1/*
2 * I2C link layer for the NXP NCI driver
3 *
4 * Copyright (C) 2014  NXP Semiconductors  All rights reserved.
5 *
6 * Authors: Clément Perrochaud <clement.perrochaud@nxp.com>
7 *
8 * Derived from PN544 device driver:
9 * Copyright (C) 2012  Intel Corporation. All rights reserved.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms and conditions of the GNU General Public License,
13 * version 2, as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, see <http://www.gnu.org/licenses/>.
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/delay.h>
27#include <linux/i2c.h>
28#include <linux/interrupt.h>
29#include <linux/miscdevice.h>
30#include <linux/module.h>
31#include <linux/nfc.h>
32#include <linux/of_gpio.h>
33#include <linux/of_irq.h>
34#include <linux/platform_data/nxp-nci.h>
35#include <linux/unaligned/access_ok.h>
36
37#include <net/nfc/nfc.h>
38
39#include "nxp-nci.h"
40
41#define NXP_NCI_I2C_DRIVER_NAME	"nxp-nci_i2c"
42
43#define NXP_NCI_I2C_MAX_PAYLOAD	32
44
45struct nxp_nci_i2c_phy {
46	struct i2c_client *i2c_dev;
47	struct nci_dev *ndev;
48
49	unsigned int gpio_en;
50	unsigned int gpio_fw;
51
52	int hard_fault; /*
53			 * < 0 if hardware error occurred (e.g. i2c err)
54			 * and prevents normal operation.
55			 */
56};
57
58static int nxp_nci_i2c_set_mode(void *phy_id,
59				    enum nxp_nci_mode mode)
60{
61	struct nxp_nci_i2c_phy *phy = (struct nxp_nci_i2c_phy *) phy_id;
62
63	gpio_set_value(phy->gpio_fw, (mode == NXP_NCI_MODE_FW) ? 1 : 0);
64	gpio_set_value(phy->gpio_en, (mode != NXP_NCI_MODE_COLD) ? 1 : 0);
65	usleep_range(10000, 15000);
66
67	if (mode == NXP_NCI_MODE_COLD)
68		phy->hard_fault = 0;
69
70	return 0;
71}
72
73static int nxp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
74{
75	int r;
76	struct nxp_nci_i2c_phy *phy = phy_id;
77	struct i2c_client *client = phy->i2c_dev;
78
79	if (phy->hard_fault != 0)
80		return phy->hard_fault;
81
82	r = i2c_master_send(client, skb->data, skb->len);
83	if (r == -EREMOTEIO) {
84		/* Retry, chip was in standby */
85		usleep_range(110000, 120000);
86		r = i2c_master_send(client, skb->data, skb->len);
87	}
88
89	if (r < 0) {
90		nfc_err(&client->dev, "Error %d on I2C send\n", r);
91	} else if (r != skb->len) {
92		nfc_err(&client->dev,
93			"Invalid length sent: %u (expected %u)\n",
94			r, skb->len);
95		r = -EREMOTEIO;
96	} else {
97		/* Success but return 0 and not number of bytes */
98		r = 0;
99	}
100
101	return r;
102}
103
104static struct nxp_nci_phy_ops i2c_phy_ops = {
105	.set_mode = nxp_nci_i2c_set_mode,
106	.write = nxp_nci_i2c_write,
107};
108
109static int nxp_nci_i2c_fw_read(struct nxp_nci_i2c_phy *phy,
110			       struct sk_buff **skb)
111{
112	struct i2c_client *client = phy->i2c_dev;
113	u16 header;
114	size_t frame_len;
115	int r;
116
117	r = i2c_master_recv(client, (u8 *) &header, NXP_NCI_FW_HDR_LEN);
118	if (r < 0) {
119		goto fw_read_exit;
120	} else if (r != NXP_NCI_FW_HDR_LEN) {
121		nfc_err(&client->dev, "Incorrect header length: %u\n", r);
122		r = -EBADMSG;
123		goto fw_read_exit;
124	}
125
126	frame_len = (get_unaligned_be16(&header) & NXP_NCI_FW_FRAME_LEN_MASK) +
127		    NXP_NCI_FW_CRC_LEN;
128
129	*skb = alloc_skb(NXP_NCI_FW_HDR_LEN + frame_len, GFP_KERNEL);
130	if (*skb == NULL) {
131		r = -ENOMEM;
132		goto fw_read_exit;
133	}
134
135	memcpy(skb_put(*skb, NXP_NCI_FW_HDR_LEN), &header, NXP_NCI_FW_HDR_LEN);
136
137	r = i2c_master_recv(client, skb_put(*skb, frame_len), frame_len);
