drivers/nfc/fdp/i2c.c

   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
  39 static 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
  48 static int fdp_nci_i2c_enable(void *phy_id)
  49 {
  50         struct fdp_i2c_phy *phy = phy_id;
  51
  52         dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
  53         fdp_nci_i2c_reset(phy);
  54
  55         return 0;
  56 }
  57
  58 static void fdp_nci_i2c_disable(void *phy_id)
  59 {
  60         struct fdp_i2c_phy *phy = phy_id;
  61
  62         dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
  63         fdp_nci_i2c_reset(phy);
  64 }
  65
  66 static void fdp_nci_i2c_add_len_lrc(struct sk_buff *skb)
  67 {
  68         u8 lrc = 0;
  69         u16 len, i;
  70
  71         /* Add length header */
  72         len = skb->len;
  73         *(u8 *)skb_push(skb, 1) = len & 0xff;
  74         *(u8 *)skb_push(skb, 1) = len >> 8;
  75
  76         /* Compute and add lrc */
  77         for (i = 0; i < len + 2; i++)
  78                 lrc ^= skb->data[i];
  79
  80         skb_put_u8(skb, lrc);
  81 }
  82
  83 static void fdp_nci_i2c_remove_len_lrc(struct sk_buff *skb)
  84 {
  85         skb_pull(skb, FDP_FRAME_HEADROOM);
  86         skb_trim(skb, skb->len - FDP_FRAME_TAILROOM);
  87 }
  88
  89 static int fdp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
  90 {
  91         struct fdp_i2c_phy *phy = phy_id;
  92         struct i2c_client *client = phy->i2c_dev;
  93         int r;
  94
  95         if (phy->hard_fault != 0)
  96                 return phy->hard_fault;
  97
  98         fdp_nci_i2c_add_len_lrc(skb);
  99         fdp_nci_i2c_dump_skb(&client->dev, "fdp_wr", skb);
 100
 101         r = i2c_master_send(client, skb->data, skb->len);
 102         if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
 103                 usleep_range(1000, 4000);
 104                 r = i2c_master_send(client, skb->data, skb->len);
 105         }
 106
 107         if (r < 0 || r != skb->len)
 108                 dev_dbg(&client->dev, "%s: error err=%d len=%d\n",
 109                         __func__, r, skb->len);
 110
 111         if (r >= 0) {
 112                 if (r != skb->len) {
 113                         phy->hard_fault = r;
 114                         r = -EREMOTEIO;
 115                 } else {
 116                         r = 0;
 117                 }
 118         }
 119
 120         fdp_nci_i2c_remove_len_lrc(skb);
 121
 122         return r;
 123 }
 124
 125 static struct nfc_phy_ops i2c_phy_ops = {
 126         .write = fdp_nci_i2c_write,
 127         .enable = fdp_nci_i2c_enable,
 128         .disable = fdp_nci_i2c_disable,
 129 };
 130
 131 static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
 132 {
 133         int r, len;
 134         u8 tmp[FDP_NCI_I2C_MAX_PAYLOAD], lrc, k;
 135         u16 i;
 136         struct i2c_client *client = phy->i2c_dev;
 137
 138         *skb = NULL;
 139
 140         /* Read the length packet and the data packet */
 141         for (k = 0; k < 2; k++) {
 142
 143                 len = phy->next_read_size;
 144
 145                 r = i2c_master_recv(client, tmp, len);
 146                 if (r != len) {
 147                         dev_dbg(&client->dev, "%s: i2c recv err: %d\n",
 148                                 __func__, r);
 149                         goto flush;
 150                 }
 151
 152                 /* Check packet integruty */
 153                 for (lrc = i = 0; i < r; i++)
 154                         lrc ^= tmp[i];
 155
 156                 /*
 157                  * LRC check failed. This may due to transmission error or
 158                  * desynchronization between driver and FDP. Drop the paquet
 159                  * and force resynchronization
 160                  */
 161                 if (lrc) {
 162                         dev_dbg(&client->dev, "%s: corrupted packet\n",
 163                                 __func__);
