HID: add driver for Valve Steam Controller

There are two ways to connect the Steam Controller: directly to the USB
or with the USB wireless adapter.  Both methods are similar, but the
wireless adapter can connect up to 4 devices at the same time.

The wired device will appear as 3 interfaces: a virtual mouse, a virtual
keyboard and a custom HID device.

The wireless device will appear as 5 interfaces: a virtual keyboard and
4 custom HID devices, that will remain silent until a device is actually
connected.

The custom HID device has a report descriptor with all vendor specific
usages, so the hid-generic is not very useful. In a PC/SteamBox Valve
Steam Client provices a software translation by using hidraw and a
creates a uinput virtual gamepad and XTest keyboard/mouse.

This driver intercepts the hidraw usage, so it can get out of the way
when the Steam Client is in use.

Signed-off-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

4 files changed, 986 insertions, 0 deletions

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 0000434a1fbd..4a6fdf346058 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -838,6 +838,14 @@ config HID_SPEEDLINK
 	---help---
 	Support for Speedlink Vicious and Divine Cezanne mouse.
 
+config HID_STEAM
+	tristate "Steam Controller support"
+	depends on HID
+	---help---
+	Say Y here if you have a Steam Controller if you want to use it
+	without running the Steam Client. It supports both the wired and
+	the wireless adaptor.
+
 config HID_STEELSERIES
 	tristate "Steelseries SRW-S1 steering wheel support"
 	depends on HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 17a8bd97da9d..b646e67abc5f 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -97,6 +97,7 @@ obj-$(CONFIG_HID_SAMSUNG)	+= hid-samsung.o
 obj-$(CONFIG_HID_SMARTJOYPLUS)	+= hid-sjoy.o
 obj-$(CONFIG_HID_SONY)		+= hid-sony.o
 obj-$(CONFIG_HID_SPEEDLINK)	+= hid-speedlink.o
+obj-$(CONFIG_HID_STEAM)		+= hid-steam.o
 obj-$(CONFIG_HID_STEELSERIES)	+= hid-steelseries.o
 obj-$(CONFIG_HID_SUNPLUS)	+= hid-sunplus.o
 obj-$(CONFIG_HID_GREENASIA)	+= hid-gaff.o
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 46f5ecd11bf7..e293506be7aa 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -1012,6 +1012,10 @@
 #define USB_VENDOR_ID_STANTUM_SITRONIX		0x1403
 #define USB_DEVICE_ID_MTP_SITRONIX		0x5001
 
+#define USB_VENDOR_ID_VALVE			0x28de
+#define USB_DEVICE_ID_STEAM_CONTROLLER		0x1102
+#define USB_DEVICE_ID_STEAM_CONTROLLER_WIRELESS	0x1142
+
 #define USB_VENDOR_ID_STEELSERIES	0x1038
 #define USB_DEVICE_ID_STEELSERIES_SRWS1	0x1410
 
diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
new file mode 100644
index 000000000000..36fc85714ea5
--- /dev/null
+++ b/drivers/hid/hid-steam.c
@@ -0,0 +1,973 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * HID driver for Valve Steam Controller
+ *
+ * Copyright (c) 2018 Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
+ *
+ * Supports both the wired and wireless interfaces.
+ *
+ * This controller has a builtin emulation of mouse and keyboard: the right pad
+ * can be used as a mouse, the shoulder buttons are mouse buttons, A and B
+ * buttons are ENTER and ESCAPE, and so on. This is implemented as additional
+ * HID interfaces.
+ *
+ * This is known as the "lizard mode", because apparently lizards like to use
+ * the computer from the coach, without a proper mouse and keyboard.
+ *
+ * This driver will disable the lizard mode when the input device is opened
+ * and re-enable it when the input device is closed, so as not to break user
+ * mode behaviour. The lizard_mode parameter can be used to change that.
+ *
+ * There are a few user space applications (notably Steam Client) that use
+ * the hidraw interface directly to create input devices (XTest, uinput...).
+ * In order to avoid breaking them this driver creates a layered hidraw device,
+ * so it can detect when the client is running and then:
+ *  - it will not send any command to the controller.
+ *  - this input device will be disabled, to avoid double input of the same
+ *    user action.
+ *
+ * For additional functions, such as changing the right-pad margin or switching
+ * the led, you can use the user-space tool at:
+ *
+ *   https://github.com/rodrigorc/steamctrl
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/rcupdate.h>
+#include <linux/delay.h>
+#include "hid-ids.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>");
+
+static bool lizard_mode = true;
+
+static DEFINE_MUTEX(steam_devices_lock);
+static LIST_HEAD(steam_devices);
+
+#define STEAM_QUIRK_WIRELESS		BIT(0)
+
+/* Touch pads are 40 mm in diameter and 65535 units */
+#define STEAM_PAD_RESOLUTION 1638
+/* Trigger runs are about 5 mm and 256 units */
+#define STEAM_TRIGGER_RESOLUTION 51
+/* Joystick runs are about 5 mm and 256 units */
+#define STEAM_JOYSTICK_RESOLUTION 51
+
+#define STEAM_PAD_FUZZ 256
+
+/*
+ * Commands that can be sent in a feature report.