138	if (r != frame_len) {
139		nfc_err(&client->dev,
140			"Invalid frame length: %u (expected %zu)\n",
141			r, frame_len);
142		r = -EBADMSG;
143		goto fw_read_exit_free_skb;
144	}
145
146	return 0;
147
148fw_read_exit_free_skb:
149	kfree_skb(*skb);
150fw_read_exit:
151	return r;
152}
153
154static int nxp_nci_i2c_nci_read(struct nxp_nci_i2c_phy *phy,
155				struct sk_buff **skb)
156{
157	struct nci_ctrl_hdr header; /* May actually be a data header */
158	struct i2c_client *client = phy->i2c_dev;
159	int r;
160
161	r = i2c_master_recv(client, (u8 *) &header, NCI_CTRL_HDR_SIZE);
162	if (r < 0) {
163		goto nci_read_exit;
164	} else if (r != NCI_CTRL_HDR_SIZE) {
165		nfc_err(&client->dev, "Incorrect header length: %u\n", r);
166		r = -EBADMSG;
167		goto nci_read_exit;
168	}
169
170	*skb = alloc_skb(NCI_CTRL_HDR_SIZE + header.plen, GFP_KERNEL);
171	if (*skb == NULL) {
172		r = -ENOMEM;
173		goto nci_read_exit;
174	}
175
176	memcpy(skb_put(*skb, NCI_CTRL_HDR_SIZE), (void *) &header,
177	       NCI_CTRL_HDR_SIZE);
178
179	r = i2c_master_recv(client, skb_put(*skb, header.plen), header.plen);
180	if (r != header.plen) {
181		nfc_err(&client->dev,
182			"Invalid frame payload length: %u (expected %u)\n",
183			r, header.plen);
184		r = -EBADMSG;
185		goto nci_read_exit_free_skb;
186	}
187
188	return 0;
189
190nci_read_exit_free_skb:
191	kfree_skb(*skb);
192nci_read_exit:
193	return r;
194}
195
196static irqreturn_t nxp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
197{
198	struct nxp_nci_i2c_phy *phy = phy_id;
199	struct i2c_client *client;
200	struct nxp_nci_info *info;
201
202	struct sk_buff *skb = NULL;
203	int r = 0;
204
205	if (!phy || !phy->ndev)
206		goto exit_irq_none;
207
208	client = phy->i2c_dev;
209
210	if (!client || irq != client->irq)
211		goto exit_irq_none;
212
213	info = nci_get_drvdata(phy->ndev);
214
215	if (!info)
216		goto exit_irq_none;
217
218	mutex_lock(&info->info_lock);
219
220	if (phy->hard_fault != 0)
221		goto exit_irq_handled;
222
223	switch (info->mode) {
224	case NXP_NCI_MODE_NCI:
225		r = nxp_nci_i2c_nci_read(phy, &skb);
226		break;
227	case NXP_NCI_MODE_FW:
228		r = nxp_nci_i2c_fw_read(phy, &skb);
229		break;
230	case NXP_NCI_MODE_COLD:
231		r = -EREMOTEIO;
232		break;
233	}
234
235	if (r == -EREMOTEIO) {
236		phy->hard_fault = r;
237		skb = NULL;
238	} else if (r < 0) {
239		nfc_err(&client->dev, "Read failed with error %d\n", r);
240		goto exit_irq_handled;
241	}
242
243	switch (info->mode) {
244	case NXP_NCI_MODE_NCI:
245		nci_recv_frame(phy->ndev, skb);
246		break;
247	case NXP_NCI_MODE_FW:
248		nxp_nci_fw_recv_frame(phy->ndev, skb);
249		break;
250	case NXP_NCI_MODE_COLD:
251		break;
252	}
253
254exit_irq_handled:
255	mutex_unlock(&info->info_lock);
256	return IRQ_HANDLED;
257exit_irq_none:
258	WARN_ON_ONCE(1);
259	return IRQ_NONE;
260}
261
262#ifdef CONFIG_OF
263
264static int nxp_nci_i2c_parse_devtree(struct i2c_client *client)
265{
266	struct nxp_nci_i2c_phy *phy = i2c_get_clientdata(client);
267	struct device_node *pp;
268	int r;
269
270	pp = client->dev.of_node;
271	if (!pp)
272		return -ENODEV;
273
274	r = of_get_named_gpio(pp, "enable-gpios", 0);
275	if (r == -EPROBE_DEFER)
276		r = of_get_named_gpio(pp, "enable-gpios", 0);
277	if (r < 0) {
278		nfc_err(&client->dev, "Failed to get EN gpio, error: %d\n", r);
279		return r;
280	}
281	phy->gpio_en = r;
282
283	r = of_get_named_gpio(pp, "firmware-gpios", 0);
