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 bool irq_active; 54 55 unsigned int gpio_reset; 56 unsigned int irq_polarity; 57 58 struct st_nci_se_status se_status; 59 }; 60 61 static int st_nci_i2c_enable(void *phy_id) 62 { 63 struct st_nci_i2c_phy *phy = phy_id; 64 65 gpio_set_value(phy->gpio_reset, 0); 66 usleep_range(10000, 15000); 67 gpio_set_value(phy->gpio_reset, 1); 68 usleep_range(80000, 85000); 69 70 if (phy->ndlc->powered == 0 && phy->irq_active == 0) { 71 enable_irq(phy->i2c_dev->irq); 72 phy->irq_active = true; 73 } 74 75 return 0; 76 } 77 78 static void st_nci_i2c_disable(void *phy_id) 79 { 80 struct st_nci_i2c_phy *phy = phy_id; 81 82 disable_irq_nosync(phy->i2c_dev->irq); 83 phy->irq_active = false; 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_i2c_write(void *phy_id, struct sk_buff *skb) 92 { 93 int r = -1; 94 struct st_nci_i2c_phy *phy = phy_id; 95 struct i2c_client *client = phy->i2c_dev; 96 97 if (phy->ndlc->hard_fault != 0) 98 return phy->ndlc->hard_fault; 99 100 r = i2c_master_send(client, skb->data, skb->len); 101 if (r < 0) { /* Retry, chip was in standby */ 102 usleep_range(1000, 4000); 103 r = i2c_master_send(client, skb->data, skb->len); 104 } 105 106 if (r >= 0) { 107 if (r != skb->len) 108 r = -EREMOTEIO; 109 else 110 r = 0; 111 } 112 113 return r; 114 } 115 116 /* 117 * Reads an ndlc frame and returns it in a newly allocated sk_buff. 118 * returns: 119 * 0 : if received frame is complete 120 * -EREMOTEIO : i2c read error (fatal) 121 * -EBADMSG : frame was incorrect and discarded 122 * -ENOMEM : cannot allocate skb, frame dropped 123 */ 124 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy, 125 struct sk_buff **skb) 126 { 127 int r; 128 u8 len; 129 u8 buf[ST_NCI_I2C_MAX_SIZE]; 130 struct i2c_client *client = phy->i2c_dev; 131 132 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 133 if (r < 0) { /* Retry, chip was in standby */ 134 usleep_range(1000, 4000); 135 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 136 } 137 138 if (r != ST_NCI_I2C_MIN_SIZE) 139 return -EREMOTEIO; 140 141 len = be16_to_cpu(*(__be16 *) (buf + 2)); 142 if (len > ST_NCI_I2C_MAX_SIZE) { 143 nfc_err(&client->dev, "invalid frame len\n"); 144 return -EBADMSG; 145 } 146 147 *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL); 148 if (*skb == NULL) 149 return -ENOMEM; 150 151 skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE); 152 skb_put(*skb, ST_NCI_I2C_MIN_SIZE); 153 memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE); 154 155 if (!len) 156 return 0; 157 158 r = i2c_master_recv(client, buf, len); 159 if (r != len) { 160 kfree_skb(*skb); 161 return -EREMOTEIO; 162 } 163 164 skb_put(*skb, len); 165 memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len); 166 167 return 0; 168 } 169 170 /* 171 * Reads an ndlc frame from the chip. 172 * 173 * On ST_NCI, IRQ goes in idle state when read starts. 174 */ 175 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 176 { 177 struct st_nci_i2c_phy *phy = phy_id; 178 struct i2c_client *client; 179 struct sk_buff *skb = NULL; 180 int r; 181 182 if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) { 183 WARN_ON_ONCE(1); 184 return IRQ_NONE; 185 } 186 187 client = phy->i2c_dev; 188 dev_dbg(&client->dev, "IRQ\n"); 189 190 if (phy->ndlc->hard_fault) 191 return IRQ_HANDLED; 192 193 if (!phy->ndlc->powered) { 194 st_nci_i2c_disable(phy); 195 return IRQ_HANDLED; 196 } 197 198 r = st_nci_i2c_read(phy, &skb); 199 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 200 return IRQ_HANDLED; 201 202 ndlc_recv(phy->ndlc, skb); 203 204 return IRQ_HANDLED; 205 } 206 207 static struct nfc_phy_ops i2c_phy_ops = { 208 .write = st_nci_i2c_write, 209 .enable = st_nci_i2c_enable, 210 .disable = st_nci_i2c_disable, 211 }; 212 213 #ifdef CONFIG_OF 214 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 215 { 216 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 217 struct device_node *pp; 218 int gpio; 219 int r; 220 221 pp = client->dev.of_node; 222 if (!pp) 223 return -ENODEV; 224 225 /* Get GPIO from device tree */ 226 gpio = of_get_named_gpio(pp, "reset-gpios", 0); 227 if (gpio < 0) { 228 nfc_err(&client->dev, 