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 /* master device state */
143 struct sur40_state {
144 
145 	struct usb_device *usbdev;
146 	struct device *dev;
147 	struct input_polled_dev *input;
148 
149 	struct v4l2_device v4l2;
150 	struct video_device vdev;
151 	struct mutex lock;
152 
153 	struct vb2_queue queue;
154 	struct list_head buf_list;
155 	spinlock_t qlock;
156 	int sequence;
157 
158 	struct sur40_data *bulk_in_buffer;
159 	size_t bulk_in_size;
160 	u8 bulk_in_epaddr;
161 
162 	char phys[64];
163 };
164 
165 struct sur40_buffer {
166 	struct vb2_v4l2_buffer vb;
167 	struct list_head list;
168 };
169 
170 /* forward declarations */
171 static const struct video_device sur40_video_device;
172 static const struct v4l2_pix_format sur40_video_format;
173 static const struct vb2_queue sur40_queue;
174 static void sur40_process_video(struct sur40_state *sur40);
175 
176 /*
177  * Note: an earlier, non-public version of this driver used USB_RECIP_ENDPOINT
178  * here by mistake which is very likely to have corrupted the firmware EEPROM
179  * on two separate SUR40 devices. Thanks to Alan Stern who spotted this bug.
180  * Should you ever run into a similar problem, the background story to this
181  * incident and instructions on how to fix the corrupted EEPROM are available
182  * at https://floe.butterbrot.org/matrix/hacking/surface/brick.html
183 */
184 
185 /* command wrapper */
186 static int sur40_command(struct sur40_state *dev,
187 			 u8 command, u16 index, void *buffer, u16 size)
188 {
189 	return usb_control_msg(dev->usbdev, usb_rcvctrlpipe(dev->usbdev, 0),
190 			       command,
191 			       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
192 			       0x00, index, buffer, size, 1000);
193 }
194 
195 /* Initialization routine, called from sur40_open */
196 static int sur40_init(struct sur40_state *dev)
197 {
198 	int result;
199 	u8 *buffer;
200 
201 	buffer = kmalloc(24, GFP_KERNEL);
202 	if (!buffer) {
203 		result = -ENOMEM;
204 		goto error;
205 	}
206 
207 	/* stupidly replay the original MS driver init sequence */
208 	result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
209 	if (result < 0)
210 		goto error;
211 
212 	result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
213 	if (result < 0)
214 		goto error;
215 
216 	result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
217 	if (result < 0)
218 		goto error;
219 
220 	result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
221 	if (result < 0)
222 		goto error;
223 
224 	result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
225 	if (result < 0)
226 		goto error;
227 
228 	result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
229 
230 	/*
231 	 * Discard the result buffer - no known data inside except
232 	 * some version strings, maybe extract these sometime...
233 	 */
234 error:
235 	kfree(buffer);
236 	return result;
237 }
238 
239 /*
240  * Callback routines from input_polled_dev
241  */
242 
243 /* Enable the device, polling will now start. */
244 static void sur40_open(struct input_polled_dev *polldev)
245 {
246 	struct sur40_state *sur40 = polldev->private;
247 
248 	dev_dbg(sur40->dev, "open\n");
249 	sur40_init(sur40);
250 }
251 
252 /* Disable device, polling has stopped. */
253 static void sur40_close(struct input_polled_dev *polldev)
254 {
255 	struct sur40_state *sur40 = polldev->private;
256 
257 	dev_dbg(sur40->dev, "close\n");
258 	/*
259 	 * There is no known way to stop the device, so we simply
260 	 * stop polling.
261 	 */
262 }
263 
264 /*
265  * This function is called when a whole contact has been processed,
266  * so that it can assign it to a slot and store the data there.
