drivers/staging/pi433/pi433_if.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * userspace interface for pi433 radio module
   4  *
   5  * Pi433 is a 433MHz radio module for the Raspberry Pi.
   6  * It is based on the HopeRf Module RFM69CW. Therefore inside of this
   7  * driver, you'll find an abstraction of the rf69 chip.
   8  *
   9  * If needed, this driver could be extended, to also support other
  10  * devices, basing on HopeRfs rf69.
  11  *
  12  * The driver can also be extended, to support other modules of
  13  * HopeRf with a similar interace - e. g. RFM69HCW, RFM12, RFM95, ...
  14  *
  15  * Copyright (C) 2016 Wolf-Entwicklungen
  16  *      Marcus Wolf <linux@wolf-entwicklungen.de>
  17  */
  18
  19 #undef DEBUG
  20
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/idr.h>
  24 #include <linux/ioctl.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/fs.h>
  27 #include <linux/device.h>
  28 #include <linux/cdev.h>
  29 #include <linux/err.h>
  30 #include <linux/kfifo.h>
  31 #include <linux/errno.h>
  32 #include <linux/mutex.h>
  33 #include <linux/of.h>
  34 #include <linux/of_device.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/irq.h>
  37 #include <linux/gpio/consumer.h>
  38 #include <linux/kthread.h>
  39 #include <linux/wait.h>
  40 #include <linux/spi/spi.h>
  41 #ifdef CONFIG_COMPAT
  42 #include <linux/compat.h>
  43 #endif
  44
  45 #include "pi433_if.h"
  46 #include "rf69.h"
  47
  48 #define N_PI433_MINORS                  BIT(MINORBITS) /*32*/   /* ... up to 256 */
  49 #define MAX_MSG_SIZE                    900     /* min: FIFO_SIZE! */
  50 #define MSG_FIFO_SIZE                   65536   /* 65536 = 2^16  */
  51 #define NUM_DIO                         2
  52
  53 static dev_t pi433_dev;
  54 static DEFINE_IDR(pi433_idr);
  55 static DEFINE_MUTEX(minor_lock); /* Protect idr accesses */
  56
  57 static struct class *pi433_class; /* mainly for udev to create /dev/pi433 */
  58
  59 /*
  60  * tx config is instance specific
  61  * so with each open a new tx config struct is needed
  62  */
  63 /*
  64  * rx config is device specific
  65  * so we have just one rx config, ebedded in device struct
  66  */
  67 struct pi433_device {
  68         /* device handling related values */
  69         dev_t                   devt;
  70         int                     minor;
  71         struct device           *dev;
  72         struct cdev             *cdev;
  73         struct spi_device       *spi;
  74
  75         /* irq related values */
  76         struct gpio_desc        *gpiod[NUM_DIO];
  77         int                     irq_num[NUM_DIO];
  78         u8                      irq_state[NUM_DIO];
  79
  80         /* tx related values */
  81         STRUCT_KFIFO_REC_1(MSG_FIFO_SIZE) tx_fifo;
  82         struct mutex            tx_fifo_lock; /* serialize userspace writers */
  83         struct task_struct      *tx_task_struct;
  84         wait_queue_head_t       tx_wait_queue;
  85         u8                      free_in_fifo;
  86         char                    buffer[MAX_MSG_SIZE];
  87
  88         /* rx related values */
  89         struct pi433_rx_cfg     rx_cfg;
  90         u8                      *rx_buffer;
  91         unsigned int            rx_buffer_size;
  92         u32                     rx_bytes_to_drop;
  93         u32                     rx_bytes_dropped;
  94         unsigned int            rx_position;
  95         struct mutex            rx_lock;
  96         wait_queue_head_t       rx_wait_queue;
  97
  98         /* fifo wait queue */
  99         struct task_struct      *fifo_task_struct;
 100         wait_queue_head_t       fifo_wait_queue;
 101
 102         /* flags */
 103         bool                    rx_active;
 104         bool                    tx_active;
 105         bool                    interrupt_rx_allowed;
 106 };
 107
 108 struct pi433_instance {
 109         struct pi433_device     *device;
 110         struct pi433_tx_cfg     tx_cfg;
 111 };
 112
 113 /*-------------------------------------------------------------------------*/
 114
 115 /* GPIO interrupt handlers */
 116 static irqreturn_t DIO0_irq_handler(int irq, void *dev_id)
 117 {
 118         struct pi433_device *device = dev_id;
 119
 120         if (device->irq_state[DIO0] == DIO_PACKET_SENT) {
 121                 device->free_in_fifo = FIFO_SIZE;
 122                 dev_dbg(device->dev, "DIO0 irq: Packet sent\n");
 123                 wake_up_interruptible(&device->fifo_wait_queue);
 124         } else if (device->irq_state[DIO0] == DIO_RSSI_DIO0) {
 125                 dev_dbg(device->dev, "DIO0 irq: RSSI level over threshold\n");
 126                 wake_up_interruptible(&device->rx_wait_queue);
 127         } else if (device->irq_state[DIO0] == DIO_PAYLOAD_READY) {
 128                 dev_dbg(device->dev, "DIO0 irq: Payload ready\n");
 129                 device->free_in_fifo = 0;
 130                 wake_up_interruptible(&device->fifo_wait_queue);
 131         }
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 static irqreturn_t DIO1_irq_handler(int irq, void *dev_id)
 137 {
 138         struct pi433_device *device = dev_id;
 139
 140         if (device->irq_state[DIO1] == DIO_FIFO_NOT_EMPTY_DIO1) {
 141                 device->free_in_fifo = FIFO_SIZE;
 142         } else if (device->irq_state[DIO1] == DIO_FIFO_LEVEL) {
 143                 if (device->rx_active)
 144                         device->free_in_fifo = FIFO_THRESHOLD - 1;
 145                 else
 146                         device->free_in_fifo = FIFO_SIZE - FIFO_THRESHOLD - 1;
 147         }
 148         dev_dbg(device->dev,
 149                 "DIO1 irq: %d bytes free in fifo\n", device->free_in_fifo);
 150         wake_up_interruptible(&device->fifo_wait_queue);
 151
 152         return IRQ_HANDLED;
 153 }
 154
 155 /*-------------------------------------------------------------------------*/
 156
 157 static int
 158 rf69_set_rx_cfg(struct pi433_device *dev, struct pi433_rx_cfg *rx_cfg)
 159 {
 160         int ret;
