1 /*
2  * Surface2.0/SUR40/PixelSense input driver
3  *
4  * Copyright (c) 2014 by Florian 'floe' Echtler <floe@butterbrot.org>
5  *
6  * Derived from the USB Skeleton driver 1.1,
7  * Copyright (c) 2003 Greg Kroah-Hartman (greg@kroah.com)
8  *
9  * and from the Apple USB BCM5974 multitouch driver,
10  * Copyright (c) 2008 Henrik Rydberg (rydberg@euromail.se)
11  *
12  * and from the generic hid-multitouch driver,
13  * Copyright (c) 2010-2012 Stephane Chatty <chatty@enac.fr>
14  *
15  * and from the v4l2-pci-skeleton driver,
16  * Copyright (c) Copyright 2014 Cisco Systems, Inc.
17  *
18  * This program is free software; you can redistribute it and/or
19  * modify it under the terms of the GNU General Public License as
20  * published by the Free Software Foundation; either version 2 of
21  * the License, or (at your option) any later version.
22  */
23 
24 #include <linux/kernel.h>
25 #include <linux/errno.h>
26 #include <linux/delay.h>
27 #include <linux/init.h>
28 #include <linux/slab.h>
29 #include <linux/module.h>
30 #include <linux/completion.h>
31 #include <linux/uaccess.h>
32 #include <linux/usb.h>
33 #include <linux/printk.h>
34 #include <linux/input-polldev.h>
35 #include <linux/input/mt.h>
36 #include <linux/usb/input.h>
37 #include <linux/videodev2.h>
38 #include <media/v4l2-device.h>
39 #include <media/v4l2-dev.h>
40 #include <media/v4l2-ioctl.h>
41 #include <media/videobuf2-v4l2.h>
42 #include <media/videobuf2-dma-sg.h>
43 
44 /* read 512 bytes from endpoint 0x86 -> get header + blobs */
45 struct sur40_header {
46 
47 	__le16 type;       /* always 0x0001 */
48 	__le16 count;      /* count of blobs (if 0: continue prev. packet) */
49 
50 	__le32 packet_id;  /* unique ID for all packets in one frame */
51 
52 	__le32 timestamp;  /* milliseconds (inc. by 16 or 17 each frame) */
53 	__le32 unknown;    /* "epoch?" always 02/03 00 00 00 */
54 
55 } __packed;
56 
57 struct sur40_blob {
58 
59 	__le16 blob_id;
60 
61 	u8 action;         /* 0x02 = enter/exit, 0x03 = update (?) */
62 	u8 unknown;        /* always 0x01 or 0x02 (no idea what this is?) */
63 
64 	__le16 bb_pos_x;   /* upper left corner of bounding box */
65 	__le16 bb_pos_y;
66 
67 	__le16 bb_size_x;  /* size of bounding box */
68 	__le16 bb_size_y;
69 
70 	__le16 pos_x;      /* finger tip position */
71 	__le16 pos_y;
72 
73 	__le16 ctr_x;      /* centroid position */
74 	__le16 ctr_y;
75 
76 	__le16 axis_x;     /* somehow related to major/minor axis, mostly: */
77 	__le16 axis_y;     /* axis_x == bb_size_y && axis_y == bb_size_x */
78 
79 	__le32 angle;      /* orientation in radians relative to x axis -
80 	                      actually an IEEE754 float, don't use in kernel */
81 
82 	__le32 area;       /* size in pixels/pressure (?) */
83 
84 	u8 padding[32];
85 
86 } __packed;
87 
88 /* combined header/blob data */
89 struct sur40_data {
90 	struct sur40_header header;
91 	struct sur40_blob   blobs[];
92 } __packed;
93 
94 /* read 512 bytes from endpoint 0x82 -> get header below
95  * continue reading 16k blocks until header.size bytes read */
96 struct sur40_image_header {
97 	__le32 magic;     /* "SUBF" */
98 	__le32 packet_id;
99 	__le32 size;      /* always 0x0007e900 = 960x540 */
100 	__le32 timestamp; /* milliseconds (increases by 16 or 17 each frame) */
101 	__le32 unknown;   /* "epoch?" always 02/03 00 00 00 */
102 } __packed;
103 
104 /* version information */
105 #define DRIVER_SHORT   "sur40"
106 #define DRIVER_LONG    "Samsung SUR40"
107 #define DRIVER_AUTHOR  "Florian 'floe' Echtler <floe@butterbrot.org>"
108 #define DRIVER_DESC    "Surface2.0/SUR40/PixelSense input driver"
109 
110 /* vendor and device IDs */
111 #define ID_MICROSOFT 0x045e
112 #define ID_SUR40     0x0775
113 
114 /* sensor resolution */
115 #define SENSOR_RES_X 1920
116 #define SENSOR_RES_Y 1080
117 
118 /* touch data endpoint */
119 #define TOUCH_ENDPOINT 0x86
120 
121 /* video data endpoint */
122 #define VIDEO_ENDPOINT 0x82
123 
124 /* video header fields */