+ * Thanks to Valve for some valuable hints.
+ */
+#define STEAM_CMD_SET_MAPPINGS		0x80
+#define STEAM_CMD_CLEAR_MAPPINGS	0x81
+#define STEAM_CMD_GET_MAPPINGS		0x82
+#define STEAM_CMD_GET_ATTRIB		0x83
+#define STEAM_CMD_GET_ATTRIB_LABEL	0x84
+#define STEAM_CMD_DEFAULT_MAPPINGS	0x85
+#define STEAM_CMD_FACTORY_RESET		0x86
+#define STEAM_CMD_WRITE_REGISTER	0x87
+#define STEAM_CMD_CLEAR_REGISTER	0x88
+#define STEAM_CMD_READ_REGISTER		0x89
+#define STEAM_CMD_GET_REGISTER_LABEL	0x8a
+#define STEAM_CMD_GET_REGISTER_MAX	0x8b
+#define STEAM_CMD_GET_REGISTER_DEFAULT	0x8c
+#define STEAM_CMD_SET_MODE		0x8d
+#define STEAM_CMD_DEFAULT_MOUSE		0x8e
+#define STEAM_CMD_FORCEFEEDBAK		0x8f
+#define STEAM_CMD_REQUEST_COMM_STATUS	0xb4
+#define STEAM_CMD_GET_SERIAL		0xae
+
+/* Some useful register ids */
+#define STEAM_REG_LPAD_MODE		0x07
+#define STEAM_REG_RPAD_MODE		0x08
+#define STEAM_REG_RPAD_MARGIN		0x18
+#define STEAM_REG_LED			0x2d
+#define STEAM_REG_GYRO_MODE		0x30
+
+/* Raw event identifiers */
+#define STEAM_EV_INPUT_DATA		0x01
+#define STEAM_EV_CONNECT		0x03
+#define STEAM_EV_BATTERY		0x04
+
+/* Values for GYRO_MODE (bitmask) */
+#define STEAM_GYRO_MODE_OFF		0x0000
+#define STEAM_GYRO_MODE_STEERING	0x0001
+#define STEAM_GYRO_MODE_TILT		0x0002
+#define STEAM_GYRO_MODE_SEND_ORIENTATION	0x0004
+#define STEAM_GYRO_MODE_SEND_RAW_ACCEL		0x0008
+#define STEAM_GYRO_MODE_SEND_RAW_GYRO		0x0010
+
+/* Other random constants */
+#define STEAM_SERIAL_LEN 10
+
+struct steam_device {
+	struct list_head list;
+	spinlock_t lock;
+	struct hid_device *hdev, *client_hdev;
+	struct mutex mutex;
+	bool client_opened, input_opened;
+	struct input_dev __rcu *input;
+	unsigned long quirks;
+	struct work_struct work_connect;
+	bool connected;
+	char serial_no[STEAM_SERIAL_LEN + 1];
+};
+
+static int steam_recv_report(struct steam_device *steam,
+		u8 *data, int size)
+{
+	struct hid_report *r;
+	u8 *buf;
+	int ret;
+
+	r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
+	if (hid_report_len(r) < 64)
+		return -EINVAL;
+
+	buf = hid_alloc_report_buf(r, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/*
+	 * The report ID is always 0, so strip the first byte from the output.
+	 * hid_report_len() is not counting the report ID, so +1 to the length
+	 * or else we get a EOVERFLOW. We are safe from a buffer overflow
+	 * because hid_alloc_report_buf() allocates +7 bytes.
+	 */
+	ret = hid_hw_raw_request(steam->hdev, 0x00,
+			buf, hid_report_len(r) + 1,
+			HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+	if (ret > 0)
+		memcpy(data, buf + 1, min(size, ret - 1));
+	kfree(buf);
+	return ret;
+}
+
+static int steam_send_report(struct steam_device *steam,
+		u8 *cmd, int size)
+{
+	struct hid_report *r;
+	u8 *buf;
+	unsigned int retries = 50;
+	int ret;
+
+	r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
+	if (hid_report_len(r) < 64)
+		return -EINVAL;
+
+	buf = hid_alloc_report_buf(r, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* The report ID is always 0 */
+	memcpy(buf + 1, cmd, size);
+
+	/*
+	 * Sometimes the wireless controller fails with EPIPE
+	 * when sending a feature report.
+	 * Doing a HID_REQ_GET_REPORT and waiting for a while
+	 * seems to fix that.
+	 */
+	do {
+		ret = hid_hw_raw_request(steam->hdev, 0,
+				buf, size + 1,
+				HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+		if (ret != -EPIPE)
+			break;
+		msleep(20);
+	} while (--retries);
+
+	kfree(buf);
+	if (ret < 0)
+		hid_err(steam->hdev, "%s: error %d (%*ph)\n", __func__,
+				ret, size, cmd);
+	return ret;
+}
+
+static inline int steam_send_report_byte(struct steam_device *steam, u8 cmd)
+{
+	return steam_send_report(steam, &cmd, 1);
+}
+
+static int steam_write_registers(struct steam_device *steam,
+		/* u8 reg, u16 val */...)
