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/consumer.h>
  23 #include <linux/acpi.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/delay.h>
  26 #include <linux/nfc.h>
  27 #include <linux/of.h>
  28 #include <net/nfc/nci.h>
  29
  30 #include "st-nci.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_DRIVER_NAME "st_nci"
  42 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
  43
  44 struct st_nci_spi_phy {
  45         struct spi_device *spi_dev;
  46         struct llt_ndlc *ndlc;
  47
  48         bool irq_active;
  49
  50         struct gpio_desc *gpiod_reset;
  51
  52         struct st_nci_se_status se_status;
  53 };
  54
  55 static int st_nci_spi_enable(void *phy_id)
  56 {
  57         struct st_nci_spi_phy *phy = phy_id;
  58
  59         gpiod_set_value(phy->gpiod_reset, 0);
  60         usleep_range(10000, 15000);
  61         gpiod_set_value(phy->gpiod_reset, 1);
  62         usleep_range(80000, 85000);
  63
  64         if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  65                 enable_irq(phy->spi_dev->irq);
  66                 phy->irq_active = true;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static void st_nci_spi_disable(void *phy_id)
  73 {
  74         struct st_nci_spi_phy *phy = phy_id;
  75
  76         disable_irq_nosync(phy->spi_dev->irq);
  77         phy->irq_active = false;
  78 }
  79
  80 /*
  81  * Writing a frame must not return the number of written bytes.
  82  * It must return either zero for success, or <0 for error.
  83  * In addition, it must not alter the skb
  84  */
  85 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
  86 {
  87         int r;
  88         struct st_nci_spi_phy *phy = phy_id;
  89         struct spi_device *dev = phy->spi_dev;
  90         struct sk_buff *skb_rx;
  91         u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
  92                ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
  93         struct spi_transfer spi_xfer = {
  94                 .tx_buf = skb->data,
  95                 .rx_buf = buf,
  96                 .len = skb->len,
  97         };
  98
  99         if (phy->ndlc->hard_fault != 0)
 100                 return phy->ndlc->hard_fault;
 101
 102         r = spi_sync_transfer(dev, &spi_xfer, 1);
 103         /*
 104          * We may have received some valuable data on miso line.
 105          * Send them back in the ndlc state machine.
 106          */
 107         if (!r) {
 108                 skb_rx = alloc_skb(skb->len, GFP_KERNEL);
 109                 if (!skb_rx) {
 110                         r = -ENOMEM;
 111                         goto exit;
 112                 }
 113
 114                 skb_put(skb_rx, skb->len);
 115                 memcpy(skb_rx->data, buf, skb->len);
 116                 ndlc_recv(phy->ndlc, skb_rx);
 117         }
 118
 119 exit:
 120         return r;
 121 }
 122
 123 /*
 124  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 125  * returns:
 126  * 0 : if received frame is complete
 127  * -EREMOTEIO : i2c read error (fatal)
 128  * -EBADMSG : frame was incorrect and discarded
 129  * -ENOMEM : cannot allocate skb, frame dropped
 130  */
 131 static int st_nci_spi_read(struct st_nci_spi_phy *phy,
 132                         struct sk_buff **skb)
 133 {
 134         int r;
 135         u8 len;
 136         u8 buf[ST_NCI_SPI_MAX_SIZE];
 137         struct spi_device *dev = phy->spi_dev;
 138         struct spi_transfer spi_xfer = {
 139                 .rx_buf = buf,
 140                 .len = ST_NCI_SPI_MIN_SIZE,
 141         };
 142
 143         r = spi_sync_transfer(dev, &spi_xfer, 1);
 144         if (r < 0)
 145                 return -EREMOTEIO;
 146
 147         len = be16_to_cpu(*(__be16 *) (buf + 2));
 148         if (len > ST_NCI_SPI_MAX_SIZE) {
 149                 nfc_err(&dev->dev, "invalid frame len\n");
 150                 phy->ndlc->hard_fault = 1;
 151                 return -EBADMSG;
 152         }
 153
 154         *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
 155         if (*skb == NULL)
 156                 return -ENOMEM;
 157
 158         skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
 159         skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
 160         memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
 161
 162         if (!len)
 163                 return 0;
 164
 165         spi_xfer.len = len;
 166         r = spi_sync_transfer(dev, &spi_xfer, 1);
 167         if (r < 0) {
 168                 kfree_skb(*skb);
 169                 return -EREMOTEIO;
 170         }
 171
 172         skb_put(*skb, len);
 173         memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
 174
 175         return 0;
 176 }
 177
 178 /*
 179  * Reads an ndlc frame from the chip.
