1 /*
2 * SPI Link Layer for ST NCI 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/spi/spi.h>
22 #include <linux/gpio.h>
23 #include <linux/gpio/consumer.h>
24 #include <linux/of_irq.h>
25 #include <linux/of_gpio.h>
26 #include <linux/acpi.h>
27 #include <linux/interrupt.h>
28 #include <linux/delay.h>
29 #include <linux/nfc.h>
30 #include <net/nfc/nci.h>
31 #include <linux/platform_data/st-nci.h>
32
33 #include "st-nci.h"
34
35 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
36
37 /* ndlc header */
38 #define ST_NCI_FRAME_HEADROOM 1
39 #define ST_NCI_FRAME_TAILROOM 0
40
41 #define ST_NCI_SPI_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
42 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
43
44 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
45
46 #define ST_NCI_GPIO_NAME_RESET "reset"
47
48 struct st_nci_spi_phy {
49 struct spi_device *spi_dev;
50 struct llt_ndlc *ndlc;
51
52 bool irq_active;
53
54 unsigned int gpio_reset;
55 unsigned int irq_polarity;
56
57 struct st_nci_se_status se_status;
58 };
59
st_nci_spi_enable(void * phy_id)60 static int st_nci_spi_enable(void *phy_id)
61 {
62 struct st_nci_spi_phy *phy = phy_id;
63
64 gpio_set_value(phy->gpio_reset, 0);
65 usleep_range(10000, 15000);
66 gpio_set_value(phy->gpio_reset, 1);
67 usleep_range(80000, 85000);
68
69 if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
70 enable_irq(phy->spi_dev->irq);
71 phy->irq_active = true;
72 }
73
74 return 0;
75 }
76
st_nci_spi_disable(void * phy_id)77 static void st_nci_spi_disable(void *phy_id)
78 {
79 struct st_nci_spi_phy *phy = phy_id;
80
81 disable_irq_nosync(phy->spi_dev->irq);
82 phy->irq_active = false;
83 }
84
85 /*
86 * Writing a frame must not return the number of written bytes.
87 * It must return either zero for success, or <0 for error.
88 * In addition, it must not alter the skb
89 */
st_nci_spi_write(void * phy_id,struct sk_buff * skb)90 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
91 {
92 int r;
93 struct st_nci_spi_phy *phy = phy_id;
94 struct spi_device *dev = phy->spi_dev;
95 struct sk_buff *skb_rx;
96 u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
97 ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
98 struct spi_transfer spi_xfer = {
99 .tx_buf = skb->data,
100 .rx_buf = buf,
101 .len = skb->len,
102 };
103
104 if (phy->ndlc->hard_fault != 0)
105 return phy->ndlc->hard_fault;
106
107 r = spi_sync_transfer(dev, &spi_xfer, 1);
108 /*
109 * We may have received some valuable data on miso line.
110 * Send them back in the ndlc state machine.
111 */
112 if (!r) {
113 skb_rx = alloc_skb(skb->len, GFP_KERNEL);
114 if (!skb_rx) {
115 r = -ENOMEM;
116 goto exit;
117 }
118
119 skb_put(skb_rx, skb->len);
120 memcpy(skb_rx->data, buf, skb->len);
121 ndlc_recv(phy->ndlc, skb_rx);
122 }
123
124 exit:
125 return r;
126 }
127
128 /*
129 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
130 * returns:
131 * 0 : if received frame is complete
132 * -EREMOTEIO : i2c read error (fatal)
133 * -EBADMSG : frame was incorrect and discarded
134 * -ENOMEM : cannot allocate skb, frame dropped
135 */
st_nci_spi_read(struct st_nci_spi_phy * phy,struct sk_buff ** skb)136 static int st_nci_spi_read(struct st_nci_spi_phy *phy,
137 struct sk_buff **skb)
138 {
139 int r;
140 u8 len;
141 u8 buf[ST_NCI_SPI_MAX_SIZE];
142 struct spi_device *dev = phy->spi_dev;
143 struct spi_transfer spi_xfer = {
144 .rx_buf = buf,
145 .len = ST_NCI_SPI_MIN_SIZE,
146 };
147
148 r = spi_sync_transfer(dev, &spi_xfer, 1);
149 if (r < 0)
150 return -EREMOTEIO;
151
152 len = be16_to_cpu(*(__be16 *) (buf + 2));
153 if (len > ST_NCI_SPI_MAX_SIZE) {
154 nfc_err(&dev->dev, "invalid frame len\n");
155 phy->ndlc->hard_fault = 1;
156 return -EBADMSG;
157 }
158
159 *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
160 if (*skb == NULL)
161 return -ENOMEM;
162
163 skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
164 skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
165 memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
166
167 if (!len)
168 return 0;
169
170 spi_xfer.len = len;
171 r = spi_sync_transfer(dev, &spi_xfer, 1);
172 if (r < 0) {
173 kfree_skb(*skb);
174 return -EREMOTEIO;
175 }
176
177 skb_put(*skb, len);
178 memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
179
180 return 0;
181 }
182
183 /*
184 * Reads an ndlc frame from the chip.