+{
+	/* Send: 0x87 len (reg valLo valHi)* */
+	u8 reg;
+	u16 val;
+	u8 cmd[64] = {STEAM_CMD_WRITE_REGISTER, 0x00};
+	va_list args;
+
+	va_start(args, steam);
+	for (;;) {
+		reg = va_arg(args, int);
+		if (reg == 0)
+			break;
+		val = va_arg(args, int);
+		cmd[cmd[1] + 2] = reg;
+		cmd[cmd[1] + 3] = val & 0xff;
+		cmd[cmd[1] + 4] = val >> 8;
+		cmd[1] += 3;
+	}
+	va_end(args);
+
+	return steam_send_report(steam, cmd, 2 + cmd[1]);
+}
+
+static int steam_get_serial(struct steam_device *steam)
+{
+	/*
+	 * Send: 0xae 0x15 0x01
+	 * Recv: 0xae 0x15 0x01 serialnumber (10 chars)
+	 */
+	int ret;
+	u8 cmd[] = {STEAM_CMD_GET_SERIAL, 0x15, 0x01};
+	u8 reply[3 + STEAM_SERIAL_LEN + 1];
+
+	ret = steam_send_report(steam, cmd, sizeof(cmd));
+	if (ret < 0)
+		return ret;
+	ret = steam_recv_report(steam, reply, sizeof(reply));
+	if (ret < 0)
+		return ret;
+	if (reply[0] != 0xae || reply[1] != 0x15 || reply[2] != 0x01)
+		return -EIO;
+	reply[3 + STEAM_SERIAL_LEN] = 0;
+	strlcpy(steam->serial_no, reply + 3, sizeof(steam->serial_no));
+	return 0;
+}
+
+/*
+ * This command requests the wireless adaptor to post an event
+ * with the connection status. Useful if this driver is loaded when
+ * the controller is already connected.
+ */
+static inline int steam_request_conn_status(struct steam_device *steam)
+{
+	return steam_send_report_byte(steam, STEAM_CMD_REQUEST_COMM_STATUS);
+}
+
+static void steam_set_lizard_mode(struct steam_device *steam, bool enable)
+{
+	if (enable) {
+		/* enable esc, enter, cursors */
+		steam_send_report_byte(steam, STEAM_CMD_DEFAULT_MAPPINGS);
+		/* enable mouse */
+		steam_send_report_byte(steam, STEAM_CMD_DEFAULT_MOUSE);
+		steam_write_registers(steam,
+			STEAM_REG_RPAD_MARGIN, 0x01, /* enable margin */
+			0);
+	} else {
+		/* disable esc, enter, cursor */
+		steam_send_report_byte(steam, STEAM_CMD_CLEAR_MAPPINGS);
+		steam_write_registers(steam,
+			STEAM_REG_RPAD_MODE, 0x07, /* disable mouse */
+			STEAM_REG_RPAD_MARGIN, 0x00, /* disable margin */
+			0);
+	}
+}
+
+static void steam_update_lizard_mode(struct steam_device *steam)
+{
+	mutex_lock(&steam->mutex);
+	if (!steam->client_opened) {
+		if (steam->input_opened)
+			steam_set_lizard_mode(steam, false);
+		else
+			steam_set_lizard_mode(steam, lizard_mode);
+	}
+	mutex_unlock(&steam->mutex);
+}
+
+static int steam_input_open(struct input_dev *dev)
+{
+	struct steam_device *steam = input_get_drvdata(dev);
+	int ret;
+
+	ret = hid_hw_open(steam->hdev);
+	if (ret)
+		return ret;
+
+	mutex_lock(&steam->mutex);
+	steam->input_opened = true;
+	if (!steam->client_opened && lizard_mode)
+		steam_set_lizard_mode(steam, false);
+	mutex_unlock(&steam->mutex);
+	return 0;
+}
+
+static void steam_input_close(struct input_dev *dev)
+{
+	struct steam_device *steam = input_get_drvdata(dev);
+
+	mutex_lock(&steam->mutex);
+	steam->input_opened = false;
+	if (!steam->client_opened && lizard_mode)
+		steam_set_lizard_mode(steam, true);
+	mutex_unlock(&steam->mutex);
+
+	hid_hw_close(steam->hdev);
+}
+
+static int steam_register(struct steam_device *steam)
+{
+	struct hid_device *hdev = steam->hdev;
+	struct input_dev *input;
+	int ret;
+
+	rcu_read_lock();
+	input = rcu_dereference(steam->input);
+	rcu_read_unlock();
+	if (input) {
+		dbg_hid("%s: already connected\n", __func__);
+		return 0;
+	}
+
+	/*
+	 * Unlikely, but getting the serial could fail, and it is not so
+	 * important, so make up a serial number and go on.
