summaryrefslogtreecommitdiff
path: root/drivers/nfc/st21nfcb/i2c.c
blob: 8af880ead5db3f1b558aaa1ff28ac38c1b1e078c (plain)
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
/*
 * I2C Link Layer for ST21NFCB NCI based Driver
 * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/crc-ccitt.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>
#include <linux/miscdevice.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/nfc.h>
#include <linux/firmware.h>
#include <linux/unaligned/access_ok.h>
#include <linux/platform_data/st21nfcb.h>

#include <net/nfc/nci.h>
#include <net/nfc/llc.h>
#include <net/nfc/nfc.h>

#include "ndlc.h"

#define DRIVER_DESC "NCI NFC driver for ST21NFCB"

/* ndlc header */
#define ST21NFCB_FRAME_HEADROOM	1
#define ST21NFCB_FRAME_TAILROOM 0

#define ST21NFCB_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */

#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"

static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
	{ST21NFCB_NCI_DRIVER_NAME, 0},
	{}
};
MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);

struct st21nfcb_i2c_phy {
	struct i2c_client *i2c_dev;
	struct llt_ndlc *ndlc;

	unsigned int gpio_irq;
	unsigned int gpio_reset;
	unsigned int irq_polarity;

	int powered;

	/*
	 * < 0 if hardware error occured (e.g. i2c err)
	 * and prevents normal operation.
	 */
	int hard_fault;
};

#define I2C_DUMP_SKB(info, skb)					\
do {								\
	pr_debug("%s:\n", info);				\
	print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET,	\
		       16, 1, (skb)->data, (skb)->len, 0);	\
} while (0)

static int st21nfcb_nci_i2c_enable(void *phy_id)
{
	struct st21nfcb_i2c_phy *phy = phy_id;

	gpio_set_value(phy->gpio_reset, 0);
	usleep_range(10000, 15000);
	gpio_set_value(phy->gpio_reset, 1);
	phy->powered = 1;
	usleep_range(80000, 85000);

	return 0;
}

static void st21nfcb_nci_i2c_disable(void *phy_id)
{
	struct st21nfcb_i2c_phy *phy = phy_id;

	pr_info("\n");

	phy->powered = 0;
	/* reset chip in order to flush clf */
	gpio_set_value(phy->gpio_reset, 0);
	usleep_range(10000, 15000);
	gpio_set_value(phy->gpio_reset, 1);
}

static void st21nfcb_nci_remove_header(struct sk_buff *skb)
{
	skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
}

/*
 * Writing a frame must not return the number of written bytes.
 * It must return either zero for success, or <0 for error.
 * In addition, it must not alter the skb
 */
static int st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
{
	int r = -1;
	struct st21nfcb_i2c_phy *phy = phy_id;
	struct i2c_client *client = phy->i2c_dev;

	I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);

	if (phy->hard_fault != 0)
		return phy->hard_fault;

	r = i2c_master_send(client, skb->data, skb->len);
	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
		usleep_range(1000, 4000);
		r = i2c_master_send(client, skb->data, skb->len);
	}

	if (r >= 0) {
		if (r != skb->len)
			r = -EREMOTEIO;
		else
			r = 0;
	}

	st21nfcb_nci_remove_header(skb);

	return r;
}

/*
 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 * returns:
 * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
 * end of read)
 * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
 * at end of read)
 * -EREMOTEIO : i2c read error (fatal)
 * -EBADMSG : frame was incorrect and discarded
 * (value returned from st21nfcb_nci_i2c_repack)
 * -EIO : if no ST21NFCB_SOF_EOF is found after reaching
 * the read length end sequence
 */
static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
				 struct sk_buff **skb)
{
	int r;
	u8 len;
	u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
	struct i2c_client *client = phy->i2c_dev;

	r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
		usleep_range(1000, 4000);
		r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
	} else if (r != ST21NFCB_NCI_I2C_MIN_SIZE) {
		nfc_err(&client->dev, "cannot read ndlc & nci header\n");
		return -EREMOTEIO;
	}

	len = be16_to_cpu(*(__be16 *) (buf + 2));
	if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
		nfc_err(&client->dev, "invalid frame len\n");
		return -EBADMSG;
	}

	*skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
	if (*skb == NULL)
		return -ENOMEM;

	skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
	skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
	memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE);

	if (!len)
		return 0;

	r = i2c_master_recv(client, buf, len);
	if (r != len) {
		kfree_skb(*skb);
		return -EREMOTEIO;
	}

	skb_put(*skb, len);
	memcpy((*skb)->data + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);

	I2C_DUMP_SKB("i2c frame read", *skb);

	return 0;
}

/*
 * Reads an ndlc frame from the chip.
 *
 * On ST21NFCB, IRQ goes in idle state when read starts.
 */
static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
{
	struct st21nfcb_i2c_phy *phy = phy_id;
	struct i2c_client *client;
	struct sk_buff *skb = NULL;
	int r;

	if (!phy || irq != phy->i2c_dev->irq) {
		WARN_ON_ONCE(1);
		return IRQ_NONE;
	}

	client = phy->i2c_dev;
	dev_dbg(&client->dev, "IRQ\n");

	if (phy->hard_fault)
		return IRQ_HANDLED;

	if (!phy->powered) {
		st21nfcb_nci_i2c_disable(phy);
		return IRQ_HANDLED;
	}

	r = st21nfcb_nci_i2c_read(phy, &skb);
	if (r == -EREMOTEIO) {
		phy->hard_fault = r;
                ndlc_recv(phy->ndlc, NULL);
		return IRQ_HANDLED;
	} else if (r == -ENOMEM || r == -EBADMSG) {
		return IRQ_HANDLED;
	}

	ndlc_recv(phy->ndlc, skb);

	return IRQ_HANDLED;
}

static struct nfc_phy_ops i2c_phy_ops = {
	.write = st21nfcb_nci_i2c_write,
	.enable = st21nfcb_nci_i2c_enable,
	.disable = st21nfcb_nci_i2c_disable,
};

