[RFC PATCH v6 0/1] hid-steam driver with user mode client dection

[RFC PATCH v6 0/1] hid-steam driver with user mode client dection

[Rodrigo Rivas Costa]

This is a RFC for the problem of how to work with the Steam Controller from
a kernel driver without disturbing the user mode drivers.

The main user mode driver is the Steam Controller itself. From now on I will
call any user mode driver a "hidraw client" because that is the mode most of
them use.

Steam Client is able to use a raw libusb user mode driver, but it
looks like it does so only if hidraw is not available, so I'm not currently
concerned with those.

This driver, as is, does the following:
 1. It keeps the mouse/keyboard emulation (lizard mode) working while the
    hid-steam input device is not in use.
 2. When the hid-steam input device is opened, lizard mode is disabled, but
    ONLY IF there are no hidraw clients. This is necessary because with the
    lizard mode on, a gesture in the gamepad can make several unrelated input
    events and games go crazy.
 3. When the hid-steam input device is closed, lizard mode is re-enabled, but
    ONLY IF there are no hidraw clients.
 4. If while the hid-steam input device is opened, a hidraw client starts,
    then the input events are disabled for this driver, in order to avoid 
    double inputs in games that read all available game controllers.
 4. If a hid-steam input device and a hidraw client are running, and then the
    hidraw client finishes, then lizard mode is disabled, just like in 2.

Other than what to do exactly, IMO, there are three tricky parts that deserve
the RFC:
 1. Is the procedure avobe the right way to do it?
 2. How to detect whether a hidraw client is in use. Currently I'm looking at
    hid_device::ll_open_count and compare with the number of times I called
    hid_hw_open() - hid_hw_close(). I'm exploring using a custom hid_ll_driver
    instead...
 3. How to disable the lizard mode. Currently I'm sending a few feature
    reports that prevent the hardware from sending keyboard/mouse events. But
    maybe they can be disabled at hid level, so we can avoid messing with the
    hardware configuration, and the possible incompatibilities and races that
    arise.

PS. I've collapsed the patch-set into a single bigger commit, because my
original split makes sense no longer. Sorry for the inconvenience.

Thank you in advance for any comment.

Rodrigo Rivas Costa (1):
  HID: add driver for Valve Steam Controller

 drivers/hid/Kconfig     |   8 +
 drivers/hid/Makefile    |   1 +
 drivers/hid/hid-ids.h   |   4 +
 drivers/hid/hid-steam.c | 874 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 887 insertions(+)
 create mode 100644 drivers/hid/hid-steam.c

-- 
2.16.2

[RFC PATCH v6 1/1] HID: add driver for Valve Steam Controller

[Rodrigo Rivas Costa]

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 direct USB access
and a creates a uinput virtual gamepad.