267  */
268 static void sur40_report_blob(struct sur40_blob *blob, struct input_dev *input)
269 {
270 	int wide, major, minor;
271 
272 	int bb_size_x = le16_to_cpu(blob->bb_size_x);
273 	int bb_size_y = le16_to_cpu(blob->bb_size_y);
274 
275 	int pos_x = le16_to_cpu(blob->pos_x);
276 	int pos_y = le16_to_cpu(blob->pos_y);
277 
278 	int ctr_x = le16_to_cpu(blob->ctr_x);
279 	int ctr_y = le16_to_cpu(blob->ctr_y);
280 
281 	int slotnum = input_mt_get_slot_by_key(input, blob->blob_id);
282 	if (slotnum < 0 || slotnum >= MAX_CONTACTS)
283 		return;
284 
285 	input_mt_slot(input, slotnum);
286 	input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
287 	wide = (bb_size_x > bb_size_y);
288 	major = max(bb_size_x, bb_size_y);
289 	minor = min(bb_size_x, bb_size_y);
290 
291 	input_report_abs(input, ABS_MT_POSITION_X, pos_x);
292 	input_report_abs(input, ABS_MT_POSITION_Y, pos_y);
293 	input_report_abs(input, ABS_MT_TOOL_X, ctr_x);
294 	input_report_abs(input, ABS_MT_TOOL_Y, ctr_y);
295 
296 	/* TODO: use a better orientation measure */
297 	input_report_abs(input, ABS_MT_ORIENTATION, wide);
298 	input_report_abs(input, ABS_MT_TOUCH_MAJOR, major);
299 	input_report_abs(input, ABS_MT_TOUCH_MINOR, minor);
300 }
301 
302 /* core function: poll for new input data */
303 static void sur40_poll(struct input_polled_dev *polldev)
304 {
305 	struct sur40_state *sur40 = polldev->private;
306 	struct input_dev *input = polldev->input;
307 	int result, bulk_read, need_blobs, packet_blobs, i;
308 	u32 uninitialized_var(packet_id);
309 
310 	struct sur40_header *header = &sur40->bulk_in_buffer->header;
311 	struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0];
312 
313 	dev_dbg(sur40->dev, "poll\n");
314 
315 	need_blobs = -1;
316 
317 	do {
318 
319 		/* perform a blocking bulk read to get data from the device */
320 		result = usb_bulk_msg(sur40->usbdev,
321 			usb_rcvbulkpipe(sur40->usbdev, sur40->bulk_in_epaddr),
322 			sur40->bulk_in_buffer, sur40->bulk_in_size,
323 			&bulk_read, 1000);
324 
325 		dev_dbg(sur40->dev, "received %d bytes\n", bulk_read);
326 
327 		if (result < 0) {
328 			dev_err(sur40->dev, "error in usb_bulk_read\n");
329 			return;
330 		}
331 
332 		result = bulk_read - sizeof(struct sur40_header);
333 
334 		if (result % sizeof(struct sur40_blob) != 0) {
335 			dev_err(sur40->dev, "transfer size mismatch\n");
336 			return;
337 		}
338 
339 		/* first packet? */
340 		if (need_blobs == -1) {
341 			need_blobs = le16_to_cpu(header->count);
342 			dev_dbg(sur40->dev, "need %d blobs\n", need_blobs);
343 			packet_id = le32_to_cpu(header->packet_id);
344 		}
345 
346 		/*
347 		 * Sanity check. when video data is also being retrieved, the
348 		 * packet ID will usually increase in the middle of a series
349 		 * instead of at the end.
350 		 */
351 		if (packet_id != header->packet_id)
352 			dev_dbg(sur40->dev, "packet ID mismatch\n");
353 
354 		packet_blobs = result / sizeof(struct sur40_blob);
355 		dev_dbg(sur40->dev, "received %d blobs\n", packet_blobs);
356 
357 		/* packets always contain at least 4 blobs, even if empty */
358 		if (packet_blobs > need_blobs)
359 			packet_blobs = need_blobs;
360 
361 		for (i = 0; i < packet_blobs; i++) {
362 			need_blobs--;
363 			dev_dbg(sur40->dev, "processing blob\n");
364 			sur40_report_blob(&(inblob[i]), input);
365 		}
366 
367 	} while (need_blobs > 0);
368 
369 	input_mt_sync_frame(input);
370 	input_sync(input);
371 
372 	sur40_process_video(sur40);
373 }
374 
375 /* deal with video data */
376 static void sur40_process_video(struct sur40_state *sur40)
377 {
378 
