]> git.karo-electronics.de Git - karo-tx-linux.git/blob - drivers/nfc/st21nfcb/i2c.c
Merge tag 'clk-for-linus-3.18' of git://git.linaro.org/people/mike.turquette/linux
[karo-tx-linux.git] / drivers / nfc / st21nfcb / i2c.c
1 /*
2  * I2C Link Layer for ST21NFCB NCI based Driver
3  * Copyright (C) 2014  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.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_gpio.h>
25 #include <linux/interrupt.h>
26 #include <linux/delay.h>
27 #include <linux/nfc.h>
28 #include <linux/platform_data/st21nfcb.h>
29
30 #include "ndlc.h"
31
32 #define DRIVER_DESC "NCI NFC driver for ST21NFCB"
33
34 /* ndlc header */
35 #define ST21NFCB_FRAME_HEADROOM 1
36 #define ST21NFCB_FRAME_TAILROOM 0
37
38 #define ST21NFCB_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
39 #define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
40
41 #define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
42
43 static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
44         {ST21NFCB_NCI_DRIVER_NAME, 0},
45         {}
46 };
47 MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
48
49 struct st21nfcb_i2c_phy {
50         struct i2c_client *i2c_dev;
51         struct llt_ndlc *ndlc;
52
53         unsigned int gpio_irq;
54         unsigned int gpio_reset;
55         unsigned int irq_polarity;
56
57         int powered;
58 };
59
60 #define I2C_DUMP_SKB(info, skb)                                 \
61 do {                                                            \
62         pr_debug("%s:\n", info);                                \
63         print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
64                        16, 1, (skb)->data, (skb)->len, 0);      \
65 } while (0)
66
67 static int st21nfcb_nci_i2c_enable(void *phy_id)
68 {
69         struct st21nfcb_i2c_phy *phy = phy_id;
70
71         gpio_set_value(phy->gpio_reset, 0);
72         usleep_range(10000, 15000);
73         gpio_set_value(phy->gpio_reset, 1);
74         phy->powered = 1;
75         usleep_range(80000, 85000);
76
77         return 0;
78 }
79
80 static void st21nfcb_nci_i2c_disable(void *phy_id)
81 {
82         struct st21nfcb_i2c_phy *phy = phy_id;
83
84         pr_info("\n");
85
86         phy->powered = 0;
87         /* reset chip in order to flush clf */
88         gpio_set_value(phy->gpio_reset, 0);
89         usleep_range(10000, 15000);
90         gpio_set_value(phy->gpio_reset, 1);
91 }
92
93 static void st21nfcb_nci_remove_header(struct sk_buff *skb)
94 {
95         skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
96 }
97
98 /*
99  * Writing a frame must not return the number of written bytes.
100  * It must return either zero for success, or <0 for error.
101  * In addition, it must not alter the skb
102  */
103 static int st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
104 {
105         int r = -1;
106         struct st21nfcb_i2c_phy *phy = phy_id;
107         struct i2c_client *client = phy->i2c_dev;
108
109         I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
110
111         if (phy->ndlc->hard_fault != 0)
112                 return phy->ndlc->hard_fault;
113
114         r = i2c_master_send(client, skb->data, skb->len);
115         if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
116                 usleep_range(1000, 4000);
117                 r = i2c_master_send(client, skb->data, skb->len);
118         }
119
120         if (r >= 0) {
121                 if (r != skb->len)
122                         r = -EREMOTEIO;
123                 else
124                         r = 0;
125         }
126
127         st21nfcb_nci_remove_header(skb);
128
129         return r;
130 }
131
132 /*
133  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
134  * returns:
135  * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
136  * end of read)
137  * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
138  * at end of read)
139  * -EREMOTEIO : i2c read error (fatal)
140  * -EBADMSG : frame was incorrect and discarded
141  * (value returned from st21nfcb_nci_i2c_repack)
142  * -EIO : if no ST21NFCB_SOF_EOF is found after reaching
143  * the read length end sequence
144  */
145 static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
146                                  struct sk_buff **skb)
147 {
148         int r;
149         u8 len;
150         u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
151         struct i2c_client *client = phy->i2c_dev;
152
153         r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
154         if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
155                 usleep_range(1000, 4000);
156                 r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
157         }
158
159         if (r != ST21NFCB_NCI_I2C_MIN_SIZE)
160                 return -EREMOTEIO;
161
162         len = be16_to_cpu(*(__be16 *) (buf + 2));
163         if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
164                 nfc_err(&client->dev, "invalid frame len\n");
165                 return -EBADMSG;
166         }
167
168         *skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
169         if (*skb == NULL)
170                 return -ENOMEM;
171
172         skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
173         skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
174         memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
175
176         if (!len)
177                 return 0;
178
179         r = i2c_master_recv(client, buf, len);
180         if (r != len) {
181                 kfree_skb(*skb);
182                 return -EREMOTEIO;
183         }
184
185         skb_put(*skb, len);
186         memcpy((*skb)->data + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
187
188         I2C_DUMP_SKB("i2c frame read", *skb);
189
190         return 0;
191 }
192
193 /*
194  * Reads an ndlc frame from the chip.
