drivers/nfc/st-nci/spi.c

   1 /*
   2  * SPI Link Layer for ST NCI 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/spi/spi.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 <net/nfc/nci.h>
  31 #include <linux/platform_data/st-nci.h>
  32
  33 #include "st-nci.h"
  34
  35 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
  36
  37 /* ndlc header */
  38 #define ST_NCI_FRAME_HEADROOM   1
  39 #define ST_NCI_FRAME_TAILROOM   0
  40
  41 #define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  42 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
  43
  44 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
  45
  46 #define ST_NCI_GPIO_NAME_RESET "reset"
  47
  48 struct st_nci_spi_phy {
  49         struct spi_device *spi_dev;
  50         struct llt_ndlc *ndlc;
  51
  52         bool irq_active;
  53
  54         unsigned int gpio_reset;
  55         unsigned int irq_polarity;
  56
  57         struct st_nci_se_status se_status;
  58 };
  59
  60 static int st_nci_spi_enable(void *phy_id)
  61 {
  62         struct st_nci_spi_phy *phy = phy_id;
  63
  64         gpio_set_value(phy->gpio_reset, 0);
  65         usleep_range(10000, 15000);
  66         gpio_set_value(phy->gpio_reset, 1);
  67         usleep_range(80000, 85000);
  68
  69         if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  70                 enable_irq(phy->spi_dev->irq);
  71                 phy->irq_active = true;
  72         }
  73
  74         return 0;
  75 }
  76
  77 static void st_nci_spi_disable(void *phy_id)
  78 {
  79         struct st_nci_spi_phy *phy = phy_id;
  80
  81         disable_irq_nosync(phy->spi_dev->irq);
  82         phy->irq_active = false;
  83 }
  84
  85 /*
  86  * Writing a frame must not return the number of written bytes.
  87  * It must return either zero for success, or <0 for error.
  88  * In addition, it must not alter the skb
  89  */
  90 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
  91 {
  92         int r;
  93         struct st_nci_spi_phy *phy = phy_id;
  94         struct spi_device *dev = phy->spi_dev;
  95         struct sk_buff *skb_rx;
  96         u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
  97                ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
  98         struct spi_transfer spi_xfer = {
  99                 .tx_buf = skb->data,
 100                 .rx_buf = buf,
 101                 .len = skb->len,
 102         };
 103
 104         if (phy->ndlc->hard_fault != 0)
 105                 return phy->ndlc->hard_fault;
 106
 107         r = spi_sync_transfer(dev, &spi_xfer, 1);
 108         /*
 109          * We may have received some valuable data on miso line.
 110          * Send them back in the ndlc state machine.
 111          */
 112         if (!r) {
 113                 skb_rx = alloc_skb(skb->len, GFP_KERNEL);
 114                 if (!skb_rx) {
 115                         r = -ENOMEM;
 116                         goto exit;
 117                 }
 118
 119                 skb_put(skb_rx, skb->len);
 120                 memcpy(skb_rx->data, buf, skb->len);
 121                 ndlc_recv(phy->ndlc, skb_rx);
 122         }
 123
 124 exit:
 125         return r;
 126 }
 127
 128 /*
 129  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 130  * returns:
 131  * 0 : if received frame is complete
 132  * -EREMOTEIO : i2c read error (fatal)
 133  * -EBADMSG : frame was incorrect and discarded
 134  * -ENOMEM : cannot allocate skb, frame dropped
 135  */
 136 static int st_nci_spi_read(struct st_nci_spi_phy *phy,
 137                         struct sk_buff **skb)
 138 {
 139         int r;
 140         u8 len;
 141         u8 buf[ST_NCI_SPI_MAX_SIZE];
 142         struct spi_device *dev = phy->spi_dev;
 143         struct spi_transfer spi_xfer = {
 144                 .rx_buf = buf,
 145                 .len = ST_NCI_SPI_MIN_SIZE,
 146         };
 147
 148         r = spi_sync_transfer(dev, &spi_xfer, 1);
 149         if (r < 0)
 150                 return -EREMOTEIO;
 151
 152         len = be16_to_cpu(*(__be16 *) (buf + 2));
 153         if (len > ST_NCI_SPI_MAX_SIZE) {
 154                 nfc_err(&dev->dev, "invalid frame len\n");
 155                 phy->ndlc->hard_fault = 1;
 156                 return -EBADMSG;
 157         }
 158
 159         *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
 160         if (*skb == NULL)
 161                 return -ENOMEM;
 162
 163         skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
 164         skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
 165         memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
 166
 167         if (!len)
 168                 return 0;
 169
 170         spi_xfer.len = len;
 171         r = spi_sync_transfer(dev, &spi_xfer, 1);
 172         if (r < 0) {
 173                 kfree_skb(*skb);
 174                 return -EREMOTEIO;
 175         }
 176
 177         skb_put(*skb, len);
 178         memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * Reads an ndlc frame from the chip.