379 	struct sur40_image_header *img = (void *)(sur40->bulk_in_buffer);
380 	struct sur40_buffer *new_buf;
381 	struct usb_sg_request sgr;
382 	struct sg_table *sgt;
383 	int result, bulk_read;
384 
385 	if (!vb2_start_streaming_called(&sur40->queue))
386 		return;
387 
388 	/* get a new buffer from the list */
389 	spin_lock(&sur40->qlock);
390 	if (list_empty(&sur40->buf_list)) {
391 		dev_dbg(sur40->dev, "buffer queue empty\n");
392 		spin_unlock(&sur40->qlock);
393 		return;
394 	}
395 	new_buf = list_entry(sur40->buf_list.next, struct sur40_buffer, list);
396 	list_del(&new_buf->list);
397 	spin_unlock(&sur40->qlock);
398 
399 	dev_dbg(sur40->dev, "buffer acquired\n");
400 
401 	/* retrieve data via bulk read */
402 	result = usb_bulk_msg(sur40->usbdev,
403 			usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT),
404 			sur40->bulk_in_buffer, sur40->bulk_in_size,
405 			&bulk_read, 1000);
406 
407 	if (result < 0) {
408 		dev_err(sur40->dev, "error in usb_bulk_read\n");
409 		goto err_poll;
410 	}
411 
412 	if (bulk_read != sizeof(struct sur40_image_header)) {
413 		dev_err(sur40->dev, "received %d bytes (%zd expected)\n",
414 			bulk_read, sizeof(struct sur40_image_header));
415 		goto err_poll;
416 	}
417 
418 	if (le32_to_cpu(img->magic) != VIDEO_HEADER_MAGIC) {
419 		dev_err(sur40->dev, "image magic mismatch\n");
420 		goto err_poll;
421 	}
422 
423 	if (le32_to_cpu(img->size) != sur40_video_format.sizeimage) {
424 		dev_err(sur40->dev, "image size mismatch\n");
425 		goto err_poll;
426 	}
427 
428 	dev_dbg(sur40->dev, "header acquired\n");
429 
430 	sgt = vb2_dma_sg_plane_desc(&new_buf->vb.vb2_buf, 0);
431 
432 	result = usb_sg_init(&sgr, sur40->usbdev,
433 		usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT), 0,
434 		sgt->sgl, sgt->nents, sur40_video_format.sizeimage, 0);
435 	if (result < 0) {
436 		dev_err(sur40->dev, "error %d in usb_sg_init\n", result);
437 		goto err_poll;
438 	}
439 
440 	usb_sg_wait(&sgr);
441 	if (sgr.status < 0) {
442 		dev_err(sur40->dev, "error %d in usb_sg_wait\n", sgr.status);
443 		goto err_poll;
444 	}
445 
446 	dev_dbg(sur40->dev, "image acquired\n");
447 
448 	/* return error if streaming was stopped in the meantime */
449 	if (sur40->sequence == -1)
450 		return;
451 
452 	/* mark as finished */
453 	new_buf->vb.vb2_buf.timestamp = ktime_get_ns();
454 	new_buf->vb.sequence = sur40->sequence++;
455 	new_buf->vb.field = V4L2_FIELD_NONE;
456 	vb2_buffer_done(&new_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
457 	dev_dbg(sur40->dev, "buffer marked done\n");
458 	return;
459 
460 err_poll:
461 	vb2_buffer_done(&new_buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
462 }
463 
464 /* Initialize input device parameters. */
465 static void sur40_input_setup(struct input_dev *input_dev)
466 {
467 	__set_bit(EV_KEY, input_dev->evbit);
468 	__set_bit(EV_ABS, input_dev->evbit);
469 
470 	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
471 			     0, SENSOR_RES_X, 0, 0);
472 	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
473 			     0, SENSOR_RES_Y, 0, 0);
474 
475 	input_set_abs_params(input_dev, ABS_MT_TOOL_X,
476 			     0, SENSOR_RES_X, 0, 0);
477 	input_set_abs_params(input_dev, ABS_MT_TOOL_Y,
478 			     0, SENSOR_RES_Y, 0, 0);
479 
480 	/* max value unknown, but major/minor axis
481 	 * can never be larger than screen */
482 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
483 			     0, SENSOR_RES_X, 0, 0);
484 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
485 			     0, SENSOR_RES_Y, 0, 0);
486 
487 	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
488 
489 	input_mt_init_slots(input_dev, MAX_CONTACTS,