 180  *
 181  * On ST21NFCB, IRQ goes in idle state when read starts.
 182  */
 183 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 184 {
 185         struct st_nci_spi_phy *phy = phy_id;
 186         struct spi_device *dev;
 187         struct sk_buff *skb = NULL;
 188         int r;
 189
 190         if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
 191                 WARN_ON_ONCE(1);
 192                 return IRQ_NONE;
 193         }
 194
 195         dev = phy->spi_dev;
 196         dev_dbg(&dev->dev, "IRQ\n");
 197
 198         if (phy->ndlc->hard_fault)
 199                 return IRQ_HANDLED;
 200
 201         if (!phy->ndlc->powered) {
 202                 st_nci_spi_disable(phy);
 203                 return IRQ_HANDLED;
 204         }
 205
 206         r = st_nci_spi_read(phy, &skb);
 207         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 208                 return IRQ_HANDLED;
 209
 210         ndlc_recv(phy->ndlc, skb);
 211
 212         return IRQ_HANDLED;
 213 }
 214
 215 static struct nfc_phy_ops spi_phy_ops = {
 216         .write = st_nci_spi_write,
 217         .enable = st_nci_spi_enable,
 218         .disable = st_nci_spi_disable,
 219 };
 220
 221 static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
 222
 223 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
 224         { "reset-gpios", &reset_gpios, 1 },
 225         {},
 226 };
 227
 228 static int st_nci_spi_probe(struct spi_device *dev)
 229 {
 230         struct st_nci_spi_phy *phy;
 231         int r;
 232
 233         dev_dbg(&dev->dev, "%s\n", __func__);
 234         dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
 235
 236         /* Check SPI platform functionnalities */
 237         if (!dev) {
 238                 pr_debug("%s: dev is NULL. Device is not accessible.\n",
 239                         __func__);
 240                 return -ENODEV;
 241         }
 242
 243         phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
 244                            GFP_KERNEL);
 245         if (!phy)
 246                 return -ENOMEM;
 247
 248         phy->spi_dev = dev;
 249
 250         spi_set_drvdata(dev, phy);
 251
 252         r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
 253         if (r)
 254                 dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
 255
 256         /* Get RESET GPIO */
 257         phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
 258         if (IS_ERR(phy->gpiod_reset)) {
 259                 nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
 260                 return PTR_ERR(phy->gpiod_reset);
 261         }
 262
 263         phy->se_status.is_ese_present =
 264                         device_property_read_bool(&dev->dev, "ese-present");
 265         phy->se_status.is_uicc_present =
 266                         device_property_read_bool(&dev->dev, "uicc-present");
 267
 268         r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
 269                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 270                         &phy->ndlc, &phy->se_status);
 271         if (r < 0) {
 272                 nfc_err(&dev->dev, "Unable to register ndlc layer\n");
 273                 return r;
 274         }
 275
 276         phy->irq_active = true;
 277         r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
 278                                 st_nci_irq_thread_fn,
 279                                 IRQF_ONESHOT,
 280                                 ST_NCI_SPI_DRIVER_NAME, phy);
 281         if (r < 0)
 282                 nfc_err(&dev->dev, "Unable to register IRQ handler\n");
 283
 284         return r;
 285 }
 286
 287 static int st_nci_spi_remove(struct spi_device *dev)
 288 {
 289         struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 290
 291         dev_dbg(&dev->dev, "%s\n", __func__);
 292
 293         ndlc_remove(phy->ndlc);
 294
 295         return 0;
 296 }
 297
 298 static struct spi_device_id st_nci_spi_id_table[] = {
 299         {ST_NCI_SPI_DRIVER_NAME, 0},
 300         {}
 301 };
 302 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
 303
 304 static const struct acpi_device_id st_nci_spi_acpi_match[] = {
 305         {"SMO2101", 0},
 306         {}
 307 };
 308 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
 309
 310 static const struct of_device_id of_st_nci_spi_match[] = {
 311         { .compatible = "st,st21nfcb-spi", },
 312         {}
 313 };
 314 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
 315
 316 static struct spi_driver st_nci_spi_driver = {
 317         .driver = {
 318                 .name = ST_NCI_SPI_DRIVER_NAME,
 319                 .of_match_table = of_match_ptr(of_st_nci_spi_match),
 320                 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
 321         },
 322         .probe = st_nci_spi_probe,
 323         .id_table = st_nci_spi_id_table,
 324         .remove = st_nci_spi_remove,
 325 };
 326 module_spi_driver(st_nci_spi_driver);
 327
 328 MODULE_LICENSE("GPL");
 329 MODULE_DESCRIPTION(DRIVER_DESC);