1 /*
2 * I2C Link Layer for ST NCI NFC controller familly based Driver
3 * Copyright (C) 2014-2015 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/module.h>
21 #include <linux/i2c.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/acpi.h>
24 #include <linux/interrupt.h>
25 #include <linux/delay.h>
26 #include <linux/nfc.h>
27 #include <linux/of.h>
28
29 #include "st-nci.h"
30
31 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
32
33 /* ndlc header */
34 #define ST_NCI_FRAME_HEADROOM 1
35 #define ST_NCI_FRAME_TAILROOM 0
36
37 #define ST_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
38 #define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
39
40 #define ST_NCI_DRIVER_NAME "st_nci"
41 #define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
42
43 struct st_nci_i2c_phy {
44 struct i2c_client *i2c_dev;
45 struct llt_ndlc *ndlc;
46
47 bool irq_active;
48
49 struct gpio_desc *gpiod_reset;
50
51 struct st_nci_se_status se_status;
52 };
53
st_nci_i2c_enable(void * phy_id)54 static int st_nci_i2c_enable(void *phy_id)
55 {
56 struct st_nci_i2c_phy *phy = phy_id;
57
58 gpiod_set_value(phy->gpiod_reset, 0);
59 usleep_range(10000, 15000);
60 gpiod_set_value(phy->gpiod_reset, 1);
61 usleep_range(80000, 85000);
62
63 if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
64 enable_irq(phy->i2c_dev->irq);
65 phy->irq_active = true;
66 }
67
68 return 0;
69 }
70
st_nci_i2c_disable(void * phy_id)71 static void st_nci_i2c_disable(void *phy_id)
72 {
73 struct st_nci_i2c_phy *phy = phy_id;
74
75 disable_irq_nosync(phy->i2c_dev->irq);
76 phy->irq_active = false;
77 }
78
79 /*
80 * Writing a frame must not return the number of written bytes.
81 * It must return either zero for success, or <0 for error.
82 * In addition, it must not alter the skb
83 */
st_nci_i2c_write(void * phy_id,struct sk_buff * skb)84 static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
85 {
86 int r = -1;
87 struct st_nci_i2c_phy *phy = phy_id;
88 struct i2c_client *client = phy->i2c_dev;
89
90 if (phy->ndlc->hard_fault != 0)
91 return phy->ndlc->hard_fault;
92
93 r = i2c_master_send(client, skb->data, skb->len);
94 if (r < 0) { /* Retry, chip was in standby */
95 usleep_range(1000, 4000);
96 r = i2c_master_send(client, skb->data, skb->len);
97 }
98
99 if (r >= 0) {
100 if (r != skb->len)
101 r = -EREMOTEIO;
102 else
103 r = 0;
104 }
105
106 return r;
107 }
108
109 /*
110 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
111 * returns:
112 * 0 : if received frame is complete
113 * -EREMOTEIO : i2c read error (fatal)
114 * -EBADMSG : frame was incorrect and discarded
115 * -ENOMEM : cannot allocate skb, frame dropped
116 */
st_nci_i2c_read(struct st_nci_i2c_phy * phy,struct sk_buff ** skb)117 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
118 struct sk_buff **skb)
119 {
120 int r;
121 u8 len;
122 u8 buf[ST_NCI_I2C_MAX_SIZE];
123 struct i2c_client *client = phy->i2c_dev;
124
125 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
126 if (r < 0) { /* Retry, chip was in standby */
127 usleep_range(1000, 4000);
128 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
129 }
130
131 if (r != ST_NCI_I2C_MIN_SIZE)
132 return -EREMOTEIO;
133
134 len = be16_to_cpu(*(__be16 *) (buf + 2));
135 if (len > ST_NCI_I2C_MAX_SIZE) {
136 nfc_err(&client->dev, "invalid frame len\n");
137 return -EBADMSG;
138 }
139
140 *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
141 if (*skb == NULL)
142 return -ENOMEM;
143
144 skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
145 skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
146 memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
147
148 if (!len)
149 return 0;
150
151 r = i2c_master_recv(client, buf, len);
152 if (r != len) {
153 kfree_skb(*skb);
154 return -EREMOTEIO;
155 }
156
157 skb_put(*skb, len);
158 memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
159
160 return 0;
161 }
162
163 /*
164 * Reads an ndlc frame from the chip.
165 *
166 * On ST_NCI, IRQ goes in idle state when read starts.
