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 ST21NFCB" 33 34 /* ndlc header */ 35 #define ST21NFCB_FRAME_HEADROOM 1 36 #define ST21NFCB_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 * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at 122 * end of read) 123 * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF 124 * at end of read) 125 * -EREMOTEIO : i2c read error (fatal) 126 * -EBADMSG : frame was incorrect and discarded 127 * (value returned from st_nci_i2c_repack) 128 * -EIO : if no ST21NFCB_SOF_EOF is found after reaching 129 * the read length end sequence 130 */ 131 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy, 132 struct sk_buff **skb) 133 { 134 int r; 135 u8 len; 136 u8 buf[ST_NCI_I2C_MAX_SIZE]; 137 struct i2c_client *client = phy->i2c_dev; 138 139 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 140 if (r < 0) { /* Retry, chip was in standby */ 141 usleep_range(1000, 4000); 142 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE); 143 } 144 145 if (r != ST_NCI_I2C_MIN_SIZE) 146 return -EREMOTEIO; 147 148 len = be16_to_cpu(*(__be16 *) (buf + 2)); 149 if (len > ST_NCI_I2C_MAX_SIZE) { 150 nfc_err(&client->dev, "invalid frame len\n"); 151 return -EBADMSG; 152 } 153 154 *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL); 155 if (*skb == NULL) 156 return -ENOMEM; 157 158 skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE); 159 skb_put(*skb, ST_NCI_I2C_MIN_SIZE); 160 memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE); 161 162 if (!len) 163 return 0; 164 165 r = i2c_master_recv(client, buf, len); 166 if (r != len) { 167 kfree_skb(*skb); 168 return -EREMOTEIO; 169 } 170 171 skb_put(*skb, len); 172 memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len); 173 174 I2C_DUMP_SKB("i2c frame read", *skb); 175 176 return 0; 177 } 178 179 /* 180 * Reads an ndlc frame from the chip. 181 * 182 * On ST21NFCB, IRQ goes in idle state when read starts. 183 */ 184 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 185 { 186 struct st_nci_i2c_phy *phy = phy_id; 187 struct i2c_client *client; 188 struct sk_buff *skb = NULL; 189 int r; 190 191 if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) { 192 WARN_ON_ONCE(1); 193 return IRQ_NONE; 194 } 195 196 client = phy->i2c_dev; 197 dev_dbg(&client->dev, "IRQ\n"); 198 199 if (phy->ndlc->hard_fault) 200 return IRQ_HANDLED; 201 202 if (!phy->ndlc->powered) { 203 st_nci_i2c_disable(phy); 204 return IRQ_HANDLED; 205 } 206 207 r = st_nci_i2c_read(phy, &skb); 208 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 209 return IRQ_HANDLED; 210 211 ndlc_recv(phy->ndlc, skb); 212 213 return IRQ_HANDLED; 214 } 215 216 static struct nfc_phy_ops i2c_phy_ops = { 217 .write = st_nci_i2c_write, 218 .enable = st_nci_i2c_enable, 219 .disable = st_nci_i2c_disable, 220 }; 221 222 #ifdef CONFIG_OF 223 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 224 { 225 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 226 struct device_node *pp; 227 int gpio; 228 int r; 229 230 pp = client->dev.of_node; 231 if (!pp) 232 return -ENODEV; 233 234 /* Get GPIO from device tree */ 235 gpio = of_get_named_gpio(pp, "reset-gpios", 0); 236 if (gpio < 0) { 237 nfc_err(&client->dev, 238 "Failed to retrieve reset-gpios from device tree\n"); 239 return gpio; 240 } 241 242 /* GPIO request and configuration */ 243 r = devm_gpio_request_one(&client->dev, gpio, 244 GPIOF_OUT_INIT_HIGH, "clf_reset"); 245 if (r) { 246 nfc_err(&client->dev, "Failed to request reset pin\n"); 247 return r; 248 } 249 phy->gpio_reset = gpio; 250 251 phy->irq_polarity = irq_get_trigger_type(client->irq); 252 253 return 0; 254 } 255 #else 256 static int st_nci_i2c_of_request_resources(struct i2c_client *client) 257 { 258 return -ENODEV; 259 } 260 #endif 261 262 static int st_nci_i2c_request_resources(struct i2c_client *client) 263 { 264 struct st_nci_nfc_platform_data *pdata; 265 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 266 int r; 267 268 pdata = client->dev.platform_data; 269 if (pdata == NULL) { 270 nfc_err(&client->dev, "No platform data\n"); 271 return -EINVAL; 272 } 273 274 /* store for later use */ 275 phy->gpio_reset = pdata->gpio_reset; 276 phy->irq_polarity = pdata->irq_polarity; 277 278 r = devm_gpio_request_one(&client->dev, 279 phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset"); 280 if (r) { 281 pr_err("%s : reset gpio_request failed\n", __FILE__); 282 return r; 283 } 284 285 return 0; 286 } 287 288 static int st_nci_i2c_probe(struct i2c_client *client, 289 const struct i2c_device_id *id) 290 { 291 struct st_nci_i2c_phy *phy; 292 struct st_nci_nfc_platform_data *pdata; 293 int r; 294 295 dev_dbg(&client->dev, "%s\n", __func__); 296 dev_dbg(&client->dev, "IRQ: %d\n", client->irq); 297 298 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 299 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n"); 300 return -ENODEV; 301 } 302 303 phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy), 304 GFP_KERNEL); 305 if (!phy) 306 return -ENOMEM; 307 308 phy->i2c_dev = client; 309 310 i2c_set_clientdata(client, phy); 311 312 pdata = client->dev.platform_data; 313 if (!pdata && client->dev.of_node) { 314 r = st_nci_i2c_of_request_resources(client); 315 if (r) { 316 nfc_err(&client->dev, "No platform data\n"); 317 return r; 318 } 319 } else if (pdata) { 320 r = st_nci_i2c_request_resources(client); 321 if (r) { 322 nfc_err(&client->dev, 323 "Cannot get platform resources\n"); 324 return r; 325 } 326 } else { 327 nfc_err(&client->dev, 328 "st21nfcb platform resources not available\n"); 329 return -ENODEV; 330 } 331 332 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, 333 ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM, 334 &phy->ndlc); 335 if (r < 0) { 336 nfc_err(&client->dev, "Unable to register ndlc layer\n"); 337 return r; 338 } 339 340 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