 185  *
 186  * On ST21NFCB, IRQ goes in idle state when read starts.
 187  */
 188 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 189 {
 190         struct st_nci_spi_phy *phy = phy_id;
 191         struct spi_device *dev;
 192         struct sk_buff *skb = NULL;
 193         int r;
 194
 195         if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
 196                 WARN_ON_ONCE(1);
 197                 return IRQ_NONE;
 198         }
 199
 200         dev = phy->spi_dev;
 201         dev_dbg(&dev->dev, "IRQ\n");
 202
 203         if (phy->ndlc->hard_fault)
 204                 return IRQ_HANDLED;
 205
 206         if (!phy->ndlc->powered) {
 207                 st_nci_spi_disable(phy);
 208                 return IRQ_HANDLED;
 209         }
 210
 211         r = st_nci_spi_read(phy, &skb);
 212         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 213                 return IRQ_HANDLED;
 214
 215         ndlc_recv(phy->ndlc, skb);
 216
 217         return IRQ_HANDLED;
 218 }
 219
 220 static struct nfc_phy_ops spi_phy_ops = {
 221         .write = st_nci_spi_write,
 222         .enable = st_nci_spi_enable,
 223         .disable = st_nci_spi_disable,
 224 };
 225
 226 static int st_nci_spi_acpi_request_resources(struct spi_device *spi_dev)
 227 {
 228         struct st_nci_spi_phy *phy = spi_get_drvdata(spi_dev);
 229         struct gpio_desc *gpiod_reset;
 230         struct device *dev = &spi_dev->dev;
 231         u8 tmp;
 232
 233         /* Get RESET GPIO from ACPI */
 234         gpiod_reset = devm_gpiod_get_index(dev, ST_NCI_GPIO_NAME_RESET, 1,
 235                                            GPIOD_OUT_HIGH);
 236         if (IS_ERR(gpiod_reset)) {
 237                 nfc_err(dev, "Unable to get RESET GPIO\n");
 238                 return -ENODEV;
 239         }
 240
 241         phy->gpio_reset = desc_to_gpio(gpiod_reset);
 242
 243         phy->irq_polarity = irq_get_trigger_type(spi_dev->irq);
 244
 245         phy->se_status.is_ese_present = false;
 246         phy->se_status.is_uicc_present = false;
 247
 248         if (device_property_present(dev, "ese-present")) {
 249                 device_property_read_u8(dev, "ese-present", &tmp);
 250                 tmp = phy->se_status.is_ese_present;
 251         }
 252
 253         if (device_property_present(dev, "uicc-present")) {
 254                 device_property_read_u8(dev, "uicc-present", &tmp);
 255                 tmp = phy->se_status.is_uicc_present;
 256         }
 257
 258         return 0;
 259 }
 260
 261 static int st_nci_spi_of_request_resources(struct spi_device *dev)
 262 {
 263         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 264         struct device_node *pp;
 265         int gpio;
 266         int r;
 267
 268         pp = dev->dev.of_node;
 269         if (!pp)
 270                 return -ENODEV;
 271
 272         /* Get GPIO from device tree */
 273         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
 274         if (gpio < 0) {
 275                 nfc_err(&dev->dev,
 276                         "Failed to retrieve reset-gpios from device tree\n");
 277                 return gpio;
 278         }
 279
 280         /* GPIO request and configuration */
 281         r = devm_gpio_request_one(&dev->dev, gpio,
 282                                 GPIOF_OUT_INIT_HIGH, ST_NCI_GPIO_NAME_RESET);
 283         if (r) {
 284                 nfc_err(&dev->dev, "Failed to request reset pin\n");
 285                 return r;
 286         }
 287         phy->gpio_reset = gpio;
 288
 289         phy->irq_polarity = irq_get_trigger_type(dev->irq);
 290
 291         phy->se_status.is_ese_present =
 292                                 of_property_read_bool(pp, "ese-present");
 293         phy->se_status.is_uicc_present =
 294                                 of_property_read_bool(pp, "uicc-present");
 295
 296         return 0;
 297 }
 298
 299 static int st_nci_spi_request_resources(struct spi_device *dev)
 300 {
 301         struct st_nci_nfc_platform_data *pdata;
 302         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 303         int r;
 304
 305         pdata = dev->dev.platform_data;
 306         if (pdata == NULL) {
 307                 nfc_err(&dev->dev, "No platform data\n");
 308                 return -EINVAL;
 309         }
 310
 311         /* store for later use */
 312         phy->gpio_reset = pdata->gpio_reset;
 313         phy->irq_polarity = pdata->irq_polarity;
 314
 315         r = devm_gpio_request_one(&dev->dev,
