drivers/nfc/fdp/i2c.c

   1 /* -------------------------------------------------------------------------
   2  * Copyright (C) 2014-2016, Intel Corporation
   3  *
   4  *  This program is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU General Public License as published by
   6  *  the Free Software Foundation; either version 2 of the License, or
   7  *  (at your option) any later version.
   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  */
  15
  16 #include <linux/module.h>
  17 #include <linux/acpi.h>
  18 #include <linux/i2c.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/nfc.h>
  21 #include <linux/delay.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <net/nfc/nfc.h>
  24 #include <net/nfc/nci_core.h>
  25
  26 #include "fdp.h"
  27
  28 #define FDP_I2C_DRIVER_NAME     "fdp_nci_i2c"
  29
  30 #define FDP_DP_POWER_GPIO_NAME  "power"
  31 #define FDP_DP_CLOCK_TYPE_NAME  "clock-type"
  32 #define FDP_DP_CLOCK_FREQ_NAME  "clock-freq"
  33 #define FDP_DP_FW_VSC_CFG_NAME  "fw-vsc-cfg"
  34
  35 #define FDP_FRAME_HEADROOM      2
  36 #define FDP_FRAME_TAILROOM      1
  37
  38 #define FDP_NCI_I2C_MIN_PAYLOAD 5
  39 #define FDP_NCI_I2C_MAX_PAYLOAD 261
  40
  41 #define FDP_POWER_OFF           0
  42 #define FDP_POWER_ON            1
  43
  44 #define fdp_nci_i2c_dump_skb(dev, prefix, skb)                          \
  45         print_hex_dump(KERN_DEBUG, prefix": ", DUMP_PREFIX_OFFSET,      \
  46                        16, 1, (skb)->data, (skb)->len, 0)
  47
  48 static void fdp_nci_i2c_reset(struct fdp_i2c_phy *phy)
  49 {
  50         /* Reset RST/WakeUP for at least 100 micro-second */
  51         gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_OFF);
  52         usleep_range(1000, 4000);
  53         gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_ON);
  54         usleep_range(10000, 14000);
  55 }
  56
  57 static int fdp_nci_i2c_enable(void *phy_id)
  58 {
  59         struct fdp_i2c_phy *phy = phy_id;
  60
  61         dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
  62         fdp_nci_i2c_reset(phy);
  63
  64         return 0;
  65 }
  66
  67 static void fdp_nci_i2c_disable(void *phy_id)
  68 {
  69         struct fdp_i2c_phy *phy = phy_id;
  70
  71         dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
  72         fdp_nci_i2c_reset(phy);
  73 }
  74
  75 static void fdp_nci_i2c_add_len_lrc(struct sk_buff *skb)
  76 {
  77         u8 lrc = 0;
  78         u16 len, i;
  79
  80         /* Add length header */
  81         len = skb->len;
  82         *skb_push(skb, 1) = len & 0xff;
  83         *skb_push(skb, 1) = len >> 8;
  84
  85         /* Compute and add lrc */
  86         for (i = 0; i < len + 2; i++)
  87                 lrc ^= skb->data[i];
  88
  89         *skb_put(skb, 1) = lrc;
  90 }
  91
  92 static void fdp_nci_i2c_remove_len_lrc(struct sk_buff *skb)
  93 {
  94         skb_pull(skb, FDP_FRAME_HEADROOM);
  95         skb_trim(skb, skb->len - FDP_FRAME_TAILROOM);
  96 }
  97
  98 static int fdp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
  99 {
 100         struct fdp_i2c_phy *phy = phy_id;
 101         struct i2c_client *client = phy->i2c_dev;
 102         int r;
 103
 104         if (phy->hard_fault != 0)
 105                 return phy->hard_fault;
 106
 107         fdp_nci_i2c_add_len_lrc(skb);
 108         fdp_nci_i2c_dump_skb(&client->dev, "fdp_wr", skb);
 109
 110         r = i2c_master_send(client, skb->data, skb->len);
 111         if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
 112                 usleep_range(1000, 4000);
 113                 r = i2c_master_send(client, skb->data, skb->len);
 114         }
 115
 116         if (r < 0 || r != skb->len)
 117                 dev_dbg(&client->dev, "%s: error err=%d len=%d\n",
 118                         __func__, r, skb->len);
 119
 120         if (r >= 0) {
 121                 if (r != skb->len) {
 122                         phy->hard_fault = r;
 123                         r = -EREMOTEIO;
 124                 } else {
 125                         r = 0;
 126                 }
 127         }
 128
 129         fdp_nci_i2c_remove_len_lrc(skb);
 130
 131         return r;
 132 }
 133
 134 static struct nfc_phy_ops i2c_phy_ops = {
 135         .write = fdp_nci_i2c_write,
 136         .enable = fdp_nci_i2c_enable,
 137         .disable = fdp_nci_i2c_disable,
 138 };
 139
 140 static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
 141 {
 142         int r, len;