 161         int payload_length;
 162
 163         /* receiver config */
 164         ret = rf69_set_frequency(dev->spi, rx_cfg->frequency);
 165         if (ret < 0)
 166                 return ret;
 167         ret = rf69_set_bit_rate(dev->spi, rx_cfg->bit_rate);
 168         if (ret < 0)
 169                 return ret;
 170         ret = rf69_set_modulation(dev->spi, rx_cfg->modulation);
 171         if (ret < 0)
 172                 return ret;
 173         ret = rf69_set_antenna_impedance(dev->spi, rx_cfg->antenna_impedance);
 174         if (ret < 0)
 175                 return ret;
 176         ret = rf69_set_rssi_threshold(dev->spi, rx_cfg->rssi_threshold);
 177         if (ret < 0)
 178                 return ret;
 179         ret = rf69_set_ook_threshold_dec(dev->spi, rx_cfg->threshold_decrement);
 180         if (ret < 0)
 181                 return ret;
 182         ret = rf69_set_bandwidth(dev->spi, rx_cfg->bw_mantisse,
 183                                  rx_cfg->bw_exponent);
 184         if (ret < 0)
 185                 return ret;
 186         ret = rf69_set_bandwidth_during_afc(dev->spi, rx_cfg->bw_mantisse,
 187                                             rx_cfg->bw_exponent);
 188         if (ret < 0)
 189                 return ret;
 190         ret = rf69_set_dagc(dev->spi, rx_cfg->dagc);
 191         if (ret < 0)
 192                 return ret;
 193
 194         dev->rx_bytes_to_drop = rx_cfg->bytes_to_drop;
 195
 196         /* packet config */
 197         /* enable */
 198         if (rx_cfg->enable_sync == OPTION_ON) {
 199                 ret = rf69_enable_sync(dev->spi);
 200                 if (ret < 0)
 201                         return ret;
 202
 203                 ret = rf69_set_fifo_fill_condition(dev->spi,
 204                                                    after_sync_interrupt);
 205                 if (ret < 0)
 206                         return ret;
 207         } else {
 208                 ret = rf69_disable_sync(dev->spi);
 209                 if (ret < 0)
 210                         return ret;
 211
 212                 ret = rf69_set_fifo_fill_condition(dev->spi, always);
 213                 if (ret < 0)
 214                         return ret;
 215         }
 216         if (rx_cfg->enable_length_byte == OPTION_ON) {
 217                 ret = rf69_set_packet_format(dev->spi, packet_length_var);
 218                 if (ret < 0)
 219                         return ret;
 220         } else {
 221                 ret = rf69_set_packet_format(dev->spi, packet_length_fix);
 222                 if (ret < 0)
 223                         return ret;
 224         }
 225         ret = rf69_set_address_filtering(dev->spi,
 226                                          rx_cfg->enable_address_filtering);
 227         if (ret < 0)
 228                 return ret;
 229
 230         if (rx_cfg->enable_crc == OPTION_ON) {
 231                 ret = rf69_enable_crc(dev->spi);
 232                 if (ret < 0)
 233                         return ret;
 234         } else {
 235                 ret = rf69_disable_crc(dev->spi);
 236                 if (ret < 0)
 237                         return ret;
 238         }
 239
 240         /* lengths */
 241         ret = rf69_set_sync_size(dev->spi, rx_cfg->sync_length);
 242         if (ret < 0)
 243                 return ret;
 244         if (rx_cfg->enable_length_byte == OPTION_ON) {
 245                 ret = rf69_set_payload_length(dev->spi, 0xff);
 246                 if (ret < 0)
 247                         return ret;
 248         } else if (rx_cfg->fixed_message_length != 0) {
 249                 payload_length = rx_cfg->fixed_message_length;
 250                 if (rx_cfg->enable_length_byte  == OPTION_ON)
 251                         payload_length++;
 252                 if (rx_cfg->enable_address_filtering != filtering_off)
 253                         payload_length++;
 254                 ret = rf69_set_payload_length(dev->spi, payload_length);
 255                 if (ret < 0)
 256                         return ret;
 257         } else {
 258                 ret = rf69_set_payload_length(dev->spi, 0);
 259                 if (ret < 0)
 260                         return ret;
 261         }
 262
 263         /* values */
 264         if (rx_cfg->enable_sync == OPTION_ON) {
 265                 ret = rf69_set_sync_values(dev->spi, rx_cfg->sync_pattern);
 266                 if (ret < 0)
 267                         return ret;
 268         }
 269         if (rx_cfg->enable_address_filtering != filtering_off) {
 270                 ret = rf69_set_node_address(dev->spi, rx_cfg->node_address);
 271                 if (ret < 0)
 272                         return ret;
 273                 ret = rf69_set_broadcast_address(dev->spi,
 274                                                  rx_cfg->broadcast_address);
 275                 if (ret < 0)
 276                         return ret;
 277         }
 278
 279         return 0;
 280 }
 281
 282 static int
 283 rf69_set_tx_cfg(struct pi433_device *dev, struct pi433_tx_cfg *tx_cfg)
 284 {
 285         int ret;
 286
 287         ret = rf69_set_frequency(dev->spi, tx_cfg->frequency);
 288         if (ret < 0)
 289                 return ret;
 290         ret = rf69_set_bit_rate(dev->spi, tx_cfg->bit_rate);
 291         if (ret < 0)
 292                 return ret;
 293         ret = rf69_set_modulation(dev->spi, tx_cfg->modulation);
 294         if (ret < 0)
 295                 return ret;
 296         ret = rf69_set_deviation(dev->spi, tx_cfg->dev_frequency);
 297         if (ret < 0)
 298                 return ret;
 299         ret = rf69_set_pa_ramp(dev->spi, tx_cfg->pa_ramp);
 300         if (ret < 0)
 301                 return ret;
 302         ret = rf69_set_modulation_shaping(dev->spi, tx_cfg->mod_shaping);
 303         if (ret < 0)
 304                 return ret;
 305         ret = rf69_set_tx_start_condition(dev->spi, tx_cfg->tx_start_condition);
 306         if (ret < 0)
 307                 return ret;
 308
