i2c.c revision ac633ba6acb94a11b09a7ec417c72f65c6308b7a 
1/*
2 * I2C Link Layer for ST21NFCB NCI based Driver
3 * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/crc-ccitt.h>
21#include <linux/module.h>
22#include <linux/i2c.h>
23#include <linux/gpio.h>
24#include <linux/of_irq.h>
25#include <linux/of_gpio.h>
26#include <linux/miscdevice.h>
27#include <linux/interrupt.h>
28#include <linux/delay.h>
29#include <linux/nfc.h>
30#include <linux/firmware.h>
31#include <linux/unaligned/access_ok.h>
32#include <linux/platform_data/st21nfcb.h>
33
34#include <net/nfc/nci.h>
35#include <net/nfc/llc.h>
36#include <net/nfc/nfc.h>
37
38#include "ndlc.h"
39
40#define DRIVER_DESC "NCI NFC driver for ST21NFCB"
41
42/* ndlc header */
43#define ST21NFCB_FRAME_HEADROOM	1
44#define ST21NFCB_FRAME_TAILROOM 0
45
46#define ST21NFCB_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
47#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
48
49#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
50
51static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
52	{ST21NFCB_NCI_DRIVER_NAME, 0},
53	{}
54};
55MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
56
57struct st21nfcb_i2c_phy {
58	struct i2c_client *i2c_dev;
59	struct llt_ndlc *ndlc;
60
61	unsigned int gpio_irq;
62	unsigned int gpio_reset;
63	unsigned int irq_polarity;
64
65	int powered;
66
67	/*
68	 * < 0 if hardware error occured (e.g. i2c err)
69	 * and prevents normal operation.
70	 */
71	int hard_fault;
72};
73
74#define I2C_DUMP_SKB(info, skb)					\
75do {								\
76	pr_debug("%s:\n", info);				\
77	print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET,	\
78		       16, 1, (skb)->data, (skb)->len, 0);	\
79} while (0)
80
81static int st21nfcb_nci_i2c_enable(void *phy_id)
82{
83	struct st21nfcb_i2c_phy *phy = phy_id;
84
85	gpio_set_value(phy->gpio_reset, 0);
86	usleep_range(10000, 15000);
87	gpio_set_value(phy->gpio_reset, 1);
88	phy->powered = 1;
89	usleep_range(80000, 85000);
90
91	return 0;
92}
93
94static void st21nfcb_nci_i2c_disable(void *phy_id)
95{
96	struct st21nfcb_i2c_phy *phy = phy_id;
97
98	pr_info("\n");
99
100	phy->powered = 0;
101	/* reset chip in order to flush clf */
102	gpio_set_value(phy->gpio_reset, 0);
103	usleep_range(10000, 15000);
104	gpio_set_value(phy->gpio_reset, 1);
105}
106
107static void st21nfcb_nci_remove_header(struct sk_buff *skb)
108{
109	skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
110}
111
112/*
113 * Writing a frame must not return the number of written bytes.
114 * It must return either zero for success, or <0 for error.