+	 */
+	if (steam_get_serial(steam) < 0)
+		strlcpy(steam->serial_no, "XXXXXXXXXX",
+				sizeof(steam->serial_no));
+
+	hid_info(hdev, "Steam Controller '%s' connected",
+			steam->serial_no);
+
+	input = input_allocate_device();
+	if (!input)
+		return -ENOMEM;
+
+	input_set_drvdata(input, steam);
+	input->dev.parent = &hdev->dev;
+	input->open = steam_input_open;
+	input->close = steam_input_close;
+
+	input->name = (steam->quirks & STEAM_QUIRK_WIRELESS) ?
+		"Wireless Steam Controller" :
+		"Steam Controller";
+	input->phys = hdev->phys;
+	input->uniq = steam->serial_no;
+	input->id.bustype = hdev->bus;
+	input->id.vendor = hdev->vendor;
+	input->id.product = hdev->product;
+	input->id.version = hdev->version;
+
+	input_set_capability(input, EV_KEY, BTN_TR2);
+	input_set_capability(input, EV_KEY, BTN_TL2);
+	input_set_capability(input, EV_KEY, BTN_TR);
+	input_set_capability(input, EV_KEY, BTN_TL);
+	input_set_capability(input, EV_KEY, BTN_Y);
+	input_set_capability(input, EV_KEY, BTN_B);
+	input_set_capability(input, EV_KEY, BTN_X);
+	input_set_capability(input, EV_KEY, BTN_A);
+	input_set_capability(input, EV_KEY, BTN_DPAD_UP);
+	input_set_capability(input, EV_KEY, BTN_DPAD_RIGHT);
+	input_set_capability(input, EV_KEY, BTN_DPAD_LEFT);
+	input_set_capability(input, EV_KEY, BTN_DPAD_DOWN);
+	input_set_capability(input, EV_KEY, BTN_SELECT);
+	input_set_capability(input, EV_KEY, BTN_MODE);
+	input_set_capability(input, EV_KEY, BTN_START);
+	input_set_capability(input, EV_KEY, BTN_GEAR_DOWN);
+	input_set_capability(input, EV_KEY, BTN_GEAR_UP);
+	input_set_capability(input, EV_KEY, BTN_THUMBR);
+	input_set_capability(input, EV_KEY, BTN_THUMBL);
+	input_set_capability(input, EV_KEY, BTN_THUMB);
+	input_set_capability(input, EV_KEY, BTN_THUMB2);
+
+	input_set_abs_params(input, ABS_HAT2Y, 0, 255, 0, 0);
+	input_set_abs_params(input, ABS_HAT2X, 0, 255, 0, 0);
+	input_set_abs_params(input, ABS_X, -32767, 32767, 0, 0);
+	input_set_abs_params(input, ABS_Y, -32767, 32767, 0, 0);
+	input_set_abs_params(input, ABS_RX, -32767, 32767,
+			STEAM_PAD_FUZZ, 0);
+	input_set_abs_params(input, ABS_RY, -32767, 32767,
+			STEAM_PAD_FUZZ, 0);
+	input_set_abs_params(input, ABS_HAT0X, -32767, 32767,
+			STEAM_PAD_FUZZ, 0);
+	input_set_abs_params(input, ABS_HAT0Y, -32767, 32767,
+			STEAM_PAD_FUZZ, 0);
+	input_abs_set_res(input, ABS_X, STEAM_JOYSTICK_RESOLUTION);
+	input_abs_set_res(input, ABS_Y, STEAM_JOYSTICK_RESOLUTION);
+	input_abs_set_res(input, ABS_RX, STEAM_PAD_RESOLUTION);
+	input_abs_set_res(input, ABS_RY, STEAM_PAD_RESOLUTION);
+	input_abs_set_res(input, ABS_HAT0X, STEAM_PAD_RESOLUTION);
+	input_abs_set_res(input, ABS_HAT0Y, STEAM_PAD_RESOLUTION);
+	input_abs_set_res(input, ABS_HAT2Y, STEAM_TRIGGER_RESOLUTION);
+	input_abs_set_res(input, ABS_HAT2X, STEAM_TRIGGER_RESOLUTION);
+
+	ret = input_register_device(input);
+	if (ret)
+		goto input_register_fail;
+
+	rcu_assign_pointer(steam->input, input);
+
+	return 0;
+
+input_register_fail:
+	input_free_device(input);
+	return ret;
+}
+
+static void steam_unregister(struct steam_device *steam)
+{
+	struct input_dev *input;
+
+	rcu_read_lock();
+	input = rcu_dereference(steam->input);
+	rcu_read_unlock();
+
+	if (input) {
+		RCU_INIT_POINTER(steam->input, NULL);
+		synchronize_rcu();
+		hid_info(steam->hdev, "Steam Controller '%s' disconnected",
+				steam->serial_no);
+		input_unregister_device(input);
+	}
+}
+
+static void steam_work_connect_cb(struct work_struct *work)
+{
+	struct steam_device *steam = container_of(work, struct steam_device,
+							work_connect);
+	unsigned long flags;
+	bool connected;
+	int ret;
+
+	spin_lock_irqsave(&steam->lock, flags);
+	connected = steam->connected;
+	spin_unlock_irqrestore(&steam->lock, flags);
+
+	if (connected) {
+		ret = steam_register(steam);
+		if (ret) {
+			hid_err(steam->hdev,
+				"%s:steam_register failed with error %d\n",
+				__func__, ret);
+		}
+	} else {
+		steam_unregister(steam);
+	}
+}
+
+static bool steam_is_valve_interface(struct hid_device *hdev)
+{
+	struct hid_report_enum *rep_enum;
+
+	/*
+	 * The wired device creates 3 interfaces:
+	 *  0: emulated mouse.