#ifdef CONFIG_OF
static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
{
	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
	struct device_node *pp;
	int gpio;
	int r;

	pp = client->dev.of_node;
	if (!pp)
		return -ENODEV;

	/* Get GPIO from device tree */
	gpio = of_get_named_gpio(pp, "reset-gpios", 0);
	if (gpio < 0) {
		nfc_err(&client->dev,
			"Failed to retrieve reset-gpios from device tree\n");
		return gpio;
	}

	/* GPIO request and configuration */
	r = devm_gpio_request(&client->dev, gpio, "clf_reset");
	if (r) {
		nfc_err(&client->dev, "Failed to request reset pin\n");
		return -ENODEV;
	}

	r = gpio_direction_output(gpio, 1);
	if (r) {
		nfc_err(&client->dev,
			"Failed to set reset pin direction as output\n");
		return -ENODEV;
	}
	phy->gpio_reset = gpio;

	/* IRQ */
	r = irq_of_parse_and_map(pp, 0);
	if (r < 0) {
		nfc_err(&client->dev,
				"Unable to get irq, error: %d\n", r);
		return r;
	}

	phy->irq_polarity = irq_get_trigger_type(r);
	client->irq = r;

	return 0;
}
#else
static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
{
	return -ENODEV;
}
#endif

static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
{
	struct st21nfcb_nfc_platform_data *pdata;
	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
	int r;
	int irq;

	pdata = client->dev.platform_data;
	if (pdata == NULL) {
		nfc_err(&client->dev, "No platform data\n");
		return -EINVAL;
	}

	/* store for later use */
	phy->gpio_irq = pdata->gpio_irq;
	phy->gpio_reset = pdata->gpio_reset;
	phy->irq_polarity = pdata->irq_polarity;

	r = devm_gpio_request(&client->dev, phy->gpio_irq, "wake_up");
	if (r) {
		pr_err("%s : gpio_request failed\n", __FILE__);
		return -ENODEV;
	}

	r = gpio_direction_input(phy->gpio_irq);
	if (r) {
		pr_err("%s : gpio_direction_input failed\n", __FILE__);
		return -ENODEV;
	}

	r = devm_gpio_request(&client->dev,
			      phy->gpio_reset, "clf_reset");
	if (r) {
		pr_err("%s : reset gpio_request failed\n", __FILE__);
		return -ENODEV;
	}

	r = gpio_direction_output(phy->gpio_reset, 1);
	if (r) {
		pr_err("%s : reset gpio_direction_output failed\n",
			__FILE__);
		return -ENODEV;
	}

	/* IRQ */
	irq = gpio_to_irq(phy->gpio_irq);
	if (irq < 0) {
		nfc_err(&client->dev,
			"Unable to get irq number for GPIO %d error %d\n",
			phy->gpio_irq, r);
		return -ENODEV;
	}
	client->irq = irq;

	return 0;
}

static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
				  const struct i2c_device_id *id)
{
	struct st21nfcb_i2c_phy *phy;
	struct st21nfcb_nfc_platform_data *pdata;
	int r;

	dev_dbg(&client->dev, "%s\n", __func__);
	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
		return -ENODEV;
	}

	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
			   GFP_KERNEL);
	if (!phy) {
		nfc_err(&client->dev,
			"Cannot allocate memory for st21nfcb i2c phy.\n");
		return -ENOMEM;
	}

	phy->i2c_dev = client;

	i2c_set_clientdata(client, phy);

	pdata = client->dev.platform_data;
	if (!pdata && client->dev.of_node) {
		r = st21nfcb_nci_i2c_of_request_resources(client);
		if (r) {
			nfc_err(&client->dev, "No platform data\n");
			return r;
		}
	} else if (pdata) {
		r = st21nfcb_nci_i2c_request_resources(client);
		if (r) {
			nfc_err(&client->dev,
				"Cannot get platform resources\n");
			return r;
		}
	} else {
		nfc_err(&client->dev,
			"st21nfcb platform resources not available\n");
		return -ENODEV;
	}

	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
				st21nfcb_nci_irq_thread_fn,
				phy->irq_polarity | IRQF_ONESHOT,
				ST21NFCB_NCI_DRIVER_NAME, phy);
	if (r < 0) {
		nfc_err(&client->dev, "Unable to register IRQ handler\n");
		return r;
	}

	return ndlc_probe(phy, &i2c_phy_ops, &client->dev,
			ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
			&phy->ndlc);
}

static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
{
	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);

	dev_dbg(&client->dev, "%s\n", __func__);

	ndlc_remove(phy->ndlc);

	if (phy->powered)
		st21nfcb_nci_i2c_disable(phy);

	return 0;
}

static const struct of_device_id of_st21nfcb_i2c_match[] = {
	{ .compatible = "st,st21nfcb_i2c", },
	{}
};

static struct i2c_driver st21nfcb_nci_i2c_driver = {
	.driver = {
		.owner = THIS_MODULE,
		.name = ST21NFCB_NCI_I2C_DRIVER_NAME,
		.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
	},
	.probe = st21nfcb_nci_i2c_probe,
	.id_table = st21nfcb_nci_i2c_id_table,
	.remove = st21nfcb_nci_i2c_remove,
};

module_i2c_driver(st21nfcb_nci_i2c_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);