linux/drivers/nfc/fdp/i2c.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* -------------------------------------------------------------------------
   3 * Copyright (C) 2014-2016, Intel Corporation
   4 *
   5 * -------------------------------------------------------------------------
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/acpi.h>
  10#include <linux/i2c.h>
  11#include <linux/interrupt.h>
  12#include <linux/nfc.h>
  13#include <linux/delay.h>
  14#include <linux/gpio/consumer.h>
  15#include <net/nfc/nfc.h>
  16#include <net/nfc/nci_core.h>
  17
  18#include "fdp.h"
  19
  20#define FDP_I2C_DRIVER_NAME     "fdp_nci_i2c"
  21
  22#define FDP_DP_CLOCK_TYPE_NAME  "clock-type"
  23#define FDP_DP_CLOCK_FREQ_NAME  "clock-freq"
  24#define FDP_DP_FW_VSC_CFG_NAME  "fw-vsc-cfg"
  25
  26#define FDP_FRAME_HEADROOM      2
  27#define FDP_FRAME_TAILROOM      1
  28
  29#define FDP_NCI_I2C_MIN_PAYLOAD 5
  30#define FDP_NCI_I2C_MAX_PAYLOAD 261
  31
  32#define FDP_POWER_OFF           0
  33#define FDP_POWER_ON            1
  34
  35#define fdp_nci_i2c_dump_skb(dev, prefix, skb)                          \
  36        print_hex_dump(KERN_DEBUG, prefix": ", DUMP_PREFIX_OFFSET,      \
  37                       16, 1, (skb)->data, (skb)->len, 0)
  38
  39static void fdp_nci_i2c_reset(struct fdp_i2c_phy *phy)
  40{
  41        /* Reset RST/WakeUP for at least 100 micro-second */
  42        gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_OFF);
  43        usleep_range(1000, 4000);
  44        gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_ON);
  45        usleep_range(10000, 14000);
  46}
  47
  48static int fdp_nci_i2c_enable(void *phy_id)
  49{
  50        struct fdp_i2c_phy *phy = phy_id;
  51
  52        fdp_nci_i2c_reset(phy);
  53
  54        return 0;
  55}
  56
  57static void fdp_nci_i2c_disable(void *phy_id)
  58{
  59        struct fdp_i2c_phy *phy = phy_id;
  60
  61        fdp_nci_i2c_reset(phy);
  62}
  63
  64static void fdp_nci_i2c_add_len_lrc(struct sk_buff *skb)
  65{
  66        u8 lrc = 0;
  67        u16 len, i;
  68
  69        /* Add length header */
  70        len = skb->len;
  71        *(u8 *)skb_push(skb, 1) = len & 0xff;
  72        *(u8 *)skb_push(skb, 1) = len >> 8;
  73
  74        /* Compute and add lrc */
  75        for (i = 0; i < len + 2; i++)
  76                lrc ^= skb->data[i];
  77
  78        skb_put_u8(skb, lrc);
  79}
  80
  81static void fdp_nci_i2c_remove_len_lrc(struct sk_buff *skb)
  82{
  83        skb_pull(skb, FDP_FRAME_HEADROOM);
  84        skb_trim(skb, skb->len - FDP_FRAME_TAILROOM);
  85}
  86
  87static int fdp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
  88{
  89        struct fdp_i2c_phy *phy = phy_id;
  90        struct i2c_client *client = phy->i2c_dev;
  91        int r;
  92
  93        if (phy->hard_fault != 0)
  94                return phy->hard_fault;
  95
  96        fdp_nci_i2c_add_len_lrc(skb);
  97        fdp_nci_i2c_dump_skb(&client->dev, "fdp_wr", skb);
  98
  99        r = i2c_master_send(client, skb->data, skb->len);
 100        if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
 101                usleep_range(1000, 4000);
 102                r = i2c_master_send(client, skb->data, skb->len);
 103        }
 104
 105        if (r < 0 || r != skb->len)
 106                dev_dbg(&client->dev, "%s: error err=%d len=%d\n",
 107                        __func__, r, skb->len);
 108
 109        if (r >= 0) {
 110                if (r != skb->len) {
 111                        phy->hard_fault = r;
 112                        r = -EREMOTEIO;
 113                } else {
 114                        r = 0;
 115                }
 116        }
 117
 118        fdp_nci_i2c_remove_len_lrc(skb);
 119
 120        return r;
 121}
 122
 123static struct nfc_phy_ops i2c_phy_ops = {
 124        .write = fdp_nci_i2c_write,
 125        .enable = fdp_nci_i2c_enable,
 126        .disable = fdp_nci_i2c_disable,
 127};
 128
 129static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
 130{
 131        int r, len;
 132        u8 tmp[FDP_NCI_I2C_MAX_PAYLOAD], lrc, k;
 133        u16 i;
 134        struct i2c_client *client = phy->i2c_dev;
 135
 136        *skb = NULL;
 137
