i2c.c revision 35630df68d6030daf12dde12ed07bbe26324e6ac 
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, 4);
168	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
169		usleep_range(1000, 4000);
170		r = i2c_master_recv(client, buf, 4);
171	} else if (r != 4) {
172		nfc_err(&client->dev, "cannot read ndlc & nci header\n");
173		return -EREMOTEIO;
174	}
175
176	len = be16_to_cpu(*(__be16 *) (buf + 2));
177	if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
178		nfc_err(&client->dev, "invalid frame len\n");
179		return -EBADMSG;
180	}
181
182	*skb = alloc_skb(4 + len, GFP_KERNEL);
183	if (*skb == NULL)
184		return -ENOMEM;
185
186	skb_reserve(*skb, 4);
187	skb_put(*skb, 4);
188	memcpy((*skb)->data, buf, 4);
189
190	if (!len)
191		return 0;
192
193	r = i2c_master_recv(client, buf, len);
194	if (r != len) {
195		kfree_skb(*skb);
196		return -EREMOTEIO;
197	}
198
199	skb_put(*skb, len);
200	memcpy((*skb)->data + 4, buf, len);
201
202	I2C_DUMP_SKB("i2c frame read", *skb);
203
204	return 0;
205}
206
207/*
208 * Reads an ndlc frame from the chip.
209 *
210 * On ST21NFCB, IRQ goes in idle state when read starts.
211 */
212static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
213{
214	struct st21nfcb_i2c_phy *phy = phy_id;
215	struct i2c_client *client;
216	struct sk_buff *skb = NULL;
217	int r;
218
219	if (!phy || irq != phy->i2c_dev->irq) {
220		WARN_ON_ONCE(1);
221		return IRQ_NONE;
222	}
223
224	client = phy->i2c_dev;
225	dev_dbg(&client->dev, "IRQ\n");
226
227	if (phy->hard_fault)
228		return IRQ_HANDLED;
229
230	if (!phy->powered) {
231		st21nfcb_nci_i2c_disable(phy);
232		return IRQ_HANDLED;
233	}
234
235	r = st21nfcb_nci_i2c_read(phy, &skb);
236	if (r == -EREMOTEIO) {
237		phy->hard_fault = r;
238                ndlc_recv(phy->ndlc, NULL);
239		return IRQ_HANDLED;
240	} else if (r == -ENOMEM || r == -EBADMSG) {
241		return IRQ_HANDLED;
242	}
243
244	ndlc_recv(phy->ndlc, skb);
245
246	return IRQ_HANDLED;
247}
248
249static struct nfc_phy_ops i2c_phy_ops = {
250	.write = st21nfcb_nci_i2c_write,
251	.enable = st21nfcb_nci_i2c_enable,
252	.disable = st21nfcb_nci_i2c_disable,
253};
254
255#ifdef CONFIG_OF
256static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
257{
258	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
259	struct device_node *pp;
260	int gpio;
261	int r;
262
263	pp = client->dev.of_node;
264	if (!pp)
265		return -ENODEV;
266
267	/* Get GPIO from device tree */
268	gpio = of_get_named_gpio(pp, "reset-gpios", 0);
269	if (gpio < 0) {
270		nfc_err(&client->dev,
271			"Failed to retrieve reset-gpios from device tree\n");
272		return gpio;
273	}
274
275	/* GPIO request and configuration */
276	r = devm_gpio_request(&client->dev, gpio, "clf_reset");
277	if (r) {
278		nfc_err(&client->dev, "Failed to request reset pin\n");
279		return -ENODEV;
280	}
281
282	r = gpio_direction_output(gpio, 1);
283	if (r) {
284		nfc_err(&client->dev,
285			"Failed to set reset pin direction as output\n");
286		return -ENODEV;
287	}
288	phy->gpio_reset = gpio;
289
290	/* IRQ */
291	r = irq_of_parse_and_map(pp, 0);
292	if (r < 0) {
293		nfc_err(&client->dev,
294				"Unable to get irq, error: %d\n", r);
295		return r;
296	}
297
298	phy->irq_polarity = irq_get_trigger_type(r);
299	client->irq = r;
300
301	return 0;
302}
303#else
304static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
305{
306	return -ENODEV;
307}
308#endif
309
310static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
311{
312	struct st21nfcb_nfc_platform_data *pdata;
313	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
314	int r;
315	int irq;
316
317	pdata = client->dev.platform_data;
318	if (pdata == NULL) {
319		nfc_err(&client->dev, "No platform data\n");