185 *
186 * On ST21NFCB, IRQ goes in idle state when read starts.
187 */
st_nci_irq_thread_fn(int irq,void * phy_id)188 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
189 {
190 struct st_nci_spi_phy *phy = phy_id;
191 struct spi_device *dev;
192 struct sk_buff *skb = NULL;
193 int r;
194
195 if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
196 WARN_ON_ONCE(1);
197 return IRQ_NONE;
198 }
199
200 dev = phy->spi_dev;
201 dev_dbg(&dev->dev, "IRQ\n");
202
203 if (phy->ndlc->hard_fault)
204 return IRQ_HANDLED;
205
206 if (!phy->ndlc->powered) {
207 st_nci_spi_disable(phy);
208 return IRQ_HANDLED;
209 }
210
211 r = st_nci_spi_read(phy, &skb);
212 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
213 return IRQ_HANDLED;
214
215 ndlc_recv(phy->ndlc, skb);
216
217 return IRQ_HANDLED;
218 }
219
220 static struct nfc_phy_ops spi_phy_ops = {
221 .write = st_nci_spi_write,
222 .enable = st_nci_spi_enable,
223 .disable = st_nci_spi_disable,
224 };
225
st_nci_spi_acpi_request_resources(struct spi_device * spi_dev)226 static int st_nci_spi_acpi_request_resources(struct spi_device *spi_dev)
227 {
228 struct st_nci_spi_phy *phy = spi_get_drvdata(spi_dev);
229 struct gpio_desc *gpiod_reset;
230 struct device *dev = &spi_dev->dev;
231 u8 tmp;
232
233 /* Get RESET GPIO from ACPI */
234 gpiod_reset = devm_gpiod_get_index(dev, ST_NCI_GPIO_NAME_RESET, 1,
235 GPIOD_OUT_HIGH);
236 if (IS_ERR(gpiod_reset)) {
237 nfc_err(dev, "Unable to get RESET GPIO\n");
238 return -ENODEV;
239 }
240
241 phy->gpio_reset = desc_to_gpio(gpiod_reset);
242
243 phy->irq_polarity = irq_get_trigger_type(spi_dev->irq);
244
245 phy->se_status.is_ese_present = false;
246 phy->se_status.is_uicc_present = false;
247
248 if (device_property_present(dev, "ese-present")) {
249 device_property_read_u8(dev, "ese-present", &tmp);
250 tmp = phy->se_status.is_ese_present;
251 }
252
253 if (device_property_present(dev, "uicc-present")) {
254 device_property_read_u8(dev, "uicc-present", &tmp);
255 tmp = phy->se_status.is_uicc_present;
256 }
257
258 return 0;
259 }
260
st_nci_spi_of_request_resources(struct spi_device * dev)261 static int st_nci_spi_of_request_resources(struct spi_device *dev)
262 {
263 struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
264 struct device_node *pp;
265 int gpio;
266 int r;
267
268 pp = dev->dev.of_node;
269 if (!pp)
270 return -ENODEV;
271
272 /* Get GPIO from device tree */
273 gpio = of_get_named_gpio(pp, "reset-gpios", 0);
274 if (gpio < 0) {
275 nfc_err(&dev->dev,
276 "Failed to retrieve reset-gpios from device tree\n");
277 return gpio;
278 }
279
280 /* GPIO request and configuration */
281 r = devm_gpio_request_one(&dev->dev, gpio,
282 GPIOF_OUT_INIT_HIGH, ST_NCI_GPIO_NAME_RESET);
283 if (r) {
284 nfc_err(&dev->dev, "Failed to request reset pin\n");
285 return r;
286 }
287 phy->gpio_reset = gpio;
288
289 phy->irq_polarity = irq_get_trigger_type(dev->irq);
290
291 phy->se_status.is_ese_present =
292 of_property_read_bool(pp, "ese-present");
293 phy->se_status.is_uicc_present =
294 of_property_read_bool(pp, "uicc-present");
295
296 return 0;
297 }
298
st_nci_spi_request_resources(struct spi_device * dev)299 static int st_nci_spi_request_resources(struct spi_device *dev)
300 {
301 struct st_nci_nfc_platform_data *pdata;
302 struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
303 int r;
304
305 pdata = dev->dev.platform_data;
306 if (pdata == NULL) {
307 nfc_err(&dev->dev, "No platform data\n");
308 return -EINVAL;
309 }
310
311 /* store for later use */
