path: root/drivers/hid/hid-steam.c

// 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 removed, to avoid double input of the same
 *    user action.
 * When the client is closed, this input device will be created again.
 *
 * 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 <linux/power_supply.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;
	struct input_dev __rcu *input;
	unsigned long quirks;
	struct work_struct work_connect;
	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 = 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