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         fdp_nci_i2c_reset(phy);
  53
  54         return 0;
  55 }
  56
  57 static 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
  64 static 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
  81 static 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
  87 static 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
 123 static 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
 129 static 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
 187 flush:
 188         /* Flush the remaining data */
 189         if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
 190                 r = -EREMOTEIO;
 191
 192         return r;
 193 }
 194
 195 static 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
 219 static 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 {
 260 vsc_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
 269 static const struct acpi_gpio_params power_gpios = { 0, 0, false };
 270
 271 static const struct acpi_gpio_mapping acpi_fdp_gpios[] = {
 272         { "power-gpios", &power_gpios, 1 },
 273         {},
 274 };
 275
 276 static 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
 342 static 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
 352 static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
 353         {"INT339A", 0},
 354         {}
 355 };
 356 MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);
 357
 358 static 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 };
 366 module_i2c_driver(fdp_nci_i2c_driver);
 367
 368 MODULE_LICENSE("GPL");
 369 MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
 370 MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");