320		return -EINVAL;
321	}
322
323	/* store for later use */
324	phy->gpio_irq = pdata->gpio_irq;
325	phy->gpio_reset = pdata->gpio_reset;
326	phy->irq_polarity = pdata->irq_polarity;
327
328	r = devm_gpio_request(&client->dev, phy->gpio_irq, "wake_up");
329	if (r) {
330		pr_err("%s : gpio_request failed\n", __FILE__);
331		return -ENODEV;
332	}
333
334	r = gpio_direction_input(phy->gpio_irq);
335	if (r) {
336		pr_err("%s : gpio_direction_input failed\n", __FILE__);
337		return -ENODEV;
338	}
339
340	r = devm_gpio_request(&client->dev,
341			      phy->gpio_reset, "clf_reset");
342	if (r) {
343		pr_err("%s : reset gpio_request failed\n", __FILE__);
344		return -ENODEV;
345	}
346
347	r = gpio_direction_output(phy->gpio_reset, 1);
348	if (r) {
349		pr_err("%s : reset gpio_direction_output failed\n",
350			__FILE__);
351		return -ENODEV;
352	}
353
354	/* IRQ */
355	irq = gpio_to_irq(phy->gpio_irq);
356	if (irq < 0) {
357		nfc_err(&client->dev,
358			"Unable to get irq number for GPIO %d error %d\n",
359			phy->gpio_irq, r);
360		return -ENODEV;
361	}
362	client->irq = irq;
363
364	return 0;
365}
366
367static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
368				  const struct i2c_device_id *id)
369{
370	struct st21nfcb_i2c_phy *phy;
371	struct st21nfcb_nfc_platform_data *pdata;
372	int r;
373
374	dev_dbg(&client->dev, "%s\n", __func__);
375	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
376
377	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
378		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
379		return -ENODEV;
380	}
381
382	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
383			   GFP_KERNEL);
384	if (!phy) {
385		nfc_err(&client->dev,
386			"Cannot allocate memory for st21nfcb i2c phy.\n");
387		return -ENOMEM;
388	}
389
390	phy->i2c_dev = client;
391
392	i2c_set_clientdata(client, phy);
393
394	pdata = client->dev.platform_data;
395	if (!pdata && client->dev.of_node) {
396		r = st21nfcb_nci_i2c_of_request_resources(client);
397		if (r) {
398			nfc_err(&client->dev, "No platform data\n");
399			return r;
400		}
401	} else if (pdata) {
402		r = st21nfcb_nci_i2c_request_resources(client);
403		if (r) {
404			nfc_err(&client->dev,
405				"Cannot get platform resources\n");
406			return r;
407		}
408	} else {
409		nfc_err(&client->dev,
410			"st21nfcb platform resources not available\n");
411		return -ENODEV;
412	}
413
414	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
415				st21nfcb_nci_irq_thread_fn,
416				phy->irq_polarity | IRQF_ONESHOT,
417				ST21NFCB_NCI_DRIVER_NAME, phy);
418	if (r < 0) {
419		nfc_err(&client->dev, "Unable to register IRQ handler\n");
420		return r;
421	}
422
423	return ndlc_probe(phy, &i2c_phy_ops, &client->dev,
424			ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
425			&phy->ndlc);
426}
427
428static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
429{
430	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
431
432	dev_dbg(&client->dev, "%s\n", __func__);
433
434	ndlc_remove(phy->ndlc);
435
436	if (phy->powered)
437		st21nfcb_nci_i2c_disable(phy);
438
439	return 0;
440}
441
442static const struct of_device_id of_st21nfcb_i2c_match[] = {
443	{ .compatible = "st,st21nfcb_i2c", },
444	{}
445};
446
447static struct i2c_driver st21nfcb_nci_i2c_driver = {
448	.driver = {
449		.owner = THIS_MODULE,
450		.name = ST21NFCB_NCI_I2C_DRIVER_NAME,
451		.owner = THIS_MODULE,
452		.of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
453	},
454	.probe = st21nfcb_nci_i2c_probe,
455	.id_table = st21nfcb_nci_i2c_id_table,
456	.remove = st21nfcb_nci_i2c_remove,
457};
458
459module_i2c_driver(st21nfcb_nci_i2c_driver);
460
461MODULE_LICENSE("GPL");
462MODULE_DESCRIPTION(DRIVER_DESC);
463