490 			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
491 }
492 
493 /* Check candidate USB interface. */
494 static int sur40_probe(struct usb_interface *interface,
495 		       const struct usb_device_id *id)
496 {
497 	struct usb_device *usbdev = interface_to_usbdev(interface);
498 	struct sur40_state *sur40;
499 	struct usb_host_interface *iface_desc;
500 	struct usb_endpoint_descriptor *endpoint;
501 	struct input_polled_dev *poll_dev;
502 	int error;
503 
504 	/* Check if we really have the right interface. */
505 	iface_desc = &interface->altsetting[0];
506 	if (iface_desc->desc.bInterfaceClass != 0xFF)
507 		return -ENODEV;
508 
509 	/* Use endpoint #4 (0x86). */
510 	endpoint = &iface_desc->endpoint[4].desc;
511 	if (endpoint->bEndpointAddress != TOUCH_ENDPOINT)
512 		return -ENODEV;
513 
514 	/* Allocate memory for our device state and initialize it. */
515 	sur40 = kzalloc(sizeof(struct sur40_state), GFP_KERNEL);
516 	if (!sur40)
517 		return -ENOMEM;
518 
519 	poll_dev = input_allocate_polled_device();
520 	if (!poll_dev) {
521 		error = -ENOMEM;
522 		goto err_free_dev;
523 	}
524 
525 	/* initialize locks/lists */
526 	INIT_LIST_HEAD(&sur40->buf_list);
527 	spin_lock_init(&sur40->qlock);
528 	mutex_init(&sur40->lock);
529 
530 	/* Set up polled input device control structure */
531 	poll_dev->private = sur40;
532 	poll_dev->poll_interval = POLL_INTERVAL;
533 	poll_dev->open = sur40_open;
534 	poll_dev->poll = sur40_poll;
535 	poll_dev->close = sur40_close;
536 
537 	/* Set up regular input device structure */
538 	sur40_input_setup(poll_dev->input);
539 
540 	poll_dev->input->name = DRIVER_LONG;
541 	usb_to_input_id(usbdev, &poll_dev->input->id);
542 	usb_make_path(usbdev, sur40->phys, sizeof(sur40->phys));
543 	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
544 	poll_dev->input->phys = sur40->phys;
545 	poll_dev->input->dev.parent = &interface->dev;
546 
547 	sur40->usbdev = usbdev;
548 	sur40->dev = &interface->dev;
549 	sur40->input = poll_dev;
550 
551 	/* use the bulk-in endpoint tested above */
552 	sur40->bulk_in_size = usb_endpoint_maxp(endpoint);
553 	sur40->bulk_in_epaddr = endpoint->bEndpointAddress;
554 	sur40->bulk_in_buffer = kmalloc(sur40->bulk_in_size, GFP_KERNEL);
555 	if (!sur40->bulk_in_buffer) {
556 		dev_err(&interface->dev, "Unable to allocate input buffer.");
557 		error = -ENOMEM;
558 		goto err_free_polldev;
559 	}
560 
561 	/* register the polled input device */
562 	error = input_register_polled_device(poll_dev);
563 	if (error) {
564 		dev_err(&interface->dev,
565 			"Unable to register polled input device.");
566 		goto err_free_buffer;
567 	}
568 
569 	/* register the video master device */
570 	snprintf(sur40->v4l2.name, sizeof(sur40->v4l2.name), "%s", DRIVER_LONG);
571 	error = v4l2_device_register(sur40->dev, &sur40->v4l2);
572 	if (error) {
573 		dev_err(&interface->dev,
574 			"Unable to register video master device.");
575 		goto err_unreg_v4l2;
576 	}
577 
578 	/* initialize the lock and subdevice */
579 	sur40->queue = sur40_queue;
580 	sur40->queue.drv_priv = sur40;
581 	sur40->queue.lock = &sur40->lock;
582 	sur40->queue.dev = sur40->dev;
583 
584 	/* initialize the queue */
585 	error = vb2_queue_init(&sur40->queue);
586 	if (error)
587 		goto err_unreg_v4l2;
588 
589 	sur40->vdev = sur40_video_device;
590 	sur40->vdev.v4l2_dev = &sur40->v4l2;
591 	sur40->vdev.lock = &sur40->lock;
592 	sur40->vdev.queue = &sur40->queue;
593 	video_set_drvdata(&sur40->vdev, sur40);
594 
595 	error = video_register_device(&sur40->vdev, VFL_TYPE_GRABBER, -1);
596 	if (error) {
597 		dev_err(&interface->dev,
