Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
/*
 * HID class driver for the Greybus.
 *
 * Copyright 2014 Google Inc.
 * Copyright 2014 Linaro Ltd.
 *
 * Released under the GPLv2 only.
 */

#include <linux/bitops.h>
#include <linux/hid.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>

#include "greybus.h"

/* Greybus HID device's structure */
struct gb_hid {
	struct gb_bundle *bundle;
	struct gb_connection		*connection;

	struct hid_device		*hid;
	struct gb_hid_desc_response	hdesc;

	unsigned long			flags;
#define GB_HID_STARTED			0x01
#define GB_HID_READ_PENDING		0x04

	unsigned int			bufsize;
	char				*inbuf;
};

/* Routines to get controller's information over greybus */

/* Operations performed on greybus */
static int gb_hid_get_desc(struct gb_hid *ghid)
{
	return gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_DESC, NULL,
				 0, &ghid->hdesc, sizeof(ghid->hdesc));
}

static int gb_hid_get_report_desc(struct gb_hid *ghid, char *rdesc)
{
	int ret;

	ret = gb_pm_runtime_get_sync(ghid->bundle);
	if (ret)
		return ret;

	ret = gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_REPORT_DESC,
				 NULL, 0, rdesc,
				 le16_to_cpu(ghid->hdesc.wReportDescLength));

	gb_pm_runtime_put_autosuspend(ghid->bundle);

	return ret;
}

static int gb_hid_set_power(struct gb_hid *ghid, int type)
{
	int ret;

	ret = gb_pm_runtime_get_sync(ghid->bundle);
	if (ret)
		return ret;

	ret = gb_operation_sync(ghid->connection, type, NULL, 0, NULL, 0);

	gb_pm_runtime_put_autosuspend(ghid->bundle);

	return ret;
}

static int gb_hid_get_report(struct gb_hid *ghid, u8 report_type, u8 report_id,
			     unsigned char *buf, int len)
{
	struct gb_hid_get_report_request request;
	int ret;

	ret = gb_pm_runtime_get_sync(ghid->bundle);
	if (ret)
		return ret;

	request.report_type = report_type;
	request.report_id = report_id;

	ret = gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_REPORT,
				 &request, sizeof(request), buf, len);

	gb_pm_runtime_put_autosuspend(ghid->bundle);

	return ret;
}

static int gb_hid_set_report(struct gb_hid *ghid, u8 report_type, u8 report_id,
			     unsigned char *buf, int len)
{
	struct gb_hid_set_report_request *request;
	struct gb_operation *operation;
	int ret, size = sizeof(*request) + len - 1;

	ret = gb_pm_runtime_get_sync(ghid->bundle);
	if (ret)
		return ret;

	operation = gb_operation_create(ghid->connection,
					GB_HID_TYPE_SET_REPORT, size, 0,
					GFP_KERNEL);
	if (!operation) {
		gb_pm_runtime_put_autosuspend(ghid->bundle);
		return -ENOMEM;
	}

	request = operation->request->payload;
	request->report_type = report_type;
	request->report_id = report_id;
	memcpy(request->report, buf, len);

	ret = gb_operation_request_send_sync(operation);
	if (ret) {
		dev_err(&operation->connection->bundle->dev,
			"failed to set report: %d\n", ret);
	} else {
		ret = len;
	}

	gb_operation_put(operation);
	gb_pm_runtime_put_autosuspend(ghid->bundle);

	return ret;
}

static int gb_hid_request_handler(struct gb_operation *op)
{
	struct gb_connection *connection = op->connection;
	struct gb_hid *ghid = gb_connection_get_data(connection);
	struct gb_hid_input_report_request *request = op->request->payload;

	if (op->type != GB_HID_TYPE_IRQ_EVENT) {
		dev_err(&connection->bundle->dev,
			"unsupported unsolicited request\n");
		return -EINVAL;
	}

	if (test_bit(GB_HID_STARTED, &ghid->flags))
		hid_input_report(ghid->hid, HID_INPUT_REPORT,
				 request->report, op->request->payload_size, 1);

	return 0;
}

static int gb_hid_report_len(struct hid_report *report)
{
	return ((report->size - 1) >> 3) + 1 +
		report->device->report_enum[report->type].numbered;
}

static void gb_hid_find_max_report(struct hid_device *hid, unsigned int type,
				   unsigned int *max)
{
	struct hid_report *report;
	unsigned int size;

	list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
		size = gb_hid_report_len(report);
		if (*max < size)
			*max = size;
	}
}

static void gb_hid_free_buffers(struct gb_hid *ghid)
{
	kfree(ghid->inbuf);
	ghid->inbuf = NULL;
	ghid->bufsize = 0;
}

static int gb_hid_alloc_buffers(struct gb_hid *ghid, size_t bufsize)
{
	ghid->inbuf = kzalloc(bufsize, GFP_KERNEL);
	if (!ghid->inbuf)
		return -ENOMEM;

	ghid->bufsize = bufsize;

	return 0;
}

/* Routines dealing with reports */
static void gb_hid_init_report(struct gb_hid *ghid, struct hid_report *report)
{
	unsigned int size;

	size = gb_hid_report_len(report);
	if (gb_hid_get_report(ghid, report->type, report->id, ghid->inbuf,
			      size))
		return;

