linux/drivers/nfc/st-nci/spi.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * SPI Link Layer for ST NCI based Driver
   4 * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
   5 */
   6
   7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9#include <linux/module.h>
  10#include <linux/spi/spi.h>
  11#include <linux/gpio/consumer.h>
  12#include <linux/acpi.h>
  13#include <linux/interrupt.h>
  14#include <linux/delay.h>
  15#include <linux/nfc.h>
  16#include <linux/of.h>
  17#include <net/nfc/nci.h>
  18
  19#include "st-nci.h"
  20
  21#define DRIVER_DESC "NCI NFC driver for ST_NCI"
  22
  23/* ndlc header */
  24#define ST_NCI_FRAME_HEADROOM   1
  25#define ST_NCI_FRAME_TAILROOM   0
  26
  27#define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  28#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
  29
  30#define ST_NCI_DRIVER_NAME "st_nci"
  31#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
  32
  33struct st_nci_spi_phy {
  34        struct spi_device *spi_dev;
  35        struct llt_ndlc *ndlc;
  36
  37        bool irq_active;
  38
  39        struct gpio_desc *gpiod_reset;
  40
  41        struct st_nci_se_status se_status;
  42};
  43
  44static int st_nci_spi_enable(void *phy_id)
  45{
  46        struct st_nci_spi_phy *phy = phy_id;
  47
  48        gpiod_set_value(phy->gpiod_reset, 0);
  49        usleep_range(10000, 15000);
  50        gpiod_set_value(phy->gpiod_reset, 1);
  51        usleep_range(80000, 85000);
  52
  53        if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  54                enable_irq(phy->spi_dev->irq);
  55                phy->irq_active = true;
  56        }
  57
  58        return 0;
  59}
  60
  61static void st_nci_spi_disable(void *phy_id)
  62{
  63        struct st_nci_spi_phy *phy = phy_id;
  64
  65        disable_irq_nosync(phy->spi_dev->irq);
  66        phy->irq_active = false;
  67}
  68
  69/*
  70 * Writing a frame must not return the number of written bytes.
  71 * It must return either zero for success, or <0 for error.
  72 * In addition, it must not alter the skb
  73 */
  74static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
  75{
  76        int r;
  77        struct st_nci_spi_phy *phy = phy_id;
  78        struct spi_device *dev = phy->spi_dev;
  79        struct sk_buff *skb_rx;
  80        u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
  81               ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
  82        struct spi_transfer spi_xfer = {
  83                .tx_buf = skb->data,
  84                .rx_buf = buf,
  85                .len = skb->len,
  86        };
  87
  88        if (phy->ndlc->hard_fault != 0)
  89                return phy->ndlc->hard_fault;
  90
  91        r = spi_sync_transfer(dev, &spi_xfer, 1);
  92        /*
  93         * We may have received some valuable data on miso line.
  94         * Send them back in the ndlc state machine.
  95         */
  96        if (!r) {
  97                skb_rx = alloc_skb(skb->len, GFP_KERNEL);
  98                if (!skb_rx)
  99                        return -ENOMEM;
 100
 101                skb_put(skb_rx, skb->len);
 102                memcpy(skb_rx->data, buf, skb->len);
 103                ndlc_recv(phy->ndlc, skb_rx);
 104        }
 105
 106        return r;
 107}
 108
 109/*
 110 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 111 * returns:
 112 * 0 : if received frame is complete
 113 * -EREMOTEIO : i2c read error (fatal)
 114 * -EBADMSG : frame was incorrect and discarded
 115 * -ENOMEM : cannot allocate skb, frame dropped
 116 */
 117static int st_nci_spi_read(struct st_nci_spi_phy *phy,
 118                        struct sk_buff **skb)
 119{
 120        int r;
 121        u8 len;
 122        u8 buf[ST_NCI_SPI_MAX_SIZE];
 123        struct spi_device *dev = phy->spi_dev;
 124        struct spi_transfer spi_xfer = {
 125                .rx_buf = buf,
 126                .len = ST_NCI_SPI_MIN_SIZE,
 127        };
 128
 129        r = spi_sync_transfer(dev, &spi_xfer, 1);
 130        if (r < 0)
 131                return -EREMOTEIO;
 132
 133        len = be16_to_cpu(*(__be16 *) (buf + 2));
 134        if (len > ST_NCI_SPI_MAX_SIZE) {
 135                nfc_err(&dev->dev, "invalid frame len\n");
 136                phy->ndlc->hard_fault = 1;
 137                return -EBADMSG;
 138        }
 139
 140        *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
 141        if (*skb == NULL)
 142                return -ENOMEM;
 143
 144        skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
 145        skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
 146        memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
 147
 148        if (!len)
 149                return 0;
 150
 151        spi_xfer.len = len;
 152        r = spi_sync_transfer(dev, &spi_xfer, 1);
 153        if (r < 0) {
 154                kfree_skb(*skb);
 155                return -EREMOTEIO;
 156        }
 157
 158        skb_put(*skb, len);
 159        memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
 160
 161        return 0;
 162}
 163
 164/*
 165 * Reads an ndlc frame from the chip.
