drivers/nfc/st-nci/i2c.c

   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/gpio/consumer.h>
  24 #include <linux/of_irq.h>
  25 #include <linux/of_gpio.h>
  26 #include <linux/acpi.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/delay.h>
  29 #include <linux/nfc.h>
  30 #include <linux/platform_data/st-nci.h>
  31
  32 #include "st-nci.h"
  33
  34 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
  35
  36 /* ndlc header */
  37 #define ST_NCI_FRAME_HEADROOM 1
  38 #define ST_NCI_FRAME_TAILROOM 0
  39
  40 #define ST_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  41 #define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
  42
  43 #define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
  44
  45 #define ST_NCI_GPIO_NAME_RESET "clf_reset"
  46
  47 struct st_nci_i2c_phy {
  48         struct i2c_client *i2c_dev;
  49         struct llt_ndlc *ndlc;
  50
  51         bool irq_active;
  52
  53         unsigned int gpio_reset;
  54         unsigned int irq_polarity;
  55
  56         struct st_nci_se_status se_status;
  57 };
  58
  59 static int st_nci_i2c_enable(void *phy_id)
  60 {
  61         struct st_nci_i2c_phy *phy = phy_id;
  62
  63         gpio_set_value(phy->gpio_reset, 0);
  64         usleep_range(10000, 15000);
  65         gpio_set_value(phy->gpio_reset, 1);
  66         usleep_range(80000, 85000);
  67
  68         if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  69                 enable_irq(phy->i2c_dev->irq);
  70                 phy->irq_active = true;
  71         }
  72
  73         return 0;
  74 }
  75
  76 static void st_nci_i2c_disable(void *phy_id)
  77 {
  78         struct st_nci_i2c_phy *phy = phy_id;
  79
  80         disable_irq_nosync(phy->i2c_dev->irq);
  81         phy->irq_active = false;
  82 }
  83
  84 /*
  85  * Writing a frame must not return the number of written bytes.
  86  * It must return either zero for success, or <0 for error.
  87  * In addition, it must not alter the skb
  88  */
  89 static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
  90 {
  91         int r = -1;
  92         struct st_nci_i2c_phy *phy = phy_id;
  93         struct i2c_client *client = phy->i2c_dev;
  94
  95         if (phy->ndlc->hard_fault != 0)
  96                 return phy->ndlc->hard_fault;
  97
  98         r = i2c_master_send(client, skb->data, skb->len);
  99         if (r < 0) {  /* Retry, chip was in standby */
 100                 usleep_range(1000, 4000);
 101                 r = i2c_master_send(client, skb->data, skb->len);
 102         }
 103
 104         if (r >= 0) {
 105                 if (r != skb->len)
 106                         r = -EREMOTEIO;
 107                 else
 108                         r = 0;
 109         }
 110
 111         return r;
 112 }
 113
 114 /*
 115  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 116  * returns:
 117  * 0 : if received frame is complete
 118  * -EREMOTEIO : i2c read error (fatal)
 119  * -EBADMSG : frame was incorrect and discarded
 120  * -ENOMEM : cannot allocate skb, frame dropped
 121  */
 122 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
 123                                  struct sk_buff **skb)
 124 {
 125         int r;
 126         u8 len;
 127         u8 buf[ST_NCI_I2C_MAX_SIZE];
 128         struct i2c_client *client = phy->i2c_dev;
 129
 130         r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
 131         if (r < 0) {  /* Retry, chip was in standby */
 132                 usleep_range(1000, 4000);
 133                 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
 134         }
 135
 136         if (r != ST_NCI_I2C_MIN_SIZE)
 137                 return -EREMOTEIO;
 138
 139         len = be16_to_cpu(*(__be16 *) (buf + 2));
 140         if (len > ST_NCI_I2C_MAX_SIZE) {
 141                 nfc_err(&client->dev, "invalid frame len\n");
 142                 return -EBADMSG;
 143         }
 144
 145         *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
 146         if (*skb == NULL)
 147                 return -ENOMEM;
 148
 149         skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
 150         skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
 151         memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
 152
 153         if (!len)
 154                 return 0;
 155
 156         r = i2c_master_recv(client, buf, len);
 157         if (r != len) {
 158                 kfree_skb(*skb);
 159                 return -EREMOTEIO;
 160         }
 161
 162         skb_put(*skb, len);
 163         memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
 164
 165         return 0;
 166 }
 167
 168 /*
 169  * Reads an ndlc frame from the chip.