	/*
	 * hid->driver_lock is held as we are in probe function,
	 * we just need to setup the input fields, so using
	 * hid_report_raw_event is safe.
	 */
	hid_report_raw_event(ghid->hid, report->type, ghid->inbuf, size, 1);
}

static void gb_hid_init_reports(struct gb_hid *ghid)
{
	struct hid_device *hid = ghid->hid;
	struct hid_report *report;

	list_for_each_entry(report,
		&hid->report_enum[HID_INPUT_REPORT].report_list, list)
		gb_hid_init_report(ghid, report);

	list_for_each_entry(report,
		&hid->report_enum[HID_FEATURE_REPORT].report_list, list)
		gb_hid_init_report(ghid, report);
}

static int __gb_hid_get_raw_report(struct hid_device *hid,
		unsigned char report_number, __u8 *buf, size_t count,
		unsigned char report_type)
{
	struct gb_hid *ghid = hid->driver_data;
	int ret;

	if (report_type == HID_OUTPUT_REPORT)
		return -EINVAL;

	ret = gb_hid_get_report(ghid, report_type, report_number, buf, count);
	if (!ret)
		ret = count;

	return ret;
}

static int __gb_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
				      size_t len, unsigned char report_type)
{
	struct gb_hid *ghid = hid->driver_data;
	int report_id = buf[0];
	int ret;

	if (report_type == HID_INPUT_REPORT)
		return -EINVAL;

	if (report_id) {
		buf++;
		len--;
	}

	ret = gb_hid_set_report(ghid, report_type, report_id, buf, len);
	if (report_id && ret >= 0)
		ret++; /* add report_id to the number of transfered bytes */

	return 0;
}

static int gb_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
			       __u8 *buf, size_t len, unsigned char rtype,
			       int reqtype)
{
	switch (reqtype) {
	case HID_REQ_GET_REPORT:
		return __gb_hid_get_raw_report(hid, reportnum, buf, len, rtype);
	case HID_REQ_SET_REPORT:
		if (buf[0] != reportnum)
			return -EINVAL;
		return __gb_hid_output_raw_report(hid, buf, len, rtype);
	default:
		return -EIO;
	}
}

/* HID Callbacks */
static int gb_hid_parse(struct hid_device *hid)
{
	struct gb_hid *ghid = hid->driver_data;
	unsigned int rsize;
	char *rdesc;
	int ret;

	rsize = le16_to_cpu(ghid->hdesc.wReportDescLength);
	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
		dbg_hid("weird size of report descriptor (%u)\n", rsize);
		return -EINVAL;
	}

	rdesc = kzalloc(rsize, GFP_KERNEL);
	if (!rdesc) {
		dbg_hid("couldn't allocate rdesc memory\n");
		return -ENOMEM;
	}

	ret = gb_hid_get_report_desc(ghid, rdesc);
	if (ret) {
		hid_err(hid, "reading report descriptor failed\n");
		goto free_rdesc;
	}

	ret = hid_parse_report(hid, rdesc, rsize);
	if (ret)
		dbg_hid("parsing report descriptor failed\n");

free_rdesc:
	kfree(rdesc);

	return ret;
}

static int gb_hid_start(struct hid_device *hid)
{
	struct gb_hid *ghid = hid->driver_data;
	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
	int ret;

	gb_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
	gb_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
	gb_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);

	if (bufsize > HID_MAX_BUFFER_SIZE)
		bufsize = HID_MAX_BUFFER_SIZE;

	ret = gb_hid_alloc_buffers(ghid, bufsize);
	if (ret)
		return ret;

	if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
		gb_hid_init_reports(ghid);

	return 0;
}

static void gb_hid_stop(struct hid_device *hid)
{
	struct gb_hid *ghid = hid->driver_data;

	gb_hid_free_buffers(ghid);
}

static int gb_hid_open(struct hid_device *hid)
{
	struct gb_hid *ghid = hid->driver_data;
	int ret;

	ret = gb_hid_set_power(ghid, GB_HID_TYPE_PWR_ON);
	if (ret < 0)
		return ret;

	set_bit(GB_HID_STARTED, &ghid->flags);
	return 0;
}

static void gb_hid_close(struct hid_device *hid)
{
	struct gb_hid *ghid = hid->driver_data;
	int ret;

	clear_bit(GB_HID_STARTED, &ghid->flags);

