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 <linux/platform_data/st-nci.h> 29 30 #include "ndlc.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_SPI_DRIVER_NAME "st_nci_spi" 42 43 static struct spi_device_id st_nci_spi_id_table[] = { 44 {ST_NCI_SPI_DRIVER_NAME, 0}, 45 {} 46 }; 47 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table); 48 49 struct st_nci_spi_phy { 50 struct spi_device *spi_dev; 51 struct llt_ndlc *ndlc; 52 53 unsigned int gpio_reset; 54 unsigned int irq_polarity; 55 }; 56 57 #define SPI_DUMP_SKB(info, skb) \ 58 do { \ 59 pr_debug("%s:\n", info); \ 60 print_hex_dump(KERN_DEBUG, "spi: ", DUMP_PREFIX_OFFSET, \ 61 16, 1, (skb)->data, (skb)->len, 0); \ 62 } while (0) 63 64 static int st_nci_spi_enable(void *phy_id) 65 { 66 struct st_nci_spi_phy *phy = phy_id; 67 68 gpio_set_value(phy->gpio_reset, 0); 69 usleep_range(10000, 15000); 70 gpio_set_value(phy->gpio_reset, 1); 71 usleep_range(80000, 85000); 72 73 if (phy->ndlc->powered == 0) 74 enable_irq(phy->spi_dev->irq); 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 } 85 86 /* 87 * Writing a frame must not return the number of written bytes. 88 * It must return either zero for success, or <0 for error. 89 * In addition, it must not alter the skb 90 */ 91 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb) 92 { 93 int r; 94 struct st_nci_spi_phy *phy = phy_id; 95 struct spi_device *dev = phy->spi_dev; 96 struct sk_buff *skb_rx; 97 u8 buf[ST_NCI_SPI_MAX_SIZE]; 98 struct spi_transfer spi_xfer = { 99 .tx_buf = skb->data, 100 .rx_buf = buf, 101 .len = skb->len, 102 }; 103 104 SPI_DUMP_SKB("st_nci_spi_write", skb); 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 SPI_DUMP_SKB("spi frame read", *skb); 183 184 return 0; 185 } 186 187 /* 188 * Reads an ndlc frame from the chip. 189 * 190 * On ST21NFCB, IRQ goes in idle state when read starts. 191 */ 192 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 193 { 194 struct st_nci_spi_phy *phy = phy_id; 195 struct spi_device *dev; 196 struct sk_buff *skb = NULL; 197 int r; 198 199 if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) { 200 WARN_ON_ONCE(1); 201 return IRQ_NONE; 202 } 203 204 dev = phy->spi_dev; 205 dev_dbg(&dev->dev, "IRQ\n"); 206 207 if (phy->ndlc->hard_fault) 208 return IRQ_HANDLED; 209 210 if (!phy->ndlc->powered) { 211 st_nci_spi_disable(phy); 212 return IRQ_HANDLED; 213 } 214 215 r = st_nci_spi_read(phy, &skb); 216 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 217 return IRQ_HANDLED; 218 219 ndlc_recv(phy->ndlc, skb); 220 221 return IRQ_HANDLED; 222 } 223 224 static struct nfc_phy_ops spi_phy_ops = { 225 .write = st_nci_spi_write, 226 .enable = st_nci_spi_enable, 227 .disable = st_nci_spi_disable, 228 }; 229 230 #ifdef CONFIG_OF 231 static int st_nci_spi_of_request_resources(struct spi_device *dev) 232 { 233 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 234 struct device_node *pp; 235 int gpio; 236 int r; 237 238 pp = dev->dev.of_node; 239 if (!pp) 240 return -ENODEV; 241 242 /* Get GPIO from device tree */ 243 gpio = of_get_named_gpio(pp, "reset-gpios", 0); 244 if (gpio < 0) { 245 nfc_err(&dev->dev, 246 "Failed to retrieve reset-gpios from device tree\n"); 247 return gpio; 248 } 249 250 /* GPIO request and configuration */ 251 r = devm_gpio_request_one(&dev->dev, gpio, 252 GPIOF_OUT_INIT_HIGH, "clf_reset"); 253 if (r) { 254 nfc_err(&dev->dev, "Failed to request