125 #define VIDEO_HEADER_MAGIC 0x46425553
126 #define VIDEO_PACKET_SIZE  16384
127 
128 /* polling interval (ms) */
129 #define POLL_INTERVAL 1
130 
131 /* maximum number of contacts FIXME: this is a guess? */
132 #define MAX_CONTACTS 64
133 
134 /* control commands */
135 #define SUR40_GET_VERSION 0xb0 /* 12 bytes string    */
136 #define SUR40_UNKNOWN1    0xb3 /*  5 bytes           */
137 #define SUR40_UNKNOWN2    0xc1 /* 24 bytes           */
138 
139 #define SUR40_GET_STATE   0xc5 /*  4 bytes state (?) */
140 #define SUR40_GET_SENSORS 0xb1 /*  8 bytes sensors   */
141 
142 static const struct v4l2_pix_format sur40_pix_format[] = {
143 	{
144 		.pixelformat = V4L2_TCH_FMT_TU08,
145 		.width  = SENSOR_RES_X / 2,
146 		.height = SENSOR_RES_Y / 2,
147 		.field = V4L2_FIELD_NONE,
148 		.colorspace = V4L2_COLORSPACE_SRGB,
149 		.bytesperline = SENSOR_RES_X / 2,
150 		.sizeimage = (SENSOR_RES_X/2) * (SENSOR_RES_Y/2),
151 	},
152 	{
153 		.pixelformat = V4L2_PIX_FMT_GREY,
154 		.width  = SENSOR_RES_X / 2,
155 		.height = SENSOR_RES_Y / 2,
156 		.field = V4L2_FIELD_NONE,
157 		.colorspace = V4L2_COLORSPACE_SRGB,
158 		.bytesperline = SENSOR_RES_X / 2,
159 		.sizeimage = (SENSOR_RES_X/2) * (SENSOR_RES_Y/2),
160 	}
161 };
162 
163 /* master device state */
164 struct sur40_state {
165 
166 	struct usb_device *usbdev;
167 	struct device *dev;
168 	struct input_polled_dev *input;
169 
170 	struct v4l2_device v4l2;
171 	struct video_device vdev;
172 	struct mutex lock;
173 	struct v4l2_pix_format pix_fmt;
174 
175 	struct vb2_queue queue;
176 	struct list_head buf_list;
177 	spinlock_t qlock;
178 	int sequence;
179 
180 	struct sur40_data *bulk_in_buffer;
181 	size_t bulk_in_size;
182 	u8 bulk_in_epaddr;
183 
184 	char phys[64];
185 };
186 
187 struct sur40_buffer {
188 	struct vb2_v4l2_buffer vb;
189 	struct list_head list;
190 };
191 
192 /* forward declarations */
193 static const struct video_device sur40_video_device;
194 static const struct vb2_queue sur40_queue;
195 static void sur40_process_video(struct sur40_state *sur40);
196 
197 /*
198  * Note: an earlier, non-public version of this driver used USB_RECIP_ENDPOINT
199  * here by mistake which is very likely to have corrupted the firmware EEPROM
200  * on two separate SUR40 devices. Thanks to Alan Stern who spotted this bug.
201  * Should you ever run into a similar problem, the background story to this
202  * incident and instructions on how to fix the corrupted EEPROM are available
203  * at https://floe.butterbrot.org/matrix/hacking/surface/brick.html
204 */
205 
206 /* command wrapper */
207 static int sur40_command(struct sur40_state *dev,
208 			 u8 command, u16 index, void *buffer, u16 size)
209 {
210 	return usb_control_msg(dev->usbdev, usb_rcvctrlpipe(dev->usbdev, 0),
211 			       command,
212 			       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
213 			       0x00, index, buffer, size, 1000);
214 }
215 
216 /* Initialization routine, called from sur40_open */
217 static int sur40_init(struct sur40_state *dev)
218 {
219 	int result;
220 	u8 *buffer;
221 
222 	buffer = kmalloc(24, GFP_KERNEL);
223 	if (!buffer) {
224 		result = -ENOMEM;
225 		goto error;
226 	}
227 
228 	/* stupidly replay the original MS driver init sequence */
229 	result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
230 	if (result < 0)
231 		goto error;
232 
233 	result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
234 	if (result < 0)
235 		goto error;
236 
237 	result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
238 	if (result < 0)
239 		goto error;
240 
241 	result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
242 	if (result < 0)
243 		goto error;
244 
245 	result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
246 	if (result < 0)
247 		goto error;
248 
249 	result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
250 
251 	/*
252 	 * Discard the result buffer - no known data inside except
253 	 * some version strings, maybe extract these sometime...
