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 <linux/platform_data/st-nci.h>
  29
  30 #include "ndlc.h"
  31
  32 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
  33
  34 /* ndlc header */
  35 #define ST_NCI_FRAME_HEADROOM   1
  36 #define ST_NCI_FRAME_TAILROOM 0
  37
  38 #define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  39 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
  40
  41 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
  42
  43 static struct spi_device_id st_nci_spi_id_table[] = {
  44         {ST_NCI_SPI_DRIVER_NAME, 0},
  45         {}
  46 };
  47 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
  48
  49 struct st_nci_spi_phy {
  50         struct spi_device *spi_dev;
  51         struct llt_ndlc *ndlc;
  52
  53         unsigned int gpio_reset;
  54         unsigned int irq_polarity;
  55 };
  56
  57 #define SPI_DUMP_SKB(info, skb)                                 \
  58 do {                                                            \
  59         pr_debug("%s:\n", info);                                \
  60         print_hex_dump(KERN_DEBUG, "spi: ", DUMP_PREFIX_OFFSET, \
  61                        16, 1, (skb)->data, (skb)->len, 0);      \
  62 } while (0)
  63
  64 static int st_nci_spi_enable(void *phy_id)
  65 {
  66         struct st_nci_spi_phy *phy = phy_id;
  67
  68         gpio_set_value(phy->gpio_reset, 0);
  69         usleep_range(10000, 15000);
  70         gpio_set_value(phy->gpio_reset, 1);
  71         usleep_range(80000, 85000);
  72
  73         if (phy->ndlc->powered == 0)
  74                 enable_irq(phy->spi_dev->irq);
  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 }
  85
  86 /*
  87  * Writing a frame must not return the number of written bytes.
  88  * It must return either zero for success, or <0 for error.
  89  * In addition, it must not alter the skb
  90  */
  91 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
  92 {
  93         int r;
  94         struct st_nci_spi_phy *phy = phy_id;
  95         struct spi_device *dev = phy->spi_dev;
  96         struct sk_buff *skb_rx;
  97         u8 buf[ST_NCI_SPI_MAX_SIZE];
  98         struct spi_transfer spi_xfer = {
  99                 .tx_buf = skb->data,
 100                 .rx_buf = buf,
 101                 .len = skb->len,
 102         };
 103
 104         SPI_DUMP_SKB("st_nci_spi_write", skb);
 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         SPI_DUMP_SKB("spi frame read", *skb);
 183
 184         return 0;
 185 }
 186
 187 /*
 188  * Reads an ndlc frame from the chip.
 189  *
 190  * On ST21NFCB, IRQ goes in idle state when read starts.
 191  */
 192 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 193 {
 194         struct st_nci_spi_phy *phy = phy_id;
 195         struct spi_device *dev;
 196         struct sk_buff *skb = NULL;
 197         int r;
 198
 199         if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
 200                 WARN_ON_ONCE(1);
 201                 return IRQ_NONE;
 202         }
 203
 204         dev = phy->spi_dev;
 205         dev_dbg(&dev->dev, "IRQ\n");
 206
 207         if (phy->ndlc->hard_fault)
 208                 return IRQ_HANDLED;
 209
 210         if (!phy->ndlc->powered) {
 211                 st_nci_spi_disable(phy);
 212                 return IRQ_HANDLED;
 213         }
 214
 215         r = st_nci_spi_read(phy, &skb);
 216         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 217                 return IRQ_HANDLED;
 218
 219         ndlc_recv(phy->ndlc, skb);
 220
 221         return IRQ_HANDLED;
 222 }
 223
 224 static struct nfc_phy_ops spi_phy_ops = {
 225         .write = st_nci_spi_write,
 226         .enable = st_nci_spi_enable,
 227         .disable = st_nci_spi_disable,
 228 };
 229
 230 #ifdef CONFIG_OF
 231 static int st_nci_spi_of_request_resources(struct spi_device *dev)
 232 {
 233         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 234         struct device_node *pp;
 235         int gpio;
 236         int r;
 237
 238         pp = dev->dev.of_node;
 239         if (!pp)
 240                 return -ENODEV;
 241
 242         /* Get GPIO from device tree */
 243         gpio = of_get_named_gpio(pp, "reset-gpios", 0);
 244         if (gpio < 0) {
 245                 nfc_err(&dev->dev,
 246                         "Failed to retrieve reset-gpios from device tree\n");
 247                 return gpio;
 248         }
 249
 250         /* GPIO request and configuration */
 251         r = devm_gpio_request_one(&dev->dev, gpio,
 252                                 GPIOF_OUT_INIT_HIGH, "clf_reset");
 253         if (r) {
