drivers/nfc/st21nfcb/i2c.c

   1 /*
   2  * I2C Link Layer for ST21NFCB NCI based Driver
   3  * Copyright (C) 2014  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/crc-ccitt.h>
  21 #include <linux/module.h>
  22 #include <linux/i2c.h>
  23 #include <linux/gpio.h>
  24 #include <linux/of_irq.h>
  25 #include <linux/of_gpio.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/delay.h>
  29 #include <linux/nfc.h>
  30 #include <linux/firmware.h>
  31 #include <linux/unaligned/access_ok.h>
  32 #include <linux/platform_data/st21nfcb.h>
  33
  34 #include <net/nfc/nci.h>
  35 #include <net/nfc/llc.h>
  36 #include <net/nfc/nfc.h>
  37
  38 #include "ndlc.h"
  39
  40 #define DRIVER_DESC "NCI NFC driver for ST21NFCB"
  41
  42 /* ndlc header */
  43 #define ST21NFCB_FRAME_HEADROOM 1
  44 #define ST21NFCB_FRAME_TAILROOM 0
  45
  46 #define ST21NFCB_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  47 #define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
  48
  49 #define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
  50
  51 static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
  52         {ST21NFCB_NCI_DRIVER_NAME, 0},
  53         {}
  54 };
  55 MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
  56
  57 struct st21nfcb_i2c_phy {
  58         struct i2c_client *i2c_dev;
  59         struct llt_ndlc *ndlc;
  60
  61         unsigned int gpio_irq;
  62         unsigned int gpio_reset;
  63         unsigned int irq_polarity;
  64
  65         int powered;
  66
  67         /*
  68          * < 0 if hardware error occured (e.g. i2c err)
  69          * and prevents normal operation.
  70          */
  71         int hard_fault;
  72 };
  73
  74 #define I2C_DUMP_SKB(info, skb)                                 \
  75 do {                                                            \
  76         pr_debug("%s:\n", info);                                \
  77         print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
  78                        16, 1, (skb)->data, (skb)->len, 0);      \
  79 } while (0)
  80
  81 static int st21nfcb_nci_i2c_enable(void *phy_id)
  82 {
  83         struct st21nfcb_i2c_phy *phy = phy_id;
  84
  85         gpio_set_value(phy->gpio_reset, 0);
  86         usleep_range(10000, 15000);
  87         gpio_set_value(phy->gpio_reset, 1);
  88         phy->powered = 1;
  89         usleep_range(80000, 85000);
  90
  91         return 0;
  92 }
  93
  94 static void st21nfcb_nci_i2c_disable(void *phy_id)
  95 {
  96         struct st21nfcb_i2c_phy *phy = phy_id;
  97
  98         pr_info("\n");
  99
 100         phy->powered = 0;
 101         /* reset chip in order to flush clf */
 102         gpio_set_value(phy->gpio_reset, 0);
 103         usleep_range(10000, 15000);
 104         gpio_set_value(phy->gpio_reset, 1);
 105 }
 106
 107 static void st21nfcb_nci_remove_header(struct sk_buff *skb)
 108 {
 109         skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
 110 }
 111
 112 /*
 113  * Writing a frame must not return the number of written bytes.
 114  * It must return either zero for success, or <0 for error.
 115  * In addition, it must not alter the skb
 116  */
 117 static int st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
 118 {
 119         int r = -1;
 120         struct st21nfcb_i2c_phy *phy = phy_id;
 121         struct i2c_client *client = phy->i2c_dev;
 122
 123         I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
 124
 125         if (phy->hard_fault != 0)
 126                 return phy->hard_fault;
 127
 128         r = i2c_master_send(client, skb->data, skb->len);
 129         if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
 130                 usleep_range(1000, 4000);
 131                 r = i2c_master_send(client, skb->data, skb->len);
 132         }
 133
 134         if (r >= 0) {
 135                 if (r != skb->len)
 136                         r = -EREMOTEIO;
 137                 else
 138                         r = 0;
 139         }
 140
 141         st21nfcb_nci_remove_header(skb);
 142
 143         return r;
 144 }
 145
 146 /*
 147  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 148  * returns:
 149  * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
 150  * end of read)
 151  * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
 152  * at end of read)
 153  * -EREMOTEIO : i2c read error (fatal)
 154  * -EBADMSG : frame was incorrect and discarded
 155  * (value returned from st21nfcb_nci_i2c_repack)
 156  * -EIO : if no ST21NFCB_SOF_EOF is found after reaching
 157  * the read length end sequence
 158  */
 159 static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
 160                                  struct sk_buff **skb)
 161 {
 162         int r;
 163         u8 len;
 164         u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
 165         struct i2c_client *client = phy->i2c_dev;
 166
 167         r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
 168         if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
 169                 usleep_range(1000, 4000);
 170                 r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
 171         } else if (r != ST21NFCB_NCI_I2C_MIN_SIZE) {
 172                 nfc_err(&client->dev, "cannot read ndlc & nci header\n");
 173                 return -EREMOTEIO;
 174         }
 175
 176         len = be16_to_cpu(*(__be16 *) (buf + 2));
 177         if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
 178                 nfc_err(&client->dev, "invalid frame len\n");
 179                 return -EBADMSG;
 180         }
 181
 182         *skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
 183         if (*skb == NULL)
 184                 return -ENOMEM;
 185
 186         skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
 187         skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
 188         memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
 189
 190         if (!len)
 191                 return 0;
 192
 193         r = i2c_master_recv(client, buf, len);
 194         if (r != len) {
 195                 kfree_skb(*skb);
 196                 return -EREMOTEIO;
 197         }
 198
 199         skb_put(*skb, len);
 200         memcpy((*skb)->data + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
 201
 202         I2C_DUMP_SKB("i2c frame read", *skb);
 203
 204         return 0;
 205 }
 206
 207 /*
 208  * Reads an ndlc frame from the chip.