Signed-off-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
---
 drivers/hid/Kconfig     |   8 +
 drivers/hid/Makefile    |   1 +
 drivers/hid/hid-ids.h   |   4 +
 drivers/hid/hid-steam.c | 874 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 887 insertions(+)
 create mode 100644 drivers/hid/hid-steam.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 779c5ae47f36..de5f4849bfe4 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -811,6 +811,14 @@ 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 235bd2a7b333..e146c257285a 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -94,6 +94,7 @@ 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 a0baa5ba5b84..3014991e5d4b 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -987,6 +987,10 @@
 #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..88acd8f7fbf3
--- /dev/null
+++ b/drivers/hid/hid-steam.c
@@ -0,0 +1,874 @@
+// 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.
+ *
+ * For additional functions, such as disabling the virtual mouse/keyboard or
+ * changing the right-pad margin 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 <linux/power_supply.h>
+#include "hid-ids.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>");
+
+#define STEAM_QUIRK_WIRELESS		BIT(0)
+#define STEAM_IS_ONLY_CLIENT		BIT(1)
+
+#define STEAM_SERIAL_LEN 10
+/* 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
+
+struct steam_device {
+	spinlock_t lock;
+	struct mutex mutex;
+	struct hid_device *hdev;
+	int hid_usage_count;
+	struct input_dev __rcu *input;
+	unsigned long quirks;
+	struct work_struct work_connect, work_disable_lizard;
+	bool connected;
+	char serial_no[STEAM_SERIAL_LEN + 1];
+	struct power_supply_desc battery_desc;
+	struct power_supply __rcu *battery;
+	u8 battery_charge;
+	u16 voltage;
+};
+
+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 = 10;
+	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;
+		steam_recv_report(steam, NULL, 0);
+		msleep(50);
+	} 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 inline int steam_write_register(struct steam_device *steam, u8 reg, u16 value)
+{
+    u8 cmd[] = {0x87, 0x03, reg, value & 0xFF, value >> 8};
+    return steam_send_report(steam, cmd, sizeof(cmd));
+}
+
+static int steam_get_serial(struct steam_device *steam)
+{
+	/*
+	 * Send: 0xae 0x15 0x01
+	 * Recv: 0xae 0x15 0x01 serialnumber (10 chars)
+	 */
+	int ret;
+	u8 cmd[] = {0xae, 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;
+	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, 0xb4);
+}
+
+static void steam_set_lizard_mode(struct steam_device *steam, bool enabled)
+{
+	if (enabled) {
+		steam_send_report_byte(steam, 0x8e); //enable mouse
+		steam_send_report_byte(steam, 0x85); //enable esc, enter and cursor keys
+	} else {
+		steam_send_report_byte(steam, 0x81); //disable esc, enter and cursor keys
+		steam_write_register(steam, 0x08, 0x07); //disable mouse
+	}
+}
+
+static bool steam_is_only_client(struct steam_device *steam)
+{
+	unsigned int count = steam->hdev->ll_open_count;
+	if (steam->hid_usage_count == ((steam->quirks & STEAM_QUIRK_WIRELESS) ? 1 : 0))
+		return false;
+
+	return count == steam->hid_usage_count;
+}
+
+static void steam_disable_lizard_mode(struct steam_device *steam)
+{
+	mutex_lock(&steam->mutex);
+	if (!(steam->quirks & STEAM_IS_ONLY_CLIENT) &&
+			steam_is_only_client(steam)) {
+		steam_set_lizard_mode(steam, false);
+		steam->quirks |= STEAM_IS_ONLY_CLIENT;
+	}
+	mutex_unlock(&steam->mutex);
+}
+
+static void steam_enable_lizard_mode(struct steam_device *steam)
+{
+	mutex_lock(&steam->mutex);
+	if (steam->quirks & STEAM_IS_ONLY_CLIENT) {
+		if (steam_is_only_client(steam))
+			steam_set_lizard_mode(steam, true);
+		steam->quirks &= ~STEAM_IS_ONLY_CLIENT;
+	}
+	mutex_unlock(&steam->mutex);
+}
+
+static int steam_input_open(struct input_dev *dev)
+{
+	struct steam_device *steam = input_get_drvdata(dev);
+	int res;
+
+	res = hid_hw_open(steam->hdev);
+	if (res)
+		return res;
+	++steam->hid_usage_count;
+	steam_disable_lizard_mode(steam);
+	return 0;
+}
+
+static void steam_input_close(struct input_dev *dev)
+{
+	struct steam_device *steam = input_get_drvdata(dev);
+
+	steam_enable_lizard_mode(steam);
+	hid_hw_close(steam->hdev);
+	--steam->hid_usage_count;
+}
+
+static enum power_supply_property steam_battery_props[] = {
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_SCOPE,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+};
+