598 			"Unable to register video subdevice.");
599 		goto err_unreg_video;
600 	}
601 
602 	/* we can register the device now, as it is ready */
603 	usb_set_intfdata(interface, sur40);
604 	dev_dbg(&interface->dev, "%s is now attached\n", DRIVER_DESC);
605 
606 	return 0;
607 
608 err_unreg_video:
609 	video_unregister_device(&sur40->vdev);
610 err_unreg_v4l2:
611 	v4l2_device_unregister(&sur40->v4l2);
612 err_free_buffer:
613 	kfree(sur40->bulk_in_buffer);
614 err_free_polldev:
615 	input_free_polled_device(sur40->input);
616 err_free_dev:
617 	kfree(sur40);
618 
619 	return error;
620 }
621 
622 /* Unregister device & clean up. */
623 static void sur40_disconnect(struct usb_interface *interface)
624 {
625 	struct sur40_state *sur40 = usb_get_intfdata(interface);
626 
627 	video_unregister_device(&sur40->vdev);
628 	v4l2_device_unregister(&sur40->v4l2);
629 
630 	input_unregister_polled_device(sur40->input);
631 	input_free_polled_device(sur40->input);
632 	kfree(sur40->bulk_in_buffer);
633 	kfree(sur40);
634 
635 	usb_set_intfdata(interface, NULL);
636 	dev_dbg(&interface->dev, "%s is now disconnected\n", DRIVER_DESC);
637 }
638 
639 /*
640  * Setup the constraints of the queue: besides setting the number of planes
641  * per buffer and the size and allocation context of each plane, it also
642  * checks if sufficient buffers have been allocated. Usually 3 is a good
643  * minimum number: many DMA engines need a minimum of 2 buffers in the
644  * queue and you need to have another available for userspace processing.
645  */
646 static int sur40_queue_setup(struct vb2_queue *q,
647 		       unsigned int *nbuffers, unsigned int *nplanes,
648 		       unsigned int sizes[], struct device *alloc_devs[])
649 {
650 	if (q->num_buffers + *nbuffers < 3)
651 		*nbuffers = 3 - q->num_buffers;
652 
653 	if (*nplanes)
654 		return sizes[0] < sur40_video_format.sizeimage ? -EINVAL : 0;
655 
656 	*nplanes = 1;
657 	sizes[0] = sur40_video_format.sizeimage;
658 
659 	return 0;
660 }
661 
662 /*
663  * Prepare the buffer for queueing to the DMA engine: check and set the
664  * payload size.
665  */
666 static int sur40_buffer_prepare(struct vb2_buffer *vb)
667 {
668 	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
669 	unsigned long size = sur40_video_format.sizeimage;
670 
671 	if (vb2_plane_size(vb, 0) < size) {
672 		dev_err(&sur40->usbdev->dev, "buffer too small (%lu < %lu)\n",
673 			 vb2_plane_size(vb, 0), size);
674 		return -EINVAL;
675 	}
676 
677 	vb2_set_plane_payload(vb, 0, size);
678 	return 0;
679 }
680 
681 /*
682  * Queue this buffer to the DMA engine.
683  */
684 static void sur40_buffer_queue(struct vb2_buffer *vb)
685 {
686 	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
687 	struct sur40_buffer *buf = (struct sur40_buffer *)vb;
688 
689 	spin_lock(&sur40->qlock);
690 	list_add_tail(&buf->list, &sur40->buf_list);
691 	spin_unlock(&sur40->qlock);
692 }
693 
694 static void return_all_buffers(struct sur40_state *sur40,
695 			       enum vb2_buffer_state state)
696 {
697 	struct sur40_buffer *buf, *node;
698 
699 	spin_lock(&sur40->qlock);
700 	list_for_each_entry_safe(buf, node, &sur40->buf_list, list) {
701 		vb2_buffer_done(&buf->vb.vb2_buf, state);
702 		list_del(&buf->list);
703 	}
704 	spin_unlock(&sur40->qlock);
705 }
706 
707 /*
708  * Start streaming. First check if the minimum number of buffers have been
709  * queued. If not, then return -ENOBUFS and the vb2 framework will call
710  * this function again the next time a buffer has been queued until enough
711  * buffers are available to actually start the DMA engine.