195  *
196  * On ST21NFCB, IRQ goes in idle state when read starts.
197  */
198 static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
199 {
200         struct st21nfcb_i2c_phy *phy = phy_id;
201         struct i2c_client *client;
202         struct sk_buff *skb = NULL;
203         int r;
204
205         if (!phy || irq != phy->i2c_dev->irq) {
206                 WARN_ON_ONCE(1);
207                 return IRQ_NONE;
208         }
209
210         client = phy->i2c_dev;
211         dev_dbg(&client->dev, "IRQ\n");
212
213         if (phy->ndlc->hard_fault)
214                 return IRQ_HANDLED;
215
216         if (!phy->powered) {
217                 st21nfcb_nci_i2c_disable(phy);
218                 return IRQ_HANDLED;
219         }
220
221         r = st21nfcb_nci_i2c_read(phy, &skb);
222         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
223                 return IRQ_HANDLED;
224
225         ndlc_recv(phy->ndlc, skb);
226
227         return IRQ_HANDLED;
228 }
229
230 static struct nfc_phy_ops i2c_phy_ops = {
231         .write = st21nfcb_nci_i2c_write,
232         .enable = st21nfcb_nci_i2c_enable,
233         .disable = st21nfcb_nci_i2c_disable,
234 };
235
236 #ifdef CONFIG_OF
237 static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
238 {
239         struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
240         struct device_node *pp;
241         int gpio;
242         int r;
243
244         pp = client->dev.of_node;
245         if (!pp)
246                 return -ENODEV;
247
248         /* Get GPIO from device tree */
249         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
250         if (gpio < 0) {
251                 nfc_err(&client->dev,
252                         "Failed to retrieve reset-gpios from device tree\n");
253                 return gpio;
254         }
255
256         /* GPIO request and configuration */
257         r = devm_gpio_request_one(&client->dev, gpio,
258                                 GPIOF_OUT_INIT_HIGH, "clf_reset");
259         if (r) {
260                 nfc_err(&client->dev, "Failed to request reset pin\n");
261                 return -ENODEV;
262         }
263         phy->gpio_reset = gpio;
264
265         /* IRQ */
266         r = irq_of_parse_and_map(pp, 0);
267         if (r < 0) {
268                 nfc_err(&client->dev, "Unable to get irq, error: %d\n", r);
269                 return r;
270         }
271
272         phy->irq_polarity = irq_get_trigger_type(r);
273         client->irq = r;
274
275         return 0;
276 }
277 #else
278 static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
279 {
280         return -ENODEV;
281 }
282 #endif
283
284 static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
285 {
286         struct st21nfcb_nfc_platform_data *pdata;
287         struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
288         int r;
289         int irq;
290
291         pdata = client->dev.platform_data;
292         if (pdata == NULL) {
293                 nfc_err(&client->dev, "No platform data\n");
294                 return -EINVAL;
295         }
296
297         /* store for later use */
298         phy->gpio_irq = pdata->gpio_irq;
299         phy->gpio_reset = pdata->gpio_reset;
300         phy->irq_polarity = pdata->irq_polarity;
301
302         r = devm_gpio_request_one(&client->dev, phy->gpio_irq,
303                                 GPIOF_IN, "clf_irq");
304         if (r) {
305                 pr_err("%s : gpio_request failed\n", __FILE__);
306                 return -ENODEV;
307         }
308
309         r = devm_gpio_request_one(&client->dev,
310                         phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
311         if (r) {
312                 pr_err("%s : reset gpio_request failed\n", __FILE__);
313                 return -ENODEV;
314         }
