Input: add sur40 driver for Samsung SUR40 (aka MS Surface 2.0/Pixelsense)

This patch adds support for the built-in multitouch sensor in the Samsung
SUR40 touchscreen device, also known as Microsoft Surface 2.0 or Microsoft
Pixelsense. Support for raw video output from the sensor as well as the
accelerometer will be added in a later patch.
Signed-off-by: Florian Echtler <floe@butterbrot.org>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/Kconfig

@@ -906,6 +906,17 @@ config TOUCHSCREEN_STMPE
 	  To compile this driver as a module, choose M here: the
 	  module will be called stmpe-ts.
 
+config TOUCHSCREEN_SUR40
+	tristate "Samsung SUR40 (Surface 2.0/PixelSense) touchscreen"
+	depends on USB
+	select INPUT_POLLDEV
+	help
+	  Say Y here if you want support for the Samsung SUR40 touchscreen
+	  (also known as Microsoft Surface 2.0 or Microsoft PixelSense).
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sur40.
+
 config TOUCHSCREEN_TPS6507X
 	tristate "TPS6507x based touchscreens"
 	depends on I2C

drivers/input/touchscreen/Makefile

@@ -54,6 +54,7 @@ obj-$(CONFIG_TOUCHSCREEN_PIXCIR)	+= pixcir_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o
 obj-$(CONFIG_TOUCHSCREEN_ST1232)	+= st1232.o
 obj-$(CONFIG_TOUCHSCREEN_STMPE)		+= stmpe-ts.o
+obj-$(CONFIG_TOUCHSCREEN_SUR40)		+= sur40.o
 obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC)	+= ti_am335x_tsc.o
 obj-$(CONFIG_TOUCHSCREEN_TNETV107X)	+= tnetv107x-ts.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)	+= touchit213.o