 143         u8 tmp[FDP_NCI_I2C_MAX_PAYLOAD], lrc, k;
 144         u16 i;
 145         struct i2c_client *client = phy->i2c_dev;
 146
 147         *skb = NULL;
 148
 149         /* Read the length packet and the data packet */
 150         for (k = 0; k < 2; k++) {
 151
 152                 len = phy->next_read_size;
 153
 154                 r = i2c_master_recv(client, tmp, len);
 155                 if (r != len) {
 156                         dev_dbg(&client->dev, "%s: i2c recv err: %d\n",
 157                                 __func__, r);
 158                         goto flush;
 159                 }
 160
 161                 /* Check packet integruty */
 162                 for (lrc = i = 0; i < r; i++)
 163                         lrc ^= tmp[i];
 164
 165                 /*
 166                  * LRC check failed. This may due to transmission error or
 167                  * desynchronization between driver and FDP. Drop the paquet
 168                  * and force resynchronization
 169                  */
 170                 if (lrc) {
 171                         dev_dbg(&client->dev, "%s: corrupted packet\n",
 172                                 __func__);
 173                         phy->next_read_size = 5;
 174                         goto flush;
 175                 }
 176
 177                 /* Packet that contains a length */
 178                 if (tmp[0] == 0 && tmp[1] == 0) {
 179                         phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
 180                 } else {
 181                         phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
 182
 183                         *skb = alloc_skb(len, GFP_KERNEL);
 184                         if (*skb == NULL) {
 185                                 r = -ENOMEM;
 186                                 goto flush;
 187                         }
 188
 189                         memcpy(skb_put(*skb, len), tmp, len);
 190                         fdp_nci_i2c_dump_skb(&client->dev, "fdp_rd", *skb);
 191
 192                         fdp_nci_i2c_remove_len_lrc(*skb);
 193                 }
 194         }
 195
 196         return 0;
 197
 198 flush:
 199         /* Flush the remaining data */
 200         if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
 201                 r = -EREMOTEIO;
 202
 203         return r;
 204 }
 205
 206 static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
 207 {
 208         struct fdp_i2c_phy *phy = phy_id;
 209         struct i2c_client *client;
 210         struct sk_buff *skb;
 211         int r;
 212
 213         client = phy->i2c_dev;
 214         dev_dbg(&client->dev, "%s\n", __func__);
 215
 216         if (!phy || irq != phy->i2c_dev->irq) {
 217                 WARN_ON_ONCE(1);
 218                 return IRQ_NONE;
 219         }
 220
 221         r = fdp_nci_i2c_read(phy, &skb);
 222
 223         if (r == -EREMOTEIO)
 224                 return IRQ_HANDLED;
 225         else if (r == -ENOMEM || r == -EBADMSG)
 226                 return IRQ_HANDLED;
 227
 228         if (skb != NULL)
 229                 fdp_nci_recv_frame(phy->ndev, skb);
 230
 231         return IRQ_HANDLED;
 232 }
 233
 234 static void fdp_nci_i2c_read_device_properties(struct device *dev,
 235                                                u8 *clock_type, u32 *clock_freq,
 236                                                u8 **fw_vsc_cfg)
 237 {
 238         int r;
 239         u8 len;
 240
 241         r = device_property_read_u8(dev, FDP_DP_CLOCK_TYPE_NAME, clock_type);
 242         if (r) {
 243                 dev_dbg(dev, "Using default clock type");
 244                 *clock_type = 0;
 245         }
 246
 247         r = device_property_read_u32(dev, FDP_DP_CLOCK_FREQ_NAME, clock_freq);
 248         if (r) {
 249                 dev_dbg(dev, "Using default clock frequency\n");
 250                 *clock_freq = 26000;
 251         }
 252
 253         if (device_property_present(dev, FDP_DP_FW_VSC_CFG_NAME)) {
 254                 r = device_property_read_u8(dev, FDP_DP_FW_VSC_CFG_NAME,
 255                                             &len);
 256
 257                 if (r || len <= 0)
 258                         goto vsc_read_err;
 259
 260                 /* Add 1 to the length to inclue the length byte itself */
 261                 len++;
 262
 263                 *fw_vsc_cfg = devm_kmalloc(dev,
 264                                            len * sizeof(**fw_vsc_cfg),
 265                                            GFP_KERNEL);
