1/*
  2 * I2C Link Layer for Samsung S3FWRN5 NCI based Driver
  3 *
  4 * Copyright (C) 2015 Samsung Electrnoics
  5 * Robert Baldyga <r.baldyga@samsung.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify it
  8 * under the terms and conditions of the GNU General Public License,
  9 * version 2 or later, as published by the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 14 * GNU General Public License for more details.
 15 *
 16 * You should have received a copy of the GNU General Public License
 17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 18 */
 19
 20#include <linux/i2c.h>
 21#include <linux/gpio.h>
 22#include <linux/delay.h>
 23#include <linux/of_gpio.h>
 24#include <linux/of_irq.h>
 25#include <linux/module.h>
 26
 27#include <net/nfc/nfc.h>
 28
 29#include "s3fwrn5.h"
 30
 31#define S3FWRN5_I2C_DRIVER_NAME "s3fwrn5_i2c"
 32
 33#define S3FWRN5_I2C_MAX_PAYLOAD 32
 34#define S3FWRN5_EN_WAIT_TIME 150
 35
 36struct s3fwrn5_i2c_phy {
 37	struct i2c_client *i2c_dev;
 38	struct nci_dev *ndev;
 39
 40	unsigned int gpio_en;
 41	unsigned int gpio_fw_wake;
 42
 43	struct mutex mutex;
 44
 45	enum s3fwrn5_mode mode;
 46	unsigned int irq_skip:1;
 47};
 48
 49static void s3fwrn5_i2c_set_wake(void *phy_id, bool wake)
 50{
 51	struct s3fwrn5_i2c_phy *phy = phy_id;
 52
 53	mutex_lock(&phy->mutex);
 54	gpio_set_value(phy->gpio_fw_wake, wake);
 55	msleep(S3FWRN5_EN_WAIT_TIME/2);
 56	mutex_unlock(&phy->mutex);
 57}
 58
 59static void s3fwrn5_i2c_set_mode(void *phy_id, enum s3fwrn5_mode mode)
 60{
 61	struct s3fwrn5_i2c_phy *phy = phy_id;
 62
 63	mutex_lock(&phy->mutex);
 64
 65	if (phy->mode == mode)
 66		goto out;
 67
 68	phy->mode = mode;
 69
 70	gpio_set_value(phy->gpio_en, 1);
 71	gpio_set_value(phy->gpio_fw_wake, 0);
 72	if (mode == S3FWRN5_MODE_FW)
 73		gpio_set_value(phy->gpio_fw_wake, 1);
 74
 75	if (mode != S3FWRN5_MODE_COLD) {
 76		msleep(S3FWRN5_EN_WAIT_TIME);
 77		gpio_set_value(phy->gpio_en, 0);
 78		msleep(S3FWRN5_EN_WAIT_TIME/2);
 79	}
 80
 81	phy->irq_skip = true;
 82
 83out:
 84	mutex_unlock(&phy->mutex);
 85}
 86
 87static enum s3fwrn5_mode s3fwrn5_i2c_get_mode(void *phy_id)
 88{
 89	struct s3fwrn5_i2c_phy *phy = phy_id;
 90	enum s3fwrn5_mode mode;
 91
 92	mutex_lock(&phy->mutex);
 93
 94	mode = phy->mode;
 95
 96	mutex_unlock(&phy->mutex);
 97
 98	return mode;
 99}
100
101static int s3fwrn5_i2c_write(void *phy_id, struct sk_buff *skb)
102{
103	struct s3fwrn5_i2c_phy *phy = phy_id;
104	int ret;
105
106	mutex_lock(&phy->mutex);
107
108	phy->irq_skip = false;
109
110	ret = i2c_master_send(phy->i2c_dev, skb->data, skb->len);
111	if (ret == -EREMOTEIO) {
112		/* Retry, chip was in standby */
113		usleep_range(110000, 120000);
114		ret  = i2c_master_send(phy->i2c_dev, skb->data, skb->len);
115	}
116
117	mutex_unlock(&phy->mutex);
118
119	if (ret < 0)
120		return ret;
121
122	if (ret != skb->len)
123		return -EREMOTEIO;
124
125	return 0;
126}
127
128static const struct s3fwrn5_phy_ops i2c_phy_ops = {
129	.set_wake = s3fwrn5_i2c_set_wake,
130	.set_mode = s3fwrn5_i2c_set_mode,
131	.get_mode = s3fwrn5_i2c_get_mode,
132	.write = s3fwrn5_i2c_write,
133};
134
135static int s3fwrn5_i2c_read(struct s3fwrn5_i2c_phy *phy)
136{
137	struct sk_buff *skb;
138	size_t hdr_size;
139	size_t data_len;
140	char hdr[4];
141	int ret;
142
143	hdr_size = (phy->mode == S3FWRN5_MODE_NCI) ?
144		NCI_CTRL_HDR_SIZE : S3FWRN5_FW_HDR_SIZE;
145	ret = i2c_master_recv(phy->i2c_dev, hdr, hdr_size);
146	if (ret < 0)
147		return ret;
148
149	if (ret < hdr_size)
150		return -EBADMSG;
151
152	data_len = (phy->mode == S3FWRN5_MODE_NCI) ?