712  */
713 static int sur40_start_streaming(struct vb2_queue *vq, unsigned int count)
714 {
715 	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
716 
717 	sur40->sequence = 0;
718 	return 0;
719 }
720 
721 /*
722  * Stop the DMA engine. Any remaining buffers in the DMA queue are dequeued
723  * and passed on to the vb2 framework marked as STATE_ERROR.
724  */
725 static void sur40_stop_streaming(struct vb2_queue *vq)
726 {
727 	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
728 	vb2_wait_for_all_buffers(vq);
729 	sur40->sequence = -1;
730 
731 	/* Release all active buffers */
732 	return_all_buffers(sur40, VB2_BUF_STATE_ERROR);
733 }
734 
735 /* V4L ioctl */
736 static int sur40_vidioc_querycap(struct file *file, void *priv,
737 				 struct v4l2_capability *cap)
738 {
739 	struct sur40_state *sur40 = video_drvdata(file);
740 
741 	strlcpy(cap->driver, DRIVER_SHORT, sizeof(cap->driver));
742 	strlcpy(cap->card, DRIVER_LONG, sizeof(cap->card));
743 	usb_make_path(sur40->usbdev, cap->bus_info, sizeof(cap->bus_info));
744 	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE |
745 		V4L2_CAP_READWRITE |
746 		V4L2_CAP_STREAMING;
747 	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
748 	return 0;
749 }
750 
751 static int sur40_vidioc_enum_input(struct file *file, void *priv,
752 				   struct v4l2_input *i)
753 {
754 	if (i->index != 0)
755 		return -EINVAL;
756 	i->type = V4L2_INPUT_TYPE_CAMERA;
757 	i->std = V4L2_STD_UNKNOWN;
758 	strlcpy(i->name, "In-Cell Sensor", sizeof(i->name));
759 	i->capabilities = 0;
760 	return 0;
761 }
762 
763 static int sur40_vidioc_s_input(struct file *file, void *priv, unsigned int i)
764 {
765 	return (i == 0) ? 0 : -EINVAL;
766 }
767 
768 static int sur40_vidioc_g_input(struct file *file, void *priv, unsigned int *i)
769 {
770 	*i = 0;
771 	return 0;
772 }
773 
774 static int sur40_vidioc_fmt(struct file *file, void *priv,
775 			    struct v4l2_format *f)
776 {
777 	f->fmt.pix = sur40_video_format;
778 	return 0;
779 }
780 
781 static int sur40_vidioc_enum_fmt(struct file *file, void *priv,
782 				 struct v4l2_fmtdesc *f)
783 {
784 	if (f->index != 0)
785 		return -EINVAL;
786 	f->pixelformat = V4L2_PIX_FMT_GREY;
787 	f->flags = 0;
788 	return 0;
789 }
790 
791 static int sur40_vidioc_enum_framesizes(struct file *file, void *priv,
792 					struct v4l2_frmsizeenum *f)
793 {
794 	if ((f->index != 0) || (f->pixel_format != V4L2_PIX_FMT_GREY))
795 		return -EINVAL;
796 
797 	f->type = V4L2_FRMSIZE_TYPE_DISCRETE;
798 	f->discrete.width  = sur40_video_format.width;
799 	f->discrete.height = sur40_video_format.height;
800 	return 0;
801 }
802 
803 static int sur40_vidioc_enum_frameintervals(struct file *file, void *priv,
804 					    struct v4l2_frmivalenum *f)
805 {
806 	if ((f->index > 1) || (f->pixel_format != V4L2_PIX_FMT_GREY)
807 		|| (f->width  != sur40_video_format.width)
808 		|| (f->height != sur40_video_format.height))
809 			return -EINVAL;
810 
811 	f->type = V4L2_FRMIVAL_TYPE_DISCRETE;
812 	f->discrete.denominator  = 60/(f->index+1);
813 	f->discrete.numerator = 1;
814 	return 0;
815 }
816 
817 
818 static const struct usb_device_id sur40_table[] = {
819 	{ USB_DEVICE(ID_MICROSOFT, ID_SUR40) },  /* Samsung SUR40 */
820 	{ }                                      /* terminating null entry */
821 };
822 MODULE_DEVICE_TABLE(usb, sur40_table);
823 
824 /* V4L2 structures */
825 static const struct vb2_ops sur40_queue_ops = {
826 	.queue_setup		= sur40_queue_setup,
827 	.buf_prepare		= sur40_buffer_prepare,
828 	.buf_queue		= sur40_buffer_queue,
829 	.start_streaming	= sur40_start_streaming,
830 	.stop_streaming		= sur40_stop_streaming,
831 	.wait_prepare		= vb2_ops_wait_prepare,
832 	.wait_finish		= vb2_ops_wait_finish,
833 };
834 
835 static const struct vb2_queue sur40_queue = {
836 	.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
837 	/*
838 	 * VB2_USERPTR in currently not enabled: passing a user pointer to
839 	 * dma-sg will result in segment sizes that are not a multiple of
840 	 * 512 bytes, which is required by the host controller.