229 "Failed to retrieve reset-gpios from device tree\n"); 230 return gpio; 231 } 232 233 /* GPIO request and configuration */ 234 r = devm_gpio_request_one(&client->dev, gpio, 235 GPIOF_OUT_INIT_HIGH, "clf_reset"); 236 if (r) { 237 nfc_err(&client->dev, "Failed to request reset pin\n"); 238 return r; 239 } 240 phy->gpio_reset = gpio; 241 242 phy->irq_polarity = irq_get_trigger_type(client->irq); 243 244 phy->se_status.is_ese_present = 245 of_property_read_bool(pp, "ese-present"); 246 phy->se_status.is_uicc_present = 247 of_property_read_bool(pp, "uicc-present"); 248 249 return 0; 250 } 251 #else 252 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 253 { 254 return -ENODEV; 255 } 256 #endif 257 258 static int st_nci_i2c_request_resources(struct i2c_client *client) 259 { 260 struct st_nci_nfc_platform_data *pdata; 261 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 262 int r; 263 264 pdata = client->dev.platform_data; 265 if (pdata == NULL) { 266 nfc_err(&client->dev, "No platform data\n"); 267 return -EINVAL; 268 } 269 270 /* store for later use */ 271 phy->gpio_reset = pdata->gpio_reset; 272 phy->irq_polarity = pdata->irq_polarity; 273 274 r = devm_gpio_request_one(&client->dev, 275 phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset"); 276 if (r) { 277 pr_err("%s : reset gpio_request failed\n", __FILE__); 278 return r; 279 } 280 281 phy->se_status.is_ese_present = pdata->is_ese_present; 282 phy->se_status.is_uicc_present = pdata->is_uicc_present; 283 284 return 0; 285 } 286 287 static int st_nci_i2c_probe(struct i2c_client *client, 288 const struct i2c_device_id *id) 289 { 290 struct st_nci_i2c_phy *phy; 291 struct st_nci_nfc_platform_data *pdata; 292 int r; 293 294 dev_dbg(&client->dev, "%s\n", __func__); 295 dev_dbg(&client->dev, "IRQ: %d\n", client->irq); 296 297 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 298 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n"); 299 return -ENODEV; 300 } 301 302 phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy), 303 GFP_KERNEL); 304 if (!phy) 305 return -ENOMEM; 306 307 phy->i2c_dev = client; 308 309 i2c_set_clientdata(client, phy); 310 311 pdata = client->dev.platform_data; 312 if (!pdata && client->dev.of_node) { 313 r = st_nci_i2c_of_request_resources(client); 314 if (r) { 315 nfc_err(&client->dev, "No platform data\n"); 316 return r; 317 } 318 } else if (pdata) { 319 r = st_nci_i2c_request_resources(client); 320 if (r) { 321 nfc_err(&client->dev, 322 "Cannot get platform resources\n"); 323 return r; 324 } 325 } else { 326 nfc_err(&client->dev, 327 "st_nci platform resources not available\n"); 328 return -ENODEV; 329 } 330 331 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, 332 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 333 &phy->ndlc, &phy->se_status); 334 if (r < 0) { 335 nfc_err(&client->dev, "Unable to register ndlc layer\n"); 336 return r; 337 } 338 339 phy->irq_active = true; 340 r = devm_request_threaded_irq(&client->dev, client->irq, NULL, 341 st_nci_irq_thread_fn, 342 phy->irq_polarity | IRQF_ONESHOT, 343 ST_NCI_DRIVER_NAME, phy); 344 if (r < 0) 345 nfc_err(&client->dev, "Unable to register IRQ handler\n"); 346 347 return r; 348 } 349 350 static int st_nci_i2c_remove(struct i2c_client *client) 351 { 352 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 353 354 dev_dbg(&client->dev, "%s\n", __func__); 355 356 ndlc_remove(phy->ndlc); 357 358 return 0; 359 } 360 361 #ifdef CONFIG_OF 362 static const struct of_device_id of_st_nci_i2c_match[] = { 363 { .compatible = "st,st21nfcb-i2c", }, 364 { .compatible = "st,st21nfcb_i2c", }, 365 { .compatible = "st,st21nfcc-i2c", }, 366 {} 367 }; 368 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match); 369 #endif 370 371 static struct i2c_driver st_nci_i2c_driver = { 372 .driver = { 373 .owner = THIS_MODULE, 374 .name = ST_NCI_I2C_DRIVER_NAME, 375 .of_match_table = of_match_ptr(of_st_nci_i2c_match), 376 }, 377 .probe = st_nci_i2c_probe, 378 .id_table = st_nci_i2c_id_table, 379 .remove = st_nci_i2c_remove, 380 }; 381 382 module_i2c_driver(st_nci_i2c_driver); 383 384 MODULE_LICENSE("GPL"); 385 MODULE_DESCRIPTION(DRIVER_DESC); 386