 209  *
 210  * On ST21NFCB, IRQ goes in idle state when read starts.
 211  */
 212 static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
 213 {
 214         struct st21nfcb_i2c_phy *phy = phy_id;
 215         struct i2c_client *client;
 216         struct sk_buff *skb = NULL;
 217         int r;
 218
 219         if (!phy || irq != phy->i2c_dev->irq) {
 220                 WARN_ON_ONCE(1);
 221                 return IRQ_NONE;
 222         }
 223
 224         client = phy->i2c_dev;
 225         dev_dbg(&client->dev, "IRQ\n");
 226
 227         if (phy->hard_fault)
 228                 return IRQ_HANDLED;
 229
 230         if (!phy->powered) {
 231                 st21nfcb_nci_i2c_disable(phy);
 232                 return IRQ_HANDLED;
 233         }
 234
 235         r = st21nfcb_nci_i2c_read(phy, &skb);
 236         if (r == -EREMOTEIO) {
 237                 phy->hard_fault = r;
 238                 ndlc_recv(phy->ndlc, NULL);
 239                 return IRQ_HANDLED;
 240         } else if (r == -ENOMEM || r == -EBADMSG) {
 241                 return IRQ_HANDLED;
 242         }
 243
 244         ndlc_recv(phy->ndlc, skb);
 245
 246         return IRQ_HANDLED;
 247 }
 248
 249 static struct nfc_phy_ops i2c_phy_ops = {
 250         .write = st21nfcb_nci_i2c_write,
 251         .enable = st21nfcb_nci_i2c_enable,
 252         .disable = st21nfcb_nci_i2c_disable,
 253 };
 254
 255 #ifdef CONFIG_OF
 256 static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
 257 {
 258         struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
 259         struct device_node *pp;
 260         int gpio;
 261         int r;
 262
 263         pp = client->dev.of_node;
 264         if (!pp)
 265                 return -ENODEV;
 266
 267         /* Get GPIO from device tree */
 268         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
 269         if (gpio < 0) {
 270                 nfc_err(&client->dev,
 271                         "Failed to retrieve reset-gpios from device tree\n");
 272                 return gpio;
 273         }
 274
 275         /* GPIO request and configuration */
 276         r = devm_gpio_request(&client->dev, gpio, "clf_reset");
 277         if (r) {
 278                 nfc_err(&client->dev, "Failed to request reset pin\n");
 279                 return -ENODEV;
 280         }
 281
 282         r = gpio_direction_output(gpio, 1);
 283         if (r) {
 284                 nfc_err(&client->dev,
 285                         "Failed to set reset pin direction as output\n");
 286                 return -ENODEV;
 287         }
 288         phy->gpio_reset = gpio;
 289
 290         /* IRQ */
 291         r = irq_of_parse_and_map(pp, 0);
 292         if (r < 0) {
 293                 nfc_err(&client->dev,
 294                                 "Unable to get irq, error: %d\n", r);
 295                 return r;
 296         }
 297
 298         phy->irq_polarity = irq_get_trigger_type(r);
 299         client->irq = r;
 300
 301         return 0;
 302 }
 303 #else
 304 static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
 305 {
 306         return -ENODEV;
 307 }
 308 #endif
 309
 310 static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
 311 {
 312         struct st21nfcb_nfc_platform_data *pdata;
 313         struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
 314         int r;
 315         int irq;
 316
 317         pdata = client->dev.platform_data;
 318         if (pdata == NULL) {
 319                 nfc_err(&client->dev, "No platform data\n");
 320                 return -EINVAL;
 321         }
 322
 323         /* store for later use */
 324         phy->gpio_irq = pdata->gpio_irq;
 325         phy->gpio_reset = pdata->gpio_reset;
 326         phy->irq_polarity = pdata->irq_polarity;
 327
 328         r = devm_gpio_request(&client->dev, phy->gpio_irq, "wake_up");
 329         if (r) {
 330                 pr_err("%s : gpio_request failed\n", __FILE__);
 331                 return -ENODEV;
 332         }
 333
 334         r = gpio_direction_input(phy->gpio_irq);
 335         if (r) {
 336                 pr_err("%s : gpio_direction_input failed\n", __FILE__);
 337                 return -ENODEV;
 338         }
 339
 340         r = devm_gpio_request(&client->dev,
 341                               phy->gpio_reset, "clf_reset");
 342         if (r) {
