1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * I2C Link Layer for Samsung S3FWRN5 NCI based Driver
4 *
5 * Copyright (C) 2015 Samsung Electrnoics
6 * Robert Baldyga <r.baldyga@samsung.com>
7 */
8
9#include <linux/i2c.h>
10#include <linux/gpio.h>
11#include <linux/delay.h>
12#include <linux/of_gpio.h>
13#include <linux/of_irq.h>
14#include <linux/module.h>
15
16#include <net/nfc/nfc.h>
17
18#include "s3fwrn5.h"
19
20#define S3FWRN5_I2C_DRIVER_NAME "s3fwrn5_i2c"
21
22#define S3FWRN5_I2C_MAX_PAYLOAD 32
23#define S3FWRN5_EN_WAIT_TIME 150
24
25struct s3fwrn5_i2c_phy {
26	struct i2c_client *i2c_dev;
27	struct nci_dev *ndev;
28
29	int gpio_en;
30	int gpio_fw_wake;
31
32	struct mutex mutex;
33
34	enum s3fwrn5_mode mode;
35	unsigned int irq_skip:1;
36};
37
38static void s3fwrn5_i2c_set_wake(void *phy_id, bool wake)
39{
40	struct s3fwrn5_i2c_phy *phy = phy_id;
41
42	mutex_lock(&phy->mutex);
43	gpio_set_value(phy->gpio_fw_wake, wake);
44	msleep(S3FWRN5_EN_WAIT_TIME/2);
45	mutex_unlock(&phy->mutex);
46}
47
48static void s3fwrn5_i2c_set_mode(void *phy_id, enum s3fwrn5_mode mode)
49{
50	struct s3fwrn5_i2c_phy *phy = phy_id;
51
52	mutex_lock(&phy->mutex);
53
54	if (phy->mode == mode)
55		goto out;
56
57	phy->mode = mode;
58
59	gpio_set_value(phy->gpio_en, 1);
60	gpio_set_value(phy->gpio_fw_wake, 0);
61	if (mode == S3FWRN5_MODE_FW)
62		gpio_set_value(phy->gpio_fw_wake, 1);
63
64	if (mode != S3FWRN5_MODE_COLD) {
65		msleep(S3FWRN5_EN_WAIT_TIME);
66		gpio_set_value(phy->gpio_en, 0);
67		msleep(S3FWRN5_EN_WAIT_TIME/2);
68	}
69
70	phy->irq_skip = true;
71
72out:
73	mutex_unlock(&phy->mutex);
74}
75
76static enum s3fwrn5_mode s3fwrn5_i2c_get_mode(void *phy_id)
77{
78	struct s3fwrn5_i2c_phy *phy = phy_id;
79	enum s3fwrn5_mode mode;
80
81	mutex_lock(&phy->mutex);
82
83	mode = phy->mode;
84
85	mutex_unlock(&phy->mutex);
86
87	return mode;
88}
89
90static int s3fwrn5_i2c_write(void *phy_id, struct sk_buff *skb)
91{
92	struct s3fwrn5_i2c_phy *phy = phy_id;
93	int ret;
94
95	mutex_lock(&phy->mutex);
96
97	phy->irq_skip = false;
98
99	ret = i2c_master_send(phy->i2c_dev, skb->data, skb->len);
100	if (ret == -EREMOTEIO) {
101		/* Retry, chip was in standby */
102		usleep_range(110000, 120000);
103		ret  = i2c_master_send(phy->i2c_dev, skb->data, skb->len);
104	}
105
106	mutex_unlock(&phy->mutex);
107
108	if (ret < 0)
109		return ret;
110
111	if (ret != skb->len)
112		return -EREMOTEIO;
113
114	return 0;
115}
116
117static const struct s3fwrn5_phy_ops i2c_phy_ops = {
118	.set_wake = s3fwrn5_i2c_set_wake,
119	.set_mode = s3fwrn5_i2c_set_mode,
120	.get_mode = s3fwrn5_i2c_get_mode,
121	.write = s3fwrn5_i2c_write,
122};
123
124static int s3fwrn5_i2c_read(struct s3fwrn5_i2c_phy *phy)
125{
126	struct sk_buff *skb;
127	size_t hdr_size;
128	size_t data_len;
129	char hdr[4];
130	int ret;
131
132	hdr_size = (phy->mode == S3FWRN5_MODE_NCI) ?
133		NCI_CTRL_HDR_SIZE : S3FWRN5_FW_HDR_SIZE;
134	ret = i2c_master_recv(phy->i2c_dev, hdr, hdr_size);
135	if (ret < 0)
136		return ret;
137
138	if (ret < hdr_size)
139		return -EBADMSG;
140
141	data_len = (phy->mode == S3FWRN5_MODE_NCI) ?