254 	 */
255 error:
256 	kfree(buffer);
257 	return result;
258 }
259 
260 /*
261  * Callback routines from input_polled_dev
262  */
263 
264 /* Enable the device, polling will now start. */
265 static void sur40_open(struct input_polled_dev *polldev)
266 {
267 	struct sur40_state *sur40 = polldev->private;
268 
269 	dev_dbg(sur40->dev, "open\n");
270 	sur40_init(sur40);
271 }
272 
273 /* Disable device, polling has stopped. */
274 static void sur40_close(struct input_polled_dev *polldev)
275 {
276 	struct sur40_state *sur40 = polldev->private;
277 
278 	dev_dbg(sur40->dev, "close\n");
279 	/*
280 	 * There is no known way to stop the device, so we simply
281 	 * stop polling.
282 	 */
283 }
284 
285 /*
286  * This function is called when a whole contact has been processed,
287  * so that it can assign it to a slot and store the data there.
288  */
289 static void sur40_report_blob(struct sur40_blob *blob, struct input_dev *input)
290 {
291 	int wide, major, minor;
292 
293 	int bb_size_x = le16_to_cpu(blob->bb_size_x);
294 	int bb_size_y = le16_to_cpu(blob->bb_size_y);
295 
296 	int pos_x = le16_to_cpu(blob->pos_x);
297 	int pos_y = le16_to_cpu(blob->pos_y);
298 
299 	int ctr_x = le16_to_cpu(blob->ctr_x);
300 	int ctr_y = le16_to_cpu(blob->ctr_y);
301 
302 	int slotnum = input_mt_get_slot_by_key(input, blob->blob_id);
303 	if (slotnum < 0 || slotnum >= MAX_CONTACTS)
304 		return;
305 
306 	input_mt_slot(input, slotnum);
307 	input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
308 	wide = (bb_size_x > bb_size_y);
309 	major = max(bb_size_x, bb_size_y);
310 	minor = min(bb_size_x, bb_size_y);
311 
312 	input_report_abs(input, ABS_MT_POSITION_X, pos_x);
313 	input_report_abs(input, ABS_MT_POSITION_Y, pos_y);
314 	input_report_abs(input, ABS_MT_TOOL_X, ctr_x);
315 	input_report_abs(input, ABS_MT_TOOL_Y, ctr_y);
316 
317 	/* TODO: use a better orientation measure */
318 	input_report_abs(input, ABS_MT_ORIENTATION, wide);
319 	input_report_abs(input, ABS_MT_TOUCH_MAJOR, major);
320 	input_report_abs(input, ABS_MT_TOUCH_MINOR, minor);
321 }
322 
323 /* core function: poll for new input data */
324 static void sur40_poll(struct input_polled_dev *polldev)
325 {
326 	struct sur40_state *sur40 = polldev->private;
327 	struct input_dev *input = polldev->input;
328 	int result, bulk_read, need_blobs, packet_blobs, i;
329 	u32 uninitialized_var(packet_id);
330 
331 	struct sur40_header *header = &sur40->bulk_in_buffer->header;
332 	struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0];
333 
334 	dev_dbg(sur40->dev, "poll\n");
335 
336 	need_blobs = -1;
337 
338 	do {
339 
340 		/* perform a blocking bulk read to get data from the device */
341 		result = usb_bulk_msg(sur40->usbdev,
342 			usb_rcvbulkpipe(sur40->usbdev, sur40->bulk_in_epaddr),
343 			sur40->bulk_in_buffer, sur40->bulk_in_size,
344 			&bulk_read, 1000);
345 
346 		dev_dbg(sur40->dev, "received %d bytes\n", bulk_read);
347 
348 		if (result < 0) {
349 			dev_err(sur40->dev, "error in usb_bulk_read\n");
350 			return;
351 		}
352 
353 		result = bulk_read - sizeof(struct sur40_header);
354 
355 		if (result % sizeof(struct sur40_blob) != 0) {
356 			dev_err(sur40->dev, "transfer size mismatch\n");
357 			return;
358 		}
359 
360 		/* first packet? */
361 		if (need_blobs == -1) {
362 			need_blobs = le16_to_cpu(header->count);
363 			dev_dbg(sur40->dev, "need %d blobs\n", need_blobs);
364 			packet_id = le32_to_cpu(header->packet_id);
365 		}
366 
367 		/*
368 		 * Sanity check. when video data is also being retrieved, the
369 		 * packet ID will usually increase in the middle of a series
370 		 * instead of at the end.
