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/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 <net/nfc/nci.h>
  29 #include <linux/platform_data/st-nci.h>
  30
  31 #include "st-nci.h"
  32
  33 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
  34
  35 /* ndlc header */
  36 #define ST_NCI_FRAME_HEADROOM   1
  37 #define ST_NCI_FRAME_TAILROOM 0
  38
  39 #define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  40 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
  41
  42 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
  43
  44 static struct spi_device_id st_nci_spi_id_table[] = {
  45         {ST_NCI_SPI_DRIVER_NAME, 0},
  46         {}
  47 };
  48 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
  49
  50 struct st_nci_spi_phy {
  51         struct spi_device *spi_dev;
  52         struct llt_ndlc *ndlc;
  53
  54         bool irq_active;
  55
  56         unsigned int gpio_reset;
  57         unsigned int irq_polarity;
  58
  59         struct st_nci_se_status se_status;
  60 };
  61
  62 static int st_nci_spi_enable(void *phy_id)
  63 {
  64         struct st_nci_spi_phy *phy = phy_id;
  65
  66         gpio_set_value(phy->gpio_reset, 0);
  67         usleep_range(10000, 15000);
  68         gpio_set_value(phy->gpio_reset, 1);
  69         usleep_range(80000, 85000);
  70
  71         if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  72                 enable_irq(phy->spi_dev->irq);
  73                 phy->irq_active = true;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static void st_nci_spi_disable(void *phy_id)
  80 {
  81         struct st_nci_spi_phy *phy = phy_id;
  82
  83         disable_irq_nosync(phy->spi_dev->irq);
  84         phy->irq_active = false;
  85 }
  86
  87 /*
  88  * Writing a frame must not return the number of written bytes.
  89  * It must return either zero for success, or <0 for error.
  90  * In addition, it must not alter the skb
  91  */
  92 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
  93 {
  94         int r;
  95         struct st_nci_spi_phy *phy = phy_id;
  96         struct spi_device *dev = phy->spi_dev;
  97         struct sk_buff *skb_rx;
  98         u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
  99                ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
 100         struct spi_transfer spi_xfer = {
 101                 .tx_buf = skb->data,
 102                 .rx_buf = buf,
 103                 .len = skb->len,
 104         };
 105
 106         if (phy->ndlc->hard_fault != 0)
 107                 return phy->ndlc->hard_fault;
 108
 109         r = spi_sync_transfer(dev, &spi_xfer, 1);
 110         /*
 111          * We may have received some valuable data on miso line.
 112          * Send them back in the ndlc state machine.
 113          */
 114         if (!r) {
 115                 skb_rx = alloc_skb(skb->len, GFP_KERNEL);
 116                 if (!skb_rx) {
 117                         r = -ENOMEM;
 118                         goto exit;
 119                 }
 120
 121                 skb_put(skb_rx, skb->len);
 122                 memcpy(skb_rx->data, buf, skb->len);
 123                 ndlc_recv(phy->ndlc, skb_rx);
 124         }
 125
 126 exit:
 127         return r;
 128 }
 129
 130 /*
 131  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 132  * returns:
 133  * 0 : if received frame is complete
 134  * -EREMOTEIO : i2c read error (fatal)
 135  * -EBADMSG : frame was incorrect and discarded
 136  * -ENOMEM : cannot allocate skb, frame dropped
 137  */
 138 static int st_nci_spi_read(struct st_nci_spi_phy *phy,
 139                         struct sk_buff **skb)
 140 {
 141         int r;
 142         u8 len;
 143         u8 buf[ST_NCI_SPI_MAX_SIZE];
 144         struct spi_device *dev = phy->spi_dev;
 145         struct spi_transfer spi_xfer = {
 146                 .rx_buf = buf,
 147                 .len = ST_NCI_SPI_MIN_SIZE,
 148         };
 149
 150         r = spi_sync_transfer(dev, &spi_xfer, 1);
 151         if (r < 0)
 152                 return -EREMOTEIO;
 153
 154         len = be16_to_cpu(*(__be16 *) (buf + 2));
 155         if (len > ST_NCI_SPI_MAX_SIZE) {
 156                 nfc_err(&dev->dev, "invalid frame len\n");
 157                 phy->ndlc->hard_fault = 1;
 158                 return -EBADMSG;
 159         }
 160
 161         *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
 162         if (*skb == NULL)
 163                 return -ENOMEM;
 164
 165         skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
 166         skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
 167         memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
 168
 169         if (!len)
 170                 return 0;
 171
 172         spi_xfer.len = len;
 173         r = spi_sync_transfer(dev, &spi_xfer, 1);
 174         if (r < 0) {
 175                 kfree_skb(*skb);
 176                 return -EREMOTEIO;
 177         }
 178
 179         skb_put(*skb, len);
 180         memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
 181
 182         return 0;
 183 }
 184
 185 /*
 186  * Reads an ndlc frame from the chip.