 343                 pr_err("%s : reset gpio_request failed\n", __FILE__);
 344                 return -ENODEV;
 345         }
 346
 347         r = gpio_direction_output(phy->gpio_reset, 1);
 348         if (r) {
 349                 pr_err("%s : reset gpio_direction_output failed\n",
 350                         __FILE__);
 351                 return -ENODEV;
 352         }
 353
 354         /* IRQ */
 355         irq = gpio_to_irq(phy->gpio_irq);
 356         if (irq < 0) {
 357                 nfc_err(&client->dev,
 358                         "Unable to get irq number for GPIO %d error %d\n",
 359                         phy->gpio_irq, r);
 360                 return -ENODEV;
 361         }
 362         client->irq = irq;
 363
 364         return 0;
 365 }
 366
 367 static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
 368                                   const struct i2c_device_id *id)
 369 {
 370         struct st21nfcb_i2c_phy *phy;
 371         struct st21nfcb_nfc_platform_data *pdata;
 372         int r;
 373
 374         dev_dbg(&client->dev, "%s\n", __func__);
 375         dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
 376
 377         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 378                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
 379                 return -ENODEV;
 380         }
 381
 382         phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
 383                            GFP_KERNEL);
 384         if (!phy) {
 385                 nfc_err(&client->dev,
 386                         "Cannot allocate memory for st21nfcb i2c phy.\n");
 387                 return -ENOMEM;
 388         }
 389
 390         phy->i2c_dev = client;
 391
 392         i2c_set_clientdata(client, phy);
 393
 394         pdata = client->dev.platform_data;
 395         if (!pdata && client->dev.of_node) {
 396                 r = st21nfcb_nci_i2c_of_request_resources(client);
 397                 if (r) {
 398                         nfc_err(&client->dev, "No platform data\n");
 399                         return r;
 400                 }
 401         } else if (pdata) {
 402                 r = st21nfcb_nci_i2c_request_resources(client);
 403                 if (r) {
 404                         nfc_err(&client->dev,
 405                                 "Cannot get platform resources\n");
 406                         return r;
 407                 }
 408         } else {
 409                 nfc_err(&client->dev,
 410                         "st21nfcb platform resources not available\n");
 411                 return -ENODEV;
 412         }
 413
 414         r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 415                                 st21nfcb_nci_irq_thread_fn,
 416                                 phy->irq_polarity | IRQF_ONESHOT,
 417                                 ST21NFCB_NCI_DRIVER_NAME, phy);
 418         if (r < 0) {
 419                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 420                 return r;
 421         }
 422
 423         return ndlc_probe(phy, &i2c_phy_ops, &client->dev,
 424                         ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
 425                         &phy->ndlc);
 426 }
 427
 428 static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
 429 {
 430         struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
 431
 432         dev_dbg(&client->dev, "%s\n", __func__);
 433
 434         ndlc_remove(phy->ndlc);
 435
 436         if (phy->powered)
 437                 st21nfcb_nci_i2c_disable(phy);
 438
 439         return 0;
 440 }
 441
 442 static const struct of_device_id of_st21nfcb_i2c_match[] = {
 443         { .compatible = "st,st21nfcb_i2c", },
 444         {}
 445 };
 446
 447 static struct i2c_driver st21nfcb_nci_i2c_driver = {
 448         .driver = {
 449                 .owner = THIS_MODULE,
 450                 .name = ST21NFCB_NCI_I2C_DRIVER_NAME,
 451                 .owner = THIS_MODULE,
 452                 .of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
 453         },
 454         .probe = st21nfcb_nci_i2c_probe,
 455         .id_table = st21nfcb_nci_i2c_id_table,
 456         .remove = st21nfcb_nci_i2c_remove,
 457 };
 458
 459 module_i2c_driver(st21nfcb_nci_i2c_driver);
 460
 461 MODULE_LICENSE("GPL");
 462 MODULE_DESCRIPTION(DRIVER_DESC);