1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * SPI Link Layer for ST NCI based Driver
4 * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
5 */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 #include <linux/module.h>
10 #include <linux/spi/spi.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/acpi.h>
13 #include <linux/interrupt.h>
14 #include <linux/delay.h>
15 #include <linux/nfc.h>
16 #include <linux/of.h>
17 #include <net/nfc/nci.h>
18
19 #include "st-nci.h"
20
21 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
22
23 /* ndlc header */
24 #define ST_NCI_FRAME_HEADROOM 1
25 #define ST_NCI_FRAME_TAILROOM 0
26
27 #define ST_NCI_SPI_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
28 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
29
30 #define ST_NCI_DRIVER_NAME "st_nci"
31 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
32
33 struct st_nci_spi_phy {
34 struct spi_device *spi_dev;
35 struct llt_ndlc *ndlc;
36
37 bool irq_active;
38
39 struct gpio_desc *gpiod_reset;
40
41 struct st_nci_se_status se_status;
42 };
43
st_nci_spi_enable(void * phy_id)44 static int st_nci_spi_enable(void *phy_id)
45 {
46 struct st_nci_spi_phy *phy = phy_id;
47
48 gpiod_set_value(phy->gpiod_reset, 0);
49 usleep_range(10000, 15000);
50 gpiod_set_value(phy->gpiod_reset, 1);
51 usleep_range(80000, 85000);
52
53 if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
54 enable_irq(phy->spi_dev->irq);
55 phy->irq_active = true;
56 }
57
58 return 0;
59 }
60
st_nci_spi_disable(void * phy_id)61 static void st_nci_spi_disable(void *phy_id)
62 {
63 struct st_nci_spi_phy *phy = phy_id;
64
65 disable_irq_nosync(phy->spi_dev->irq);
66 phy->irq_active = false;
67 }
68
69 /*
70 * Writing a frame must not return the number of written bytes.
71 * It must return either zero for success, or <0 for error.
72 * In addition, it must not alter the skb
73 */
st_nci_spi_write(void * phy_id,struct sk_buff * skb)74 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
75 {
76 int r;
77 struct st_nci_spi_phy *phy = phy_id;
78 struct spi_device *dev = phy->spi_dev;
79 struct sk_buff *skb_rx;
80 u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
81 ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
82 struct spi_transfer spi_xfer = {
83 .tx_buf = skb->data,
84 .rx_buf = buf,
85 .len = skb->len,
86 };
87
88 if (phy->ndlc->hard_fault != 0)
89 return phy->ndlc->hard_fault;
90
91 r = spi_sync_transfer(dev, &spi_xfer, 1);
92 /*
93 * We may have received some valuable data on miso line.
94 * Send them back in the ndlc state machine.
95 */
96 if (!r) {
97 skb_rx = alloc_skb(skb->len, GFP_KERNEL);
98 if (!skb_rx)
99 return -ENOMEM;
100
101 skb_put(skb_rx, skb->len);
102 memcpy(skb_rx->data, buf, skb->len);
103 ndlc_recv(phy->ndlc, skb_rx);
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_spi_read(struct st_nci_spi_phy * phy,struct sk_buff ** skb)117 static int st_nci_spi_read(struct st_nci_spi_phy *phy,
118 struct sk_buff **skb)
119 {
120 int r;
121 u8 len;
122 u8 buf[ST_NCI_SPI_MAX_SIZE];
123 struct spi_device *dev = phy->spi_dev;
124 struct spi_transfer spi_xfer = {
125 .rx_buf = buf,
126 .len = ST_NCI_SPI_MIN_SIZE,
127 };
128
129 r = spi_sync_transfer(dev, &spi_xfer, 1);
130 if (r < 0)
131 return -EREMOTEIO;
132
133 len = be16_to_cpu(*(__be16 *) (buf + 2));
134 if (len > ST_NCI_SPI_MAX_SIZE) {
135 nfc_err(&dev->dev, "invalid frame len\n");
136 phy->ndlc->hard_fault = 1;
137 return -EBADMSG;
138 }
139
140 *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
141 if (*skb == NULL)
142 return -ENOMEM;
143
144 skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
145 skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
146 memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
147
148 if (!len)
149 return 0;
150
151 spi_xfer.len = len;
152 r = spi_sync_transfer(dev, &spi_xfer, 1);
153 if (r < 0) {
154 kfree_skb(*skb);
155 return -EREMOTEIO;
156 }
157
158 skb_put(*skb, len);
159 memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
160
161 return 0;
162 }
163
164 /*
165 * Reads an ndlc frame from the chip.