+static int steam_battery_get_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				union power_supply_propval *val)
+{
+	struct steam_device *steam = power_supply_get_drvdata(psy);
+	unsigned long flags;
+	s16 volts;
+	u8 batt;
+	int ret = 0;
+
+	spin_lock_irqsave(&steam->lock, flags);
+	volts = steam->voltage;
+	batt = steam->battery_charge;
+	spin_unlock_irqrestore(&steam->lock, flags);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_PRESENT:
+		val->intval = 1;
+		break;
+	case POWER_SUPPLY_PROP_SCOPE:
+		val->intval = POWER_SUPPLY_SCOPE_DEVICE;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = volts * 1000; /* mV -> uV */
+		break;
+	case POWER_SUPPLY_PROP_CAPACITY:
+		val->intval = batt;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+
+static int steam_battery_register(struct steam_device *steam)
+{
+	struct power_supply *battery;
+	struct power_supply_config battery_cfg = { .drv_data = steam, };
+	unsigned long flags;
+	int ret;
+
+	steam->battery_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+	steam->battery_desc.properties = steam_battery_props;
+	steam->battery_desc.num_properties = ARRAY_SIZE(steam_battery_props);
+	steam->battery_desc.get_property = steam_battery_get_property;
+	steam->battery_desc.name = devm_kasprintf(&steam->hdev->dev,
+			GFP_KERNEL, "steam-controller-%s-battery",
+			steam->serial_no);
+	if (!steam->battery_desc.name)
+		return -ENOMEM;
+
+	/* avoid the warning of 0% battery while waiting for the first info */
+	spin_lock_irqsave(&steam->lock, flags);
+	steam->voltage = 3000;
+	steam->battery_charge = 100;
+	spin_unlock_irqrestore(&steam->lock, flags);
+
+	battery = power_supply_register(&steam->hdev->dev,
+			&steam->battery_desc, &battery_cfg);
+	if (IS_ERR(battery)) {
+		ret = PTR_ERR(battery);
+		hid_err(steam->hdev,
+				"%s:power_supply_register failed with error %d\n",
+				__func__, ret);
+		return ret;
+	}
+	rcu_assign_pointer(steam->battery, battery);
+	power_supply_powers(battery, &steam->hdev->dev);
+	return 0;
+}
+
+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;
+	}
+
+	ret = steam_get_serial(steam);
+	if (ret)
+		return ret;
+
+	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_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_Z, 0, 255, 0, 0);
+	input_set_abs_params(input, ABS_RZ, 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_HAT1X, -32767, 32767,
+			STEAM_PAD_FUZZ, 0);
+	input_set_abs_params(input, ABS_HAT1Y, -32767, 32767,
+			STEAM_PAD_FUZZ, 0);
+	input_set_abs_params(input, ABS_HAT0X, -1, 1, 0, 0);
+	input_set_abs_params(input, ABS_HAT0Y, -1, 1, 0, 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_HAT1X, STEAM_PAD_RESOLUTION);
+	input_abs_set_res(input, ABS_HAT1Y, STEAM_PAD_RESOLUTION);
+	input_abs_set_res(input, ABS_Z, STEAM_TRIGGER_RESOLUTION);
+	input_abs_set_res(input, ABS_RZ, STEAM_TRIGGER_RESOLUTION);
+
+	ret = input_register_device(input);
+	if (ret)
+		goto input_register_fail;
+
+	rcu_assign_pointer(steam->input, input);
+
+	/* ignore battery errors, we can live without it */
+	if (steam->quirks & STEAM_QUIRK_WIRELESS)
+		steam_battery_register(steam);
+
+	return 0;
+
+input_register_fail:
+	input_free_device(input);
+	return ret;
+}
+
+static void steam_unregister(struct steam_device *steam)
+{
+	struct input_dev *input;
+	struct power_supply *battery;
+
+	rcu_read_lock();
+	input = rcu_dereference(steam->input);
+	battery = rcu_dereference(steam->battery);
+	rcu_read_unlock();
+
+	if (battery) {
+		RCU_INIT_POINTER(steam->battery, NULL);
+		synchronize_rcu();
+		power_supply_unregister(battery);
+	}
+	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 void steam_work_disable_lizard_cb(struct work_struct *work)
+{
+	struct steam_device *steam = container_of(work, struct steam_device,
+							work_disable_lizard);
+	steam_disable_lizard_mode(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_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;
+	}
+
+	/*
+	 * Connect the HID device so that Steam Controller keeps on working
+	 * without changes.
+	 */
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev,
+			"%s:hid_hw_start failed with error %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	if (!steam_is_valve_interface(hdev))
+		return 0;
+
+	/*
+	 * From this point on, if anything fails return 0 and ignores
+	 * the error, so that the default HID devices are still bound.
+	 */
+	steam = devm_kzalloc(&hdev->dev, sizeof(*steam), GFP_KERNEL);
+	if (!steam) {
+		ret = -ENOMEM;
