GNU Linux-libre 4.19.314-gnu1
[releases.git] / drivers / nfc / st-nci / i2c.c
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
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
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  */
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  */
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  */
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
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
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);