371 		 */
372 		if (packet_id != header->packet_id)
373 			dev_dbg(sur40->dev, "packet ID mismatch\n");
374 
375 		packet_blobs = result / sizeof(struct sur40_blob);
376 		dev_dbg(sur40->dev, "received %d blobs\n", packet_blobs);
377 
378 		/* packets always contain at least 4 blobs, even if empty */
379 		if (packet_blobs > need_blobs)
380 			packet_blobs = need_blobs;
381 
382 		for (i = 0; i < packet_blobs; i++) {
383 			need_blobs--;
384 			dev_dbg(sur40->dev, "processing blob\n");
385 			sur40_report_blob(&(inblob[i]), input);
386 		}
387 
388 	} while (need_blobs > 0);
389 
390 	input_mt_sync_frame(input);
391 	input_sync(input);
392 
393 	sur40_process_video(sur40);
394 }
395 
396 /* deal with video data */
397 static void sur40_process_video(struct sur40_state *sur40)
398 {
399 
400 	struct sur40_image_header *img = (void *)(sur40->bulk_in_buffer);
401 	struct sur40_buffer *new_buf;
402 	struct usb_sg_request sgr;
403 	struct sg_table *sgt;
404 	int result, bulk_read;
405 
406 	if (!vb2_start_streaming_called(&sur40->queue))
407 		return;
408 
409 	/* get a new buffer from the list */
410 	spin_lock(&sur40->qlock);
411 	if (list_empty(&sur40->buf_list)) {
412 		dev_dbg(sur40->dev, "buffer queue empty\n");
413 		spin_unlock(&sur40->qlock);
414 		return;
415 	}
416 	new_buf = list_entry(sur40->buf_list.next, struct sur40_buffer, list);
417 	list_del(&new_buf->list);
418 	spin_unlock(&sur40->qlock);
419 
420 	dev_dbg(sur40->dev, "buffer acquired\n");
421 
422 	/* retrieve data via bulk read */
423 	result = usb_bulk_msg(sur40->usbdev,
424 			usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT),
425 			sur40->bulk_in_buffer, sur40->bulk_in_size,
426 			&bulk_read, 1000);
427 
428 	if (result < 0) {
429 		dev_err(sur40->dev, "error in usb_bulk_read\n");
430 		goto err_poll;
431 	}
432 
433 	if (bulk_read != sizeof(struct sur40_image_header)) {
434 		dev_err(sur40->dev, "received %d bytes (%zd expected)\n",
435 			bulk_read, sizeof(struct sur40_image_header));
436 		goto err_poll;
437 	}
438 
439 	if (le32_to_cpu(img->magic) != VIDEO_HEADER_MAGIC) {
440 		dev_err(sur40->dev, "image magic mismatch\n");
441 		goto err_poll;
442 	}
443 
444 	if (le32_to_cpu(img->size) != sur40->pix_fmt.sizeimage) {
445 		dev_err(sur40->dev, "image size mismatch\n");
446 		goto err_poll;
447 	}
448 
449 	dev_dbg(sur40->dev, "header acquired\n");
450 
451 	sgt = vb2_dma_sg_plane_desc(&new_buf->vb.vb2_buf, 0);
452 
453 	result = usb_sg_init(&sgr, sur40->usbdev,
454 		usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT), 0,
455 		sgt->sgl, sgt->nents, sur40->pix_fmt.sizeimage, 0);
456 	if (result < 0) {
457 		dev_err(sur40->dev, "error %d in usb_sg_init\n", result);
458 		goto err_poll;
459 	}
460 
461 	usb_sg_wait(&sgr);
462 	if (sgr.status < 0) {
463 		dev_err(sur40->dev, "error %d in usb_sg_wait\n", sgr.status);
464 		goto err_poll;
465 	}
466 
467 	dev_dbg(sur40->dev, "image acquired\n");
468 
469 	/* return error if streaming was stopped in the meantime */
470 	if (sur40->sequence == -1)
471 		return;
472 
473 	/* mark as finished */
474 	new_buf->vb.vb2_buf.timestamp = ktime_get_ns();
475 	new_buf->vb.sequence = sur40->sequence++;
476 	new_buf->vb.field = V4L2_FIELD_NONE;
477 	vb2_buffer_done(&new_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
478 	dev_dbg(sur40->dev, "buffer marked done\n");
479 	return;
480 
481 err_poll:
482 	vb2_buffer_done(&new_buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
483 }
484 
485 /* Initialize input device parameters. */
486 static void sur40_input_setup(struct input_dev *input_dev)
487 {
488 	__set_bit(EV_KEY, input_dev->evbit);
489 	__set_bit(EV_ABS, input_dev->evbit);
490 
491 	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
492 			     0, SENSOR_RES_X, 0, 0);
493 	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
494 			     0, SENSOR_RES_Y, 0, 0);
495 
496 	input_set_abs_params(input_dev, ABS_MT_TOOL_X,
497 			     0, SENSOR_RES_X, 0, 0);
498 	input_set_abs_params(input_dev, ABS_MT_TOOL_Y,
499 			     0, SENSOR_RES_Y, 0, 0);
500 