 309         /* packet format enable */
 310         if (tx_cfg->enable_preamble == OPTION_ON) {
 311                 ret = rf69_set_preamble_length(dev->spi,
 312                                                tx_cfg->preamble_length);
 313                 if (ret < 0)
 314                         return ret;
 315         } else {
 316                 ret = rf69_set_preamble_length(dev->spi, 0);
 317                 if (ret < 0)
 318                         return ret;
 319         }
 320
 321         if (tx_cfg->enable_sync == OPTION_ON) {
 322                 ret = rf69_enable_sync(dev->spi);
 323                 if (ret < 0)
 324                         return ret;
 325         } else {
 326                 ret = rf69_disable_sync(dev->spi);
 327                 if (ret < 0)
 328                         return ret;
 329         }
 330
 331         if (tx_cfg->enable_length_byte == OPTION_ON) {
 332                 ret = rf69_set_packet_format(dev->spi, packet_length_var);
 333                 if (ret < 0)
 334                         return ret;
 335         } else {
 336                 ret = rf69_set_packet_format(dev->spi, packet_length_fix);
 337                 if (ret < 0)
 338                         return ret;
 339         }
 340
 341         if (tx_cfg->enable_crc == OPTION_ON) {
 342                 ret = rf69_enable_crc(dev->spi);
 343                 if (ret < 0)
 344                         return ret;
 345         } else {
 346                 ret = rf69_disable_crc(dev->spi);
 347                 if (ret < 0)
 348                         return ret;
 349         }
 350
 351         /* configure sync, if enabled */
 352         if (tx_cfg->enable_sync == OPTION_ON) {
 353                 ret = rf69_set_sync_size(dev->spi, tx_cfg->sync_length);
 354                 if (ret < 0)
 355                         return ret;
 356                 ret = rf69_set_sync_values(dev->spi, tx_cfg->sync_pattern);
 357                 if (ret < 0)
 358                         return ret;
 359         }
 360
 361         return 0;
 362 }
 363
 364 /*-------------------------------------------------------------------------*/
 365
 366 static int
 367 pi433_start_rx(struct pi433_device *dev)
 368 {
 369         int retval;
 370
 371         /* return without action, if no pending read request */
 372         if (!dev->rx_active)
 373                 return 0;
 374
 375         /* setup for receiving */
 376         retval = rf69_set_rx_cfg(dev, &dev->rx_cfg);
 377         if (retval)
 378                 return retval;
 379
 380         /* setup rssi irq */
 381         retval = rf69_set_dio_mapping(dev->spi, DIO0, DIO_RSSI_DIO0);
 382         if (retval < 0)
 383                 return retval;
 384         dev->irq_state[DIO0] = DIO_RSSI_DIO0;
 385         irq_set_irq_type(dev->irq_num[DIO0], IRQ_TYPE_EDGE_RISING);
 386
 387         /* setup fifo level interrupt */
 388         retval = rf69_set_fifo_threshold(dev->spi, FIFO_SIZE - FIFO_THRESHOLD);
 389         if (retval < 0)
 390                 return retval;
 391         retval = rf69_set_dio_mapping(dev->spi, DIO1, DIO_FIFO_LEVEL);
 392         if (retval < 0)
 393                 return retval;
 394         dev->irq_state[DIO1] = DIO_FIFO_LEVEL;
 395         irq_set_irq_type(dev->irq_num[DIO1], IRQ_TYPE_EDGE_RISING);
 396
 397         /* set module to receiving mode */
 398         retval = rf69_set_mode(dev->spi, receive);
 399         if (retval < 0)
 400                 return retval;
 401
 402         return 0;
 403 }
 404
 405 /*-------------------------------------------------------------------------*/
 406
 407 static int
 408 pi433_receive(void *data)
 409 {
 410         struct pi433_device *dev = data;
 411         struct spi_device *spi = dev->spi;
 412         int bytes_to_read, bytes_total;
 413         int retval;
 414
 415         dev->interrupt_rx_allowed = false;
 416
 417         /* wait for any tx to finish */
 418         dev_dbg(dev->dev, "rx: going to wait for any tx to finish");
 419         retval = wait_event_interruptible(dev->rx_wait_queue, !dev->tx_active);
 420         if (retval) {
 421                 /* wait was interrupted */
 422                 dev->interrupt_rx_allowed = true;
 423                 wake_up_interruptible(&dev->tx_wait_queue);
 424                 return retval;
 425         }
 426
 427         /* prepare status vars */
 428         dev->free_in_fifo = FIFO_SIZE;
 429         dev->rx_position = 0;
 430         dev->rx_bytes_dropped = 0;
 431
 432         /* setup radio module to listen for something "in the air" */
 433         retval = pi433_start_rx(dev);
 434         if (retval)
 435                 return retval;
 436
 437         /* now check RSSI, if low wait for getting high (RSSI interrupt) */
 438         while (!rf69_get_flag(dev->spi, rssi_exceeded_threshold)) {
 439                 /* allow tx to interrupt us while waiting for high RSSI */
 440                 dev->interrupt_rx_allowed = true;
 441                 wake_up_interruptible(&dev->tx_wait_queue);
 442
 443                 /* wait for RSSI level to become high */
 444                 dev_dbg(dev->dev, "rx: going to wait for high RSSI level");
 445                 retval = wait_event_interruptible(dev->rx_wait_queue,
 446                                                   rf69_get_flag(dev->spi,
 447                                                                 rssi_exceeded_threshold));
 448                 if (retval) /* wait was interrupted */
 449                         goto abort;
 450                 dev->interrupt_rx_allowed = false;
 451
 452                 /* cross check for ongoing tx */
 453                 if (!dev->tx_active)
 454                         break;
 455         }
 456
 457         /* configure payload ready irq */
 458         retval = rf69_set_dio_mapping(spi, DIO0, DIO_PAYLOAD_READY);
 459         if (retval < 0)
 460                 goto abort;
 461         dev->irq_state[DIO0] = DIO_PAYLOAD_READY;
 462         irq_set_irq_type(dev->irq_num[DIO0], IRQ_TYPE_EDGE_RISING);
 463