115 * In addition, it must not alter the skb
116 */
117static int st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
118{
119	int r = -1;
120	struct st21nfcb_i2c_phy *phy = phy_id;
121	struct i2c_client *client = phy->i2c_dev;
122
123	I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
124
125	if (phy->hard_fault != 0)
126		return phy->hard_fault;
127
128	r = i2c_master_send(client, skb->data, skb->len);
129	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
130		usleep_range(1000, 4000);
131		r = i2c_master_send(client, skb->data, skb->len);
132	}
133
134	if (r >= 0) {
135		if (r != skb->len)
136			r = -EREMOTEIO;
137		else
138			r = 0;
139	}
140
141	st21nfcb_nci_remove_header(skb);
142
143	return r;
144}
145
146/*
147 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
148 * returns:
149 * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
150 * end of read)
151 * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
152 * at end of read)
153 * -EREMOTEIO : i2c read error (fatal)
154 * -EBADMSG : frame was incorrect and discarded
155 * (value returned from st21nfcb_nci_i2c_repack)
156 * -EIO : if no ST21NFCB_SOF_EOF is found after reaching
157 * the read length end sequence
158 */
159static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
160				 struct sk_buff **skb)
161{
162	int r;
163	u8 len;
164	u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
165	struct i2c_client *client = phy->i2c_dev;
166
167	r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
168	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
169		usleep_range(1000, 4000);
170		r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
171	}
172
173	if (r != ST21NFCB_NCI_I2C_MIN_SIZE) {
174		nfc_err(&client->dev, "cannot read ndlc & nci header\n");
175		return -EREMOTEIO;
176	}
177
178	len = be16_to_cpu(*(__be16 *) (buf + 2));
179	if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
180		nfc_err(&client->dev, "invalid frame len\n");
181		return -EBADMSG;
182	}
183
184	*skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
185	if (*skb == NULL)
186		return -ENOMEM;
187
188	skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
189	skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
190	memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
191
192	if (!len)
193		return 0;
194
195	r = i2c_master_recv(client, buf, len);
196	if (r != len) {
197		kfree_skb(*skb);
198		return -EREMOTEIO;
199	}
200
201	skb_put(*skb, len);
202	memcpy((*skb)->data + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
203
204	I2C_DUMP_SKB("i2c frame read", *skb);
205
206	return 0;
207}
208
209/*
210 * Reads an ndlc frame from the chip.
211 *
212 * On ST21NFCB, IRQ goes in idle state when read starts.
213 */
214static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
215{
216	struct st21nfcb_i2c_phy *phy = phy_id;
217	struct i2c_client *client;
218	struct sk_buff *skb = NULL;
219	int r;
220
221	if (!phy || irq != phy->i2c_dev->irq) {
222		WARN_ON_ONCE(1);
223		return IRQ_NONE;
224	}
225
226	client = phy->i2c_dev;
227	dev_dbg(&client->dev, "IRQ\n");
228
229	if (phy->hard_fault)
230		return IRQ_HANDLED;
231
232	if (!phy->powered) {
233		st21nfcb_nci_i2c_disable(phy);
234		return IRQ_HANDLED;
235	}
236
237	r = st21nfcb_nci_i2c_read(phy, &skb);
238	if (r == -EREMOTEIO) {
239		phy->hard_fault = r;
240		ndlc_recv(phy->ndlc, NULL);
241		return IRQ_HANDLED;
242	} else if (r == -ENOMEM || r == -EBADMSG) {
243		return IRQ_HANDLED;
244	}
245
246	ndlc_recv(phy->ndlc, skb);
247
248	return IRQ_HANDLED;
249}
250
251static struct nfc_phy_ops i2c_phy_ops = {
252	.write = st21nfcb_nci_i2c_write,
253	.enable = st21nfcb_nci_i2c_enable,
254	.disable = st21nfcb_nci_i2c_disable,
255};
256
257#ifdef CONFIG_OF
258static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
259{
260	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
261	struct device_node *pp;
262	int gpio;
263	int r;
264
265	pp = client->dev.of_node;
266	if (!pp)
267		return -ENODEV;
268
269	/* Get GPIO from device tree */
270	gpio = of_get_named_gpio(pp, "reset-gpios", 0);
271	if (gpio < 0) {
272		nfc_err(&client->dev,
273			"Failed to retrieve reset-gpios from device tree\n");
274		return gpio;
275	}
276
277	/* GPIO request and configuration */
278	r = devm_gpio_request_one(&client->dev, gpio,