501 	/* max value unknown, but major/minor axis
502 	 * can never be larger than screen */
503 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
504 			     0, SENSOR_RES_X, 0, 0);
505 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
506 			     0, SENSOR_RES_Y, 0, 0);
507 
508 	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
509 
510 	input_mt_init_slots(input_dev, MAX_CONTACTS,
511 			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
512 }
513 
514 /* Check candidate USB interface. */
515 static int sur40_probe(struct usb_interface *interface,
516 		       const struct usb_device_id *id)
517 {
518 	struct usb_device *usbdev = interface_to_usbdev(interface);
519 	struct sur40_state *sur40;
520 	struct usb_host_interface *iface_desc;
521 	struct usb_endpoint_descriptor *endpoint;
522 	struct input_polled_dev *poll_dev;
523 	int error;
524 
525 	/* Check if we really have the right interface. */
526 	iface_desc = &interface->altsetting[0];
527 	if (iface_desc->desc.bInterfaceClass != 0xFF)
528 		return -ENODEV;
529 
530 	if (iface_desc->desc.bNumEndpoints < 5)
531 		return -ENODEV;
532 
533 	/* Use endpoint #4 (0x86). */
534 	endpoint = &iface_desc->endpoint[4].desc;
535 	if (endpoint->bEndpointAddress != TOUCH_ENDPOINT)
536 		return -ENODEV;
537 
538 	/* Allocate memory for our device state and initialize it. */
539 	sur40 = kzalloc(sizeof(struct sur40_state), GFP_KERNEL);
540 	if (!sur40)
541 		return -ENOMEM;
542 
543 	poll_dev = input_allocate_polled_device();
544 	if (!poll_dev) {
545 		error = -ENOMEM;
546 		goto err_free_dev;
547 	}
548 
549 	/* initialize locks/lists */
550 	INIT_LIST_HEAD(&sur40->buf_list);
551 	spin_lock_init(&sur40->qlock);
552 	mutex_init(&sur40->lock);
553 
554 	/* Set up polled input device control structure */
555 	poll_dev->private = sur40;
556 	poll_dev->poll_interval = POLL_INTERVAL;
557 	poll_dev->open = sur40_open;
558 	poll_dev->poll = sur40_poll;
559 	poll_dev->close = sur40_close;
560 
561 	/* Set up regular input device structure */
562 	sur40_input_setup(poll_dev->input);
563 
564 	poll_dev->input->name = DRIVER_LONG;
565 	usb_to_input_id(usbdev, &poll_dev->input->id);
566 	usb_make_path(usbdev, sur40->phys, sizeof(sur40->phys));
567 	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
568 	poll_dev->input->phys = sur40->phys;
569 	poll_dev->input->dev.parent = &interface->dev;
570 
571 	sur40->usbdev = usbdev;
572 	sur40->dev = &interface->dev;
573 	sur40->input = poll_dev;
574 
575 	/* use the bulk-in endpoint tested above */
576 	sur40->bulk_in_size = usb_endpoint_maxp(endpoint);
577 	sur40->bulk_in_epaddr = endpoint->bEndpointAddress;
578 	sur40->bulk_in_buffer = kmalloc(sur40->bulk_in_size, GFP_KERNEL);
579 	if (!sur40->bulk_in_buffer) {
580 		dev_err(&interface->dev, "Unable to allocate input buffer.");
581 		error = -ENOMEM;
582 		goto err_free_polldev;
583 	}
584 
585 	/* register the polled input device */
586 	error = input_register_polled_device(poll_dev);
587 	if (error) {
588 		dev_err(&interface->dev,
589 			"Unable to register polled input device.");
590 		goto err_free_buffer;
591 	}
592 
593 	/* register the video master device */
594 	snprintf(sur40->v4l2.name, sizeof(sur40->v4l2.name), "%s", DRIVER_LONG);
595 	error = v4l2_device_register(sur40->dev, &sur40->v4l2);
596 	if (error) {
597 		dev_err(&interface->dev,
598 			"Unable to register video master device.");
599 		goto err_unreg_v4l2;
600 	}
601 
602 	/* initialize the lock and subdevice */
603 	sur40->queue = sur40_queue;
604 	sur40->queue.drv_priv = sur40;
605 	sur40->queue.lock = &sur40->lock;
606 	sur40->queue.dev = sur40->dev;
607 
608 	/* initialize the queue */
609 	error = vb2_queue_init(&sur40->queue);
610 	if (error)
611 		goto err_unreg_v4l2;
612 
613 	sur40->pix_fmt = sur40_pix_format[0];
614 	sur40->vdev = sur40_video_device;
615 	sur40->vdev.v4l2_dev = &sur40->v4l2;
616 	sur40->vdev.lock = &sur40->lock;
617 	sur40->vdev.queue = &sur40->queue;
618 	video_set_drvdata(&sur40->vdev, sur40);
619 
620 	error = video_register_device(&sur40->vdev, VFL_TYPE_TOUCH, -1);