312 phy->gpio_reset = pdata->gpio_reset;
313 phy->irq_polarity = pdata->irq_polarity;
314
315 r = devm_gpio_request_one(&dev->dev,
316 phy->gpio_reset, GPIOF_OUT_INIT_HIGH,
317 ST_NCI_GPIO_NAME_RESET);
318 if (r) {
319 pr_err("%s : reset gpio_request failed\n", __FILE__);
320 return r;
321 }
322
323 phy->se_status.is_ese_present = pdata->is_ese_present;
324 phy->se_status.is_uicc_present = pdata->is_uicc_present;
325
326 return 0;
327 }
328
st_nci_spi_probe(struct spi_device * dev)329 static int st_nci_spi_probe(struct spi_device *dev)
330 {
331 struct st_nci_spi_phy *phy;
332 struct st_nci_nfc_platform_data *pdata;
333 int r;
334
335 dev_dbg(&dev->dev, "%s\n", __func__);
336 dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
337
338 /* Check SPI platform functionnalities */
339 if (!dev) {
340 pr_debug("%s: dev is NULL. Device is not accessible.\n",
341 __func__);
342 return -ENODEV;
343 }
344
345 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
346 GFP_KERNEL);
347 if (!phy)
348 return -ENOMEM;
349
350 phy->spi_dev = dev;
351
352 spi_set_drvdata(dev, phy);
353
354 pdata = dev->dev.platform_data;
355 if (!pdata && dev->dev.of_node) {
356 r = st_nci_spi_of_request_resources(dev);
357 if (r) {
358 nfc_err(&dev->dev, "No platform data\n");
359 return r;
360 }
361 } else if (pdata) {
362 r = st_nci_spi_request_resources(dev);
363 if (r) {
364 nfc_err(&dev->dev,
365 "Cannot get platform resources\n");
366 return r;
367 }
368 } else if (ACPI_HANDLE(&dev->dev)) {
369 r = st_nci_spi_acpi_request_resources(dev);
370 if (r) {
371 nfc_err(&dev->dev, "Cannot get ACPI data\n");
372 return r;
373 }
374 } else {
375 nfc_err(&dev->dev,
376 "st_nci platform resources not available\n");
377 return -ENODEV;
378 }
379
380 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
381 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
382 &phy->ndlc, &phy->se_status);
383 if (r < 0) {
384 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
385 return r;
386 }
387
388 phy->irq_active = true;
389 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
390 st_nci_irq_thread_fn,
391 phy->irq_polarity | IRQF_ONESHOT,
392 ST_NCI_SPI_DRIVER_NAME, phy);
393 if (r < 0)
394 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
395
396 return r;
397 }
398
st_nci_spi_remove(struct spi_device * dev)399 static int st_nci_spi_remove(struct spi_device *dev)
400 {
401 struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
402
403 dev_dbg(&dev->dev, "%s\n", __func__);
404
405 ndlc_remove(phy->ndlc);
406
407 return 0;
408 }
409
410 static struct spi_device_id st_nci_spi_id_table[] = {
411 {ST_NCI_SPI_DRIVER_NAME, 0},
412 {}
413 };
414 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
415
416 static const struct acpi_device_id st_nci_spi_acpi_match[] = {
417 {"SMO2101", 0},
418 {}
419 };
420 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
421
422 static const struct of_device_id of_st_nci_spi_match[] = {
423 { .compatible = "st,st21nfcb-spi", },
424 {}
425 };
426 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
427
428 static struct spi_driver st_nci_spi_driver = {
429 .driver = {
430 .name = ST_NCI_SPI_DRIVER_NAME,
431 .of_match_table = of_match_ptr(of_st_nci_spi_match),
432 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
433 },
434 .probe = st_nci_spi_probe,
435 .id_table = st_nci_spi_id_table,
436 .remove = st_nci_spi_remove,
437 };
438 module_spi_driver(st_nci_spi_driver);
439
440 MODULE_LICENSE("GPL");
441 MODULE_DESCRIPTION(DRIVER_DESC);
442