 187  *
 188  * On ST21NFCB, IRQ goes in idle state when read starts.
 189  */
 190 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 191 {
 192         struct st_nci_spi_phy *phy = phy_id;
 193         struct spi_device *dev;
 194         struct sk_buff *skb = NULL;
 195         int r;
 196
 197         if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
 198                 WARN_ON_ONCE(1);
 199                 return IRQ_NONE;
 200         }
 201
 202         dev = phy->spi_dev;
 203         dev_dbg(&dev->dev, "IRQ\n");
 204
 205         if (phy->ndlc->hard_fault)
 206                 return IRQ_HANDLED;
 207
 208         if (!phy->ndlc->powered) {
 209                 st_nci_spi_disable(phy);
 210                 return IRQ_HANDLED;
 211         }
 212
 213         r = st_nci_spi_read(phy, &skb);
 214         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 215                 return IRQ_HANDLED;
 216
 217         ndlc_recv(phy->ndlc, skb);
 218
 219         return IRQ_HANDLED;
 220 }
 221
 222 static struct nfc_phy_ops spi_phy_ops = {
 223         .write = st_nci_spi_write,
 224         .enable = st_nci_spi_enable,
 225         .disable = st_nci_spi_disable,
 226 };
 227
 228 #ifdef CONFIG_OF
 229 static int st_nci_spi_of_request_resources(struct spi_device *dev)
 230 {
 231         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 232         struct device_node *pp;
 233         int gpio;
 234         int r;
 235
 236         pp = dev->dev.of_node;
 237         if (!pp)
 238                 return -ENODEV;
 239
 240         /* Get GPIO from device tree */
 241         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
 242         if (gpio < 0) {
 243                 nfc_err(&dev->dev,
 244                         "Failed to retrieve reset-gpios from device tree\n");
 245                 return gpio;
 246         }
 247
 248         /* GPIO request and configuration */
 249         r = devm_gpio_request_one(&dev->dev, gpio,
 250                                 GPIOF_OUT_INIT_HIGH, "clf_reset");
 251         if (r) {
 252                 nfc_err(&dev->dev, "Failed to request reset pin\n");
 253                 return r;
 254         }
 255         phy->gpio_reset = gpio;
 256
 257         phy->irq_polarity = irq_get_trigger_type(dev->irq);
 258
 259         phy->se_status.is_ese_present =
 260                                 of_property_read_bool(pp, "ese-present");
 261         phy->se_status.is_uicc_present =
 262                                 of_property_read_bool(pp, "uicc-present");
 263
 264         return 0;
 265 }
 266 #else
 267 static int st_nci_spi_of_request_resources(struct spi_device *dev)
 268 {
 269         return -ENODEV;
 270 }
 271 #endif
 272
 273 static int st_nci_spi_request_resources(struct spi_device *dev)
 274 {
 275         struct st_nci_nfc_platform_data *pdata;
 276         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 277         int r;
 278
 279         pdata = dev->dev.platform_data;
 280         if (pdata == NULL) {
 281                 nfc_err(&dev->dev, "No platform data\n");
 282                 return -EINVAL;
 283         }
 284
 285         /* store for later use */
 286         phy->gpio_reset = pdata->gpio_reset;
 287         phy->irq_polarity = pdata->irq_polarity;
 288
 289         r = devm_gpio_request_one(&dev->dev,
 290                         phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
 291         if (r) {
 292                 pr_err("%s : reset gpio_request failed\n", __FILE__);
 293                 return r;
 294         }
 295