167 */
st_nci_irq_thread_fn(int irq,void * phy_id)168 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
169 {
170 struct st_nci_i2c_phy *phy = phy_id;
171 struct i2c_client *client;
172 struct sk_buff *skb = NULL;
173 int r;
174
175 if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
176 WARN_ON_ONCE(1);
177 return IRQ_NONE;
178 }
179
180 client = phy->i2c_dev;
181 dev_dbg(&client->dev, "IRQ\n");
182
183 if (phy->ndlc->hard_fault)
184 return IRQ_HANDLED;
185
186 if (!phy->ndlc->powered) {
187 st_nci_i2c_disable(phy);
188 return IRQ_HANDLED;
189 }
190
191 r = st_nci_i2c_read(phy, &skb);
192 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
193 return IRQ_HANDLED;
194
195 ndlc_recv(phy->ndlc, skb);
196
197 return IRQ_HANDLED;
198 }
199
200 static struct nfc_phy_ops i2c_phy_ops = {
201 .write = st_nci_i2c_write,
202 .enable = st_nci_i2c_enable,
203 .disable = st_nci_i2c_disable,
204 };
205
206 static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
207
208 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
209 { "reset-gpios", &reset_gpios, 1 },
210 {},
211 };
212
st_nci_i2c_probe(struct i2c_client * client,const struct i2c_device_id * id)213 static int st_nci_i2c_probe(struct i2c_client *client,
214 const struct i2c_device_id *id)
215 {
216 struct device *dev = &client->dev;
217 struct st_nci_i2c_phy *phy;
218 int r;
219
220 dev_dbg(&client->dev, "%s\n", __func__);
221 dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
222
223 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
224 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
225 return -ENODEV;
226 }
227
228 phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL);
229 if (!phy)
230 return -ENOMEM;
231
232 phy->i2c_dev = client;
233
234 i2c_set_clientdata(client, phy);
235
236 r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios);
237 if (r)
238 dev_dbg(dev, "Unable to add GPIO mapping table\n");
239
240 /* Get RESET GPIO */
241 phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
242 if (IS_ERR(phy->gpiod_reset)) {
243 nfc_err(dev, "Unable to get RESET GPIO\n");
244 return -ENODEV;
245 }
246
247 phy->se_status.is_ese_present =
248 device_property_read_bool(dev, "ese-present");
249 phy->se_status.is_uicc_present =
250 device_property_read_bool(dev, "uicc-present");
251
252 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
253 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
254 &phy->ndlc, &phy->se_status);
255 if (r < 0) {
256 nfc_err(&client->dev, "Unable to register ndlc layer\n");
257 return r;
258 }
259
260 phy->irq_active = true;
261 r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
262 st_nci_irq_thread_fn,
263 IRQF_ONESHOT,
264 ST_NCI_DRIVER_NAME, phy);
265 if (r < 0)
266 nfc_err(&client->dev, "Unable to register IRQ handler\n");
267
268 return r;
269 }
270
st_nci_i2c_remove(struct i2c_client * client)271 static int st_nci_i2c_remove(struct i2c_client *client)
272 {
273 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
274
275 dev_dbg(&client->dev, "%s\n", __func__);
276
277 ndlc_remove(phy->ndlc);
278
279 return 0;
280 }
281
282 static const struct i2c_device_id st_nci_i2c_id_table[] = {
283 {ST_NCI_DRIVER_NAME, 0},
284 {}
285 };
286 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
287
288 static const struct acpi_device_id st_nci_i2c_acpi_match[] = {
289 {"SMO2101"},
290 {"SMO2102"},
291 {}
292 };
293 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
294
295 static const struct of_device_id of_st_nci_i2c_match[] = {
296 { .compatible = "st,st21nfcb-i2c", },
297 { .compatible = "st,st21nfcb_i2c", },
298 { .compatible = "st,st21nfcc-i2c", },
299 {}
300 };
301 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
302
303 static struct i2c_driver st_nci_i2c_driver = {
304 .driver = {
305 .name = ST_NCI_I2C_DRIVER_NAME,
306 .of_match_table = of_match_ptr(of_st_nci_i2c_match),
307 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
308 },
309 .probe = st_nci_i2c_probe,
310 .id_table = st_nci_i2c_id_table,
311 .remove = st_nci_i2c_remove,
312 };
313 module_i2c_driver(st_nci_i2c_driver);
314
315 MODULE_LICENSE("GPL");
316 MODULE_DESCRIPTION(DRIVER_DESC);
317