+	 *  1: emulated keyboard.
+	 *  2: the real game pad.
+	 * The wireless device creates 5 interfaces:
+	 *  0: emulated keyboard.
+	 *  1-4: slots where up to 4 real game pads will be connected to.
+	 * We know which one is the real gamepad interface because they are the
+	 * only ones with a feature report.
+	 */
+	rep_enum = &hdev->report_enum[HID_FEATURE_REPORT];
+	return !list_empty(&rep_enum->report_list);
+}
+
+static int steam_client_ll_parse(struct hid_device *hdev)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+
+	return hid_parse_report(hdev, steam->hdev->dev_rdesc,
+			steam->hdev->dev_rsize);
+}
+
+static int steam_client_ll_start(struct hid_device *hdev)
+{
+	return 0;
+}
+
+static void steam_client_ll_stop(struct hid_device *hdev)
+{
+}
+
+static int steam_client_ll_open(struct hid_device *hdev)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+	int ret;
+
+	ret = hid_hw_open(steam->hdev);
+	if (ret)
+		return ret;
+
+	mutex_lock(&steam->mutex);
+	steam->client_opened = true;
+	mutex_unlock(&steam->mutex);
+	return ret;
+}
+
+static void steam_client_ll_close(struct hid_device *hdev)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+
+	mutex_lock(&steam->mutex);
+	steam->client_opened = false;
+	if (steam->input_opened)
+		steam_set_lizard_mode(steam, false);
+	else
+		steam_set_lizard_mode(steam, lizard_mode);
+	mutex_unlock(&steam->mutex);
+
+	hid_hw_close(steam->hdev);
+}
+
+static int steam_client_ll_raw_request(struct hid_device *hdev,
+				unsigned char reportnum, u8 *buf,
+				size_t count, unsigned char report_type,
+				int reqtype)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+
+	return hid_hw_raw_request(steam->hdev, reportnum, buf, count,
+			report_type, reqtype);
+}
+
+static struct hid_ll_driver steam_client_ll_driver = {
+	.parse = steam_client_ll_parse,
+	.start = steam_client_ll_start,
+	.stop = steam_client_ll_stop,
+	.open = steam_client_ll_open,
+	.close = steam_client_ll_close,
+	.raw_request = steam_client_ll_raw_request,
+};
+
+static struct hid_device *steam_create_client_hid(struct hid_device *hdev)
+{
+	struct hid_device *client_hdev;
+
+	client_hdev = hid_allocate_device();
+	if (IS_ERR(client_hdev))
+		return client_hdev;
+
+	client_hdev->ll_driver = &steam_client_ll_driver;
+	client_hdev->dev.parent = hdev->dev.parent;
+	client_hdev->bus = hdev->bus;
+	client_hdev->vendor = hdev->vendor;
+	client_hdev->product = hdev->product;
+	strlcpy(client_hdev->name, hdev->name,
+			sizeof(client_hdev->name));
+	strlcpy(client_hdev->phys, hdev->phys,
+			sizeof(client_hdev->phys));
+	/*
+	 * Since we use the same device info than the real interface to
+	 * trick userspace, we will be calling steam_probe recursively.
+	 * We need to recognize the client interface somehow.
+	 */
+	client_hdev->group = HID_GROUP_STEAM;
+	return client_hdev;
+}
+
+static int steam_probe(struct hid_device *hdev,
+				const struct hid_device_id *id)
+{
+	struct steam_device *steam;
+	int ret;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev,
+			"%s:parse of hid interface failed\n", __func__);
+		return ret;
+	}
+
+	/*
+	 * The virtual client_dev is only used for hidraw.
+	 * Also avoid the recursive probe.
+	 */
+	if (hdev->group == HID_GROUP_STEAM)
+		return hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	/*
+	 * The non-valve interfaces (mouse and keyboard emulation) are
+	 * connected without changes.
+	 */
+	if (!steam_is_valve_interface(hdev))
+		return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+
+	steam = devm_kzalloc(&hdev->dev, sizeof(*steam), GFP_KERNEL);
+	if (!steam) {
+		ret = -ENOMEM;
+		goto steam_alloc_fail;
+	}
+	steam->hdev = hdev;
+	hid_set_drvdata(hdev, steam);
+	spin_lock_init(&steam->lock);
+	mutex_init(&steam->mutex);
+	steam->quirks = id->driver_data;
+	INIT_WORK(&steam->work_connect, steam_work_connect_cb);
+
+	steam->client_hdev = steam_create_client_hid(hdev);
+	if (IS_ERR(steam->client_hdev)) {
+		ret = PTR_ERR(steam->client_hdev);
+		goto client_hdev_fail;
+	}
+	hid_set_drvdata(steam->client_hdev, steam);
+
+	/*
+	 * With the real steam controller interface, do not connect hidraw.