142		((struct nci_ctrl_hdr *)hdr)->plen :
143		((struct s3fwrn5_fw_header *)hdr)->len;
144
145	skb = alloc_skb(hdr_size + data_len, GFP_KERNEL);
146	if (!skb)
147		return -ENOMEM;
148
149	skb_put_data(skb, hdr, hdr_size);
150
151	if (data_len == 0)
152		goto out;
153
154	ret = i2c_master_recv(phy->i2c_dev, skb_put(skb, data_len), data_len);
155	if (ret != data_len) {
156		kfree_skb(skb);
157		return -EBADMSG;
158	}
159
160out:
161	return s3fwrn5_recv_frame(phy->ndev, skb, phy->mode);
162}
163
164static irqreturn_t s3fwrn5_i2c_irq_thread_fn(int irq, void *phy_id)
165{
166	struct s3fwrn5_i2c_phy *phy = phy_id;
167
168	if (!phy || !phy->ndev) {
169		WARN_ON_ONCE(1);
170		return IRQ_NONE;
171	}
172
173	mutex_lock(&phy->mutex);
174
175	if (phy->irq_skip)
176		goto out;
177
178	switch (phy->mode) {
179	case S3FWRN5_MODE_NCI:
180	case S3FWRN5_MODE_FW:
181		s3fwrn5_i2c_read(phy);
182		break;
183	case S3FWRN5_MODE_COLD:
184		break;
185	}
186
187out:
188	mutex_unlock(&phy->mutex);
189
190	return IRQ_HANDLED;
191}
192
193static int s3fwrn5_i2c_parse_dt(struct i2c_client *client)
194{
195	struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);
196	struct device_node *np = client->dev.of_node;
197
198	if (!np)
199		return -ENODEV;
200
201	phy->gpio_en = of_get_named_gpio(np, "en-gpios", 0);
202	if (!gpio_is_valid(phy->gpio_en)) {
203		/* Support also deprecated property */
204		phy->gpio_en = of_get_named_gpio(np, "s3fwrn5,en-gpios", 0);
205		if (!gpio_is_valid(phy->gpio_en))
206			return -ENODEV;
207	}
208
209	phy->gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
210	if (!gpio_is_valid(phy->gpio_fw_wake)) {
211		/* Support also deprecated property */
212		phy->gpio_fw_wake = of_get_named_gpio(np, "s3fwrn5,fw-gpios", 0);
213		if (!gpio_is_valid(phy->gpio_fw_wake))
214			return -ENODEV;
215	}
216
217	return 0;
218}
219
220static int s3fwrn5_i2c_probe(struct i2c_client *client,
221				  const struct i2c_device_id *id)
222{
223	struct s3fwrn5_i2c_phy *phy;
224	int ret;
225
226	phy = devm_kzalloc(&client->dev, sizeof(*phy), GFP_KERNEL);
227	if (!phy)
228		return -ENOMEM;
229
230	mutex_init(&phy->mutex);
231	phy->mode = S3FWRN5_MODE_COLD;
232	phy->irq_skip = true;
233
234	phy->i2c_dev = client;
235	i2c_set_clientdata(client, phy);
236
237	ret = s3fwrn5_i2c_parse_dt(client);
238	if (ret < 0)
239		return ret;
240
241	ret = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_en,
242		GPIOF_OUT_INIT_HIGH, "s3fwrn5_en");
243	if (ret < 0)
244		return ret;
245
246	ret = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_fw_wake,
247		GPIOF_OUT_INIT_LOW, "s3fwrn5_fw_wake");
248	if (ret < 0)
249		return ret;
250
251	ret = s3fwrn5_probe(&phy->ndev, phy, &phy->i2c_dev->dev, &i2c_phy_ops,
252		S3FWRN5_I2C_MAX_PAYLOAD);
253	if (ret < 0)
254		return ret;
255
256	ret = devm_request_threaded_irq(&client->dev, phy->i2c_dev->irq, NULL,
257		s3fwrn5_i2c_irq_thread_fn, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
258		S3FWRN5_I2C_DRIVER_NAME, phy);
259	if (ret)
260		s3fwrn5_remove(phy->ndev);
261
262	return ret;
263}
264
265static int s3fwrn5_i2c_remove(struct i2c_client *client)
266{
267	struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);
268
269	s3fwrn5_remove(phy->ndev);
270
271	return 0;
272}
273
274static const struct i2c_device_id s3fwrn5_i2c_id_table[] = {
275	{S3FWRN5_I2C_DRIVER_NAME, 0},
276	{}
277};
278MODULE_DEVICE_TABLE(i2c, s3fwrn5_i2c_id_table);
279
280static const struct of_device_id of_s3fwrn5_i2c_match[] = {
281	{ .compatible = "samsung,s3fwrn5-i2c", },
282	{}
283};
284MODULE_DEVICE_TABLE(of, of_s3fwrn5_i2c_match);
285
286static struct i2c_driver s3fwrn5_i2c_driver = {
287	.driver = {
288		.name = S3FWRN5_I2C_DRIVER_NAME,
289		.of_match_table = of_match_ptr(of_s3fwrn5_i2c_match),
290	},
291	.probe = s3fwrn5_i2c_probe,
292	.remove = s3fwrn5_i2c_remove,
293	.id_table = s3fwrn5_i2c_id_table,
294};
295
296module_i2c_driver(s3fwrn5_i2c_driver);
297
298MODULE_LICENSE("GPL");
299MODULE_DESCRIPTION("I2C driver for Samsung S3FWRN5");
300MODULE_AUTHOR("Robert Baldyga <r.baldyga@samsung.com>");
301