	/* Save some power */
	ret = gb_hid_set_power(ghid, GB_HID_TYPE_PWR_OFF);
	if (ret)
		dev_err(&ghid->connection->bundle->dev,
			"failed to power off (%d)\n", ret);
}

static int gb_hid_power(struct hid_device *hid, int lvl)
{
	struct gb_hid *ghid = hid->driver_data;

	switch (lvl) {
	case PM_HINT_FULLON:
		return gb_hid_set_power(ghid, GB_HID_TYPE_PWR_ON);
	case PM_HINT_NORMAL:
		return gb_hid_set_power(ghid, GB_HID_TYPE_PWR_OFF);
	}

	return 0;
}

/* HID structure to pass callbacks */
static struct hid_ll_driver gb_hid_ll_driver = {
	.parse = gb_hid_parse,
	.start = gb_hid_start,
	.stop = gb_hid_stop,
	.open = gb_hid_open,
	.close = gb_hid_close,
	.power = gb_hid_power,
	.raw_request = gb_hid_raw_request,
};

static int gb_hid_init(struct gb_hid *ghid)
{
	struct hid_device *hid = ghid->hid;
	int ret;

	ret = gb_hid_get_desc(ghid);
	if (ret)
		return ret;

	hid->version = le16_to_cpu(ghid->hdesc.bcdHID);
	hid->vendor = le16_to_cpu(ghid->hdesc.wVendorID);
	hid->product = le16_to_cpu(ghid->hdesc.wProductID);
	hid->country = ghid->hdesc.bCountryCode;

	hid->driver_data = ghid;
	hid->ll_driver = &gb_hid_ll_driver;
	hid->dev.parent = &ghid->connection->bundle->dev;
//	hid->bus = BUS_GREYBUS; /* Need a bustype for GREYBUS in <linux/input.h> */

	/* Set HID device's name */
	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
		 dev_name(&ghid->connection->bundle->dev),
		 hid->vendor, hid->product);

	return 0;
}

static int gb_hid_probe(struct gb_bundle *bundle,
			const struct greybus_bundle_id *id)
{
	struct greybus_descriptor_cport *cport_desc;
	struct gb_connection *connection;
	struct hid_device *hid;
	struct gb_hid *ghid;
	int ret;

	if (bundle->num_cports != 1)
		return -ENODEV;

	cport_desc = &bundle->cport_desc[0];
	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_HID)
		return -ENODEV;

	ghid = kzalloc(sizeof(*ghid), GFP_KERNEL);
	if (!ghid)
		return -ENOMEM;

	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
						gb_hid_request_handler);
	if (IS_ERR(connection)) {
		ret = PTR_ERR(connection);
		goto err_free_ghid;
	}

	gb_connection_set_data(connection, ghid);
	ghid->connection = connection;

	hid = hid_allocate_device();
	if (IS_ERR(hid)) {
		ret = PTR_ERR(hid);
		goto err_connection_destroy;
	}

	ghid->hid = hid;
	ghid->bundle = bundle;

	greybus_set_drvdata(bundle, ghid);

	ret = gb_connection_enable(connection);
	if (ret)
		goto err_destroy_hid;

	ret = gb_hid_init(ghid);
	if (ret)
		goto err_connection_disable;

	ret = hid_add_device(hid);
	if (ret) {
		hid_err(hid, "can't add hid device: %d\n", ret);
		goto err_connection_disable;
	}

	gb_pm_runtime_put_autosuspend(bundle);

	return 0;

err_connection_disable:
	gb_connection_disable(connection);
err_destroy_hid:
	hid_destroy_device(hid);
err_connection_destroy:
	gb_connection_destroy(connection);
err_free_ghid:
	kfree(ghid);

	return ret;
}

static void gb_hid_disconnect(struct gb_bundle *bundle)
{
	struct gb_hid *ghid = greybus_get_drvdata(bundle);

	if (gb_pm_runtime_get_sync(bundle))
		gb_pm_runtime_get_noresume(bundle);

	hid_destroy_device(ghid->hid);
	gb_connection_disable(ghid->connection);
	gb_connection_destroy(ghid->connection);
	kfree(ghid);
}

static const struct greybus_bundle_id gb_hid_id_table[] = {
	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_HID) },
	{ }
};
MODULE_DEVICE_TABLE(greybus, gb_hid_id_table);

static struct greybus_driver gb_hid_driver = {
	.name		= "hid",
	.probe		= gb_hid_probe,
	.disconnect	= gb_hid_disconnect,
	.id_table	= gb_hid_id_table,
};
module_greybus_driver(gb_hid_driver);

MODULE_LICENSE("GPL v2");