 166 *
 167 * On ST21NFCB, IRQ goes in idle state when read starts.
 168 */
 169static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 170{
 171        struct st_nci_spi_phy *phy = phy_id;
 172        struct spi_device *dev;
 173        struct sk_buff *skb = NULL;
 174        int r;
 175
 176        if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
 177                WARN_ON_ONCE(1);
 178                return IRQ_NONE;
 179        }
 180
 181        dev = phy->spi_dev;
 182        dev_dbg(&dev->dev, "IRQ\n");
 183
 184        if (phy->ndlc->hard_fault)
 185                return IRQ_HANDLED;
 186
 187        if (!phy->ndlc->powered) {
 188                st_nci_spi_disable(phy);
 189                return IRQ_HANDLED;
 190        }
 191
 192        r = st_nci_spi_read(phy, &skb);
 193        if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 194                return IRQ_HANDLED;
 195
 196        ndlc_recv(phy->ndlc, skb);
 197
 198        return IRQ_HANDLED;
 199}
 200
 201static struct nfc_phy_ops spi_phy_ops = {
 202        .write = st_nci_spi_write,
 203        .enable = st_nci_spi_enable,
 204        .disable = st_nci_spi_disable,
 205};
 206
 207static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
 208
 209static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
 210        { "reset-gpios", &reset_gpios, 1 },
 211        {},
 212};
 213
 214static int st_nci_spi_probe(struct spi_device *dev)
 215{
 216        struct st_nci_spi_phy *phy;
 217        int r;
 218
 219        /* Check SPI platform functionnalities */
 220        if (!dev) {
 221                pr_debug("%s: dev is NULL. Device is not accessible.\n",
 222                        __func__);
 223                return -ENODEV;
 224        }
 225
 226        phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
 227                           GFP_KERNEL);
 228        if (!phy)
 229                return -ENOMEM;
 230
 231        phy->spi_dev = dev;
 232
 233        spi_set_drvdata(dev, phy);
 234
 235        r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
 236        if (r)
 237                dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
 238
 239        /* Get RESET GPIO */
 240        phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
 241        if (IS_ERR(phy->gpiod_reset)) {
 242                nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
 243                return PTR_ERR(phy->gpiod_reset);
 244        }
 245
 246        phy->se_status.is_ese_present =
 247                        device_property_read_bool(&dev->dev, "ese-present");
 248        phy->se_status.is_uicc_present =
 249                        device_property_read_bool(&dev->dev, "uicc-present");
 250
 251        r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
 252                        ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 253                        &phy->ndlc, &phy->se_status);
 254        if (r < 0) {
 255                nfc_err(&dev->dev, "Unable to register ndlc layer\n");
 256                return r;
 257        }
 258
 259        phy->irq_active = true;
 260        r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
 261                                st_nci_irq_thread_fn,
 262                                IRQF_ONESHOT,
 263                                ST_NCI_SPI_DRIVER_NAME, phy);
 264        if (r < 0)
 265                nfc_err(&dev->dev, "Unable to register IRQ handler\n");
 266
 267        return r;
 268}
 269
 270static int st_nci_spi_remove(struct spi_device *dev)
 271{
 272        struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
 273
 274        ndlc_remove(phy->ndlc);
 275
 276        return 0;
 277}
 278
 279static struct spi_device_id st_nci_spi_id_table[] = {
 280        {ST_NCI_SPI_DRIVER_NAME, 0},
 281        {}
 282};
 283MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
 284
 285static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = {
 286        {"SMO2101", 0},
 287        {}
 288};
 289MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
 290
 291static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = {
 292        { .compatible = "st,st21nfcb-spi", },
 293        {}
 294};
 295MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
 296
 297static struct spi_driver st_nci_spi_driver = {
 298        .driver = {
 299                .name = ST_NCI_SPI_DRIVER_NAME,
 300                .of_match_table = of_match_ptr(of_st_nci_spi_match),
 301                .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
 302        },
 303        .probe = st_nci_spi_probe,
 304        .id_table = st_nci_spi_id_table,
 305        .remove = st_nci_spi_remove,
 306};
 307module_spi_driver(st_nci_spi_driver);
 308
 309MODULE_LICENSE("GPL");
 310MODULE_DESCRIPTION(DRIVER_DESC);
 311