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 "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         struct gpio_desc *gpiod_reset;
 215         struct device *dev = &client->dev;
 216         u8 tmp;
 217
 218         /* Get RESET GPIO from ACPI */
 219         gpiod_reset = devm_gpiod_get_index(dev, ST_NCI_GPIO_NAME_RESET, 1,
 220                                            GPIOD_OUT_HIGH);
 221         if (IS_ERR(gpiod_reset)) {
 222                 nfc_err(dev, "Unable to get RESET GPIO\n");
 223                 return -ENODEV;
 224         }
 225
 226         phy->gpio_reset = desc_to_gpio(gpiod_reset);
 227
 228         phy->irq_polarity = irq_get_trigger_type(client->irq);
 229
 230         phy->se_status.is_ese_present = false;
 231         phy->se_status.is_uicc_present = false;
 232
 233         if (device_property_present(dev, "ese-present")) {
 234                 device_property_read_u8(dev, "ese-present", &tmp);
 235                 phy->se_status.is_ese_present = tmp;
 236         }
 237
 238         if (device_property_present(dev, "uicc-present")) {
 239                 device_property_read_u8(dev, "uicc-present", &tmp);
 240                 phy->se_status.is_uicc_present = tmp;
 241         }
 242
 243         return 0;
 244 }
 245
 246 static int st_nci_i2c_of_request_resources(struct i2c_client *client)
 247 {
 248         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 249         struct device_node *pp;
 250         int gpio;
 251         int r;
 252
 253         pp = client->dev.of_node;
 254         if (!pp)
 255                 return -ENODEV;
 256
 257         /* Get GPIO from device tree */
 258         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
 259         if (gpio < 0) {
 260                 nfc_err(&client->dev,
 261                         "Failed to retrieve reset-gpios from device tree\n");
 262                 return gpio;
 263         }
 264
 265         /* GPIO request and configuration */
 266         r = devm_gpio_request_one(&client->dev, gpio,
 267                                 GPIOF_OUT_INIT_HIGH, ST_NCI_GPIO_NAME_RESET);
 268         if (r) {
 269                 nfc_err(&client->dev, "Failed to request reset pin\n");
 270                 return r;
 271         }
 272         phy->gpio_reset = gpio;
 273
 274         phy->irq_polarity = irq_get_trigger_type(client->irq);
 275
 276         phy->se_status.is_ese_present =
 277                                 of_property_read_bool(pp, "ese-present");
 278         phy->se_status.is_uicc_present =
 279                                 of_property_read_bool(pp, "uicc-present");
 280
 281         return 0;
 282 }
 283
 284 static int st_nci_i2c_request_resources(struct i2c_client *client)
 285 {
 286         struct st_nci_nfc_platform_data *pdata;
 287         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 288         int r;
 289
 290         pdata = client->dev.platform_data;
 291         if (pdata == NULL) {
 292                 nfc_err(&client->dev, "No platform data\n");
 293                 return -EINVAL;
 294         }
 295
 296         /* store for later use */
 297         phy->gpio_reset = pdata->gpio_reset;
 298         phy->irq_polarity = pdata->irq_polarity;
 299
 300         r = devm_gpio_request_one(&client->dev,
 301                         phy->gpio_reset, GPIOF_OUT_INIT_HIGH,
 302                         ST_NCI_GPIO_NAME_RESET);
 303         if (r) {
 304                 pr_err("%s : reset gpio_request failed\n", __FILE__);
 305                 return r;
 306         }
 307
 308         phy->se_status.is_ese_present = pdata->is_ese_present;
 309         phy->se_status.is_uicc_present = pdata->is_uicc_present;
 310
 311         return 0;
 312 }
 313
 314 static int st_nci_i2c_probe(struct i2c_client *client,
 315                                   const struct i2c_device_id *id)
 316 {
 317         struct st_nci_i2c_phy *phy;
 318         struct st_nci_nfc_platform_data *pdata;
 319         int r;
 320
 321         dev_dbg(&client->dev, "%s\n", __func__);
 322         dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
 323
 324         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 325                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
 326                 return -ENODEV;
 327         }
 328
 329         phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy),
 330                            GFP_KERNEL);
 331         if (!phy)
 332                 return -ENOMEM;
 333
 334         phy->i2c_dev = client;
 335
 336         i2c_set_clientdata(client, phy);
 337
 338         pdata = client->dev.platform_data;
 339         if (!pdata && client->dev.of_node) {
 340                 r = st_nci_i2c_of_request_resources(client);
 341                 if (r) {
 342                         nfc_err(&client->dev, "No platform data\n");
 343                         return r;
 344                 }
 345         } else if (pdata) {
 346                 r = st_nci_i2c_request_resources(client);
 347                 if (r) {
 348                         nfc_err(&client->dev,
 349                                 "Cannot get platform resources\n");
 350                         return r;
 351                 }
 352         } else if (ACPI_HANDLE(&client->dev)) {
 353                 r = st_nci_i2c_acpi_request_resources(client);
 354                 if (r) {
 355                         nfc_err(&client->dev, "Cannot get ACPI data\n");
 356                         return r;
 357                 }
 358         } else {
 359                 nfc_err(&client->dev,
 360                         "st_nci platform resources not available\n");
 361                 return -ENODEV;
 362         }
 363
 364         r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
 365                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 366                         &phy->ndlc, &phy->se_status);
 367         if (r < 0) {
 368                 nfc_err(&client->dev, "Unable to register ndlc layer\n");
 369                 return r;
 370         }
 371
 372         phy->irq_active = true;
 373         r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 374                                 st_nci_irq_thread_fn,
 375                                 phy->irq_polarity | IRQF_ONESHOT,
 376                                 ST_NCI_DRIVER_NAME, phy);
 377         if (r < 0)
 378                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 379
 380         return r;
 381 }
 382
 383 static int st_nci_i2c_remove(struct i2c_client *client)
 384 {
 385         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 386
 387         dev_dbg(&client->dev, "%s\n", __func__);
 388
 389         ndlc_remove(phy->ndlc);
 390
 391         return 0;
 392 }
 393
 394 static struct i2c_device_id st_nci_i2c_id_table[] = {
 395         {ST_NCI_DRIVER_NAME, 0},
 396         {}
 397 };
 398 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
 399
 400 static const struct acpi_device_id st_nci_i2c_acpi_match[] = {
 401         {"SMO2101"},
 402         {"SMO2102"},
 403         {}
 404 };
 405 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
 406
 407 static const struct of_device_id of_st_nci_i2c_match[] = {
 408         { .compatible = "st,st21nfcb-i2c", },
 409         { .compatible = "st,st21nfcb_i2c", },
 410         { .compatible = "st,st21nfcc-i2c", },
 411         {}
 412 };
 413 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
 414
 415 static struct i2c_driver st_nci_i2c_driver = {
 416         .driver = {
 417                 .name = ST_NCI_I2C_DRIVER_NAME,
 418                 .of_match_table = of_match_ptr(of_st_nci_i2c_match),
 419                 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
 420         },
 421         .probe = st_nci_i2c_probe,
 422         .id_table = st_nci_i2c_id_table,
 423         .remove = st_nci_i2c_remove,
 424 };
 425 module_i2c_driver(st_nci_i2c_driver);
 426
 427 MODULE_LICENSE("GPL");
 428 MODULE_DESCRIPTION(DRIVER_DESC);