 254                 nfc_err(&dev->dev, "Failed to request reset pin\n");
 255                 return r;
 256         }
 257         phy->gpio_reset = gpio;
 258
 259         phy->irq_polarity = irq_get_trigger_type(dev->irq);
 260
 261         return 0;
 262 }
 263 #else
 264 static int st_nci_spi_of_request_resources(struct spi_device *dev)
 265 {
 266         return -ENODEV;
 267 }
 268 #endif
 269
 270 static int st_nci_spi_request_resources(struct spi_device *dev)
 271 {
 272         struct st_nci_nfc_platform_data *pdata;
 273         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 274         int r;
 275
 276         pdata = dev->dev.platform_data;
 277         if (pdata == NULL) {
 278                 nfc_err(&dev->dev, "No platform data\n");
 279                 return -EINVAL;
 280         }
 281
 282         /* store for later use */
 283         phy->gpio_reset = pdata->gpio_reset;
 284         phy->irq_polarity = pdata->irq_polarity;
 285
 286         r = devm_gpio_request_one(&dev->dev,
 287                         phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
 288         if (r) {
 289                 pr_err("%s : reset gpio_request failed\n", __FILE__);
 290                 return r;
 291         }
 292
 293         return 0;
 294 }
 295
 296 static int st_nci_spi_probe(struct spi_device *dev)
 297 {
 298         struct st_nci_spi_phy *phy;
 299         struct st_nci_nfc_platform_data *pdata;
 300         int r;
 301
 302         dev_dbg(&dev->dev, "%s\n", __func__);
 303         dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
 304
 305         /* Check SPI platform functionnalities */
 306         if (!dev) {
 307                 pr_debug("%s: dev is NULL. Device is not accessible.\n",
 308                         __func__);
 309                 return -ENODEV;
 310         }
 311
 312         phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
 313                            GFP_KERNEL);
 314         if (!phy)
 315                 return -ENOMEM;
 316
 317         phy->spi_dev = dev;
 318
 319         spi_set_drvdata(dev, phy);
 320
 321         pdata = dev->dev.platform_data;
 322         if (!pdata && dev->dev.of_node) {
 323                 r = st_nci_spi_of_request_resources(dev);
 324                 if (r) {
 325                         nfc_err(&dev->dev, "No platform data\n");
 326                         return r;
 327                 }
 328         } else if (pdata) {
 329                 r = st_nci_spi_request_resources(dev);
 330                 if (r) {
 331                         nfc_err(&dev->dev,
 332                                 "Cannot get platform resources\n");
 333                         return r;
 334                 }
 335         } else {
 336                 nfc_err(&dev->dev,
 337                         "st_nci platform resources not available\n");
 338                 return -ENODEV;
 339         }
 340
 341         r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
 342                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 343                         &phy->ndlc);
 344         if (r < 0) {
 345                 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
 346                 return r;
 347         }
 348
 349         r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
 350                                 st_nci_irq_thread_fn,
 351                                 phy->irq_polarity | IRQF_ONESHOT,
 352                                 ST_NCI_SPI_DRIVER_NAME, phy);
 353         if (r < 0)
 354                 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
 355
 356         return r;
 357 }
 358
 359 static int st_nci_spi_remove(struct spi_device *dev)
 360 {
 361         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 362
 363         dev_dbg(&dev->dev, "%s\n", __func__);
 364
 365         ndlc_remove(phy->ndlc);
 366
 367         return 0;
 368 }
 369
 370 #ifdef CONFIG_OF
 371 static const struct of_device_id of_st_nci_spi_match[] = {
 372         { .compatible = "st,st21nfcb-spi", },
 373         {}
 374 };
 375 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
 376 #endif
 377
 378 static struct spi_driver st_nci_spi_driver = {
 379         .driver = {
 380                 .owner = THIS_MODULE,
 381                 .name = ST_NCI_SPI_DRIVER_NAME,
 382                 .of_match_table = of_match_ptr(of_st_nci_spi_match),
 383         },
 384         .probe = st_nci_spi_probe,
 385         .id_table = st_nci_spi_id_table,
 386         .remove = st_nci_spi_remove,
 387 };
 388
 389 module_spi_driver(st_nci_spi_driver);
 390
 391 MODULE_LICENSE("GPL");
 392 MODULE_DESCRIPTION(DRIVER_DESC);