166 *
167 * On ST21NFCB, IRQ goes in idle state when read starts.
168 */
st_nci_irq_thread_fn(int irq,void * phy_id)169 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
170 {
171 struct st_nci_spi_phy *phy = phy_id;
172 struct sk_buff *skb = NULL;
173 int r;
174
175 if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
176 WARN_ON_ONCE(1);
177 return IRQ_NONE;
178 }
179
180 if (phy->ndlc->hard_fault)
181 return IRQ_HANDLED;
182
183 if (!phy->ndlc->powered) {
184 st_nci_spi_disable(phy);
185 return IRQ_HANDLED;
186 }
187
188 r = st_nci_spi_read(phy, &skb);
189 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
190 return IRQ_HANDLED;
191
192 ndlc_recv(phy->ndlc, skb);
193
194 return IRQ_HANDLED;
195 }
196
197 static const struct nfc_phy_ops spi_phy_ops = {
198 .write = st_nci_spi_write,
199 .enable = st_nci_spi_enable,
200 .disable = st_nci_spi_disable,
201 };
202
203 static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
204
205 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
206 { "reset-gpios", &reset_gpios, 1 },
207 {},
208 };
209
st_nci_spi_probe(struct spi_device * dev)210 static int st_nci_spi_probe(struct spi_device *dev)
211 {
212 struct st_nci_spi_phy *phy;
213 int r;
214
215 /* Check SPI platform functionnalities */
216 if (!dev) {
217 pr_debug("%s: dev is NULL. Device is not accessible.\n",
218 __func__);
219 return -ENODEV;
220 }
221
222 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
223 GFP_KERNEL);
224 if (!phy)
225 return -ENOMEM;
226
227 phy->spi_dev = dev;
228
229 spi_set_drvdata(dev, phy);
230
231 r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
232 if (r)
233 dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
234
235 /* Get RESET GPIO */
236 phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
237 if (IS_ERR(phy->gpiod_reset)) {
238 nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
239 return PTR_ERR(phy->gpiod_reset);
240 }
241
242 phy->se_status.is_ese_present =
243 device_property_read_bool(&dev->dev, "ese-present");
244 phy->se_status.is_uicc_present =
245 device_property_read_bool(&dev->dev, "uicc-present");
246
247 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
248 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
249 &phy->ndlc, &phy->se_status);
250 if (r < 0) {
251 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
252 return r;
253 }
254
255 phy->irq_active = true;
256 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
257 st_nci_irq_thread_fn,
258 IRQF_ONESHOT,
259 ST_NCI_SPI_DRIVER_NAME, phy);
260 if (r < 0)
261 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
262
263 return r;
264 }
265
st_nci_spi_remove(struct spi_device * dev)266 static void st_nci_spi_remove(struct spi_device *dev)
267 {
268 struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
269
270 ndlc_remove(phy->ndlc);
271 }
272
273 static struct spi_device_id st_nci_spi_id_table[] = {
274 {ST_NCI_SPI_DRIVER_NAME, 0},
275 {"st21nfcb-spi", 0},
276 {}
277 };
278 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
279
280 static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = {
281 {"SMO2101", 0},
282 {}
283 };
284 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
285
286 static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = {
287 { .compatible = "st,st21nfcb-spi", },
288 {}
289 };
290 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
291
292 static struct spi_driver st_nci_spi_driver = {
293 .driver = {
294 .name = ST_NCI_SPI_DRIVER_NAME,
295 .of_match_table = of_match_ptr(of_st_nci_spi_match),
296 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
297 },
298 .probe = st_nci_spi_probe,
299 .id_table = st_nci_spi_id_table,
300 .remove = st_nci_spi_remove,
301 };
302 module_spi_driver(st_nci_spi_driver);
303
304 MODULE_LICENSE("GPL");
305 MODULE_DESCRIPTION(DRIVER_DESC);
306