 164                         phy->next_read_size = 5;
 165                         goto flush;
 166                 }
 167
 168                 /* Packet that contains a length */
 169                 if (tmp[0] == 0 && tmp[1] == 0) {
 170                         phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
 171                 } else {
 172                         phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
 173
 174                         *skb = alloc_skb(len, GFP_KERNEL);
 175                         if (*skb == NULL) {
 176                                 r = -ENOMEM;
 177                                 goto flush;
 178                         }
 179
 180                         skb_put_data(*skb, tmp, len);
 181                         fdp_nci_i2c_dump_skb(&client->dev, "fdp_rd", *skb);
 182
 183                         fdp_nci_i2c_remove_len_lrc(*skb);
 184                 }
 185         }
 186
 187         return 0;
 188
 189 flush:
 190         /* Flush the remaining data */
 191         if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
 192                 r = -EREMOTEIO;
 193
 194         return r;
 195 }
 196
 197 static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
 198 {
 199         struct fdp_i2c_phy *phy = phy_id;
 200         struct i2c_client *client;
 201         struct sk_buff *skb;
 202         int r;
 203
 204         if (!phy || irq != phy->i2c_dev->irq) {
 205                 WARN_ON_ONCE(1);
 206                 return IRQ_NONE;
 207         }
 208
 209         client = phy->i2c_dev;
 210         dev_dbg(&client->dev, "%s\n", __func__);
 211
 212         r = fdp_nci_i2c_read(phy, &skb);
 213
 214         if (r == -EREMOTEIO)
 215                 return IRQ_HANDLED;
 216         else if (r == -ENOMEM || r == -EBADMSG)
 217                 return IRQ_HANDLED;
 218
 219         if (skb != NULL)
 220                 fdp_nci_recv_frame(phy->ndev, skb);
 221
 222         return IRQ_HANDLED;
 223 }
 224
 225 static void fdp_nci_i2c_read_device_properties(struct device *dev,
 226                                                u8 *clock_type, u32 *clock_freq,
 227                                                u8 **fw_vsc_cfg)
 228 {
 229         int r;
 230         u8 len;
 231
 232         r = device_property_read_u8(dev, FDP_DP_CLOCK_TYPE_NAME, clock_type);
 233         if (r) {
 234                 dev_dbg(dev, "Using default clock type");
 235                 *clock_type = 0;
 236         }
 237
 238         r = device_property_read_u32(dev, FDP_DP_CLOCK_FREQ_NAME, clock_freq);
 239         if (r) {
 240                 dev_dbg(dev, "Using default clock frequency\n");
 241                 *clock_freq = 26000;
 242         }
 243
 244         if (device_property_present(dev, FDP_DP_FW_VSC_CFG_NAME)) {
 245                 r = device_property_read_u8(dev, FDP_DP_FW_VSC_CFG_NAME,
 246                                             &len);
 247
 248                 if (r || len <= 0)
 249                         goto vsc_read_err;
 250
 251                 /* Add 1 to the length to inclue the length byte itself */
 252                 len++;
 253
 254                 *fw_vsc_cfg = devm_kmalloc_array(dev,
 255                                            len, sizeof(**fw_vsc_cfg),
 256                                            GFP_KERNEL);
 257
 258                 r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
 259                                                   *fw_vsc_cfg, len);
 260
 261                 if (r) {
 262                         devm_kfree(dev, *fw_vsc_cfg);
 263                         goto vsc_read_err;
 264                 }
 265         } else {
 266 vsc_read_err:
 267                 dev_dbg(dev, "FW vendor specific commands not present\n");
 268                 *fw_vsc_cfg = NULL;
 269         }
 270
 271         dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