drivers/input/touchscreen/sur40.c

+/*
+ * Surface2.0/SUR40/PixelSense input driver
+ *
+ * Copyright (c) 2013 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>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#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>
+
+/* 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 unknown;        /* always 0x01 or 0x02 (no idea what this is?) */
+
+	__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[32];
+
+} __packed;
+
+/* combined header/blob data */
+struct sur40_data {
+	struct sur40_header header;
+	struct sur40_blob   blobs[];
+} __packed;
+
+
+/* version information */
+#define DRIVER_SHORT   "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
+
+/* polling interval (ms) */
+#define POLL_INTERVAL 10
+
+/* 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_UNKNOWN1    0xb3 /*  5 bytes           */
+#define SUR40_UNKNOWN2    0xc1 /* 24 bytes           */
+
+#define SUR40_GET_STATE   0xc5 /*  4 bytes state (?) */
+#define SUR40_GET_SENSORS 0xb1 /*  8 bytes sensors   */
+
+/*
+ * Note: an earlier, non-public version of this driver used USB_RECIP_ENDPOINT
+ * here by mistake which is very likely to have corrupted the firmware EEPROM
+ * on two separate SUR40 devices. Thanks to Alan Stern who spotted this bug.
+ * Should you ever run into a similar problem, the background story to this
+ * incident and instructions on how to fix the corrupted EEPROM are available
+ * at https://floe.butterbrot.org/matrix/hacking/surface/brick.html
+*/
+
+struct sur40_state {
+
+	struct usb_device *usbdev;
+	struct device *dev;
+	struct input_polled_dev *input;
+
+	struct sur40_data *bulk_in_buffer;
+	size_t bulk_in_size;
+	u8 bulk_in_epaddr;
+
+	char phys[64];
+};
+
+static int sur40_command(struct sur40_state *dev,
+			 u8 command, u16 index, void *buffer, u16 size)
+{
+	return usb_control_msg(dev->usbdev, usb_rcvctrlpipe(dev->usbdev, 0),
+			       command,
+			       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			       0x00, index, buffer, size, 1000);
+}
+
+/* Initialization routine, called from sur40_open */
+static int sur40_init(struct sur40_state *dev)
+{
+	int result;
+	u8 buffer[24];
+
+	/* stupidly replay the original MS driver init sequence */
+	result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
+	if (result < 0)
+		return result;
+
+	result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
+	if (result < 0)
+		return result;
+
+	result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
+	if (result < 0)
+		return result;
+
+	result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
+	if (result < 0)
+		return result;
+
+	result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
+	if (result < 0)
+		return result;
+
+	result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
+
+	/*
+	 * Discard the result buffer - no known data inside except
+	 * some version strings, maybe extract these sometime...
+	 */
+
+	return result;
+}
+
+/*
+ * Callback routines from input_polled_dev
+ */
+
+/* Enable the device, polling will now start. */
+static void sur40_open(struct input_polled_dev *polldev)
+{
+	struct sur40_state *sur40 = polldev->private;
+
+	dev_dbg(sur40->dev, "open\n");
+	sur40_init(sur40);
+}
+
+/* Disable device, polling has stopped. */
+static void sur40_close(struct input_polled_dev *polldev)
+{
+	struct sur40_state *sur40 = polldev->private;
+
+	dev_dbg(sur40->dev, "close\n");
+	/*
+	 * There is no known way to stop the device, so we simply
+	 * stop polling.
+	 */
+}
+
+/*
+ * This function is called when a whole contact has been processed,
+ * so that it can assign it to a slot and store the data there.
+ */
+static void sur40_report_blob(struct sur40_blob *blob, struct input_dev *input)
+{
+	int wide, major, minor;
+
+	int bb_size_x = le16_to_cpu(blob->bb_size_x);
+	int bb_size_y = le16_to_cpu(blob->bb_size_y);
+
+	int pos_x = le16_to_cpu(blob->pos_x);
+	int pos_y = le16_to_cpu(blob->pos_y);
+
+	int ctr_x = le16_to_cpu(blob->ctr_x);
+	int ctr_y = le16_to_cpu(blob->ctr_y);
+
+	int slotnum = input_mt_get_slot_by_key(input, blob->blob_id);
+	if (slotnum < 0 || slotnum >= MAX_CONTACTS)
+		return;
+
+	input_mt_slot(input, slotnum);
+	input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
+	wide = (bb_size_x > bb_size_y);
+	major = max(bb_size_x, bb_size_y);
+	minor = min(bb_size_x, bb_size_y);
+
+	input_report_abs(input, ABS_MT_POSITION_X, pos_x);
+	input_report_abs(input, ABS_MT_POSITION_Y, pos_y);
+	input_report_abs(input, ABS_MT_TOOL_X, ctr_x);
+	input_report_abs(input, ABS_MT_TOOL_Y, ctr_y);
+
+	/* TODO: use a better orientation measure */
+	input_report_abs(input, ABS_MT_ORIENTATION, wide);
+	input_report_abs(input, ABS_MT_TOUCH_MAJOR, major);
+	input_report_abs(input, ABS_MT_TOUCH_MINOR, minor);
+}
+
+/* core function: poll for new input data */
+static void sur40_poll(struct input_polled_dev *polldev)
+{
+
+	struct sur40_state *sur40 = polldev->private;
+	struct input_dev *input = polldev->input;
+	int result, bulk_read, need_blobs, packet_blobs, i;
+	u32 packet_id;
+
+	struct sur40_header *header = &sur40->bulk_in_buffer->header;
+	struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0];
+
+	dev_dbg(sur40->dev, "poll\n");
+
+	need_blobs = -1;
+
+	do {
+
+		/* perform a blocking bulk read to get data from the device */
+		result = usb_bulk_msg(sur40->usbdev,
+			usb_rcvbulkpipe(sur40->usbdev, sur40->bulk_in_epaddr),
+			sur40->bulk_in_buffer, sur40->bulk_in_size,
+			&bulk_read, 1000);
+
+		dev_dbg(sur40->dev, "received %d bytes\n", bulk_read);
+
+		if (result < 0) {
+			dev_err(sur40->dev, "error in usb_bulk_read\n");
