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/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 #include <net/nfc/nci.h>
29
30 #include "st-nci.h"
31
32 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
33
34 /* ndlc header */
35 #define ST_NCI_FRAME_HEADROOM 1
36 #define ST_NCI_FRAME_TAILROOM 0
37
38 #define ST_NCI_SPI_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
39 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
40
41 #define ST_NCI_DRIVER_NAME "st_nci"
42 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
43
44 struct st_nci_spi_phy {
45 struct spi_device *spi_dev;
46 struct llt_ndlc *ndlc;
47
48 bool irq_active;
49
50 struct gpio_desc *gpiod_reset;
51
52 struct st_nci_se_status se_status;
53 };
54
st_nci_spi_enable(void * phy_id)55 static int st_nci_spi_enable(void *phy_id)
56 {
57 struct st_nci_spi_phy *phy = phy_id;
58
59 gpiod_set_value(phy->gpiod_reset, 0);
60 usleep_range(10000, 15000);
61 gpiod_set_value(phy->gpiod_reset, 1);
62 usleep_range(80000, 85000);
63
64 if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
65 enable_irq(phy->spi_dev->irq);
66 phy->irq_active = true;
67 }
68
69 return 0;
70 }
71
st_nci_spi_disable(void * phy_id)72 static void st_nci_spi_disable(void *phy_id)
73 {
74 struct st_nci_spi_phy *phy = phy_id;
75
76 disable_irq_nosync(phy->spi_dev->irq);
77 phy->irq_active = false;
78 }
79
80 /*
81 * Writing a frame must not return the number of written bytes.
82 * It must return either zero for success, or <0 for error.
83 * In addition, it must not alter the skb
84 */
st_nci_spi_write(void * phy_id,struct sk_buff * skb)85 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
86 {
87 int r;
88 struct st_nci_spi_phy *phy = phy_id;
89 struct spi_device *dev = phy->spi_dev;
90 struct sk_buff *skb_rx;
91 u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
92 ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
93 struct spi_transfer spi_xfer = {
94 .tx_buf = skb->data,
95 .rx_buf = buf,
96 .len = skb->len,
97 };
98
99 if (phy->ndlc->hard_fault != 0)
100 return phy->ndlc->hard_fault;
101
102 r = spi_sync_transfer(dev, &spi_xfer, 1);
103 /*
104 * We may have received some valuable data on miso line.
105 * Send them back in the ndlc state machine.
106 */
107 if (!r) {
108 skb_rx = alloc_skb(skb->len, GFP_KERNEL);
109 if (!skb_rx) {
110 r = -ENOMEM;
111 goto exit;
112 }
113
114 skb_put(skb_rx, skb->len);
115 memcpy(skb_rx->data, buf, skb->len);
116 ndlc_recv(phy->ndlc, skb_rx);
117 }
118
119 exit:
120 return r;
121 }
122
123 /*
124 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
125 * returns:
126 * 0 : if received frame is complete
127 * -EREMOTEIO : i2c read error (fatal)
128 * -EBADMSG : frame was incorrect and discarded
129 * -ENOMEM : cannot allocate skb, frame dropped
130 */
st_nci_spi_read(struct st_nci_spi_phy * phy,struct sk_buff ** skb)131 static int st_nci_spi_read(struct st_nci_spi_phy *phy,
132 struct sk_buff **skb)
133 {
134 int r;
135 u8 len;
136 u8 buf[ST_NCI_SPI_MAX_SIZE];
137 struct spi_device *dev = phy->spi_dev;
138 struct spi_transfer spi_xfer = {
139 .rx_buf = buf,
140 .len = ST_NCI_SPI_MIN_SIZE,
141 };
142
143 r = spi_sync_transfer(dev, &spi_xfer, 1);
144 if (r < 0)
145 return -EREMOTEIO;
146
147 len = be16_to_cpu(*(__be16 *) (buf + 2));
148 if (len > ST_NCI_SPI_MAX_SIZE) {
149 nfc_err(&dev->dev, "invalid frame len\n");
150 phy->ndlc->hard_fault = 1;
151 return -EBADMSG;
152 }
153
154 *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
155 if (*skb == NULL)
156 return -ENOMEM;
157
158 skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
159 skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
160 memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
161
162 if (!len)
163 return 0;
164
165 spi_xfer.len = len;
166 r = spi_sync_transfer(dev, &spi_xfer, 1);
167 if (r < 0) {
168 kfree_skb(*skb);
169 return -EREMOTEIO;
170 }
171
172 skb_put(*skb, len);
173 memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
174
175 return 0;
176 }
177
178 /*
179 * Reads an ndlc frame from the chip.