 138        /* Read the length packet and the data packet */
 139        for (k = 0; k < 2; k++) {
 140
 141                len = phy->next_read_size;
 142
 143                r = i2c_master_recv(client, tmp, len);
 144                if (r != len) {
 145                        dev_dbg(&client->dev, "%s: i2c recv err: %d\n",
 146                                __func__, r);
 147                        goto flush;
 148                }
 149
 150                /* Check packet integruty */
 151                for (lrc = i = 0; i < r; i++)
 152                        lrc ^= tmp[i];
 153
 154                /*
 155                 * LRC check failed. This may due to transmission error or
 156                 * desynchronization between driver and FDP. Drop the packet
 157                 * and force resynchronization
 158                 */
 159                if (lrc) {
 160                        dev_dbg(&client->dev, "%s: corrupted packet\n",
 161                                __func__);
 162                        phy->next_read_size = 5;
 163                        goto flush;
 164                }
 165
 166                /* Packet that contains a length */
 167                if (tmp[0] == 0 && tmp[1] == 0) {
 168                        phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
 169                } else {
 170                        phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
 171
 172                        *skb = alloc_skb(len, GFP_KERNEL);
 173                        if (*skb == NULL) {
 174                                r = -ENOMEM;
 175                                goto flush;
 176                        }
 177
 178                        skb_put_data(*skb, tmp, len);
 179                        fdp_nci_i2c_dump_skb(&client->dev, "fdp_rd", *skb);
 180
 181                        fdp_nci_i2c_remove_len_lrc(*skb);
 182                }
 183        }
 184
 185        return 0;
 186
 187flush:
 188        /* Flush the remaining data */
 189        if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
 190                r = -EREMOTEIO;
 191
 192        return r;
 193}
 194
 195static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
 196{
 197        struct fdp_i2c_phy *phy = phy_id;
 198        struct sk_buff *skb;
 199        int r;
 200
 201        if (!phy || irq != phy->i2c_dev->irq) {
 202                WARN_ON_ONCE(1);
 203                return IRQ_NONE;
 204        }
 205
 206        r = fdp_nci_i2c_read(phy, &skb);
 207
 208        if (r == -EREMOTEIO)
 209                return IRQ_HANDLED;
 210        else if (r == -ENOMEM || r == -EBADMSG)
 211                return IRQ_HANDLED;
 212
 213        if (skb != NULL)
 214                nci_recv_frame(phy->ndev, skb);
 215
 216        return IRQ_HANDLED;
 217}
 218
 219static void fdp_nci_i2c_read_device_properties(struct device *dev,
 220                                               u8 *clock_type, u32 *clock_freq,
 221                                               u8 **fw_vsc_cfg)
 222{
 223        int r;
 224        u8 len;
 225
 226        r = device_property_read_u8(dev, FDP_DP_CLOCK_TYPE_NAME, clock_type);
 227        if (r) {
 228                dev_dbg(dev, "Using default clock type");
 229                *clock_type = 0;
 230        }
 231
 232        r = device_property_read_u32(dev, FDP_DP_CLOCK_FREQ_NAME, clock_freq);
 233        if (r) {
 234                dev_dbg(dev, "Using default clock frequency\n");
 235                *clock_freq = 26000;
 236        }
 237
 238        if (device_property_present(dev, FDP_DP_FW_VSC_CFG_NAME)) {
 239                r = device_property_read_u8(dev, FDP_DP_FW_VSC_CFG_NAME,
 240                                            &len);
 241
 242                if (r || len <= 0)
 243                        goto vsc_read_err;
 244
 245                /* Add 1 to the length to inclue the length byte itself */
 246                len++;
 247
 248                *fw_vsc_cfg = devm_kmalloc_array(dev,
 249                                           len, sizeof(**fw_vsc_cfg),
 250                                           GFP_KERNEL);
 251
 252                r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