+		goto mem_fail;
+	}
+
+	spin_lock_init(&steam->lock);
+	mutex_init(&steam->mutex);
+	steam->hdev = hdev;
+	hid_set_drvdata(hdev, steam);
+	steam->quirks = id->driver_data;
+	INIT_WORK(&steam->work_connect, steam_work_connect_cb);
+	INIT_WORK(&steam->work_disable_lizard, steam_work_disable_lizard_cb);
+
+	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;
+		}
+		++steam->hid_usage_count;
+		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;
+		}
+	}
+
+	return 0;
+
+input_register_fail:
+hid_hw_open_fail:
+	cancel_work_sync(&steam->work_disable_lizard);
+	cancel_work_sync(&steam->work_connect);
+	hid_set_drvdata(hdev, NULL);
+mem_fail:
+	hid_err(hdev, "%s: failed with error %d\n",
+			__func__, ret);
+	return 0;
+}
+
+static void steam_remove(struct hid_device *hdev)
+{
+	struct steam_device *steam = hid_get_drvdata(hdev);
+
+	if (!steam) {
+		hid_hw_stop(hdev);
+		return;
+	}
+
+	if (steam->quirks & STEAM_QUIRK_WIRELESS) {
+		hid_info(hdev, "Steam wireless receiver disconnected");
+		hid_hw_close(hdev);
+		--steam->hid_usage_count;
+	}
+	hid_hw_stop(hdev);
+	cancel_work_sync(&steam->work_disable_lizard);
+	cancel_work_sync(&steam->work_connect);
+	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);
+}
+
+/*
+ * 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_Z     | left trigger
+ *  12    | u8    | ABS_RZ    | right trigger
+ *  13-15 | --    | --        | always 0
+ *  16-17 | s16   | ABS_X     | X value
+ *  18-19 | s16   | ABS_Y     | 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  | -ABS_HAT0Y | lef-pad up
+ *  9.1  | +ABS_HAT0X | lef-pad right
+ *  9.2  | -ABS_HAT0X | lef-pad left
+ *  9.3  | +ABS_HAT0Y | 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;
+	bool lpad_touched, lpad_and_joy;
+
+	b8 = data[8];
+	b9 = data[9];
+	b10 = data[10];
+
+	input_report_abs(input, ABS_Z, data[11]);
+	input_report_abs(input, ABS_RZ, 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);
+	input_report_abs(input, lpad_touched ? ABS_HAT1X : ABS_X,
+			(s16) le16_to_cpup((__le16 *)(data + 16)));
+	input_report_abs(input, lpad_touched ? ABS_HAT1Y : ABS_Y,
+			-(s16) le16_to_cpup((__le16 *)(data + 18)));
+	/* 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_HAT1X, 0);
+		input_report_abs(input, ABS_HAT1Y, 0);
+	}
+
+	input_report_abs(input, ABS_RX,
+			(s16) le16_to_cpup((__le16 *)(data + 20)));
+	input_report_abs(input, ABS_RY,
+			-(s16) le16_to_cpup((__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_report_abs(input, ABS_HAT0X,
+			!!(b9 & BIT(1)) - !!(b9 & BIT(2)));
+	input_report_abs(input, ABS_HAT0Y,
+			!!(b9 & BIT(3)) - !!(b9 & BIT(0)));
+
+	input_sync(input);
+}
+
+/*
+ * The size for this message payload is 11.
+ * The known values are:
+ *  Offset| Type  | Meaning
+ * -------+-------+---------------------------
+ *  4-7   | u32   | sequence number
+ *  8-11  | --    | always 0
+ *  12-13 | u16   | voltage (mV)
+ *  14    | u8    | battery percent
+ */
+static void steam_do_battery_event(struct steam_device *steam,
+		struct power_supply *battery, u8 *data)
+{
+	unsigned long flags;
+
+	s16 volts = le16_to_cpup((__le16 *)(data + 12));
+	u8 batt = data[14];
+
+	/* Creating the battery may have failed */
+	rcu_read_lock();
+	battery = rcu_dereference(steam->battery);
+	if (likely(battery)) {
+		spin_lock_irqsave(&steam->lock, flags);
+		steam->voltage = volts;
+		steam->battery_charge = batt;
+		spin_unlock_irqrestore(&steam->lock, flags);
+		power_supply_changed(battery);
+	}
+	rcu_read_unlock();
+}
+
+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;
+	struct power_supply *battery;
+
+	if (!steam)
+		return 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 0x01:
+		if (!steam_is_only_client(steam)) {
+			steam->quirks &= ~STEAM_IS_ONLY_CLIENT;
+			return 0;
+		}
+		if (!(steam->quirks & STEAM_IS_ONLY_CLIENT))
+			schedule_work(&steam->work_disable_lizard);
+		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 0x03:
+		/*
+		 * 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 0x04:
+		if (steam->quirks & STEAM_QUIRK_WIRELESS) {
+			rcu_read_lock();
+			battery = rcu_dereference(steam->battery);
+			if (likely(battery)) {
+				steam_do_battery_event(steam, battery, data);
+			} else {
+				dbg_hid(
+				  "%s: battery data without connect event\n",
+				  __func__);
+				steam_do_connect_event(steam, true);
+			}
+			rcu_read_unlock();
+		}
+		break;
+	}
+	return 0;
+}
+
+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);
-- 
2.16.2