 170  *
 171  * On ST_NCI, IRQ goes in idle state when read starts.
 172  */
 173 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 174 {
 175         struct st_nci_i2c_phy *phy = phy_id;
 176         struct i2c_client *client;
 177         struct sk_buff *skb = NULL;
 178         int r;
 179
 180         if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
 181                 WARN_ON_ONCE(1);
 182                 return IRQ_NONE;
 183         }
 184
 185         client = phy->i2c_dev;
 186         dev_dbg(&client->dev, "IRQ\n");
 187
 188         if (phy->ndlc->hard_fault)
 189                 return IRQ_HANDLED;
 190
 191         if (!phy->ndlc->powered) {
 192                 st_nci_i2c_disable(phy);
 193                 return IRQ_HANDLED;
 194         }
 195
 196         r = st_nci_i2c_read(phy, &skb);
 197         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 198                 return IRQ_HANDLED;
 199
 200         ndlc_recv(phy->ndlc, skb);
 201
 202         return IRQ_HANDLED;
 203 }
 204
 205 static struct nfc_phy_ops i2c_phy_ops = {
 206         .write = st_nci_i2c_write,
 207         .enable = st_nci_i2c_enable,
 208         .disable = st_nci_i2c_disable,
 209 };
 210
 211 static int st_nci_i2c_acpi_request_resources(struct i2c_client *client)
 212 {
 213         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 214         const struct acpi_device_id *id;
 215         struct gpio_desc *gpiod_reset;
 216         struct device *dev;
 217
 218         if (!client)
 219                 return -EINVAL;
 220
 221         dev = &client->dev;
 222
 223         /* Match the struct device against a given list of ACPI IDs */
 224         id = acpi_match_device(dev->driver->acpi_match_table, dev);
 225         if (!id)
 226                 return -ENODEV;
 227
 228         /* Get RESET GPIO from ACPI */
 229         gpiod_reset = devm_gpiod_get_index(dev, ST_NCI_GPIO_NAME_RESET, 1,
 230                                            GPIOD_OUT_HIGH);
 231         if (IS_ERR(gpiod_reset)) {
 232                 nfc_err(dev, "Unable to get RESET GPIO\n");
 233                 return -ENODEV;
 234         }
 235
 236         phy->gpio_reset = desc_to_gpio(gpiod_reset);
 237
 238         phy->irq_polarity = irq_get_trigger_type(client->irq);
 239
 240         phy->se_status.is_ese_present =
 241                                 device_property_present(dev, "ese-present");
 242         phy->se_status.is_uicc_present =
 243                                 device_property_present(dev, "uicc-present");
 244
 245         return 0;
 246 }
 247
 248 static int st_nci_i2c_of_request_resources(struct i2c_client *client)
 249 {
 250         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 251         struct device_node *pp;
 252         int gpio;
 253         int r;
 254
 255         pp = client->dev.of_node;
 256         if (!pp)
 257                 return -ENODEV;
 258
 259         /* Get GPIO from device tree */
 260         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
 261         if (gpio < 0) {
 262                 nfc_err(&client->dev,
 263                         "Failed to retrieve reset-gpios from device tree\n");
 264                 return gpio;
 265         }
 266
 267         /* GPIO request and configuration */
 268         r = devm_gpio_request_one(&client->dev, gpio,
 269                                 GPIOF_OUT_INIT_HIGH, ST_NCI_GPIO_NAME_RESET);
 270         if (r) {
 271                 nfc_err(&client->dev, "Failed to request reset pin\n");
 272                 return r;
 273         }
 274         phy->gpio_reset = gpio;
 275
 276         phy->irq_polarity = irq_get_trigger_type(client->irq);
 277
 278         phy->se_status.is_ese_present =
 279                                 of_property_read_bool(pp, "ese-present");
 280         phy->se_status.is_uicc_present =
 281                                 of_property_read_bool(pp, "uicc-present");
 282
 283         return 0;
 284 }
 285
 286 static int st_nci_i2c_request_resources(struct i2c_client *client)
 287 {
 288         struct st_nci_nfc_platform_data *pdata;
 289         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 290         int r;
 291
 292         pdata = client->dev.platform_data;
 293         if (pdata == NULL) {
 294                 nfc_err(&client->dev, "No platform data\n");
 295                 return -EINVAL;
 296         }
 297
 298         /* store for later use */
 299         phy->gpio_reset = pdata->gpio_reset;
 300         phy->irq_polarity = pdata->irq_polarity;
 301
 302         r = devm_gpio_request_one(&client->dev,
 303                         phy->gpio_reset, GPIOF_OUT_INIT_HIGH,