 464         /* fixed or unlimited length? */
 465         if (dev->rx_cfg.fixed_message_length != 0) {
 466                 if (dev->rx_cfg.fixed_message_length > dev->rx_buffer_size) {
 467                         retval = -1;
 468                         goto abort;
 469                 }
 470                 bytes_total = dev->rx_cfg.fixed_message_length;
 471                 dev_dbg(dev->dev, "rx: msg len set to %d by fixed length",
 472                         bytes_total);
 473         } else {
 474                 bytes_total = dev->rx_buffer_size;
 475                 dev_dbg(dev->dev, "rx: msg len set to %d as requested by read",
 476                         bytes_total);
 477         }
 478
 479         /* length byte enabled? */
 480         if (dev->rx_cfg.enable_length_byte == OPTION_ON) {
 481                 retval = wait_event_interruptible(dev->fifo_wait_queue,
 482                                                   dev->free_in_fifo < FIFO_SIZE);
 483                 if (retval) /* wait was interrupted */
 484                         goto abort;
 485
 486                 rf69_read_fifo(spi, (u8 *)&bytes_total, 1);
 487                 if (bytes_total > dev->rx_buffer_size) {
 488                         retval = -1;
 489                         goto abort;
 490                 }
 491                 dev->free_in_fifo++;
 492                 dev_dbg(dev->dev, "rx: msg len reset to %d due to length byte",
 493                         bytes_total);
 494         }
 495
 496         /* address byte enabled? */
 497         if (dev->rx_cfg.enable_address_filtering != filtering_off) {
 498                 u8 dummy;
 499
 500                 bytes_total--;
 501
 502                 retval = wait_event_interruptible(dev->fifo_wait_queue,
 503                                                   dev->free_in_fifo < FIFO_SIZE);
 504                 if (retval) /* wait was interrupted */
 505                         goto abort;
 506
 507                 rf69_read_fifo(spi, &dummy, 1);
 508                 dev->free_in_fifo++;
 509                 dev_dbg(dev->dev, "rx: address byte stripped off");
 510         }
 511
 512         /* get payload */
 513         while (dev->rx_position < bytes_total) {
 514                 if (!rf69_get_flag(dev->spi, payload_ready)) {
 515                         retval = wait_event_interruptible(dev->fifo_wait_queue,
 516                                                           dev->free_in_fifo < FIFO_SIZE);
 517                         if (retval) /* wait was interrupted */
 518                                 goto abort;
 519                 }
 520
 521                 /* need to drop bytes or acquire? */
 522                 if (dev->rx_bytes_to_drop > dev->rx_bytes_dropped)
 523                         bytes_to_read = dev->rx_bytes_to_drop -
 524                                         dev->rx_bytes_dropped;
 525                 else
 526                         bytes_to_read = bytes_total - dev->rx_position;
 527
 528                 /* access the fifo */
 529                 if (bytes_to_read > FIFO_SIZE - dev->free_in_fifo)
 530                         bytes_to_read = FIFO_SIZE - dev->free_in_fifo;
 531                 retval = rf69_read_fifo(spi,
 532                                         &dev->rx_buffer[dev->rx_position],
 533                                         bytes_to_read);
 534                 if (retval) /* read failed */
 535                         goto abort;
 536
 537                 dev->free_in_fifo += bytes_to_read;
 538
 539                 /* adjust status vars */
 540                 if (dev->rx_bytes_to_drop > dev->rx_bytes_dropped)
 541                         dev->rx_bytes_dropped += bytes_to_read;
 542                 else
 543                         dev->rx_position += bytes_to_read;
 544         }
 545
 546         /* rx done, wait was interrupted or error occurred */
 547 abort:
 548         dev->interrupt_rx_allowed = true;
 549         if (rf69_set_mode(dev->spi, standby))
 550                 pr_err("rf69_set_mode(): radio module failed to go standby\n");
 551         wake_up_interruptible(&dev->tx_wait_queue);
 552
 553         if (retval)
 554                 return retval;
 555         else
 556                 return bytes_total;
 557 }
 558
 559 static int
 560 pi433_tx_thread(void *data)
 561 {
 562         struct pi433_device *device = data;
 563         struct spi_device *spi = device->spi;
 564         struct pi433_tx_cfg tx_cfg;
 565         size_t size;
 566         bool   rx_interrupted = false;
 567         int    position, repetitions;
 568         int    retval;
 569
 570         while (1) {
 571                 /* wait for fifo to be populated or for request to terminate*/
 572                 dev_dbg(device->dev, "thread: going to wait for new messages");
 573                 wait_event_interruptible(device->tx_wait_queue,
 574                                          (!kfifo_is_empty(&device->tx_fifo) ||
 575                                           kthread_should_stop()));
 576                 if (kthread_should_stop())
 577                         return 0;
 578
 579                 /*
 580                  * get data from fifo in the following order:
 581                  * - tx_cfg
 582                  * - size of message
 583                  * - message
 584                  */
 585                 retval = kfifo_out(&device->tx_fifo, &tx_cfg, sizeof(tx_cfg));
 586                 if (retval != sizeof(tx_cfg)) {
 587                         dev_dbg(device->dev,
 588                                 "reading tx_cfg from fifo failed: got %d byte(s), expected %d",
 589                                 retval, (unsigned int)sizeof(tx_cfg));
 590                         continue;
 591                 }
 592
 593                 retval = kfifo_out(&device->tx_fifo, &size, sizeof(size_t));
 594                 if (retval != sizeof(size_t)) {
 595                         dev_dbg(device->dev,
 596                                 "reading msg size from fifo failed: got %d, expected %d",