+			return;
+		}
+
+		result = bulk_read - sizeof(struct sur40_header);
+
+		if (result % sizeof(struct sur40_blob) != 0) {
+			dev_err(sur40->dev, "transfer size mismatch\n");
+			return;
+		}
+
+		/* first packet? */
+		if (need_blobs == -1) {
+			need_blobs = le16_to_cpu(header->count);
+			dev_dbg(sur40->dev, "need %d blobs\n", need_blobs);
+			packet_id = header->packet_id;
+		}
+
+		/*
+		 * Sanity check. when video data is also being retrieved, the
+		 * packet ID will usually increase in the middle of a series
+		 * instead of at the end.
+		 */
+		if (packet_id != header->packet_id)
+			dev_warn(sur40->dev, "packet ID mismatch\n");
+
+		packet_blobs = result / sizeof(struct sur40_blob);
+		dev_dbg(sur40->dev, "received %d blobs\n", packet_blobs);
+
+		/* packets always contain at least 4 blobs, even if empty */
+		if (packet_blobs > need_blobs)
+			packet_blobs = need_blobs;
+
+		for (i = 0; i < packet_blobs; i++) {
+			need_blobs--;
+			dev_dbg(sur40->dev, "processing blob\n");
+			sur40_report_blob(&(inblob[i]), input);
+		}
+
+	} while (need_blobs > 0);
+
+	input_mt_sync_frame(input);
+	input_sync(input);
+}
+
+/* Initialize input device parameters. */
+static void sur40_input_setup(struct input_dev *input_dev)
+{
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(EV_ABS, input_dev->evbit);
+
+	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
+			     0, SENSOR_RES_X, 0, 0);
+	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
+			     0, SENSOR_RES_Y, 0, 0);
+
+	input_set_abs_params(input_dev, ABS_MT_TOOL_X,
+			     0, SENSOR_RES_X, 0, 0);
+	input_set_abs_params(input_dev, ABS_MT_TOOL_Y,
+			     0, SENSOR_RES_Y, 0, 0);
+
+	/* max value unknown, but major/minor axis
+	 * can never be larger than screen */
+	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
+			     0, SENSOR_RES_X, 0, 0);
+	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
+			     0, SENSOR_RES_Y, 0, 0);
+
+	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
+
+	input_mt_init_slots(input_dev, MAX_CONTACTS,
+			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+}
+
+/* Check candidate USB interface. */
+static int sur40_probe(struct usb_interface *interface,
+		       const struct usb_device_id *id)
+{
+	struct usb_device *usbdev = interface_to_usbdev(interface);
+	struct sur40_state *sur40;
+	struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor *endpoint;
+	struct input_polled_dev *poll_dev;
+	int error;
+
+	/* Check if we really have the right interface. */
+	iface_desc = &interface->altsetting[0];
+	if (iface_desc->desc.bInterfaceClass != 0xFF)
+		return -ENODEV;
+
+	/* Use endpoint #4 (0x86). */
+	endpoint = &iface_desc->endpoint[4].desc;
+	if (endpoint->bEndpointAddress != TOUCH_ENDPOINT)
+		return -ENODEV;
+
+	/* Allocate memory for our device state and initialize it. */
+	sur40 = kzalloc(sizeof(struct sur40_state), GFP_KERNEL);
+	if (!sur40)
+		return -ENOMEM;
+
+	poll_dev = input_allocate_polled_device();
+	if (!poll_dev) {
+		error = -ENOMEM;
+		goto err_free_dev;
+	}
+
+	/* Set up polled input device control structure */
+	poll_dev->private = sur40;
+	poll_dev->poll_interval = POLL_INTERVAL;
+	poll_dev->open = sur40_open;
+	poll_dev->poll = sur40_poll;
+	poll_dev->close = sur40_close;
+
+	/* Set up regular input device structure */
+	sur40_input_setup(poll_dev->input);
+
+	poll_dev->input->name = "Samsung SUR40";
+	usb_to_input_id(usbdev, &poll_dev->input->id);
+	usb_make_path(usbdev, sur40->phys, sizeof(sur40->phys));
+	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
+	poll_dev->input->phys = sur40->phys;
+	poll_dev->input->dev.parent = &interface->dev;
+
+	sur40->usbdev = usbdev;
+	sur40->dev = &interface->dev;
+	sur40->input = poll_dev;
+
+	/* use the bulk-in endpoint tested above */
+	sur40->bulk_in_size = usb_endpoint_maxp(endpoint);
+	sur40->bulk_in_epaddr = endpoint->bEndpointAddress;
+	sur40->bulk_in_buffer = kmalloc(sur40->bulk_in_size, GFP_KERNEL);
+	if (!sur40->bulk_in_buffer) {
+		dev_err(&interface->dev, "Unable to allocate input buffer.");
+		error = -ENOMEM;
+		goto err_free_polldev;
+	}
+
+	error = input_register_polled_device(poll_dev);
+	if (error) {
+		dev_err(&interface->dev,
+			"Unable to register polled input device.");
+		goto err_free_buffer;
+	}
+
+	/* we can register the device now, as it is ready */
+	usb_set_intfdata(interface, sur40);
+	dev_dbg(&interface->dev, "%s is now attached\n", DRIVER_DESC);
+
+	return 0;
+
+err_free_buffer:
+	kfree(sur40->bulk_in_buffer);
+err_free_polldev:
+	input_free_polled_device(sur40->input);
+err_free_dev:
+	kfree(sur40);
+
+	return error;
+}
+
+/* Unregister device & clean up. */
+static void sur40_disconnect(struct usb_interface *interface)
+{
+	struct sur40_state *sur40 = usb_get_intfdata(interface);
+
+	input_unregister_polled_device(sur40->input);
+	input_free_polled_device(sur40->input);
+	kfree(sur40->bulk_in_buffer);
+	kfree(sur40);
+
+	usb_set_intfdata(interface, NULL);
+	dev_dbg(&interface->dev, "%s is now disconnected\n", DRIVER_DESC);
+}
+
+static const struct usb_device_id sur40_table[] = {
+	{ USB_DEVICE(ID_MICROSOFT, ID_SUR40) },  /* Samsung SUR40 */
+	{ }                                      /* terminating null entry */
+};
+MODULE_DEVICE_TABLE(usb, sur40_table);
+
+/* USB-specific object needed to register this driver with the USB subsystem. */
+static struct usb_driver sur40_driver = {
+	.name = DRIVER_SHORT,
+	.probe = sur40_probe,
+	.disconnect = sur40_disconnect,
+	.id_table = sur40_table,
+};
+
+module_usb_driver(sur40_driver);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");