180 *
181 * On ST21NFCB, IRQ goes in idle state when read starts.
182 */
st_nci_irq_thread_fn(int irq,void * phy_id)183 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
184 {
185 struct st_nci_spi_phy *phy = phy_id;
186 struct spi_device *dev;
187 struct sk_buff *skb = NULL;
188 int r;
189
190 if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
191 WARN_ON_ONCE(1);
192 return IRQ_NONE;
193 }
194
195 dev = phy->spi_dev;
196 dev_dbg(&dev->dev, "IRQ\n");
197
198 if (phy->ndlc->hard_fault)
199 return IRQ_HANDLED;
200
201 if (!phy->ndlc->powered) {
202 st_nci_spi_disable(phy);
203 return IRQ_HANDLED;
204 }
205
206 r = st_nci_spi_read(phy, &skb);
207 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
208 return IRQ_HANDLED;
209
210 ndlc_recv(phy->ndlc, skb);
211
212 return IRQ_HANDLED;
213 }
214
215 static struct nfc_phy_ops spi_phy_ops = {
216 .write = st_nci_spi_write,
217 .enable = st_nci_spi_enable,
218 .disable = st_nci_spi_disable,
219 };
220
221 static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
222
223 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
224 { "reset-gpios", &reset_gpios, 1 },
225 {},
226 };
227
st_nci_spi_probe(struct spi_device * dev)228 static int st_nci_spi_probe(struct spi_device *dev)
229 {
230 struct st_nci_spi_phy *phy;
231 int r;
232
233 dev_dbg(&dev->dev, "%s\n", __func__);
234 dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
235
236 /* Check SPI platform functionnalities */
237 if (!dev) {
238 pr_debug("%s: dev is NULL. Device is not accessible.\n",
239 __func__);
240 return -ENODEV;
241 }
242
243 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
244 GFP_KERNEL);
245 if (!phy)
246 return -ENOMEM;
247
248 phy->spi_dev = dev;
249
250 spi_set_drvdata(dev, phy);
251
252 r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
253 if (r)
254 dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
255
256 /* Get RESET GPIO */
257 phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
258 if (IS_ERR(phy->gpiod_reset)) {
259 nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
260 return PTR_ERR(phy->gpiod_reset);
261 }
262
263 phy->se_status.is_ese_present =
264 device_property_read_bool(&dev->dev, "ese-present");
265 phy->se_status.is_uicc_present =
266 device_property_read_bool(&dev->dev, "uicc-present");
267
268 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
269 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
270 &phy->ndlc, &phy->se_status);
271 if (r < 0) {
272 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
273 return r;
274 }
275
276 phy->irq_active = true;
277 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
278 st_nci_irq_thread_fn,
279 IRQF_ONESHOT,
280 ST_NCI_SPI_DRIVER_NAME, phy);
281 if (r < 0)
282 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
283
284 return r;
285 }
286
st_nci_spi_remove(struct spi_device * dev)287 static int st_nci_spi_remove(struct spi_device *dev)
288 {
289 struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
290
291 dev_dbg(&dev->dev, "%s\n", __func__);
292
293 ndlc_remove(phy->ndlc);
294
295 return 0;
296 }
297
298 static struct spi_device_id st_nci_spi_id_table[] = {
299 {ST_NCI_SPI_DRIVER_NAME, 0},
300 {}
301 };
302 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
303
304 static const struct acpi_device_id st_nci_spi_acpi_match[] = {
305 {"SMO2101", 0},
306 {}
307 };
308 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
309
310 static const struct of_device_id of_st_nci_spi_match[] = {
311 { .compatible = "st,st21nfcb-spi", },
312 {}
313 };
314 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
315
316 static struct spi_driver st_nci_spi_driver = {
317 .driver = {
318 .name = ST_NCI_SPI_DRIVER_NAME,
319 .of_match_table = of_match_ptr(of_st_nci_spi_match),
320 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
321 },
322 .probe = st_nci_spi_probe,
323 .id_table = st_nci_spi_id_table,
324 .remove = st_nci_spi_remove,
325 };
326 module_spi_driver(st_nci_spi_driver);
327
328 MODULE_LICENSE("GPL");
329 MODULE_DESCRIPTION(DRIVER_DESC);
330