 597                                 retval, (unsigned int)sizeof(size_t));
 598                         continue;
 599                 }
 600
 601                 /* use fixed message length, if requested */
 602                 if (tx_cfg.fixed_message_length != 0)
 603                         size = tx_cfg.fixed_message_length;
 604
 605                 /* increase size, if len byte is requested */
 606                 if (tx_cfg.enable_length_byte == OPTION_ON)
 607                         size++;
 608
 609                 /* increase size, if adr byte is requested */
 610                 if (tx_cfg.enable_address_byte == OPTION_ON)
 611                         size++;
 612
 613                 /* prime buffer */
 614                 memset(device->buffer, 0, size);
 615                 position = 0;
 616
 617                 /* add length byte, if requested */
 618                 if (tx_cfg.enable_length_byte  == OPTION_ON)
 619                         /*
 620                          * according to spec, length byte itself must be
 621                          * excluded from the length calculation
 622                          */
 623                         device->buffer[position++] = size - 1;
 624
 625                 /* add adr byte, if requested */
 626                 if (tx_cfg.enable_address_byte == OPTION_ON)
 627                         device->buffer[position++] = tx_cfg.address_byte;
 628
 629                 /* finally get message data from fifo */
 630                 retval = kfifo_out(&device->tx_fifo, &device->buffer[position],
 631                                    sizeof(device->buffer) - position);
 632                 dev_dbg(device->dev,
 633                         "read %d message byte(s) from fifo queue.", retval);
 634
 635                 /*
 636                  * if rx is active, we need to interrupt the waiting for
 637                  * incoming telegrams, to be able to send something.
 638                  * We are only allowed, if currently no reception takes
 639                  * place otherwise we need to  wait for the incoming telegram
 640                  * to finish
 641                  */
 642                 wait_event_interruptible(device->tx_wait_queue,
 643                                          !device->rx_active ||
 644                                           device->interrupt_rx_allowed);
 645
 646                 /*
 647                  * prevent race conditions
 648                  * irq will be reenabled after tx config is set
 649                  */
 650                 disable_irq(device->irq_num[DIO0]);
 651                 device->tx_active = true;
 652
 653                 if (device->rx_active && !rx_interrupted) {
 654                         /*
 655                          * rx is currently waiting for a telegram;
 656                          * we need to set the radio module to standby
 657                          */
 658                         retval = rf69_set_mode(device->spi, standby);
 659                         if (retval < 0)
 660                                 return retval;
 661                         rx_interrupted = true;
 662                 }
 663
 664                 /* clear fifo, set fifo threshold, set payload length */
 665                 retval = rf69_set_mode(spi, standby); /* this clears the fifo */
 666                 if (retval < 0)
 667                         return retval;
 668                 retval = rf69_set_fifo_threshold(spi, FIFO_THRESHOLD);
 669                 if (retval < 0)
 670                         return retval;
 671                 if (tx_cfg.enable_length_byte == OPTION_ON) {
 672                         retval = rf69_set_payload_length(spi, size * tx_cfg.repetitions);
 673                         if (retval < 0)
 674                                 return retval;
 675                 } else {
 676                         retval = rf69_set_payload_length(spi, 0);
 677                         if (retval < 0)
 678                                 return retval;
 679                 }
 680
 681                 /* configure the rf chip */
 682                 retval = rf69_set_tx_cfg(device, &tx_cfg);
 683                 if (retval < 0)
 684                         return retval;
 685
 686                 /* enable fifo level interrupt */
 687                 retval = rf69_set_dio_mapping(spi, DIO1, DIO_FIFO_LEVEL);
 688                 if (retval < 0)
 689                         return retval;
 690                 device->irq_state[DIO1] = DIO_FIFO_LEVEL;
 691                 irq_set_irq_type(device->irq_num[DIO1], IRQ_TYPE_EDGE_FALLING);
 692
 693                 /* enable packet sent interrupt */
 694                 retval = rf69_set_dio_mapping(spi, DIO0, DIO_PACKET_SENT);
 695                 if (retval < 0)
 696                         return retval;
 697                 device->irq_state[DIO0] = DIO_PACKET_SENT;
 698                 irq_set_irq_type(device->irq_num[DIO0], IRQ_TYPE_EDGE_RISING);
 699                 enable_irq(device->irq_num[DIO0]); /* was disabled by rx active check */
 700
 701                 /* enable transmission */
 702                 retval = rf69_set_mode(spi, transmit);
 703                 if (retval < 0)
 704                         return retval;
 705
 706                 /* transfer this msg (and repetitions) to chip fifo */
 707                 device->free_in_fifo = FIFO_SIZE;
 708                 position = 0;
 709                 repetitions = tx_cfg.repetitions;
 710                 while ((repetitions > 0) && (size > position)) {
 711                         if ((size - position) > device->free_in_fifo) {
 712                                 /* msg to big for fifo - take a part */
 713                                 int write_size = device->free_in_fifo;
 714
 715                                 device->free_in_fifo = 0;
 716                                 rf69_write_fifo(spi,
 717                                                 &device->buffer[position],
 718                                                 write_size);