621 	if (error) {
622 		dev_err(&interface->dev,
623 			"Unable to register video subdevice.");
624 		goto err_unreg_video;
625 	}
626 
627 	/* we can register the device now, as it is ready */
628 	usb_set_intfdata(interface, sur40);
629 	dev_dbg(&interface->dev, "%s is now attached\n", DRIVER_DESC);
630 
631 	return 0;
632 
633 err_unreg_video:
634 	video_unregister_device(&sur40->vdev);
635 err_unreg_v4l2:
636 	v4l2_device_unregister(&sur40->v4l2);
637 err_free_buffer:
638 	kfree(sur40->bulk_in_buffer);
639 err_free_polldev:
640 	input_free_polled_device(sur40->input);
641 err_free_dev:
642 	kfree(sur40);
643 
644 	return error;
645 }
646 
647 /* Unregister device & clean up. */
648 static void sur40_disconnect(struct usb_interface *interface)
649 {
650 	struct sur40_state *sur40 = usb_get_intfdata(interface);
651 
652 	video_unregister_device(&sur40->vdev);
653 	v4l2_device_unregister(&sur40->v4l2);
654 
655 	input_unregister_polled_device(sur40->input);
656 	input_free_polled_device(sur40->input);
657 	kfree(sur40->bulk_in_buffer);
658 	kfree(sur40);
659 
660 	usb_set_intfdata(interface, NULL);
661 	dev_dbg(&interface->dev, "%s is now disconnected\n", DRIVER_DESC);
662 }
663 
664 /*
665  * Setup the constraints of the queue: besides setting the number of planes
666  * per buffer and the size and allocation context of each plane, it also
667  * checks if sufficient buffers have been allocated. Usually 3 is a good
668  * minimum number: many DMA engines need a minimum of 2 buffers in the
669  * queue and you need to have another available for userspace processing.
670  */
671 static int sur40_queue_setup(struct vb2_queue *q,
672 		       unsigned int *nbuffers, unsigned int *nplanes,
673 		       unsigned int sizes[], struct device *alloc_devs[])
674 {
675 	struct sur40_state *sur40 = vb2_get_drv_priv(q);
676 
677 	if (q->num_buffers + *nbuffers < 3)
678 		*nbuffers = 3 - q->num_buffers;
679 
680 	if (*nplanes)
681 		return sizes[0] < sur40->pix_fmt.sizeimage ? -EINVAL : 0;
682 
683 	*nplanes = 1;
684 	sizes[0] = sur40->pix_fmt.sizeimage;
685 
686 	return 0;
687 }
688 
689 /*
690  * Prepare the buffer for queueing to the DMA engine: check and set the
691  * payload size.
692  */
693 static int sur40_buffer_prepare(struct vb2_buffer *vb)
694 {
695 	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
696 	unsigned long size = sur40->pix_fmt.sizeimage;
697 
698 	if (vb2_plane_size(vb, 0) < size) {
699 		dev_err(&sur40->usbdev->dev, "buffer too small (%lu < %lu)\n",
700 			 vb2_plane_size(vb, 0), size);
701 		return -EINVAL;
702 	}
703 
704 	vb2_set_plane_payload(vb, 0, size);
705 	return 0;
706 }
707 
708 /*
709  * Queue this buffer to the DMA engine.
710  */
711 static void sur40_buffer_queue(struct vb2_buffer *vb)
712 {
713 	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
714 	struct sur40_buffer *buf = (struct sur40_buffer *)vb;
715 
716 	spin_lock(&sur40->qlock);
717 	list_add_tail(&buf->list, &sur40->buf_list);
718 	spin_unlock(&sur40->qlock);
719 }
720 
721 static void return_all_buffers(struct sur40_state *sur40,
722 			       enum vb2_buffer_state state)
723 {
724 	struct sur40_buffer *buf, *node;
725 
726 	spin_lock(&sur40->qlock);
727 	list_for_each_entry_safe(buf, node, &sur40->buf_list, list) {
728 		vb2_buffer_done(&buf->vb.vb2_buf, state);
729 		list_del(&buf->list);
730 	}
731 	spin_unlock(&sur40->qlock);
732 }
733 
734 /*
735  * Start streaming. First check if the minimum number of buffers have been
736  * queued. If not, then return -ENOBUFS and the vb2 framework will call
737  * this function again the next time a buffer has been queued until enough
738  * buffers are available to actually start the DMA engine.
739  */
740 static int sur40_start_streaming(struct vb2_queue *vq, unsigned int count)
741 {
742 	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
743 
744 	sur40->sequence = 0;
745 	return 0;
746 }
747 
748 /*
749  * Stop the DMA engine. Any remaining buffers in the DMA queue are dequeued
750  * and passed on to the vb2 framework marked as STATE_ERROR.