315
316         /* IRQ */
317         irq = gpio_to_irq(phy->gpio_irq);
318         if (irq < 0) {
319                 nfc_err(&client->dev,
320                         "Unable to get irq number for GPIO %d error %d\n",
321                         phy->gpio_irq, r);
322                 return -ENODEV;
323         }
324         client->irq = irq;
325
326         return 0;
327 }
328
329 static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
330                                   const struct i2c_device_id *id)
331 {
332         struct st21nfcb_i2c_phy *phy;
333         struct st21nfcb_nfc_platform_data *pdata;
334         int r;
335
336         dev_dbg(&client->dev, "%s\n", __func__);
337         dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
338
339         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
340                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
341                 return -ENODEV;
342         }
343
344         phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
345                            GFP_KERNEL);
346         if (!phy) {
347                 nfc_err(&client->dev,
348                         "Cannot allocate memory for st21nfcb i2c phy.\n");
349                 return -ENOMEM;
350         }
351
352         phy->i2c_dev = client;
353
354         i2c_set_clientdata(client, phy);
355
356         pdata = client->dev.platform_data;
357         if (!pdata && client->dev.of_node) {
358                 r = st21nfcb_nci_i2c_of_request_resources(client);
359                 if (r) {
360                         nfc_err(&client->dev, "No platform data\n");
361                         return r;
362                 }
363         } else if (pdata) {
364                 r = st21nfcb_nci_i2c_request_resources(client);
365                 if (r) {
366                         nfc_err(&client->dev,
367                                 "Cannot get platform resources\n");
368                         return r;
369                 }
370         } else {
371                 nfc_err(&client->dev,
372                         "st21nfcb platform resources not available\n");
373                 return -ENODEV;
374         }
375
376         r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
377                                 st21nfcb_nci_irq_thread_fn,
378                                 phy->irq_polarity | IRQF_ONESHOT,
379                                 ST21NFCB_NCI_DRIVER_NAME, phy);
380         if (r < 0) {
381                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
382                 return r;
383         }
384
385         return ndlc_probe(phy, &i2c_phy_ops, &client->dev,
386                         ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
387                         &phy->ndlc);
388 }
389
390 static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
391 {
392         struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
393
394         dev_dbg(&client->dev, "%s\n", __func__);
395
396         ndlc_remove(phy->ndlc);
397
398         if (phy->powered)
399                 st21nfcb_nci_i2c_disable(phy);
400
401         return 0;
402 }
403
404 static const struct of_device_id of_st21nfcb_i2c_match[] = {
405         { .compatible = "st,st21nfcb_i2c", },
406         {}
407 };
408
409 static struct i2c_driver st21nfcb_nci_i2c_driver = {
410         .driver = {
411                 .owner = THIS_MODULE,
412                 .name = ST21NFCB_NCI_I2C_DRIVER_NAME,
413                 .of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
414         },
415         .probe = st21nfcb_nci_i2c_probe,
416         .id_table = st21nfcb_nci_i2c_id_table,
417         .remove = st21nfcb_nci_i2c_remove,
418 };
419
420 module_i2c_driver(st21nfcb_nci_i2c_driver);
421
422 MODULE_LICENSE("GPL");
423 MODULE_DESCRIPTION(DRIVER_DESC);