 719                                 position += write_size;
 720                         } else {
 721                                 /* msg fits into fifo - take all */
 722                                 device->free_in_fifo -= size;
 723                                 repetitions--;
 724                                 rf69_write_fifo(spi,
 725                                                 &device->buffer[position],
 726                                                 (size - position));
 727                                 position = 0; /* reset for next repetition */
 728                         }
 729
 730                         retval = wait_event_interruptible(device->fifo_wait_queue,
 731                                                           device->free_in_fifo > 0);
 732                         if (retval) {
 733                                 dev_dbg(device->dev, "ABORT\n");
 734                                 goto abort;
 735                         }
 736                 }
 737
 738                 /* we are done. Wait for packet to get sent */
 739                 dev_dbg(device->dev,
 740                         "thread: wait for packet to get sent/fifo to be empty");
 741                 wait_event_interruptible(device->fifo_wait_queue,
 742                                          device->free_in_fifo == FIFO_SIZE ||
 743                                          kthread_should_stop());
 744                 if (kthread_should_stop())
 745                         dev_dbg(device->dev, "ABORT\n");
 746
 747                 /* STOP_TRANSMISSION */
 748                 dev_dbg(device->dev, "thread: Packet sent. Set mode to stby.");
 749                 retval = rf69_set_mode(spi, standby);
 750                 if (retval < 0)
 751                         return retval;
 752
 753                 /* everything sent? */
 754                 if (kfifo_is_empty(&device->tx_fifo)) {
 755 abort:
 756                         if (rx_interrupted) {
 757                                 rx_interrupted = false;
 758                                 pi433_start_rx(device);
 759                         }
 760                         device->tx_active = false;
 761                         wake_up_interruptible(&device->rx_wait_queue);
 762                 }
 763         }
 764 }
 765
 766 /*-------------------------------------------------------------------------*/
 767
 768 static ssize_t
 769 pi433_read(struct file *filp, char __user *buf, size_t size, loff_t *f_pos)
 770 {
 771         struct pi433_instance   *instance;
 772         struct pi433_device     *device;
 773         int                     bytes_received;
 774         ssize_t                 retval;
 775
 776         /* check, whether internal buffer is big enough for requested size */
 777         if (size > MAX_MSG_SIZE)
 778                 return -EMSGSIZE;
 779
 780         instance = filp->private_data;
 781         device = instance->device;
 782
 783         /* just one read request at a time */
 784         mutex_lock(&device->rx_lock);
 785         if (device->rx_active) {
 786                 mutex_unlock(&device->rx_lock);
 787                 return -EAGAIN;
 788         }
 789
 790         device->rx_active = true;
 791         mutex_unlock(&device->rx_lock);
 792
 793         /* start receiving */
 794         /* will block until something was received*/
 795         device->rx_buffer_size = size;
 796         bytes_received = pi433_receive(device);
 797
 798         /* release rx */
 799         mutex_lock(&device->rx_lock);
 800         device->rx_active = false;
 801         mutex_unlock(&device->rx_lock);
 802
 803         /* if read was successful copy to user space*/
 804         if (bytes_received > 0) {
 805                 retval = copy_to_user(buf, device->rx_buffer, bytes_received);
 806                 if (retval)
 807                         return -EFAULT;
 808         }
 809
 810         return bytes_received;
 811 }
 812
 813 static ssize_t
 814 pi433_write(struct file *filp, const char __user *buf,
 815             size_t count, loff_t *f_pos)
 816 {
 817         struct pi433_instance   *instance;
 818         struct pi433_device     *device;
 819         int                     retval;
 820         unsigned int            required, available, copied;
 821
 822         instance = filp->private_data;
 823         device = instance->device;
 824
 825         /*
 826          * check, whether internal buffer (tx thread) is big enough
 827          * for requested size
 828          */
 829         if (count > MAX_MSG_SIZE)
 830                 return -EMSGSIZE;
 831
 832         /*
 833          * write the following sequence into fifo:
 834          * - tx_cfg
 835          * - size of message
 836          * - message
 837          */
 838         mutex_lock(&device->tx_fifo_lock);
 839
 840         required = sizeof(instance->tx_cfg) + sizeof(size_t) + count;
 841         available = kfifo_avail(&device->tx_fifo);
 842         if (required > available) {
 843                 dev_dbg(device->dev, "write to fifo failed: %d bytes required but %d available",
 844                         required, available);
 845                 mutex_unlock(&device->tx_fifo_lock);
 846                 return -EAGAIN;
 847         }
 848
 849         retval = kfifo_in(&device->tx_fifo, &instance->tx_cfg,
 850                           sizeof(instance->tx_cfg));
 851         if (retval != sizeof(instance->tx_cfg))
 852                 goto abort;
 853
 854         retval = kfifo_in(&device->tx_fifo, &count, sizeof(size_t));
 855         if (retval != sizeof(size_t))
 856                 goto abort;
 857
 858         retval = kfifo_from_user(&device->tx_fifo, buf, count, &copied);
 859         if (retval || copied != count)
 860                 goto abort;
 861
 862         mutex_unlock(&device->tx_fifo_lock);
 863
 864         /* start transfer */
 865         wake_up_interruptible(&device->tx_wait_queue);
 866         dev_dbg(device->dev, "write: generated new msg with %d bytes.", copied);