 316                         phy->gpio_reset, GPIOF_OUT_INIT_HIGH,
 317                         ST_NCI_GPIO_NAME_RESET);
 318         if (r) {
 319                 pr_err("%s : reset gpio_request failed\n", __FILE__);
 320                 return r;
 321         }
 322
 323         phy->se_status.is_ese_present = pdata->is_ese_present;
 324         phy->se_status.is_uicc_present = pdata->is_uicc_present;
 325
 326         return 0;
 327 }
 328
 329 static int st_nci_spi_probe(struct spi_device *dev)
 330 {
 331         struct st_nci_spi_phy *phy;
 332         struct st_nci_nfc_platform_data *pdata;
 333         int r;
 334
 335         dev_dbg(&dev->dev, "%s\n", __func__);
 336         dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
 337
 338         /* Check SPI platform functionnalities */
 339         if (!dev) {
 340                 pr_debug("%s: dev is NULL. Device is not accessible.\n",
 341                         __func__);
 342                 return -ENODEV;
 343         }
 344
 345         phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
 346                            GFP_KERNEL);
 347         if (!phy)
 348                 return -ENOMEM;
 349
 350         phy->spi_dev = dev;
 351
 352         spi_set_drvdata(dev, phy);
 353
 354         pdata = dev->dev.platform_data;
 355         if (!pdata && dev->dev.of_node) {
 356                 r = st_nci_spi_of_request_resources(dev);
 357                 if (r) {
 358                         nfc_err(&dev->dev, "No platform data\n");
 359                         return r;
 360                 }
 361         } else if (pdata) {
 362                 r = st_nci_spi_request_resources(dev);
 363                 if (r) {
 364                         nfc_err(&dev->dev,
 365                                 "Cannot get platform resources\n");
 366                         return r;
 367                 }
 368         } else if (ACPI_HANDLE(&dev->dev)) {
 369                 r = st_nci_spi_acpi_request_resources(dev);
 370                 if (r) {
 371                         nfc_err(&dev->dev, "Cannot get ACPI data\n");
 372                         return r;
 373                 }
 374         } else {
 375                 nfc_err(&dev->dev,
 376                         "st_nci platform resources not available\n");
 377                 return -ENODEV;
 378         }
 379
 380         r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
 381                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 382                         &phy->ndlc, &phy->se_status);
 383         if (r < 0) {
 384                 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
 385                 return r;
 386         }
 387
 388         phy->irq_active = true;
 389         r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
 390                                 st_nci_irq_thread_fn,
 391                                 phy->irq_polarity | IRQF_ONESHOT,
 392                                 ST_NCI_SPI_DRIVER_NAME, phy);
 393         if (r < 0)
 394                 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
 395
 396         return r;
 397 }
 398
 399 static int st_nci_spi_remove(struct spi_device *dev)
 400 {
 401         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 402
 403         dev_dbg(&dev->dev, "%s\n", __func__);
 404
 405         ndlc_remove(phy->ndlc);
 406
 407         return 0;
 408 }
 409
 410 static struct spi_device_id st_nci_spi_id_table[] = {
 411         {ST_NCI_SPI_DRIVER_NAME, 0},
 412         {}
 413 };
 414 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
 415
 416 static const struct acpi_device_id st_nci_spi_acpi_match[] = {
 417         {"SMO2101", 0},
 418         {}
 419 };
 420 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
 421
 422 static const struct of_device_id of_st_nci_spi_match[] = {
 423         { .compatible = "st,st21nfcb-spi", },
 424         {}
 425 };
 426 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
 427
 428 static struct spi_driver st_nci_spi_driver = {
 429         .driver = {
 430                 .name = ST_NCI_SPI_DRIVER_NAME,
 431                 .of_match_table = of_match_ptr(of_st_nci_spi_match),
 432                 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
 433         },
 434         .probe = st_nci_spi_probe,
 435         .id_table = st_nci_spi_id_table,
 436         .remove = st_nci_spi_remove,
 437 };
 438 module_spi_driver(st_nci_spi_driver);
 439
 440 MODULE_LICENSE("GPL");
 441 MODULE_DESCRIPTION(DRIVER_DESC);