 272                 *clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
 273 }
 274
 275 static const struct acpi_gpio_params power_gpios = { 0, 0, false };
 276
 277 static const struct acpi_gpio_mapping acpi_fdp_gpios[] = {
 278         { "power-gpios", &power_gpios, 1 },
 279         {},
 280 };
 281
 282 static int fdp_nci_i2c_probe(struct i2c_client *client)
 283 {
 284         struct fdp_i2c_phy *phy;
 285         struct device *dev = &client->dev;
 286         u8 *fw_vsc_cfg;
 287         u8 clock_type;
 288         u32 clock_freq;
 289         int r = 0;
 290
 291         dev_dbg(dev, "%s\n", __func__);
 292
 293         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 294                 nfc_err(dev, "No I2C_FUNC_I2C support\n");
 295                 return -ENODEV;
 296         }
 297
 298         /* Checking if we have an irq */
 299         if (client->irq <= 0) {
 300                 nfc_err(dev, "IRQ not present\n");
 301                 return -ENODEV;
 302         }
 303
 304         phy = devm_kzalloc(dev, sizeof(struct fdp_i2c_phy), GFP_KERNEL);
 305         if (!phy)
 306                 return -ENOMEM;
 307
 308         phy->i2c_dev = client;
 309         phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
 310         i2c_set_clientdata(client, phy);
 311
 312         r = devm_request_threaded_irq(dev, client->irq,
 313                                       NULL, fdp_nci_i2c_irq_thread_fn,
 314                                       IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 315                                       FDP_I2C_DRIVER_NAME, phy);
 316
 317         if (r < 0) {
 318                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 319                 return r;
 320         }
 321
 322         r = devm_acpi_dev_add_driver_gpios(dev, acpi_fdp_gpios);
 323         if (r)
 324                 dev_dbg(dev, "Unable to add GPIO mapping table\n");
 325
 326         /* Requesting the power gpio */
 327         phy->power_gpio = devm_gpiod_get(dev, "power", GPIOD_OUT_LOW);
 328         if (IS_ERR(phy->power_gpio)) {
 329                 nfc_err(dev, "Power GPIO request failed\n");
 330                 return PTR_ERR(phy->power_gpio);
 331         }
 332
 333         /* read device properties to get the clock and production settings */
 334         fdp_nci_i2c_read_device_properties(dev, &clock_type, &clock_freq,
 335                                            &fw_vsc_cfg);
 336
 337         /* Call the NFC specific probe function */
 338         r = fdp_nci_probe(phy, &i2c_phy_ops, &phy->ndev,
 339                           FDP_FRAME_HEADROOM, FDP_FRAME_TAILROOM,
 340                           clock_type, clock_freq, fw_vsc_cfg);
 341         if (r < 0) {
 342                 nfc_err(dev, "NCI probing error\n");
 343                 return r;
 344         }
 345
 346         dev_dbg(dev, "I2C driver loaded\n");
 347         return 0;
 348 }
 349
 350 static int fdp_nci_i2c_remove(struct i2c_client *client)
 351 {
 352         struct fdp_i2c_phy *phy = i2c_get_clientdata(client);
 353
 354         dev_dbg(&client->dev, "%s\n", __func__);
 355
 356         fdp_nci_remove(phy->ndev);
 357         fdp_nci_i2c_disable(phy);
 358
 359         return 0;
 360 }
 361
 362 static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
 363         {"INT339A", 0},
 364         {}
 365 };
 366 MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);
 367
 368 static struct i2c_driver fdp_nci_i2c_driver = {
 369         .driver = {
 370                    .name = FDP_I2C_DRIVER_NAME,
 371                    .acpi_match_table = ACPI_PTR(fdp_nci_i2c_acpi_match),
 372                   },
 373         .probe_new = fdp_nci_i2c_probe,
 374         .remove = fdp_nci_i2c_remove,
 375 };
 376 module_i2c_driver(fdp_nci_i2c_driver);
 377
 378 MODULE_LICENSE("GPL");
 379 MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
 380 MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");