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