751  */
752 static void sur40_stop_streaming(struct vb2_queue *vq)
753 {
754 	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
755 	vb2_wait_for_all_buffers(vq);
756 	sur40->sequence = -1;
757 
758 	/* Release all active buffers */
759 	return_all_buffers(sur40, VB2_BUF_STATE_ERROR);
760 }
761 
762 /* V4L ioctl */
763 static int sur40_vidioc_querycap(struct file *file, void *priv,
764 				 struct v4l2_capability *cap)
765 {
766 	struct sur40_state *sur40 = video_drvdata(file);
767 
768 	strlcpy(cap->driver, DRIVER_SHORT, sizeof(cap->driver));
769 	strlcpy(cap->card, DRIVER_LONG, sizeof(cap->card));
770 	usb_make_path(sur40->usbdev, cap->bus_info, sizeof(cap->bus_info));
771 	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_TOUCH |
772 		V4L2_CAP_READWRITE |
773 		V4L2_CAP_STREAMING;
774 	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
775 	return 0;
776 }
777 
778 static int sur40_vidioc_enum_input(struct file *file, void *priv,
779 				   struct v4l2_input *i)
780 {
781 	if (i->index != 0)
782 		return -EINVAL;
783 	i->type = V4L2_INPUT_TYPE_TOUCH;
784 	i->std = V4L2_STD_UNKNOWN;
785 	strlcpy(i->name, "In-Cell Sensor", sizeof(i->name));
786 	i->capabilities = 0;
787 	return 0;
788 }
789 
790 static int sur40_vidioc_s_input(struct file *file, void *priv, unsigned int i)
791 {
792 	return (i == 0) ? 0 : -EINVAL;
793 }
794 
795 static int sur40_vidioc_g_input(struct file *file, void *priv, unsigned int *i)
796 {
797 	*i = 0;
798 	return 0;
799 }
800 
801 static int sur40_vidioc_try_fmt(struct file *file, void *priv,
802 			    struct v4l2_format *f)
803 {
804 	switch (f->fmt.pix.pixelformat) {
805 	case V4L2_PIX_FMT_GREY:
806 		f->fmt.pix = sur40_pix_format[1];
807 		break;
808 
809 	default:
810 		f->fmt.pix = sur40_pix_format[0];
811 		break;
812 	}
813 
814 	return 0;
815 }
816 
817 static int sur40_vidioc_s_fmt(struct file *file, void *priv,
818 			    struct v4l2_format *f)
819 {
820 	struct sur40_state *sur40 = video_drvdata(file);
821 
822 	switch (f->fmt.pix.pixelformat) {
823 	case V4L2_PIX_FMT_GREY:
824 		sur40->pix_fmt = sur40_pix_format[1];
825 		break;
826 
827 	default:
828 		sur40->pix_fmt = sur40_pix_format[0];
829 		break;
830 	}
831 
832 	f->fmt.pix = sur40->pix_fmt;
833 	return 0;
834 }
835 
836 static int sur40_vidioc_g_fmt(struct file *file, void *priv,
837 			    struct v4l2_format *f)
838 {
839 	struct sur40_state *sur40 = video_drvdata(file);
840 
841 	f->fmt.pix = sur40->pix_fmt;
842 	return 0;
843 }
844 
845 static int sur40_ioctl_parm(struct file *file, void *priv,
846 			    struct v4l2_streamparm *p)
847 {
848 	if (p->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
849 		return -EINVAL;
850 
851 	p->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
852 	p->parm.capture.timeperframe.numerator = 1;
853 	p->parm.capture.timeperframe.denominator = 60;
854 	p->parm.capture.readbuffers = 3;
855 	return 0;
856 }
857 
858 static int sur40_vidioc_enum_fmt(struct file *file, void *priv,
859 				 struct v4l2_fmtdesc *f)
860 {
861 	if (f->index >= ARRAY_SIZE(sur40_pix_format))
862 		return -EINVAL;
863 
864 	f->pixelformat = sur40_pix_format[f->index].pixelformat;
865 	f->flags = 0;
866 	return 0;
867 }
868 
869 static int sur40_vidioc_enum_framesizes(struct file *file, void *priv,
870 					struct v4l2_frmsizeenum *f)
871 {
872 	struct sur40_state *sur40 = video_drvdata(file);
873 
874 	if ((f->index != 0) || ((f->pixel_format != V4L2_TCH_FMT_TU08)
875 		&& (f->pixel_format != V4L2_PIX_FMT_GREY)))
876 		return -EINVAL;
877 
878 	f->type = V4L2_FRMSIZE_TYPE_DISCRETE;
879 	f->discrete.width  = sur40->pix_fmt.width;
880 	f->discrete.height = sur40->pix_fmt.height;
881 	return 0;
882 }
883 
884 static int sur40_vidioc_enum_frameintervals(struct file *file, void *priv,