 266
 267                 r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
 268                                                   *fw_vsc_cfg, len);
 269
 270                 if (r) {
 271                         devm_kfree(dev, fw_vsc_cfg);
 272                         goto vsc_read_err;
 273                 }
 274         } else {
 275 vsc_read_err:
 276                 dev_dbg(dev, "FW vendor specific commands not present\n");
 277                 *fw_vsc_cfg = NULL;
 278         }
 279
 280         dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
 281                 *clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
 282 }
 283
 284 static int fdp_nci_i2c_probe(struct i2c_client *client,
 285                              const struct i2c_device_id *id)
 286 {
 287         struct fdp_i2c_phy *phy;
 288         struct device *dev = &client->dev;
 289         u8 *fw_vsc_cfg;
 290         u8 clock_type;
 291         u32 clock_freq;
 292         int r = 0;
 293
 294         dev_dbg(dev, "%s\n", __func__);
 295
 296         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 297                 nfc_err(dev, "No I2C_FUNC_I2C support\n");
 298                 return -ENODEV;
 299         }
 300
 301         phy = devm_kzalloc(dev, sizeof(struct fdp_i2c_phy),
 302                            GFP_KERNEL);
 303         if (!phy)
 304                 return -ENOMEM;
 305
 306         phy->i2c_dev = client;
 307         phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
 308         i2c_set_clientdata(client, phy);
 309
 310         /* Checking if we have an irq */
 311         if (client->irq <= 0) {
 312                 dev_err(dev, "IRQ not present\n");
 313                 return -ENODEV;
 314         }
 315
 316         r = request_threaded_irq(client->irq, NULL, fdp_nci_i2c_irq_thread_fn,
 317                                  IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 318                                  FDP_I2C_DRIVER_NAME, phy);
 319
 320         if (r < 0) {
 321                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 322                 return r;
 323         }
 324
 325         /* Requesting the power gpio */
 326         phy->power_gpio = devm_gpiod_get(dev, FDP_DP_POWER_GPIO_NAME,
 327                                          GPIOD_OUT_LOW);
 328
 329         if (IS_ERR(phy->power_gpio)) {
 330                 nfc_err(dev, "Power GPIO request failed\n");
 331                 return PTR_ERR(phy->power_gpio);
 332         }
 333
 334         /* read device properties to get the clock and production settings */
 335         fdp_nci_i2c_read_device_properties(dev, &clock_type, &clock_freq,
 336                                            &fw_vsc_cfg);
 337
 338         /* Call the NFC specific probe function */
 339         r = fdp_nci_probe(phy, &i2c_phy_ops, &phy->ndev,
 340                           FDP_FRAME_HEADROOM, FDP_FRAME_TAILROOM,
 341                           clock_type, clock_freq, fw_vsc_cfg);
 342         if (r < 0) {
 343                 nfc_err(dev, "NCI probing error\n");
 344                 return r;
 345         }
 346
 347         dev_dbg(dev, "I2C driver loaded\n");
 348         return 0;
 349 }
 350
 351 static int fdp_nci_i2c_remove(struct i2c_client *client)
 352 {
 353         struct fdp_i2c_phy *phy = i2c_get_clientdata(client);
 354
 355         dev_dbg(&client->dev, "%s\n", __func__);
 356
 357         fdp_nci_remove(phy->ndev);
 358         fdp_nci_i2c_disable(phy);
 359
 360         return 0;
 361 }
 362
 363 static struct i2c_device_id fdp_nci_i2c_id_table[] = {
 364         {"int339a", 0},
 365         {}
 366 };
 367 MODULE_DEVICE_TABLE(i2c, fdp_nci_i2c_id_table);
 368
 369 static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
 370         {"INT339A", 0},
 371         {}
 372 };
 373 MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);
 374
 375 static struct i2c_driver fdp_nci_i2c_driver = {
 376         .driver = {
 377                    .name = FDP_I2C_DRIVER_NAME,
 378                    .acpi_match_table = ACPI_PTR(fdp_nci_i2c_acpi_match),
 379                   },
 380         .id_table = fdp_nci_i2c_id_table,
 381         .probe = fdp_nci_i2c_probe,
 382         .remove = fdp_nci_i2c_remove,
 383 };
 384 module_i2c_driver(fdp_nci_i2c_driver);
 385
 386 MODULE_LICENSE("GPL");
 387 MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
 388 MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");