 867
 868         return copied;
 869
 870 abort:
 871         dev_warn(device->dev,
 872                  "write to fifo failed, non recoverable: 0x%x", retval);
 873         mutex_unlock(&device->tx_fifo_lock);
 874         return -EAGAIN;
 875 }
 876
 877 static long
 878 pi433_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 879 {
 880         int                     retval = 0;
 881         struct pi433_instance   *instance;
 882         struct pi433_device     *device;
 883         struct pi433_tx_cfg     tx_cfg;
 884         void __user *argp = (void __user *)arg;
 885
 886         /* Check type and command number */
 887         if (_IOC_TYPE(cmd) != PI433_IOC_MAGIC)
 888                 return -ENOTTY;
 889
 890         instance = filp->private_data;
 891         device = instance->device;
 892
 893         if (!device)
 894                 return -ESHUTDOWN;
 895
 896         switch (cmd) {
 897         case PI433_IOC_RD_TX_CFG:
 898                 if (copy_to_user(argp, &instance->tx_cfg,
 899                                  sizeof(struct pi433_tx_cfg)))
 900                         return -EFAULT;
 901                 break;
 902         case PI433_IOC_WR_TX_CFG:
 903                 if (copy_from_user(&tx_cfg, argp, sizeof(struct pi433_tx_cfg)))
 904                         return -EFAULT;
 905                 mutex_lock(&device->tx_fifo_lock);
 906                 memcpy(&instance->tx_cfg, &tx_cfg, sizeof(struct pi433_tx_cfg));
 907                 mutex_unlock(&device->tx_fifo_lock);
 908                 break;
 909         case PI433_IOC_RD_RX_CFG:
 910                 if (copy_to_user(argp, &device->rx_cfg,
 911                                  sizeof(struct pi433_rx_cfg)))
 912                         return -EFAULT;
 913                 break;
 914         case PI433_IOC_WR_RX_CFG:
 915                 mutex_lock(&device->rx_lock);
 916
 917                 /* during pendig read request, change of config not allowed */
 918                 if (device->rx_active) {
 919                         mutex_unlock(&device->rx_lock);
 920                         return -EAGAIN;
 921                 }
 922
 923                 if (copy_from_user(&device->rx_cfg, argp,
 924                                    sizeof(struct pi433_rx_cfg))) {
 925                         mutex_unlock(&device->rx_lock);
 926                         return -EFAULT;
 927                 }
 928
 929                 mutex_unlock(&device->rx_lock);
 930                 break;
 931         default:
 932                 retval = -EINVAL;
 933         }
 934
 935         return retval;
 936 }
 937
 938 #ifdef CONFIG_COMPAT
 939 static long
 940 pi433_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 941 {
 942         return pi433_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
 943 }
 944 #else
 945 #define pi433_compat_ioctl NULL
 946 #endif /* CONFIG_COMPAT */
 947
 948 /*-------------------------------------------------------------------------*/
 949
 950 static int pi433_open(struct inode *inode, struct file *filp)
 951 {
 952         struct pi433_device     *device;
 953         struct pi433_instance   *instance;
 954
 955         mutex_lock(&minor_lock);
 956         device = idr_find(&pi433_idr, iminor(inode));
 957         mutex_unlock(&minor_lock);
 958         if (!device) {
 959                 pr_debug("device: minor %d unknown.\n", iminor(inode));
 960                 return -ENODEV;
 961         }
 962
 963         instance = kzalloc(sizeof(*instance), GFP_KERNEL);
 964         if (!instance)
 965                 return -ENOMEM;
 966
 967         /* setup instance data*/
 968         instance->device = device;
 969         instance->tx_cfg.bit_rate = 4711;
 970         // TODO: fill instance->tx_cfg;
 971
 972         /* instance data as context */
 973         filp->private_data = instance;
 974         nonseekable_open(inode, filp);
 975
 976         return 0;
 977 }
 978
 979 static int pi433_release(struct inode *inode, struct file *filp)
 980 {
 981         struct pi433_instance   *instance;
 982
 983         instance = filp->private_data;
 984         kfree(instance);
 985         filp->private_data = NULL;
 986
 987         return 0;
 988 }
 989
 990 /*-------------------------------------------------------------------------*/
 991
 992 static int setup_gpio(struct pi433_device *device)
 993 {
 994         char    name[5];
 995         int     retval;
 996         int     i;
 997         const irq_handler_t DIO_irq_handler[NUM_DIO] = {
 998                 DIO0_irq_handler,
 999                 DIO1_irq_handler
1000         };
1001
1002         for (i = 0; i < NUM_DIO; i++) {
1003                 /* "construct" name and get the gpio descriptor */
1004                 snprintf(name, sizeof(name), "DIO%d", i);
1005                 device->gpiod[i] = gpiod_get(&device->spi->dev, name,
1006                                              0 /*GPIOD_IN*/);
1007
1008                 if (device->gpiod[i] == ERR_PTR(-ENOENT)) {
1009                         dev_dbg(&device->spi->dev,
1010                                 "Could not find entry for %s. Ignoring.", name);
1011                         continue;
1012                 }
1013
1014                 if (device->gpiod[i] == ERR_PTR(-EBUSY))
1015                         dev_dbg(&device->spi->dev, "%s is busy.", name);
1016
1017                 if (IS_ERR(device->gpiod[i])) {
1018                         retval = PTR_ERR(device->gpiod[i]);
1019                         /* release already allocated gpios */
1020                         for (i--; i >= 0; i--) {
1021                                 free_irq(device->irq_num[i], device);
1022                                 gpiod_put(device->gpiod[i]);
1023                         }
1024                         return retval;
1025                 }
1026
1027                 /* configure the pin */
1028                 gpiod_unexport(device->gpiod[i]);
1029                 retval = gpiod_direction_input(device->gpiod[i]);
1030                 if (retval)