885 					    struct v4l2_frmivalenum *f)
886 {
887 	struct sur40_state *sur40 = video_drvdata(file);
888 
889 	if ((f->index > 0) || ((f->pixel_format != V4L2_TCH_FMT_TU08)
890 		&& (f->pixel_format != V4L2_PIX_FMT_GREY))
891 		|| (f->width  != sur40->pix_fmt.width)
892 		|| (f->height != sur40->pix_fmt.height))
893 		return -EINVAL;
894 
895 	f->type = V4L2_FRMIVAL_TYPE_DISCRETE;
896 	f->discrete.denominator  = 60;
897 	f->discrete.numerator = 1;
898 	return 0;
899 }
900 
901 
902 static const struct usb_device_id sur40_table[] = {
903 	{ USB_DEVICE(ID_MICROSOFT, ID_SUR40) },  /* Samsung SUR40 */
904 	{ }                                      /* terminating null entry */
905 };
906 MODULE_DEVICE_TABLE(usb, sur40_table);
907 
908 /* V4L2 structures */
909 static const struct vb2_ops sur40_queue_ops = {
910 	.queue_setup		= sur40_queue_setup,
911 	.buf_prepare		= sur40_buffer_prepare,
912 	.buf_queue		= sur40_buffer_queue,
913 	.start_streaming	= sur40_start_streaming,
914 	.stop_streaming		= sur40_stop_streaming,
915 	.wait_prepare		= vb2_ops_wait_prepare,
916 	.wait_finish		= vb2_ops_wait_finish,
917 };
918 
919 static const struct vb2_queue sur40_queue = {
920 	.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
921 	/*
922 	 * VB2_USERPTR in currently not enabled: passing a user pointer to
923 	 * dma-sg will result in segment sizes that are not a multiple of
924 	 * 512 bytes, which is required by the host controller.
925 	*/
926 	.io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF,
927 	.buf_struct_size = sizeof(struct sur40_buffer),
928 	.ops = &sur40_queue_ops,
929 	.mem_ops = &vb2_dma_sg_memops,
930 	.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC,
931 	.min_buffers_needed = 3,
932 };
933 
934 static const struct v4l2_file_operations sur40_video_fops = {
935 	.owner = THIS_MODULE,
936 	.open = v4l2_fh_open,
937 	.release = vb2_fop_release,
938 	.unlocked_ioctl = video_ioctl2,
939 	.read = vb2_fop_read,
940 	.mmap = vb2_fop_mmap,
941 	.poll = vb2_fop_poll,
942 };
943 
944 static const struct v4l2_ioctl_ops sur40_video_ioctl_ops = {
945 
946 	.vidioc_querycap	= sur40_vidioc_querycap,
947 
948 	.vidioc_enum_fmt_vid_cap = sur40_vidioc_enum_fmt,
949 	.vidioc_try_fmt_vid_cap	= sur40_vidioc_try_fmt,
950 	.vidioc_s_fmt_vid_cap	= sur40_vidioc_s_fmt,
951 	.vidioc_g_fmt_vid_cap	= sur40_vidioc_g_fmt,
952 
953 	.vidioc_enum_framesizes = sur40_vidioc_enum_framesizes,
954 	.vidioc_enum_frameintervals = sur40_vidioc_enum_frameintervals,
955 
956 	.vidioc_g_parm = sur40_ioctl_parm,
957 	.vidioc_s_parm = sur40_ioctl_parm,
958 
959 	.vidioc_enum_input	= sur40_vidioc_enum_input,
960 	.vidioc_g_input		= sur40_vidioc_g_input,
961 	.vidioc_s_input		= sur40_vidioc_s_input,
962 
963 	.vidioc_reqbufs		= vb2_ioctl_reqbufs,
964 	.vidioc_create_bufs	= vb2_ioctl_create_bufs,
965 	.vidioc_querybuf	= vb2_ioctl_querybuf,
966 	.vidioc_qbuf		= vb2_ioctl_qbuf,
967 	.vidioc_dqbuf		= vb2_ioctl_dqbuf,
968 	.vidioc_expbuf		= vb2_ioctl_expbuf,
969 
970 	.vidioc_streamon	= vb2_ioctl_streamon,
971 	.vidioc_streamoff	= vb2_ioctl_streamoff,
972 };
973 
974 static const struct video_device sur40_video_device = {
975 	.name = DRIVER_LONG,
976 	.fops = &sur40_video_fops,
977 	.ioctl_ops = &sur40_video_ioctl_ops,
978 	.release = video_device_release_empty,
979 };
980 
981 /* USB-specific object needed to register this driver with the USB subsystem. */
982 static struct usb_driver sur40_driver = {
983 	.name = DRIVER_SHORT,
984 	.probe = sur40_probe,
985 	.disconnect = sur40_disconnect,
986 	.id_table = sur40_table,
987 };
988 
989 module_usb_driver(sur40_driver);
990 
991 MODULE_AUTHOR(DRIVER_AUTHOR);
992 MODULE_DESCRIPTION(DRIVER_DESC);
993 MODULE_LICENSE("GPL");
994