153		((struct nci_ctrl_hdr *)hdr)->plen :
154		((struct s3fwrn5_fw_header *)hdr)->len;
155
156	skb = alloc_skb(hdr_size + data_len, GFP_KERNEL);
157	if (!skb)
158		return -ENOMEM;
159
160	memcpy(skb_put(skb, hdr_size), hdr, hdr_size);
161
162	if (data_len == 0)
163		goto out;
164
165	ret = i2c_master_recv(phy->i2c_dev, skb_put(skb, data_len), data_len);
166	if (ret != data_len) {
167		kfree_skb(skb);
168		return -EBADMSG;
169	}
170
171out:
172	return s3fwrn5_recv_frame(phy->ndev, skb, phy->mode);
173}
174
175static irqreturn_t s3fwrn5_i2c_irq_thread_fn(int irq, void *phy_id)
176{
177	struct s3fwrn5_i2c_phy *phy = phy_id;
178	int ret = 0;
179
180	if (!phy || !phy->ndev) {
181		WARN_ON_ONCE(1);
182		return IRQ_NONE;
183	}
184
185	mutex_lock(&phy->mutex);
186
187	if (phy->irq_skip)
188		goto out;
189
190	switch (phy->mode) {
191	case S3FWRN5_MODE_NCI:
192	case S3FWRN5_MODE_FW:
193		ret = s3fwrn5_i2c_read(phy);
194		break;
195	case S3FWRN5_MODE_COLD:
196		ret = -EREMOTEIO;
197		break;
198	}
199
200out:
201	mutex_unlock(&phy->mutex);
202
203	return IRQ_HANDLED;
204}
205
206static int s3fwrn5_i2c_parse_dt(struct i2c_client *client)
207{
208	struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);
209	struct device_node *np = client->dev.of_node;
210
211	if (!np)
212		return -ENODEV;
213
214	phy->gpio_en = of_get_named_gpio(np, "s3fwrn5,en-gpios", 0);
215	if (!gpio_is_valid(phy->gpio_en))
216		return -ENODEV;
217
218	phy->gpio_fw_wake = of_get_named_gpio(np, "s3fwrn5,fw-gpios", 0);
219	if (!gpio_is_valid(phy->gpio_fw_wake))
220		return -ENODEV;
221
222	return 0;
223}
224
225static int s3fwrn5_i2c_probe(struct i2c_client *client,
226				  const struct i2c_device_id *id)
227{
228	struct s3fwrn5_i2c_phy *phy;
229	int ret;
230
231	phy = devm_kzalloc(&client->dev, sizeof(*phy), GFP_KERNEL);
232	if (!phy)
233		return -ENOMEM;
234
235	mutex_init(&phy->mutex);
236	phy->mode = S3FWRN5_MODE_COLD;
237	phy->irq_skip = true;
238
239	phy->i2c_dev = client;
240	i2c_set_clientdata(client, phy);
241
242	ret = s3fwrn5_i2c_parse_dt(client);
243	if (ret < 0)
244		return ret;
245
246	ret = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_en,
247		GPIOF_OUT_INIT_HIGH, "s3fwrn5_en");
248	if (ret < 0)
249		return ret;
250
251	ret = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_fw_wake,
252		GPIOF_OUT_INIT_LOW, "s3fwrn5_fw_wake");
253	if (ret < 0)
254		return ret;
255
256	ret = s3fwrn5_probe(&phy->ndev, phy, &phy->i2c_dev->dev, &i2c_phy_ops,
257		S3FWRN5_I2C_MAX_PAYLOAD);
258	if (ret < 0)
259		return ret;
260
261	ret = devm_request_threaded_irq(&client->dev, phy->i2c_dev->irq, NULL,
262		s3fwrn5_i2c_irq_thread_fn, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
263		S3FWRN5_I2C_DRIVER_NAME, phy);
264	if (ret)
265		s3fwrn5_remove(phy->ndev);
266
267	return ret;
268}
269
270static int s3fwrn5_i2c_remove(struct i2c_client *client)
271{
272	struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);
273
274	s3fwrn5_remove(phy->ndev);
275
276	return 0;
277}
278
279static struct i2c_device_id s3fwrn5_i2c_id_table[] = {
280	{S3FWRN5_I2C_DRIVER_NAME, 0},
281	{}
282};
283MODULE_DEVICE_TABLE(i2c, s3fwrn5_i2c_id_table);
284
285static const struct of_device_id of_s3fwrn5_i2c_match[] = {
286	{ .compatible = "samsung,s3fwrn5-i2c", },
287	{}
288};
289MODULE_DEVICE_TABLE(of, of_s3fwrn5_i2c_match);
290
291static struct i2c_driver s3fwrn5_i2c_driver = {
292	.driver = {
293		.owner = THIS_MODULE,
294		.name = S3FWRN5_I2C_DRIVER_NAME,
295		.of_match_table = of_match_ptr(of_s3fwrn5_i2c_match),
296	},
297	.probe = s3fwrn5_i2c_probe,
298	.remove = s3fwrn5_i2c_remove,
299	.id_table = s3fwrn5_i2c_id_table,
300};
301
302module_i2c_driver(s3fwrn5_i2c_driver);
303
304MODULE_LICENSE("GPL");
305MODULE_DESCRIPTION("I2C driver for Samsung S3FWRN5");
306MODULE_AUTHOR("Robert Baldyga <r.baldyga@samsung.com>");