284	if (r == -EPROBE_DEFER)
285		r = of_get_named_gpio(pp, "firmware-gpios", 0);
286	if (r < 0) {
287		nfc_err(&client->dev, "Failed to get FW gpio, error: %d\n", r);
288		return r;
289	}
290	phy->gpio_fw = r;
291
292	r = irq_of_parse_and_map(pp, 0);
293	if (r < 0) {
294		nfc_err(&client->dev, "Unable to get irq, error: %d\n", r);
295		return r;
296	}
297	client->irq = r;
298
299	return 0;
300}
301
302#else
303
304static int nxp_nci_i2c_parse_devtree(struct i2c_client *client)
305{
306	return -ENODEV;
307}
308
309#endif
310
311static int nxp_nci_i2c_probe(struct i2c_client *client,
312			    const struct i2c_device_id *id)
313{
314	struct nxp_nci_i2c_phy *phy;
315	struct nxp_nci_nfc_platform_data *pdata;
316	int r;
317
318	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
319		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
320		r = -ENODEV;
321		goto probe_exit;
322	}
323
324	phy = devm_kzalloc(&client->dev, sizeof(struct nxp_nci_i2c_phy),
325			   GFP_KERNEL);
326	if (!phy) {
327		r = -ENOMEM;
328		goto probe_exit;
329	}
330
331	phy->i2c_dev = client;
332	i2c_set_clientdata(client, phy);
333
334	pdata = client->dev.platform_data;
335
336	if (!pdata && client->dev.of_node) {
337		r = nxp_nci_i2c_parse_devtree(client);
338		if (r < 0) {
339			nfc_err(&client->dev, "Failed to get DT data\n");
340			goto probe_exit;
341		}
342	} else if (pdata) {
343		phy->gpio_en = pdata->gpio_en;
344		phy->gpio_fw = pdata->gpio_fw;
345		client->irq = pdata->irq;
346	} else {
347		nfc_err(&client->dev, "No platform data\n");
348		r = -EINVAL;
349		goto probe_exit;
350	}
351
352	r = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_en,
353				  GPIOF_OUT_INIT_LOW, "nxp_nci_en");
354	if (r < 0)
355		goto probe_exit;
356
357	r = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_fw,
358				  GPIOF_OUT_INIT_LOW, "nxp_nci_fw");
359	if (r < 0)
360		goto probe_exit;
361
362	r = nxp_nci_probe(phy, &client->dev, &i2c_phy_ops,
363			  NXP_NCI_I2C_MAX_PAYLOAD, &phy->ndev);
364	if (r < 0)
365		goto probe_exit;
366
367	r = request_threaded_irq(client->irq, NULL,
368				 nxp_nci_i2c_irq_thread_fn,
369				 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
370				 NXP_NCI_I2C_DRIVER_NAME, phy);
371	if (r < 0)
372		nfc_err(&client->dev, "Unable to register IRQ handler\n");
373
374probe_exit:
375	return r;
376}
377
378static int nxp_nci_i2c_remove(struct i2c_client *client)
379{
380	struct nxp_nci_i2c_phy *phy = i2c_get_clientdata(client);
381
382	nxp_nci_remove(phy->ndev);
383	free_irq(client->irq, phy);
384
385	return 0;
386}
387
388static struct i2c_device_id nxp_nci_i2c_id_table[] = {
389	{"nxp-nci_i2c", 0},
390	{}
391};
392MODULE_DEVICE_TABLE(i2c, nxp_nci_i2c_id_table);
393
394static const struct of_device_id of_nxp_nci_i2c_match[] = {
395	{ .compatible = "nxp,nxp-nci-i2c", },
396	{},
397};
398MODULE_DEVICE_TABLE(of, of_nxp_nci_i2c_match);
399
400static struct i2c_driver nxp_nci_i2c_driver = {
401	.driver = {
402		   .name = NXP_NCI_I2C_DRIVER_NAME,
403		   .owner  = THIS_MODULE,
404		   .of_match_table = of_match_ptr(of_nxp_nci_i2c_match),
405		  },
406	.probe = nxp_nci_i2c_probe,
407	.id_table = nxp_nci_i2c_id_table,
408	.remove = nxp_nci_i2c_remove,
409};
410
411module_i2c_driver(nxp_nci_i2c_driver);
412
413MODULE_LICENSE("GPL");
414MODULE_DESCRIPTION("I2C driver for NXP NCI NFC controllers");
415MODULE_AUTHOR("Clément Perrochaud <clement.perrochaud@nxp.com>");
416