reset pin\n"); 255 return r; 256 } 257 phy->gpio_reset = gpio; 258 259 phy->irq_polarity = irq_get_trigger_type(dev->irq); 260 261 return 0; 262 } 263 #else 264 static int st_nci_spi_of_request_resources(struct spi_device *dev) 265 { 266 return -ENODEV; 267 } 268 #endif 269 270 static int st_nci_spi_request_resources(struct spi_device *dev) 271 { 272 struct st_nci_nfc_platform_data *pdata; 273 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 274 int r; 275 276 pdata = dev->dev.platform_data; 277 if (pdata == NULL) { 278 nfc_err(&dev->dev, "No platform data\n"); 279 return -EINVAL; 280 } 281 282 /* store for later use */ 283 phy->gpio_reset = pdata->gpio_reset; 284 phy->irq_polarity = pdata->irq_polarity; 285 286 r = devm_gpio_request_one(&dev->dev, 287 phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset"); 288 if (r) { 289 pr_err("%s : reset gpio_request failed\n", __FILE__); 290 return r; 291 } 292 293 return 0; 294 } 295 296 static int st_nci_spi_probe(struct spi_device *dev) 297 { 298 struct st_nci_spi_phy *phy; 299 struct st_nci_nfc_platform_data *pdata; 300 int r; 301 302 dev_dbg(&dev->dev, "%s\n", __func__); 303 dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq); 304 305 /* Check SPI platform functionnalities */ 306 if (!dev) { 307 pr_debug("%s: dev is NULL. Device is not accessible.\n", 308 __func__); 309 return -ENODEV; 310 } 311 312 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy), 313 GFP_KERNEL); 314 if (!phy) 315 return -ENOMEM; 316 317 phy->spi_dev = dev; 318 319 spi_set_drvdata(dev, phy); 320 321 pdata = dev->dev.platform_data; 322 if (!pdata && dev->dev.of_node) { 323 r = st_nci_spi_of_request_resources(dev); 324 if (r) { 325 nfc_err(&dev->dev, "No platform data\n"); 326 return r; 327 } 328 } else if (pdata) { 329 r = st_nci_spi_request_resources(dev); 330 if (r) { 331 nfc_err(&dev->dev, 332 "Cannot get platform resources\n"); 333 return r; 334 } 335 } else { 336 nfc_err(&dev->dev, 337 "st_nci platform resources not available\n"); 338 return -ENODEV; 339 } 340 341 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev, 342 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 343 &phy->ndlc); 344 if (r < 0) { 345 nfc_err(&dev->dev, "Unable to register ndlc layer\n"); 346 return r; 347 } 348 349 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL, 350 st_nci_irq_thread_fn, 351 phy->irq_polarity | IRQF_ONESHOT, 352 ST_NCI_SPI_DRIVER_NAME, phy); 353 if (r < 0) 354 nfc_err(&dev->dev, "Unable to register IRQ handler\n"); 355 356 return r; 357 } 358 359 static int st_nci_spi_remove(struct spi_device *dev) 360 { 361 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 362 363 dev_dbg(&dev->dev, "%s\n", __func__); 364 365 ndlc_remove(phy->ndlc); 366 367 return 0; 368 } 369 370 #ifdef CONFIG_OF 371 static const struct of_device_id of_st_nci_spi_match[] = { 372 { .compatible = "st,st21nfcb-spi", }, 373 {} 374 }; 375 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match); 376 #endif 377 378 static struct spi_driver st_nci_spi_driver = { 379 .driver = { 380 .owner = THIS_MODULE, 381 .name = ST_NCI_SPI_DRIVER_NAME, 382 .of_match_table = of_match_ptr(of_st_nci_spi_match), 383 }, 384 .probe = st_nci_spi_probe, 385 .id_table = st_nci_spi_id_table, 386 .remove = st_nci_spi_remove, 387 }; 388 389 module_spi_driver(st_nci_spi_driver); 390 391 MODULE_LICENSE("GPL"); 392 MODULE_DESCRIPTION(DRIVER_DESC); 393