
+
+
+/* Default key mappings. The special key COUGAR_KEY_G6 is defined first
+ * because it is more frequent to use the spacebar rather than any other
+ * special keys. Depending on the value of the parameter 'g6_is_space',
+ * the mapping will be updated in the probe function.
+ */
+static unsigned char cougar_mapping[][2] = {
+	{ COUGAR_KEY_G6,   KEY_SPACE },
+	{ COUGAR_KEY_G1,   KEY_F13 },
+	{ COUGAR_KEY_G2,   KEY_F14 },
+	{ COUGAR_KEY_G3,   KEY_F15 },
+	{ COUGAR_KEY_G4,   KEY_F16 },
+	{ COUGAR_KEY_G5,   KEY_F17 },
+	{ COUGAR_KEY_LOCK, KEY_SCREENLOCK },
+/* The following keys are handled by the hardware itself, so no special
+ * treatment is required:
+	{ COUGAR_KEY_FN, KEY_RESERVED },
+	{ COUGAR_KEY_MR, KEY_RESERVED },
+	{ COUGAR_KEY_M1, KEY_RESERVED },
+	{ COUGAR_KEY_M2, KEY_RESERVED },
+	{ COUGAR_KEY_M3, KEY_RESERVED },
+	{ COUGAR_KEY_LEDS, KEY_RESERVED },
+*/
+	{ 0, 0 },
+};
+
+struct cougar_shared {
+	struct list_head list;
+	struct kref kref;
+	bool enabled;
+	struct hid_device *dev;
+	struct input_dev *input;
+};
+
+struct cougar {
+	bool special_intf;
+	struct cougar_shared *shared;
+};
+
+static LIST_HEAD(cougar_udev_list);
+static DEFINE_MUTEX(cougar_udev_list_lock);
+
+static void cougar_fix_g6_mapping(struct hid_device *hdev)
+{
+	int i;
+
+	for (i = 0; cougar_mapping[i][0]; i++) {
+		if (cougar_mapping[i][0] == COUGAR_KEY_G6) {
+			cougar_mapping[i][1] =
+				cougar_g6_is_space ? KEY_SPACE : KEY_F18;
+			hid_info(hdev, "G6 mapped to %s\n",
+				 cougar_g6_is_space ? "space" : "F18");
+			return;
+		}
+	}
+	hid_warn(hdev, "no mapping defined for G6/spacebar");
+}
+
+/*
+ * Constant-friendly rdesc fixup for mouse interface
+ */
+static __u8 *cougar_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+				 unsigned int *rsize)
+{
+	if (rdesc[2] == 0x09 && rdesc[3] == 0x02 &&
+	    (rdesc[115] | rdesc[116] << 8) >= HID_MAX_USAGES) {
+		hid_info(hdev,
+			"usage count exceeds max: fixing up report descriptor\n");
+		rdesc[115] = ((HID_MAX_USAGES-1) & 0xff);
+		rdesc[116] = ((HID_MAX_USAGES-1) >> 8);
+	}
+	return rdesc;
+}
+
+static struct cougar_shared *cougar_get_shared_data(struct hid_device *hdev)
+{
+	struct cougar_shared *shared;
+
+	/* Try to find an already-probed interface from the same device */
+	list_for_each_entry(shared, &cougar_udev_list, list) {
+		if (hid_compare_device_paths(hdev, shared->dev, '/')) {
+			kref_get(&shared->kref);
+			return shared;
+		}
+	}
+	return NULL;
+}
+
+static void cougar_release_shared_data(struct kref *kref)
+{
+	struct cougar_shared *shared = container_of(kref,
+						    struct cougar_shared, kref);
+
+	mutex_lock(&cougar_udev_list_lock);
+	list_del(&shared->list);
+	mutex_unlock(&cougar_udev_list_lock);
+
+	kfree(shared);
+}
+
+static void cougar_remove_shared_data(void *resource)
+{
+	struct cougar *cougar = resource;
+
+	if (cougar->shared) {
+		kref_put(&cougar->shared->kref, cougar_release_shared_data);
+		cougar->shared = NULL;
+	}
+}
+
+/*
+ * Bind the device group's shared data to this cougar struct.
+ * If no shared data exists for this group, create and initialize it.
