path: root/drivers/input/touchscreen/sur40.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Surface2.0/SUR40/PixelSense input driver
 *
 * Copyright (c) 2014 by Florian 'floe' Echtler <floe@butterbrot.org>
 *
 * Derived from the USB Skeleton driver 1.1,
 * Copyright (c) 2003 Greg Kroah-Hartman (greg@kroah.com)
 *
 * and from the Apple USB BCM5974 multitouch driver,
 * Copyright (c) 2008 Henrik Rydberg (rydberg@euromail.se)
 *
 * and from the generic hid-multitouch driver,
 * Copyright (c) 2010-2012 Stephane Chatty <chatty@enac.fr>
 *
 * and from the v4l2-pci-skeleton driver,
 * Copyright (c) Copyright 2014 Cisco Systems, Inc.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/printk.h>
#include <linux/input-polldev.h>
#include <linux/input/mt.h>
#include <linux/usb/input.h>
#include <linux/videodev2.h>
#include <media/v4l2-device.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-ctrls.h>
#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-dma-sg.h>

/* read 512 bytes from endpoint 0x86 -> get header + blobs */
struct sur40_header {

	__le16 type;       /* always 0x0001 */
	__le16 count;      /* count of blobs (if 0: continue prev. packet) */

	__le32 packet_id;  /* unique ID for all packets in one frame */

	__le32 timestamp;  /* milliseconds (inc. by 16 or 17 each frame) */
	__le32 unknown;    /* "epoch?" always 02/03 00 00 00 */

} __packed;

struct sur40_blob {

	__le16 blob_id;

	u8 action;         /* 0x02 = enter/exit, 0x03 = update (?) */
	u8 type;           /* bitmask (0x01 blob,  0x02 touch, 0x04 tag) */

	__le16 bb_pos_x;   /* upper left corner of bounding box */
	__le16 bb_pos_y;

	__le16 bb_size_x;  /* size of bounding box */
	__le16 bb_size_y;

	__le16 pos_x;      /* finger tip position */
	__le16 pos_y;

	__le16 ctr_x;      /* centroid position */
	__le16 ctr_y;

	__le16 axis_x;     /* somehow related to major/minor axis, mostly: */
	__le16 axis_y;     /* axis_x == bb_size_y && axis_y == bb_size_x */

	__le32 angle;      /* orientation in radians relative to x axis -
	                      actually an IEEE754 float, don't use in kernel */

	__le32 area;       /* size in pixels/pressure (?) */

	u8 padding[24];

	__le32 tag_id;     /* valid when type == 0x04 (SUR40_TAG) */
	__le32 unknown;

} __packed;

/* combined header/blob data */
struct sur40_data {
	struct sur40_header header;
	struct sur40_blob   blobs[];
} __packed;

/* read 512 bytes from endpoint 0x82 -> get header below
 * continue reading 16k blocks until header.size bytes read */
struct sur40_image_header {
	__le32 magic;     /* "SUBF" */
	__le32 packet_id;
	__le32 size;      /* always 0x0007e900 = 960x540 */
	__le32 timestamp; /* milliseconds (increases by 16 or 17 each frame) */
	__le32 unknown;   /* "epoch?" always 02/03 00 00 00 */
} __packed;

/* version information */
#define DRIVER_SHORT   "sur40"
#define DRIVER_LONG    "Samsung SUR40"
#define DRIVER_AUTHOR  "Florian 'floe' Echtler <floe@butterbrot.org>"
#define DRIVER_DESC    "Surface2.0/SUR40/PixelSense input driver"

/* vendor and device IDs */
#define ID_MICROSOFT 0x045e
#define ID_SUR40     0x0775

/* sensor resolution */
#define SENSOR_RES_X 1920
#define SENSOR_RES_Y 1080

/* touch data endpoint */
#define TOUCH_ENDPOINT 0x86

/* video data endpoint */
#define VIDEO_ENDPOINT 0x82

/* video header fields */
#define VIDEO_HEADER_MAGIC 0x46425553
#define VIDEO_PACKET_SIZE  16384

/* polling interval (ms) */
#define POLL_INTERVAL 1

/* maximum number of contacts FIXME: this is a guess? */
#define MAX_CONTACTS 64

/* control commands */
#define SUR40_GET_VERSION 0xb0 /* 12 bytes string    */
#define SUR40_ACCEL_CAPS  0xb3 /*  5 bytes           */
#define SUR40_SENSOR_CAPS 0xc1 /* 24 bytes           */

#define SUR40_POKE        0xc5 /* poke register byte */
#define SUR40_PEEK        0xc4 /* 48 bytes registers */

#define SUR40_GET_STATE   0xc5 /*  4 bytes state (?) */
#define SUR40_GET_SENSORS 0xb1 /*  8 bytes sensors   */

#define SUR40_BLOB	0x01
#define SUR40_TOUCH	0x02
#define SUR40_TAG	0x04

/* video controls */
#define SUR40_BRIGHTNESS_MAX 0xff
#define SUR40_BRIGHTNESS_MIN 0x00
#define SUR40_BRIGHTNESS_DEF 0xff

#define SUR40_CONTRAST_MAX 0x0f
#define SUR40_CONTRAST_MIN 0x00
#define SUR40_CONTRAST_DEF 0x0a

#define SUR40_GAIN_MAX 0x09
#define SUR40_GAIN_MIN 0x00
#define SUR40_GAIN_DEF 0x08

#define SUR40_BACKLIGHT_MAX 0x01
#define SUR40_BACKLIGHT_MIN 0x00
#define SUR40_BACKLIGHT_DEF 0x01

#define sur40_str(s) #s
#define SUR40_PARAM_RANGE(lo, hi) " (range " sur40_str(lo) "-" sur40_str(hi) ")"

/* module parameters */
static uint brightness = SUR40_BRIGHTNESS_DEF;
module_param(brightness, uint, 0644);
MODULE_PARM_DESC(brightness, "set initial brightness"
	SUR40_PARAM_RANGE(SUR40_BRIGHTNESS_MIN, SUR40_BRIGHTNESS_MAX));
static uint contrast = SUR40_CONTRAST_DEF;
module_param(contrast, uint, 0644);
MODULE_PARM_DESC(contrast, "set initial contrast"
	SUR40_PARAM_RANGE(SUR40_CONTRAST_MIN, SUR40_CONTRAST_MAX));
static uint gain = SUR40_GAIN_DEF;
module_param(gain, uint, 0644);
MODULE_PARM_DESC(gain, "set initial gain"
	SUR40_PARAM_RANGE(SUR40_GAIN_MIN, SUR40_GAIN_MAX));

static const struct v4l2_pix_format sur40_pix_format[] = {
	{
		.pixelformat = V4L2_TCH_FMT_TU08,
		.width  = SENSOR_RES_X / 2,
		.height = SENSOR_RES_Y / 2,
		.field = V4L2_FIELD_NONE,
		.colorspace = V4L2_COLORSPACE_RAW,
		.bytesperline = SENSOR_RES_X / 2,
		.sizeimage = (SENSOR_RES_X/2) * (SENSOR_RES_Y/2),
	},
	{
		.pixelformat = V4L2_PIX_FMT_GREY,
		.width  =