 253                                                  *fw_vsc_cfg, len);
 254
 255                if (r) {
 256                        devm_kfree(dev, *fw_vsc_cfg);
 257                        goto vsc_read_err;
 258                }
 259        } else {
 260vsc_read_err:
 261                dev_dbg(dev, "FW vendor specific commands not present\n");
 262                *fw_vsc_cfg = NULL;
 263        }
 264
 265        dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
 266                *clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
 267}
 268
 269static const struct acpi_gpio_params power_gpios = { 0, 0, false };
 270
 271static const struct acpi_gpio_mapping acpi_fdp_gpios[] = {
 272        { "power-gpios", &power_gpios, 1 },
 273        {},
 274};
 275
 276static int fdp_nci_i2c_probe(struct i2c_client *client)
 277{
 278        struct fdp_i2c_phy *phy;
 279        struct device *dev = &client->dev;
 280        u8 *fw_vsc_cfg;
 281        u8 clock_type;
 282        u32 clock_freq;
 283        int r = 0;
 284
 285        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 286                nfc_err(dev, "No I2C_FUNC_I2C support\n");
 287                return -ENODEV;
 288        }
 289
 290        /* Checking if we have an irq */
 291        if (client->irq <= 0) {
 292                nfc_err(dev, "IRQ not present\n");
 293                return -ENODEV;
 294        }
 295
 296        phy = devm_kzalloc(dev, sizeof(struct fdp_i2c_phy), GFP_KERNEL);
 297        if (!phy)
 298                return -ENOMEM;
 299
 300        phy->i2c_dev = client;
 301        phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
 302        i2c_set_clientdata(client, phy);
 303
 304        r = devm_request_threaded_irq(dev, client->irq,
 305                                      NULL, fdp_nci_i2c_irq_thread_fn,
 306                                      IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 307                                      FDP_I2C_DRIVER_NAME, phy);
 308
 309        if (r < 0) {
 310                nfc_err(&client->dev, "Unable to register IRQ handler\n");
 311                return r;
 312        }
 313
 314        r = devm_acpi_dev_add_driver_gpios(dev, acpi_fdp_gpios);
 315        if (r)
 316                dev_dbg(dev, "Unable to add GPIO mapping table\n");
 317
 318        /* Requesting the power gpio */
 319        phy->power_gpio = devm_gpiod_get(dev, "power", GPIOD_OUT_LOW);
 320        if (IS_ERR(phy->power_gpio)) {
 321                nfc_err(dev, "Power GPIO request failed\n");
 322                return PTR_ERR(phy->power_gpio);
 323        }
 324
 325        /* read device properties to get the clock and production settings */
 326        fdp_nci_i2c_read_device_properties(dev, &clock_type, &clock_freq,
 327                                           &fw_vsc_cfg);
 328
 329        /* Call the NFC specific probe function */
 330        r = fdp_nci_probe(phy, &i2c_phy_ops, &phy->ndev,
 331                          FDP_FRAME_HEADROOM, FDP_FRAME_TAILROOM,
 332                          clock_type, clock_freq, fw_vsc_cfg);
 333        if (r < 0) {
 334                nfc_err(dev, "NCI probing error\n");
 335                return r;
 336        }
 337
 338        dev_dbg(dev, "I2C driver loaded\n");
 339        return 0;
 340}
 341
 342static int fdp_nci_i2c_remove(struct i2c_client *client)
 343{
 344        struct fdp_i2c_phy *phy = i2c_get_clientdata(client);
 345
 346        fdp_nci_remove(phy->ndev);
 347        fdp_nci_i2c_disable(phy);
 348
 349        return 0;
 350}
 351
 352static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
 353        {"INT339A", 0},
 354        {}
 355};
 356MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);
 357
 358static struct i2c_driver fdp_nci_i2c_driver = {
 359        .driver = {
 360                   .name = FDP_I2C_DRIVER_NAME,
 361                   .acpi_match_table = fdp_nci_i2c_acpi_match,
 362                  },
 363        .probe_new = fdp_nci_i2c_probe,
 364        .remove = fdp_nci_i2c_remove,
 365};
 366module_i2c_driver(fdp_nci_i2c_driver);
 367
 368MODULE_LICENSE("GPL");
 369MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
 370MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");
 371