 296         phy->se_status.is_ese_present = pdata->is_ese_present;
 297         phy->se_status.is_uicc_present = pdata->is_uicc_present;
 298
 299         return 0;
 300 }
 301
 302 static int st_nci_spi_probe(struct spi_device *dev)
 303 {
 304         struct st_nci_spi_phy *phy;
 305         struct st_nci_nfc_platform_data *pdata;
 306         int r;
 307
 308         dev_dbg(&dev->dev, "%s\n", __func__);
 309         dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
 310
 311         /* Check SPI platform functionnalities */
 312         if (!dev) {
 313                 pr_debug("%s: dev is NULL. Device is not accessible.\n",
 314                         __func__);
 315                 return -ENODEV;
 316         }
 317
 318         phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
 319                            GFP_KERNEL);
 320         if (!phy)
 321                 return -ENOMEM;
 322
 323         phy->spi_dev = dev;
 324
 325         spi_set_drvdata(dev, phy);
 326
 327         pdata = dev->dev.platform_data;
 328         if (!pdata && dev->dev.of_node) {
 329                 r = st_nci_spi_of_request_resources(dev);
 330                 if (r) {
 331                         nfc_err(&dev->dev, "No platform data\n");
 332                         return r;
 333                 }
 334         } else if (pdata) {
 335                 r = st_nci_spi_request_resources(dev);
 336                 if (r) {
 337                         nfc_err(&dev->dev,
 338                                 "Cannot get platform resources\n");
 339                         return r;
 340                 }
 341         } else {
 342                 nfc_err(&dev->dev,
 343                         "st_nci platform resources not available\n");
 344                 return -ENODEV;
 345         }
 346
 347         r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
 348                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 349                         &phy->ndlc, &phy->se_status);
 350         if (r < 0) {
 351                 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
 352                 return r;
 353         }
 354
 355         phy->irq_active = true;
 356         r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
 357                                 st_nci_irq_thread_fn,
 358                                 phy->irq_polarity | IRQF_ONESHOT,
 359                                 ST_NCI_SPI_DRIVER_NAME, phy);
 360         if (r < 0)
 361                 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
 362
 363         return r;
 364 }
 365
 366 static int st_nci_spi_remove(struct spi_device *dev)
 367 {
 368         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 369
 370         dev_dbg(&dev->dev, "%s\n", __func__);
 371
 372         ndlc_remove(phy->ndlc);
 373
 374         return 0;
 375 }
 376
 377 #ifdef CONFIG_OF
 378 static const struct of_device_id of_st_nci_spi_match[] = {
 379         { .compatible = "st,st21nfcb-spi", },
 380         {}
 381 };
 382 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
 383 #endif
 384
 385 static struct spi_driver st_nci_spi_driver = {
 386         .driver = {
 387                 .name = ST_NCI_SPI_DRIVER_NAME,
 388                 .of_match_table = of_match_ptr(of_st_nci_spi_match),
 389         },
 390         .probe = st_nci_spi_probe,
 391         .id_table = st_nci_spi_id_table,
 392         .remove = st_nci_spi_remove,
 393 };
 394
 395 module_spi_driver(st_nci_spi_driver);
 396
 397 MODULE_LICENSE("GPL");
 398 MODULE_DESCRIPTION(DRIVER_DESC);