 304                         ST_NCI_GPIO_NAME_RESET);
 305         if (r) {
 306                 pr_err("%s : reset gpio_request failed\n", __FILE__);
 307                 return r;
 308         }
 309
 310         phy->se_status.is_ese_present = pdata->is_ese_present;
 311         phy->se_status.is_uicc_present = pdata->is_uicc_present;
 312
 313         return 0;
 314 }
 315
 316 static int st_nci_i2c_probe(struct i2c_client *client,
 317                                   const struct i2c_device_id *id)
 318 {
 319         struct st_nci_i2c_phy *phy;
 320         struct st_nci_nfc_platform_data *pdata;
 321         int r;
 322
 323         dev_dbg(&client->dev, "%s\n", __func__);
 324         dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
 325
 326         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 327                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
 328                 return -ENODEV;
 329         }
 330
 331         phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy),
 332                            GFP_KERNEL);
 333         if (!phy)
 334                 return -ENOMEM;
 335
 336         phy->i2c_dev = client;
 337
 338         i2c_set_clientdata(client, phy);
 339
 340         pdata = client->dev.platform_data;
 341         if (!pdata && client->dev.of_node) {
 342                 r = st_nci_i2c_of_request_resources(client);
 343                 if (r) {
 344                         nfc_err(&client->dev, "No platform data\n");
 345                         return r;
 346                 }
 347         } else if (pdata) {
 348                 r = st_nci_i2c_request_resources(client);
 349                 if (r) {
 350                         nfc_err(&client->dev,
 351                                 "Cannot get platform resources\n");
 352                         return r;
 353                 }
 354         } else if (ACPI_HANDLE(&client->dev)) {
 355                 r = st_nci_i2c_acpi_request_resources(client);
 356                 if (r) {
 357                         nfc_err(&client->dev, "Cannot get ACPI data\n");
 358                         return r;
 359                 }
 360         } else {
 361                 nfc_err(&client->dev,
 362                         "st_nci platform resources not available\n");
 363                 return -ENODEV;
 364         }
 365
 366         r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
 367                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 368                         &phy->ndlc, &phy->se_status);
 369         if (r < 0) {
 370                 nfc_err(&client->dev, "Unable to register ndlc layer\n");
 371                 return r;
 372         }
 373
 374         phy->irq_active = true;
 375         r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 376                                 st_nci_irq_thread_fn,
 377                                 phy->irq_polarity | IRQF_ONESHOT,
 378                                 ST_NCI_DRIVER_NAME, phy);
 379         if (r < 0)
 380                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 381
 382         return r;
 383 }
 384
 385 static int st_nci_i2c_remove(struct i2c_client *client)
 386 {
 387         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 388
 389         dev_dbg(&client->dev, "%s\n", __func__);
 390
 391         ndlc_remove(phy->ndlc);
 392
 393         return 0;
 394 }
 395
 396 static struct i2c_device_id st_nci_i2c_id_table[] = {
 397         {ST_NCI_DRIVER_NAME, 0},
 398         {}
 399 };
 400 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
 401
 402 static const struct acpi_device_id st_nci_i2c_acpi_match[] = {
 403         {"SMO2101"},
 404         {"SMO2102"},
 405         {}
 406 };
 407 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
 408
 409 static const struct of_device_id of_st_nci_i2c_match[] = {
 410         { .compatible = "st,st21nfcb-i2c", },
 411         { .compatible = "st,st21nfcb_i2c", },
 412         { .compatible = "st,st21nfcc-i2c", },
 413         {}
 414 };
 415 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
 416
 417 static struct i2c_driver st_nci_i2c_driver = {
 418         .driver = {
 419                 .owner = THIS_MODULE,
 420                 .name = ST_NCI_I2C_DRIVER_NAME,
 421                 .of_match_table = of_match_ptr(of_st_nci_i2c_match),
 422                 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
 423         },
 424         .probe = st_nci_i2c_probe,
 425         .id_table = st_nci_i2c_id_table,
 426         .remove = st_nci_i2c_remove,
 427 };
 428 module_i2c_driver(st_nci_i2c_driver);
 429
 430 MODULE_LICENSE("GPL");
 431 MODULE_DESCRIPTION(DRIVER_DESC);