+	 * Instead, create the client_hid and connect that.
+	 */
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_HIDRAW);
+	if (ret)
+		goto hid_hw_start_fail;
+
+	ret = hid_add_device(steam->client_hdev);
+	if (ret)
+		goto client_hdev_add_fail;
+
+	if (steam->quirks & STEAM_QUIRK_WIRELESS) {
+		ret = hid_hw_open(hdev);
+		if (ret) {
+			hid_err(hdev,
+				"%s:hid_hw_open for wireless\n",
+				__func__);
+			goto hid_hw_open_fail;
+		}
+		hid_info(hdev, "Steam wireless receiver connected");
+		steam_request_conn_status(steam);
+	} else {
+		ret = steam_register(steam);
+		if (ret) {
+			hid_err(hdev,
+				"%s:steam_register failed with error %d\n",
+				__func__, ret);
+			goto input_register_fail;
+		}
+	}
+
+	mutex_lock(&steam_devices_lock);
+	steam_update_lizard_mode(steam);
+	list_add(&steam->list, &steam_devices);
+	mutex_unlock(&steam_devices_lock);
+
+	return 0;
+
+hid_hw_open_fail:
+input_register_fail:
+client_hdev_add_fail:
+	hid_hw_stop(hdev);
+hid_hw_start_fail:
+	hid_destroy_device(steam->client_hdev);
+client_hdev_fail:
+	cancel_work_sync(&steam->work_connect);
+steam_alloc_fail:
+	hid_err(hdev, "%s: failed with error %d\n",
+			__func__, ret);
+	return ret;
+}
+
+static void steam_remove(struct hid_device *hdev)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+
+	if (!steam || hdev->group == HID_GROUP_STEAM) {
+		hid_hw_stop(hdev);
+		return;
+	}
+
+	mutex_lock(&steam_devices_lock);
+	list_del(&steam->list);
+	mutex_unlock(&steam_devices_lock);
+
+	hid_destroy_device(steam->client_hdev);
+	steam->client_opened = false;
+	cancel_work_sync(&steam->work_connect);
+	if (steam->quirks & STEAM_QUIRK_WIRELESS) {
+		hid_info(hdev, "Steam wireless receiver disconnected");
+		hid_hw_close(hdev);
+	}
+	hid_hw_stop(hdev);
+	steam_unregister(steam);
+}
+
+static void steam_do_connect_event(struct steam_device *steam, bool connected)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&steam->lock, flags);
+	steam->connected = connected;
+	spin_unlock_irqrestore(&steam->lock, flags);
+
+	if (schedule_work(&steam->work_connect) == 0)
+		dbg_hid("%s: connected=%d event already queued\n",
+				__func__, connected);
+}
+
+/*
+ * Some input data in the protocol has the opposite sign.
+ * Clamp the values to 32767..-32767 so that the range is
+ * symmetrical and can be negated safely.
+ */
+static inline s16 steam_le16(u8 *data)
+{
+	s16 x = (s16) le16_to_cpup((__le16 *)data);
+
+	return x == -32768 ? -32767 : x;
+}
+
+/*
+ * The size for this message payload is 60.
