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 "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_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 57 #define I2C_DUMP_SKB(info, skb) \ 58 do { \ 59 pr_debug("%s:\n", info); \ 60 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \ 61 16, 1, (skb)->data, (skb)->len, 0); \ 62 } while (0) 63 64 static int st_nci_i2c_enable(void *phy_id) 65 { 66 struct st_nci_i2c_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->i2c_dev->irq); 75 76 return 0; 77 } 78 79 static void st_nci_i2c_disable(void *phy_id) 80 { 81 struct st_nci_i2c_phy *phy = phy_id; 82 83 disable_irq_nosync(phy->i2c_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_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 I2C_DUMP_SKB("st_nci_i2c_write", skb); 98 99 if (phy->ndlc->hard_fault != 0) 100 return phy->ndlc->hard_fault; 101 102 r = i2c_master_send(client, skb->data, skb->len); 103 if (r < 0) { /* Retry, chip was in standby */ 104 usleep_range(1000, 4000); 105 r = i2c_master_send(client, skb->data, skb->len); 106 } 107 108 if (r >= 0) { 109 if (r != skb->len) 110 r = -EREMOTEIO; 111 else 112 r = 0; 113 } 114 115 return r; 116 } 117 118 /* 119 * Reads an ndlc frame and returns it in a newly allocated sk_buff. 120 * returns: 121 * 0 : if received frame is complete 122 * -EREMOTEIO : i2c read error (fatal) 123 * -EBADMSG : frame was incorrect and discarded 124 * -ENOMEM : cannot allocate skb, frame dropped 125 */ 126 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy, 127 struct sk_buff **skb) 128 { 129 int r; 130 u8 len; 131 u8 buf[ST_NCI_I2C_MAX_SIZE]; 132 struct i2c_client *client = phy->i2c_dev; 133 134 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 135 if (r < 0) { /* Retry, chip was in standby */ 136 usleep_range(1000, 4000); 137 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 138 } 139 140 if (r != ST_NCI_I2C_MIN_SIZE) 141 return -EREMOTEIO; 142 143 len = be16_to_cpu(*(__be16 *) (buf + 2)); 144 if (len > ST_NCI_I2C_MAX_SIZE) { 145 nfc_err(&client->dev, "invalid frame len\n"); 146 return -EBADMSG; 147 } 148 149 *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL); 150 if (*skb == NULL) 151 return -ENOMEM; 152 153 skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE); 154 skb_put(*skb, ST_NCI_I2C_MIN_SIZE); 155 memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE); 156 157 if (!len) 158 return 0; 159 160 r = i2c_master_recv(client, buf, len); 161 if (r != len) { 162 kfree_skb(*skb); 163 return -EREMOTEIO; 164 } 165 166 skb_put(*skb, len); 167 memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len); 168 169 I2C_DUMP_SKB("i2c frame read", *skb); 170 171 return 0; 172 } 173 174 /* 175 * Reads an ndlc frame from the chip. 176 * 177 * On ST_NCI, IRQ goes in idle state when read starts. 178 */ 179 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 180 { 181 struct st_nci_i2c_phy *phy = phy_id; 182 struct i2c_client *client; 183 struct sk_buff *skb = NULL; 184 int r; 185 186 if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) { 187 WARN_ON_ONCE(1); 188 return IRQ_NONE; 189 } 190 191 client = phy->i2c_dev; 192 dev_dbg(&client->dev, "IRQ\n"); 193 194 if (phy->ndlc->hard_fault) 195 return IRQ_HANDLED; 196 197 if (!phy->ndlc->powered) { 198 st_nci_i2c_disable(phy); 199 return IRQ_HANDLED; 200 } 201 202 r = st_nci_i2c_read(phy, &skb); 203 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 204 return IRQ_HANDLED; 205 206 ndlc_recv(phy->ndlc, skb); 207 208 return IRQ_HANDLED; 209 } 210 211 static struct nfc_phy_ops i2c_phy_ops = { 212 .write = st_nci_i2c_write, 213 .enable = st_nci_i2c_enable, 214 .disable = st_nci_i2c_disable, 215 }; 216 217 #ifdef CONFIG_OF 218 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 219 { 220 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 221 struct device_node *pp; 222 int gpio; 223 int r; 224 225 pp = client->dev.of_node; 226 if (!pp) 227 return -ENODEV; 228 229 /* Get GPIO from device tree */ 230 gpio = of_get_named_gpio(pp, "reset-gpios", 0); 231 if (gpio < 0) { 232 nfc_err(&client->dev, 233 "Failed to retrieve reset-gpios from device tree\n"); 234 return gpio; 235 } 236 237 /* GPIO request and configuration */ 238 r = devm_gpio_request_one(&client->dev, gpio, 239 GPIOF_OUT_INIT_HIGH, "clf_reset"); 240 if (r) { 241 nfc_err(&client->dev, "Failed to request reset pin\n"); 242 return r; 243 } 244 phy->gpio_reset = gpio; 245 246 phy->irq_polarity = irq_get_trigger_type(client->irq); 247 248 return 0; 249 } 250 #else 251 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 252 { 253 return -ENODEV; 254 } 255 #endif 256 257 static int st_nci_i2c_request_resources(struct i2c_client *client) 258 { 259 struct st_nci_nfc_platform_data *pdata; 260 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 261 int r; 262 263 pdata = client->dev.platform_data; 264 if (pdata == NULL) { 265 nfc_err(&client->dev, "No platform data\n"); 266 return -EINVAL; 267 } 268 269 /* store for later use */ 270 phy->gpio_reset = pdata->gpio_reset; 271 phy->irq_polarity = pdata->irq_polarity; 272 273 r = devm_gpio_request_one(&client->dev, 274 phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset"); 275 if (r) { 276 pr_err("%s : reset gpio_request failed\n", __FILE__); 277 return r; 278 } 279 280 return 0; 281 } 282 283 static int st_nci_i2c_probe(struct i2c_client *client, 284 const struct i2c_device_id *id) 285 { 286 struct st_nci_i2c_phy *phy; 287 struct st_nci_nfc_platform_data *pdata; 288 int r; 289 290 dev_dbg(&client->dev, "%s\n", __func__); 291 dev_dbg(&client->dev, "IRQ: %d\n", client->irq); 292 293 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 294 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n"); 295 return -ENODEV; 296 } 297 298 phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy), 299 GFP_KERNEL); 300 if (!phy) 301 return -ENOMEM; 302 303 phy->i2c_dev = client; 304 305 i2c_set_clientdata(client, phy); 306 307 pdata = client->dev.platform_data; 308 if (!pdata && client->dev.of_node) { 309 r = st_nci_i2c_of_request_resources(client); 310 if (r) { 311 nfc_err(&client->dev, "No platform data\n"); 312 return r; 313 } 314 } else if (pdata) { 315 r = st_nci_i2c_request_resources(client); 316 if (r) { 317 nfc_err(&client->dev, 318 "Cannot get platform resources\n"); 319 return r; 320 } 321 } else { 322 nfc_err(&client->dev, 323 "st_nci platform resources not available\n"); 324 return -ENODEV; 325 } 326 327 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, 328 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 329 &phy->ndlc); 330 if (r < 0) { 331 nfc_err(&client->dev, "Unable to register ndlc layer\n"); 332 return r; 333 } 334 335 r = devm_request_threaded_irq(&client->dev, client->irq, NULL, 336 st_nci_irq_thread_fn, 337 phy->irq_polarity | IRQF_ONESHOT, 338 ST_NCI_DRIVER_NAME, phy); 339 if (r < 0) 340 nfc_err(&client->dev, "Unable to register IRQ handler\n"); 341 342 return r; 343 } 344 345 static int st_nci_i2c_remove(struct i2c_client *client) 346 { 347 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 348 349 dev_dbg(&client->dev, "%s\n", __func__); 350 351 ndlc_remove(phy->ndlc); 352 353 return 0; 354 } 355 356 #ifdef CONFIG_OF 357 static const struct of_device_id of_st_nci_i2c_match[] = { 358 { .compatible = "st,st21nfcb-i2c", }, 359 { .compatible = "st,st21nfcb_i2c", }, 360 { .compatible = "st,st21nfcc-i2c", }, 361 {} 362 }; 363 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match); 364 #endif 365 366 static struct i2c_driver st_nci_i2c_driver = { 367 .driver = { 368 .owner = THIS_MODULE, 369 .name = ST_NCI_I2C_DRIVER_NAME, 370 .of_match_table = of_match_ptr(of_st_nci_i2c_match), 371 }, 372 .probe = st_nci_i2c_probe, 373 .id_table = st_nci_i2c_id_table, 374 .remove = st_nci_i2c_remove, 375 }; 376 377 module_i2c_driver(st_nci_i2c_driver); 378 379 MODULE_LICENSE("GPL"); 380 MODULE_DESCRIPTION(DRIVER_DESC); 381