841 	*/
842 	.io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF,
843 	.buf_struct_size = sizeof(struct sur40_buffer),
844 	.ops = &sur40_queue_ops,
845 	.mem_ops = &vb2_dma_sg_memops,
846 	.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC,
847 	.min_buffers_needed = 3,
848 };
849 
850 static const struct v4l2_file_operations sur40_video_fops = {
851 	.owner = THIS_MODULE,
852 	.open = v4l2_fh_open,
853 	.release = vb2_fop_release,
854 	.unlocked_ioctl = video_ioctl2,
855 	.read = vb2_fop_read,
856 	.mmap = vb2_fop_mmap,
857 	.poll = vb2_fop_poll,
858 };
859 
860 static const struct v4l2_ioctl_ops sur40_video_ioctl_ops = {
861 
862 	.vidioc_querycap	= sur40_vidioc_querycap,
863 
864 	.vidioc_enum_fmt_vid_cap = sur40_vidioc_enum_fmt,
865 	.vidioc_try_fmt_vid_cap	= sur40_vidioc_fmt,
866 	.vidioc_s_fmt_vid_cap	= sur40_vidioc_fmt,
867 	.vidioc_g_fmt_vid_cap	= sur40_vidioc_fmt,
868 
869 	.vidioc_enum_framesizes = sur40_vidioc_enum_framesizes,
870 	.vidioc_enum_frameintervals = sur40_vidioc_enum_frameintervals,
871 
872 	.vidioc_enum_input	= sur40_vidioc_enum_input,
873 	.vidioc_g_input		= sur40_vidioc_g_input,
874 	.vidioc_s_input		= sur40_vidioc_s_input,
875 
876 	.vidioc_reqbufs		= vb2_ioctl_reqbufs,
877 	.vidioc_create_bufs	= vb2_ioctl_create_bufs,
878 	.vidioc_querybuf	= vb2_ioctl_querybuf,
879 	.vidioc_qbuf		= vb2_ioctl_qbuf,
880 	.vidioc_dqbuf		= vb2_ioctl_dqbuf,
881 	.vidioc_expbuf		= vb2_ioctl_expbuf,
882 
883 	.vidioc_streamon	= vb2_ioctl_streamon,
884 	.vidioc_streamoff	= vb2_ioctl_streamoff,
885 };
886 
887 static const struct video_device sur40_video_device = {
888 	.name = DRIVER_LONG,
889 	.fops = &sur40_video_fops,
890 	.ioctl_ops = &sur40_video_ioctl_ops,
891 	.release = video_device_release_empty,
892 };
893 
894 static const struct v4l2_pix_format sur40_video_format = {
895 	.pixelformat = V4L2_PIX_FMT_GREY,
896 	.width  = SENSOR_RES_X / 2,
897 	.height = SENSOR_RES_Y / 2,
898 	.field = V4L2_FIELD_NONE,
899 	.colorspace = V4L2_COLORSPACE_SRGB,
900 	.bytesperline = SENSOR_RES_X / 2,
901 	.sizeimage = (SENSOR_RES_X/2) * (SENSOR_RES_Y/2),
902 };
903 
904 /* USB-specific object needed to register this driver with the USB subsystem. */
905 static struct usb_driver sur40_driver = {
906 	.name = DRIVER_SHORT,
907 	.probe = sur40_probe,
908 	.disconnect = sur40_disconnect,
909 	.id_table = sur40_table,
910 };
911 
912 module_usb_driver(sur40_driver);
913 
914 MODULE_AUTHOR(DRIVER_AUTHOR);
915 MODULE_DESCRIPTION(DRIVER_DESC);
916 MODULE_LICENSE("GPL");
917