+ * The known values are:
+ *  (* values are not sent through wireless)
+ *  (* accelerator/gyro is disabled by default)
+ *  Offset| Type  | Mapped to |Meaning
+ * -------+-------+-----------+--------------------------
+ *  4-7   | u32   | --        | sequence number
+ *  8-10  | 24bit | see below | buttons
+ *  11    | u8    | ABS_HAT2Y | left trigger
+ *  12    | u8    | ABS_HAT2X | right trigger
+ *  13-15 | --    | --        | always 0
+ *  16-17 | s16   | ABS_X/ABS_HAT0X     | X value
+ *  18-19 | s16   | ABS_Y/ABS_HAT0Y     | Y value
+ *  20-21 | s16   | ABS_RX    | right-pad X value
+ *  22-23 | s16   | ABS_RY    | right-pad Y value
+ *  24-25 | s16   | --        | * left trigger
+ *  26-27 | s16   | --        | * right trigger
+ *  28-29 | s16   | --        | * accelerometer X value
+ *  30-31 | s16   | --        | * accelerometer Y value
+ *  32-33 | s16   | --        | * accelerometer Z value
+ *  34-35 | s16   | --        | gyro X value
+ *  36-36 | s16   | --        | gyro Y value
+ *  38-39 | s16   | --        | gyro Z value
+ *  40-41 | s16   | --        | quaternion W value
+ *  42-43 | s16   | --        | quaternion X value
+ *  44-45 | s16   | --        | quaternion Y value
+ *  46-47 | s16   | --        | quaternion Z value
+ *  48-49 | --    | --        | always 0
+ *  50-51 | s16   | --        | * left trigger (uncalibrated)
+ *  52-53 | s16   | --        | * right trigger (uncalibrated)
+ *  54-55 | s16   | --        | * joystick X value (uncalibrated)
+ *  56-57 | s16   | --        | * joystick Y value (uncalibrated)
+ *  58-59 | s16   | --        | * left-pad X value
+ *  60-61 | s16   | --        | * left-pad Y value
+ *  62-63 | u16   | --        | * battery voltage
+ *
+ * The buttons are:
+ *  Bit  | Mapped to  | Description
+ * ------+------------+--------------------------------
+ *  8.0  | BTN_TR2    | right trigger fully pressed
+ *  8.1  | BTN_TL2    | left trigger fully pressed
+ *  8.2  | BTN_TR     | right shoulder
+ *  8.3  | BTN_TL     | left shoulder
+ *  8.4  | BTN_Y      | button Y
+ *  8.5  | BTN_B      | button B
+ *  8.6  | BTN_X      | button X
+ *  8.7  | BTN_A      | button A
+ *  9.0  | BTN_DPAD_UP    | lef-pad up
+ *  9.1  | BTN_DPAD_RIGHT | lef-pad right
+ *  9.2  | BTN_DPAD_LEFT  | lef-pad left
+ *  9.3  | BTN_DPAD_DOWN  | lef-pad down
+ *  9.4  | BTN_SELECT | menu left
+ *  9.5  | BTN_MODE   | steam logo
+ *  9.6  | BTN_START  | menu right
+ *  9.7  | BTN_GEAR_DOWN | left back lever
+ * 10.0  | BTN_GEAR_UP   | right back lever
+ * 10.1  | --         | left-pad clicked
+ * 10.2  | BTN_THUMBR | right-pad clicked
+ * 10.3  | BTN_THUMB  | left-pad touched (but see explanation below)
+ * 10.4  | BTN_THUMB2 | right-pad touched
+ * 10.5  | --         | unknown
+ * 10.6  | BTN_THUMBL | joystick clicked
+ * 10.7  | --         | lpad_and_joy
+ */
+
+static void steam_do_input_event(struct steam_device *steam,
+		struct input_dev *input, u8 *data)
+{
+	/* 24 bits of buttons */
+	u8 b8, b9, b10;
+	s16 x, y;
+	bool lpad_touched, lpad_and_joy;
+
+	b8 = data[8];
+	b9 = data[9];
+	b10 = data[10];
+
+	input_report_abs(input, ABS_HAT2Y, data[11]);
+	input_report_abs(input, ABS_HAT2X, data[12]);
+
+	/*
+	 * These two bits tells how to interpret the values X and Y.
+	 * lpad_and_joy tells that the joystick and the lpad are used at the
+	 * same time.
+	 * lpad_touched tells whether X/Y are to be read as lpad coord or
+	 * joystick values.
+	 * (lpad_touched || lpad_and_joy) tells if the lpad is really touched.
+	 */
+	lpad_touched = b10 & BIT(3);
+	lpad_and_joy = b10 & BIT(7);
+	x = steam_le16(data + 16);
+	y = -steam_le16(data + 18);
+
+	input_report_abs(input, lpad_touched ? ABS_HAT0X : ABS_X, x);
+	input_report_abs(input, lpad_touched ? ABS_HAT0Y : ABS_Y, y);
+	/* Check if joystick is centered */
+	if (lpad_touched && !lpad_and_joy) {
+		input_report_abs(input, ABS_X, 0);
+		input_report_abs(input, ABS_Y, 0);
+	}
+	/* Check if lpad is untouched */
+	if (!(lpad_touched || lpad_and_joy)) {
+		input_report_abs(input, ABS_HAT0X, 0);
+		input_report_abs(input, ABS_HAT0Y, 0);
+	}
+
+	input_report_abs(input, ABS_RX, steam_le16(data + 20));
+	input_report_abs(input, ABS_RY, -steam_le16(data + 22));
+
+	input_event(input, EV_KEY, BTN_TR2, !!(b8 & BIT(0)));