+ */
+static int cougar_bind_shared_data(struct hid_device *hdev, struct cougar *cougar)
+{
+	struct cougar_shared *shared;
+	int error = 0;
+
+	mutex_lock(&cougar_udev_list_lock);
+
+	shared = cougar_get_shared_data(hdev);
+	if (!shared) {
+		shared = kzalloc(sizeof(*shared), GFP_KERNEL);
+		if (!shared) {
+			error = -ENOMEM;
+			goto out;
+		}
+
+		kref_init(&shared->kref);
+		shared->dev = hdev;
+		list_add_tail(&shared->list, &cougar_udev_list);
+	}
+
+	cougar->shared = shared;
+
+	error = devm_add_action(&hdev->dev, cougar_remove_shared_data, cougar);
+	if (error) {
+		mutex_unlock(&cougar_udev_list_lock);
+		cougar_remove_shared_data(cougar);
+		return error;
+	}
+
+out:
+	mutex_unlock(&cougar_udev_list_lock);
+	return error;
+}
+
+static int cougar_probe(struct hid_device *hdev,
+			const struct hid_device_id *id)
+{
+	struct cougar *cougar;
+	struct hid_input *next, *hidinput = NULL;
+	unsigned int connect_mask;
+	int error;
+
+	cougar = devm_kzalloc(&hdev->dev, sizeof(*cougar), GFP_KERNEL);
+	if (!cougar)
+		return -ENOMEM;
+	hid_set_drvdata(hdev, cougar);
+
+	error = hid_parse(hdev);
+	if (error) {
+		hid_err(hdev, "parse failed\n");
+		goto fail;
+	}
+
+	if (hdev->collection->usage == COUGAR_VENDOR_USAGE) {
+		cougar->special_intf = true;
+		connect_mask = HID_CONNECT_HIDRAW;
+	} else
+		connect_mask = HID_CONNECT_DEFAULT;
+
+	error = hid_hw_start(hdev, connect_mask);
+	if (error) {
+		hid_err(hdev, "hw start failed\n");
+		goto fail;
+	}
+
+	error = cougar_bind_shared_data(hdev, cougar);
+	if (error)
+		goto fail_stop_and_cleanup;
+
+	/* The custom vendor interface will use the hid_input registered
+	 * for the keyboard interface, in order to send translated key codes
+	 * to it.
+	 */
+	if (hdev->collection->usage == HID_GD_KEYBOARD) {
+		cougar_fix_g6_mapping(hdev);
+		list_for_each_entry_safe(hidinput, next, &hdev->inputs, list) {
+			if (hidinput->registered && hidinput->input != NULL) {
+				cougar->shared->input = hidinput->input;
+				cougar->shared->enabled = true;
+				break;
+			}
+		}
+	} else if (hdev->collection->usage == COUGAR_VENDOR_USAGE) {
+		error = hid_hw_open(hdev);
+		if (error)
+			goto fail_stop_and_cleanup;
+	}
+	return 0;
+
+fail_stop_and_cleanup:
+	hid_hw_stop(hdev);
+fail:
+	hid_set_drvdata(hdev, NULL);
+	return error;
+}
+
+/*
+ * Convert events from vendor intf to input key events
+ */
+static int cougar_raw_event(struct hid_device *hdev, struct hid_report *report,
+			    u8 *data, int size)
+{
+	struct cougar *cougar;
+	unsigned char code, action;
+	int i;
+
+	cougar = hid_get_drvdata(hdev);
+	if (!cougar->special_intf || !cougar->shared ||
+	    !cougar->shared->input || !cougar->shared->enabled)
+		return 0;
+
+	code = data[COUGAR_FIELD_CODE];
+	action = data[COUGAR_FIELD_ACTION];
+	for (i = 0; cougar_mapping[i][0]; i++) {
+		if (code == cougar_mapping[i][0]) {
+			input_event(cougar->shared->input, EV_KEY,
+				    cougar_mapping[i][1], action);
+			input_sync(cougar->shared->input);
+			return 0;
+		}
+	}
+	hid_warn(hdev, "unmapped special key code %x: ignoring\n", code);
+	return 0;
+}
+
+static void cougar_remove(struct hid_device *hdev)
+{
+	struct cougar *cougar = hid_get_drvdata(hdev);
+
+	if (cougar) {
+		/* Stop the vendor intf to process more events */
+		if (cougar->shared)
+			cougar->shared->enabled = false;
+		if (cougar->special_intf)
+			hid_hw_close(hdev);
+	}
+	hid_hw_stop(hdev);
+}
+
+static struct hid_device_id cougar_id_table[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SOLID_YEAR,
+			 USB_DEVICE_ID_COUGAR_500K_GAMING_KEYBOARD) },
+	{}
+};
+MODULE_DEVICE_TABLE(hid, cougar_id_table);
+
+static struct hid_driver cougar_driver = {
+	.name			= "cougar",
+	.id_table		= cougar_id_table,
+	.report_fixup		= cougar_report_fixup,
+	.probe			= cougar_probe,
+	.remove			= cougar_remove,
+	.raw_event		= cougar_raw_event,
+};
+
+module_hid_driver(cougar_driver);
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index c7981ddd8776..a1ee8f643f24 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -1001,6 +1001,9 @@
 #define USB_VENDOR_ID_SINO_LITE			0x1345
 #define USB_DEVICE_ID_SINO_LITE_CONTROLLER	0x3008
 
+#define USB_VENDOR_ID_SOLID_YEAR			0x060b
+#define USB_DEVICE_ID_COUGAR_500K_GAMING_KEYBOARD	0x500a
+
 #define USB_VENDOR_ID_SOUNDGRAPH	0x15c2
 #define USB_DEVICE_ID_SOUNDGRAPH_IMON_FIRST	0x0034
 #define USB_DEVICE_ID_SOUNDGRAPH_IMON_LAST	0x0046