1 /* 2 * I2C Link Layer for ST NCI NFC controller familly 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/i2c.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 "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_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */ 39 #define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */ 40 41 #define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c" 42 43 static struct i2c_device_id st_nci_i2c_id_table[] = { 44 {ST_NCI_DRIVER_NAME, 0}, 45 {} 46 }; 47 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table); 48 49 struct st_nci_i2c_phy { 50 struct i2c_client *i2c_dev; 51 struct llt_ndlc *ndlc; 52 53 unsigned int gpio_reset; 54 unsigned int irq_polarity; 55 56 struct st_nci_se_status se_status; 57 }; 58 59 #define I2C_DUMP_SKB(info, skb) \ 60 do { \ 61 pr_debug("%s:\n", info); \ 62 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \ 63 16, 1, (skb)->data, (skb)->len, 0); \ 64 } while (0) 65 66 static int st_nci_i2c_enable(void *phy_id) 67 { 68 struct st_nci_i2c_phy *phy = phy_id; 69 70 gpio_set_value(phy->gpio_reset, 0); 71 usleep_range(10000, 15000); 72 gpio_set_value(phy->gpio_reset, 1); 73 usleep_range(80000, 85000); 74 75 if (phy->ndlc->powered == 0) 76 enable_irq(phy->i2c_dev->irq); 77 78 return 0; 79 } 80 81 static void st_nci_i2c_disable(void *phy_id) 82 { 83 struct st_nci_i2c_phy *phy = phy_id; 84 85 disable_irq_nosync(phy->i2c_dev->irq); 86 } 87 88 /* 89 * Writing a frame must not return the number of written bytes. 90 * It must return either zero for success, or <0 for error. 91 * In addition, it must not alter the skb 92 */ 93 static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb) 94 { 95 int r = -1; 96 struct st_nci_i2c_phy *phy = phy_id; 97 struct i2c_client *client = phy->i2c_dev; 98 99 I2C_DUMP_SKB("st_nci_i2c_write", skb); 100 101 if (phy->ndlc->hard_fault != 0) 102 return phy->ndlc->hard_fault; 103 104 r = i2c_master_send(client, skb->data, skb->len); 105 if (r < 0) { /* Retry, chip was in standby */ 106 usleep_range(1000, 4000); 107 r = i2c_master_send(client, skb->data, skb->len); 108 } 109 110 if (r >= 0) { 111 if (r != skb->len) 112 r = -EREMOTEIO; 113 else 114 r = 0; 115 } 116 117 return r; 118 } 119 120 /* 121 * Reads an ndlc frame and returns it in a newly allocated sk_buff. 122 * returns: 123 * 0 : if received frame is complete 124 * -EREMOTEIO : i2c read error (fatal) 125 * -EBADMSG : frame was incorrect and discarded 126 * -ENOMEM : cannot allocate skb, frame dropped 127 */ 128 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy, 129 struct sk_buff **skb) 130 { 131 int r; 132 u8 len; 133 u8 buf[ST_NCI_I2C_MAX_SIZE]; 134 struct i2c_client *client = phy->i2c_dev; 135 136 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 137 if (r < 0) { /* Retry, chip was in standby */ 138 usleep_range(1000, 4000); 139 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 140 } 141 142 if (r != ST_NCI_I2C_MIN_SIZE) 143 return -EREMOTEIO; 144 145 len = be16_to_cpu(*(__be16 *) (buf + 2)); 146 if (len > ST_NCI_I2C_MAX_SIZE) { 147 nfc_err(&client->dev, "invalid frame len\n"); 148 return -EBADMSG; 149 } 150 151 *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL); 152 if (*skb == NULL) 153 return -ENOMEM; 154 155 skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE); 156 skb_put(*skb, ST_NCI_I2C_MIN_SIZE); 157 memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE); 158 159 if (!len) 160 return 0; 161 162 r = i2c_master_recv(client, buf, len); 163 if (r != len) { 164 kfree_skb(*skb); 165 return -EREMOTEIO; 166 } 167 168 skb_put(*skb, len); 169 memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len); 170 171 I2C_DUMP_SKB("i2c frame read", *skb); 172 173 return 0; 174 } 175 176 /* 177 * Reads an ndlc frame from the chip. 178 * 179 * On ST_NCI, IRQ goes in idle state when read starts. 180 */ 181 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 182 { 183 struct st_nci_i2c_phy *phy = phy_id; 184 struct i2c_client *client; 185 struct sk_buff *skb = NULL; 186 int r; 187 188 if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) { 189 WARN_ON_ONCE(1); 190 return IRQ_NONE; 191 } 192 193 client = phy->i2c_dev; 194 dev_dbg(&client->dev, "IRQ\n"); 195 196 if (phy->ndlc->hard_fault) 197 return IRQ_HANDLED; 198 199 if (!phy->ndlc->powered) { 200 st_nci_i2c_disable(phy); 201 return IRQ_HANDLED; 202 } 203 204 r = st_nci_i2c_read(phy, &skb); 205 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 206 return IRQ_HANDLED; 207 208 ndlc_recv(phy->ndlc, skb); 209 210 return IRQ_HANDLED; 211 } 212 213 static struct nfc_phy_ops i2c_phy_ops = { 214 .write = st_nci_i2c_write, 215 .enable = st_nci_i2c_enable, 216 .disable = st_nci_i2c_disable, 217 }; 218 219 #ifdef CONFIG_OF 220 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 221 { 222 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 223 struct device_node *pp; 224 int gpio; 225 int r; 226 227 pp = client->dev.of_node; 228 if (!pp) 229 return -ENODEV; 230 231 /* Get GPIO from device tree */ 232 gpio = of_get_named_gpio(pp, "reset-gpios", 0); 233 if (gpio < 0) { 234 nfc_err(&client->dev, 235 "Failed to retrieve reset-gpios from device tree\n"); 236 return gpio; 237 } 238 239 /* GPIO request and configuration */ 240 r = devm_gpio_request_one(&client->dev, gpio, 241 GPIOF_OUT_INIT_HIGH, "clf_reset"); 242 if (r) { 243 nfc_err(&client->dev, "Failed to request reset pin\n"); 244 return r; 245 } 246 phy->gpio_reset = gpio; 247 248 phy->irq_polarity = irq_get_trigger_type(client->irq); 249 250 phy->se_status.is_ese_present = 251 of_property_read_bool(pp, "ese-present"); 252 phy->se_status.is_uicc_present = 253 of_property_read_bool(pp, "uicc-present"); 254 255 return 0; 256 } 257 #else 258 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 259 { 260 return -ENODEV; 261 } 262 #endif 263 264 static int st_nci_i2c_request_resources(struct i2c_client *client) 265 { 266 struct st_nci_nfc_platform_data *pdata; 267 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 268 int r; 269 270 pdata = client->dev.platform_data; 271 if (pdata == NULL) { 272 nfc_err(&client->dev, "No platform data\n"); 273 return -EINVAL; 274 } 275 276 /* store for later use */ 277 phy->gpio_reset = pdata->gpio_reset; 278 phy->irq_polarity = pdata->irq_polarity; 279 280 r = devm_gpio_request_one(&client->dev, 281 phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset"); 282 if (r) { 283 pr_err("%s : reset gpio_request failed\n", __FILE__); 284 return r; 285 } 286 287 phy->se_status.is_ese_present = pdata->is_ese_present; 288 phy->se_status.is_uicc_present = pdata->is_uicc_present; 289 290 return 0; 291 } 292 293 static int st_nci_i2c_probe(struct i2c_client *client, 294 const struct i2c_device_id *id) 295 { 296 struct st_nci_i2c_phy *phy; 297 struct st_nci_nfc_platform_data *pdata; 298 int r; 299 300 dev_dbg(&client->dev, "%s\n", __func__); 301 dev_dbg(&client->dev, "IRQ: %d\n", client->irq); 302 303 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 304 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n"); 305 return -ENODEV; 306 } 307 308 phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy), 309 GFP_KERNEL); 310 if (!phy) 311 return -ENOMEM; 312 313 phy->i2c_dev = client; 314 315 i2c_set_clientdata(client, phy); 316 317 pdata = client->dev.platform_data; 318 if (!pdata && client->dev.of_node) { 319 r = st_nci_i2c_of_request_resources(client); 320 if (r) { 321 nfc_err(&client->dev, "No platform data\n"); 322 return r; 323 } 324 } else if (pdata) { 325 r = st_nci_i2c_request_resources(client); 326 if (r) { 327 nfc_err(&client->dev, 328 "Cannot get platform resources\n"); 329 return r; 330 } 331 } else { 332 nfc_err(&client->dev, 333 "st_nci platform resources not available\n"); 334 return -ENODEV; 335 } 336 337 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, 338 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 339 &phy->ndlc, &phy->se_status); 340 if (r < 0) { 341 nfc_err(&client->dev, "Unable to register ndlc layer\n"); 342 return r; 343 } 344 345 r = devm_request_threaded_irq(&client->dev, client->irq, NULL, 346 st_nci_irq_thread_fn, 347 phy->irq_polarity | IRQF_ONESHOT, 348 ST_NCI_DRIVER_NAME, phy); 349 if (r < 0) 350 nfc_err(&client->dev, "Unable to register IRQ handler\n"); 351 352 return r; 353 } 354 355 static int st_nci_i2c_remove(struct i2c_client *client) 356 { 357 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 358 359 dev_dbg(&client->dev, "%s\n", __func__); 360 361 ndlc_remove(phy->ndlc); 362 363 return 0; 364 } 365 366 #ifdef CONFIG_OF 367 static const struct of_device_id of_st_nci_i2c_match[] = { 368 { .compatible = "st,st21nfcb-i2c", }, 369 { .compatible = "st,st21nfcb_i2c", }, 370 { .compatible = "st,st21nfcc-i2c", }, 371 {} 372 }; 373 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match); 374 #endif 375 376 static struct i2c_driver st_nci_i2c_driver = { 377 .driver = { 378 .owner = THIS_MODULE, 379 .name = ST_NCI_I2C_DRIVER_NAME, 380 .of_match_table = of_match_ptr(of_st_nci_i2c_match), 381 }, 382 .probe = st_nci_i2c_probe, 383 .id_table = st_nci_i2c_id_table, 384 .remove = st_nci_i2c_remove, 385 }; 386 387 module_i2c_driver(st_nci_i2c_driver); 388 389 MODULE_LICENSE("GPL"); 390 MODULE_DESCRIPTION(DRIVER_DESC); 391