279				GPIOF_OUT_INIT_HIGH, "clf_reset");
280	if (r) {
281		nfc_err(&client->dev, "Failed to request reset pin\n");
282		return -ENODEV;
283	}
284	phy->gpio_reset = gpio;
285
286	/* IRQ */
287	r = irq_of_parse_and_map(pp, 0);
288	if (r < 0) {
289		nfc_err(&client->dev, "Unable to get irq, error: %d\n", r);
290		return r;
291	}
292
293	phy->irq_polarity = irq_get_trigger_type(r);
294	client->irq = r;
295
296	return 0;
297}
298#else
299static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
300{
301	return -ENODEV;
302}
303#endif
304
305static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
306{
307	struct st21nfcb_nfc_platform_data *pdata;
308	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
309	int r;
310	int irq;
311
312	pdata = client->dev.platform_data;
313	if (pdata == NULL) {
314		nfc_err(&client->dev, "No platform data\n");
315		return -EINVAL;
316	}
317
318	/* store for later use */
319	phy->gpio_irq = pdata->gpio_irq;
320	phy->gpio_reset = pdata->gpio_reset;
321	phy->irq_polarity = pdata->irq_polarity;
322
323	r = devm_gpio_request_one(&client->dev, phy->gpio_irq,
324				GPIOF_IN, "clf_irq");
325	if (r) {
326		pr_err("%s : gpio_request failed\n", __FILE__);
327		return -ENODEV;
328	}
329
330	r = devm_gpio_request_one(&client->dev,
331			phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
332	if (r) {
333		pr_err("%s : reset gpio_request failed\n", __FILE__);
334		return -ENODEV;
335	}
336
337	/* IRQ */
338	irq = gpio_to_irq(phy->gpio_irq);
339	if (irq < 0) {
340		nfc_err(&client->dev,
341			"Unable to get irq number for GPIO %d error %d\n",
342			phy->gpio_irq, r);
343		return -ENODEV;
344	}
345	client->irq = irq;
346
347	return 0;
348}
349
350static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
351				  const struct i2c_device_id *id)
352{
353	struct st21nfcb_i2c_phy *phy;
354	struct st21nfcb_nfc_platform_data *pdata;
355	int r;
356
357	dev_dbg(&client->dev, "%s\n", __func__);
358	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
359
360	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
361		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
362		return -ENODEV;
363	}
364
365	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
366			   GFP_KERNEL);
367	if (!phy) {
368		nfc_err(&client->dev,
369			"Cannot allocate memory for st21nfcb i2c phy.\n");
370		return -ENOMEM;
371	}
372
373	phy->i2c_dev = client;
374
375	i2c_set_clientdata(client, phy);
376
377	pdata = client->dev.platform_data;
378	if (!pdata && client->dev.of_node) {
379		r = st21nfcb_nci_i2c_of_request_resources(client);
380		if (r) {
381			nfc_err(&client->dev, "No platform data\n");
382			return r;
383		}
384	} else if (pdata) {
385		r = st21nfcb_nci_i2c_request_resources(client);
386		if (r) {
387			nfc_err(&client->dev,
388				"Cannot get platform resources\n");
389			return r;
390		}
391	} else {
392		nfc_err(&client->dev,
393			"st21nfcb platform resources not available\n");
394		return -ENODEV;
395	}
396
397	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
398				st21nfcb_nci_irq_thread_fn,
399				phy->irq_polarity | IRQF_ONESHOT,
400				ST21NFCB_NCI_DRIVER_NAME, phy);
401	if (r < 0) {
402		nfc_err(&client->dev, "Unable to register IRQ handler\n");
403		return r;
404	}
405
406	return ndlc_probe(phy, &i2c_phy_ops, &client->dev,
407			ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
408			&phy->ndlc);
409}
410
411static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
412{
413	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
414
415	dev_dbg(&client->dev, "%s\n", __func__);
416
417	ndlc_remove(phy->ndlc);
418
419	if (phy->powered)
420		st21nfcb_nci_i2c_disable(phy);
421
422	return 0;
423}
424
425static const struct of_device_id of_st21nfcb_i2c_match[] = {
426	{ .compatible = "st,st21nfcb_i2c", },
427	{}
428};
429
430static struct i2c_driver st21nfcb_nci_i2c_driver = {
431	.driver = {
432		.owner = THIS_MODULE,
433		.name = ST21NFCB_NCI_I2C_DRIVER_NAME,
434		.of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
435	},
436	.probe = st21nfcb_nci_i2c_probe,
437	.id_table = st21nfcb_nci_i2c_id_table,
438	.remove = st21nfcb_nci_i2c_remove,
439};
440
441module_i2c_driver(st21nfcb_nci_i2c_driver);
442
443MODULE_LICENSE("GPL");
444MODULE_DESCRIPTION(DRIVER_DESC);
445