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 "clf_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 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 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 */ 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 */ 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 */ 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 }; 225 226 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 const struct acpi_device_id *id; 230 struct gpio_desc *gpiod_reset; 231 struct device *dev; 232 233 if (!spi_dev) 234 return -EINVAL; 235 236 dev = &spi_dev->dev; 237 238 /* Match the struct device against a given list of ACPI IDs */ 239 id = acpi_match_device(dev->driver->acpi_match_table, dev); 240 if (!id) 241 return -ENODEV; 242 243 /* Get RESET GPIO from ACPI */ 244 gpiod_reset = devm_gpiod_get_index(dev, ST_NCI_GPIO_NAME_RESET, 1, 245 GPIOD_OUT_HIGH); 246 if (IS_ERR(gpiod_reset)) { 247 nfc_err(dev, "Unable to get RESET GPIO\n"); 248 return -ENODEV; 249 } 250 251 phy->gpio_reset = desc_to_gpio(gpiod_reset); 252 253 phy->irq_polarity = irq_get_trigger_type(spi_dev->irq); 254 255 phy->se_status.is_ese_present = 256 device_property_present(dev, "ese-present"); 257 phy->se_status.is_uicc_present = 258 device_property_present(dev, "uicc-present"); 259 260 return 0; 261 } 262 263 static int st_nci_spi_of_request_resources(struct spi_device *dev) 264 { 265 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 266 struct device_node *pp; 267 int gpio; 268 int r; 269 270 pp = dev->dev.of_node; 271 if (!pp) 272 return -ENODEV; 273 274 /* Get GPIO from device tree */ 275 gpio = of_get_named_gpio(pp, "reset-gpios", 0); 276 if (gpio < 0) { 277 nfc_err(&dev->dev, 278 "Failed to retrieve reset-gpios from device tree\n"); 279 return gpio; 280 } 281 282 /* GPIO request and configuration */ 283 r = devm_gpio_request_one(&dev->dev, gpio, 284 GPIOF_OUT_INIT_HIGH, ST_NCI_GPIO_NAME_RESET); 285 if (r) { 286 nfc_err(&dev->dev, "Failed to request reset pin\n"); 287 return r; 288 } 289 phy->gpio_reset = gpio; 290 291 phy->irq_polarity = irq_get_trigger_type(dev->irq); 292 293 phy->se_status.is_ese_present = 294 of_property_read_bool(pp, "ese-present"); 295 phy->se_status.is_uicc_present = 296 of_property_read_bool(pp, "uicc-present"); 297 298 return 0; 299 } 300 301 static int st_nci_spi_request_resources(struct spi_device *dev) 302 { 303 struct st_nci_nfc_platform_data *pdata; 304 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 305 int r; 306 307 pdata = dev->dev.platform_data; 308 if (pdata == NULL) { 309 nfc_err(&dev->dev, "No platform data\n"); 310 return -EINVAL; 311 } 312 313 /* store for later use */ 314 phy->gpio_reset = pdata->gpio_reset; 315 phy->irq_polarity = pdata->irq_polarity; 316 317 r = devm_gpio_request_one(&dev->dev, 318 phy->gpio_reset, GPIOF_OUT_INIT_HIGH, 319 ST_NCI_GPIO_NAME_RESET); 320 if (r) { 321 pr_err("%s : reset gpio_request failed\n", __FILE__); 322 return r; 323 } 324 325 phy->se_status.is_ese_present = pdata->is_ese_present; 326 phy->se_status.is_uicc_present = pdata->is_uicc_present; 327 328 return 0; 329 } 330 331 static int st_nci_spi_probe(struct spi_device *dev) 332 { 333 struct st_nci_spi_phy *phy; 334 struct st_nci_nfc_platform_data *pdata; 335 int r; 336 337 dev_dbg(&dev->dev, "%s\n", __func__); 338 dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq); 339 340 /* Check SPI platform functionnalities */ 341 if (!dev) { 342 pr_debug("%s: dev is NULL. Device is not accessible.\n", 343 __func__); 344 return -ENODEV; 345 } 346 347 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy), 348 GFP_KERNEL); 349 if (!phy) 350 return -ENOMEM; 351 352 phy->spi_dev = dev; 353 354 spi_set_drvdata(dev, phy); 355 356 pdata = dev->dev.platform_data; 357 if (!pdata && dev->dev.of_node) { 358 r = st_nci_spi_of_request_resources(dev); 359 if (r) { 360 nfc_err(&dev->dev, "No platform data\n"); 361 return r; 362 } 363 } else if (pdata) { 364 r = st_nci_spi_request_resources(dev); 365 if (r) { 366 nfc_err(&dev->dev, 367 "Cannot get platform resources\n"); 368 return r; 369 } 370 } else if (ACPI_HANDLE(&dev->dev)) { 371 r = st_nci_spi_acpi_request_resources(dev); 372 if (r) { 373 nfc_err(&dev->dev, "Cannot get ACPI data\n"); 374 return r; 375 } 376 } else { 377 nfc_err(&dev->dev, 378 "st_nci platform resources not available\n"); 379 return -ENODEV; 380 } 381 382 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev, 383 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 384 &phy->ndlc, &phy->se_status); 385 if (r < 0) { 386 nfc_err(&dev->dev, "Unable to register ndlc layer\n"); 387 return r; 388 } 389 390 phy->irq_active = true; 391 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL, 392 st_nci_irq_thread_fn, 393 phy->irq_polarity | IRQF_ONESHOT, 394 ST_NCI_SPI_DRIVER_NAME, phy); 395 if (r < 0) 396 nfc_err(&dev->dev, "Unable to register IRQ handler\n"); 397 398 return r; 399 } 400 401 static int st_nci_spi_remove(struct spi_device *dev) 402 { 403 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 404 405 dev_dbg(&dev->dev, "%s\n", __func__); 406 407 ndlc_remove(phy->ndlc); 408 409 return 0; 410 } 411 412 static struct spi_device_id st_nci_spi_id_table[] = { 413 {ST_NCI_SPI_DRIVER_NAME, 0}, 414 {} 415 }; 416 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table); 417 418 static const struct acpi_device_id st_nci_spi_acpi_match[] = { 419 {"SMO2101", 0}, 420 {} 421 }; 422 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match); 423 424 static const struct of_device_id of_st_nci_spi_match[] = { 425 { .compatible = "st,st21nfcb-spi", }, 426 {} 427 }; 428 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match); 429 430 static struct spi_driver st_nci_spi_driver = { 431 .driver = { 432 .name = ST_NCI_SPI_DRIVER_NAME, 433 .of_match_table = of_match_ptr(of_st_nci_spi_match), 434 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match), 435 }, 436 .probe = st_nci_spi_probe, 437 .id_table = st_nci_spi_id_table, 438 .remove = st_nci_spi_remove, 439 }; 440 module_spi_driver(st_nci_spi_driver); 441 442 MODULE_LICENSE("GPL"); 443 MODULE_DESCRIPTION(DRIVER_DESC); 444