+	input_event(input, EV_KEY, BTN_TL2, !!(b8 & BIT(1)));
+	input_event(input, EV_KEY, BTN_TR, !!(b8 & BIT(2)));
+	input_event(input, EV_KEY, BTN_TL, !!(b8 & BIT(3)));
+	input_event(input, EV_KEY, BTN_Y, !!(b8 & BIT(4)));
+	input_event(input, EV_KEY, BTN_B, !!(b8 & BIT(5)));
+	input_event(input, EV_KEY, BTN_X, !!(b8 & BIT(6)));
+	input_event(input, EV_KEY, BTN_A, !!(b8 & BIT(7)));
+	input_event(input, EV_KEY, BTN_SELECT, !!(b9 & BIT(4)));
+	input_event(input, EV_KEY, BTN_MODE, !!(b9 & BIT(5)));
+	input_event(input, EV_KEY, BTN_START, !!(b9 & BIT(6)));
+	input_event(input, EV_KEY, BTN_GEAR_DOWN, !!(b9 & BIT(7)));
+	input_event(input, EV_KEY, BTN_GEAR_UP, !!(b10 & BIT(0)));
+	input_event(input, EV_KEY, BTN_THUMBR, !!(b10 & BIT(2)));
+	input_event(input, EV_KEY, BTN_THUMBL, !!(b10 & BIT(6)));
+	input_event(input, EV_KEY, BTN_THUMB, lpad_touched || lpad_and_joy);
+	input_event(input, EV_KEY, BTN_THUMB2, !!(b10 & BIT(4)));
+	input_event(input, EV_KEY, BTN_DPAD_UP, !!(b9 & BIT(0)));
+	input_event(input, EV_KEY, BTN_DPAD_RIGHT, !!(b9 & BIT(1)));
+	input_event(input, EV_KEY, BTN_DPAD_LEFT, !!(b9 & BIT(2)));
+	input_event(input, EV_KEY, BTN_DPAD_DOWN, !!(b9 & BIT(3)));
+
+	input_sync(input);
+}
+
+static int steam_raw_event(struct hid_device *hdev,
+			struct hid_report *report, u8 *data,
+			int size)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+	struct input_dev *input;
+
+	if (!steam)
+		return 0;
+
+	if (steam->client_opened)
+		hid_input_report(steam->client_hdev, HID_FEATURE_REPORT,
+				data, size, 0);
+	/*
+	 * All messages are size=64, all values little-endian.
+	 * The format is:
+	 *  Offset| Meaning
+	 * -------+--------------------------------------------
+	 *  0-1   | always 0x01, 0x00, maybe protocol version?
+	 *  2     | type of message
+	 *  3     | length of the real payload (not checked)
+	 *  4-n   | payload data, depends on the type
+	 *
+	 * There are these known types of message:
+	 *  0x01: input data (60 bytes)
+	 *  0x03: wireless connect/disconnect (1 byte)
+	 *  0x04: battery status (11 bytes)
+	 */
+
+	if (size != 64 || data[0] != 1 || data[1] != 0)
+		return 0;
+
+	switch (data[2]) {
+	case STEAM_EV_INPUT_DATA:
+		if (steam->client_opened)
+			return 0;
+		rcu_read_lock();
+		input = rcu_dereference(steam->input);
+		if (likely(input)) {
+			steam_do_input_event(steam, input, data);
+		} else {
+			dbg_hid("%s: input data without connect event\n",
+					__func__);
+			steam_do_connect_event(steam, true);
+		}
+		rcu_read_unlock();
+		break;
+	case STEAM_EV_CONNECT:
+		/*
+		 * The payload of this event is a single byte:
+		 *  0x01: disconnected.
+		 *  0x02: connected.
+		 */
+		switch (data[4]) {
+		case 0x01:
+			steam_do_connect_event(steam, false);
+			break;
+		case 0x02:
+			steam_do_connect_event(steam, true);
+			break;
+		}
+		break;
+	case STEAM_EV_BATTERY:
+		/* TODO: battery info */
+		break;
+	}
+	return 0;
+}
+
+static int steam_param_set_lizard_mode(const char *val,
+					const struct kernel_param *kp)
+{
+	struct steam_device *steam;
+	int ret;
+
+	ret = param_set_bool(val, kp);
+	if (ret)
+		return ret;
+
+	mutex_lock(&steam_devices_lock);
+	list_for_each_entry(steam, &steam_devices, list) {
+		steam_update_lizard_mode(steam);
+	}
+	mutex_unlock(&steam_devices_lock);
+	return 0;
+}
+
+static const struct kernel_param_ops steam_lizard_mode_ops = {
+	.set	= steam_param_set_lizard_mode,
+	.get	= param_get_bool,
+};
+
+module_param_cb(lizard_mode, &steam_lizard_mode_ops, &lizard_mode, 0644);
+MODULE_PARM_DESC(lizard_mode,
+	"Enable mouse and keyboard emulation (lizard mode) when the gamepad is not in use");
+
+static const struct hid_device_id steam_controllers[] = {
+	{ /* Wired Steam Controller */
+	  HID_USB_DEVICE(USB_VENDOR_ID_VALVE,
+		USB_DEVICE_ID_STEAM_CONTROLLER)
+	},
+	{ /* Wireless Steam Controller */
+	  HID_USB_DEVICE(USB_VENDOR_ID_VALVE,
+		USB_DEVICE_ID_STEAM_CONTROLLER_WIRELESS),
+	  .driver_data = STEAM_QUIRK_WIRELESS
+	},
+	{}
+};
+
+MODULE_DEVICE_TABLE(hid, steam_controllers);
+
+static struct hid_driver steam_controller_driver = {
+	.name = "hid-steam",
+	.id_table = steam_controllers,
+	.probe = steam_probe,
+	.remove = steam_remove,
+	.raw_event = steam_raw_event,
+};
+
+module_hid_driver(steam_controller_driver);