1031                         return retval;
1032
1033                 /* configure irq */
1034                 device->irq_num[i] = gpiod_to_irq(device->gpiod[i]);
1035                 if (device->irq_num[i] < 0) {
1036                         device->gpiod[i] = ERR_PTR(-EINVAL);
1037                         return device->irq_num[i];
1038                 }
1039                 retval = request_irq(device->irq_num[i],
1040                                      DIO_irq_handler[i],
1041                                      0, /* flags */
1042                                      name,
1043                                      device);
1044
1045                 if (retval)
1046                         return retval;
1047
1048                 dev_dbg(&device->spi->dev, "%s successfully configured", name);
1049         }
1050
1051         return 0;
1052 }
1053
1054 static void free_gpio(struct pi433_device *device)
1055 {
1056         int i;
1057
1058         for (i = 0; i < NUM_DIO; i++) {
1059                 /* check if gpiod is valid */
1060                 if (IS_ERR(device->gpiod[i]))
1061                         continue;
1062
1063                 free_irq(device->irq_num[i], device);
1064                 gpiod_put(device->gpiod[i]);
1065         }
1066 }
1067
1068 static int pi433_get_minor(struct pi433_device *device)
1069 {
1070         int retval = -ENOMEM;
1071
1072         mutex_lock(&minor_lock);
1073         retval = idr_alloc(&pi433_idr, device, 0, N_PI433_MINORS, GFP_KERNEL);
1074         if (retval >= 0) {
1075                 device->minor = retval;
1076                 retval = 0;
1077         } else if (retval == -ENOSPC) {
1078                 dev_err(&device->spi->dev, "too many pi433 devices\n");
1079                 retval = -EINVAL;
1080         }
1081         mutex_unlock(&minor_lock);
1082         return retval;
1083 }
1084
1085 static void pi433_free_minor(struct pi433_device *dev)
1086 {
1087         mutex_lock(&minor_lock);
1088         idr_remove(&pi433_idr, dev->minor);
1089         mutex_unlock(&minor_lock);
1090 }
1091
1092 /*-------------------------------------------------------------------------*/
1093
1094 static const struct file_operations pi433_fops = {
1095         .owner =        THIS_MODULE,
1096         /*
1097          * REVISIT switch to aio primitives, so that userspace
1098          * gets more complete API coverage.  It'll simplify things
1099          * too, except for the locking.
1100          */
1101         .write =        pi433_write,
1102         .read =         pi433_read,
1103         .unlocked_ioctl = pi433_ioctl,
1104         .compat_ioctl = pi433_compat_ioctl,
1105         .open =         pi433_open,
1106         .release =      pi433_release,
1107         .llseek =       no_llseek,
1108 };
1109
1110 /*-------------------------------------------------------------------------*/
1111
1112 static int pi433_probe(struct spi_device *spi)
1113 {
1114         struct pi433_device     *device;
1115         int                     retval;
1116
1117         /* setup spi parameters */
1118         spi->mode = 0x00;
1119         spi->bits_per_word = 8;
1120         /*
1121          * spi->max_speed_hz = 10000000;
1122          * 1MHz already set by device tree overlay
1123          */
1124
1125         retval = spi_setup(spi);
1126         if (retval) {
1127                 dev_dbg(&spi->dev, "configuration of SPI interface failed!\n");
1128                 return retval;
1129         }
1130
1131         dev_dbg(&spi->dev,
1132                 "spi interface setup: mode 0x%2x, %d bits per word, %dhz max speed",
1133                 spi->mode, spi->bits_per_word, spi->max_speed_hz);
1134
1135         /* Ping the chip by reading the version register */
1136         retval = spi_w8r8(spi, 0x10);
1137         if (retval < 0)
1138                 return retval;
1139
1140         switch (retval) {
1141         case 0x24:
1142                 dev_dbg(&spi->dev, "found pi433 (ver. 0x%x)", retval);
1143                 break;
1144         default:
1145                 dev_dbg(&spi->dev, "unknown chip version: 0x%x", retval);
1146                 return -ENODEV;
1147         }
1148
1149         /* Allocate driver data */
1150         device = kzalloc(sizeof(*device), GFP_KERNEL);
1151         if (!device)
1152                 return -ENOMEM;
1153
1154         /* Initialize the driver data */
1155         device->spi = spi;
1156         device->rx_active = false;
1157         device->tx_active = false;
1158         device->interrupt_rx_allowed = false;
1159
1160         /* init rx buffer */
1161         device->rx_buffer = kmalloc(MAX_MSG_SIZE, GFP_KERNEL);
1162         if (!device->rx_buffer) {
1163                 retval = -ENOMEM;
1164                 goto RX_failed;
1165         }
1166
1167         /* init wait queues */
1168         init_waitqueue_head(&device->tx_wait_queue);
1169         init_waitqueue_head(&device->rx_wait_queue);
1170         init_waitqueue_head(&device->fifo_wait_queue);
1171
1172         /* init fifo */
1173         INIT_KFIFO(device->tx_fifo);
1174
1175         /* init mutexes and locks */
1176         mutex_init(&device->tx_fifo_lock);
1177         mutex_init(&device->rx_lock);
1178
1179         /* setup GPIO (including irq_handler) for the different DIOs */
1180         retval = setup_gpio(device);
1181         if (retval) {
1182                 dev_dbg(&spi->dev, "setup of GPIOs failed");
1183                 goto GPIO_failed;
1184         }
1185
1186         /* setup the radio module */
1187         retval = rf69_set_mode(spi, standby);
1188         if (retval < 0)
1189                 goto minor_failed;
1190         retval = rf69_set_data_mode(spi, DATAMODUL_MODE_PACKET);
1191         if (retval < 0)
1192                 goto minor_failed;
1193         retval = rf69_enable_amplifier(spi, MASK_PALEVEL_PA0);
1194         if (retval < 0)
1195                 goto minor_failed;
1196         retval = rf69_disable_amplifier(spi, MASK_PALEVEL_PA1);
1197         if (retval < 0)
1198                 goto minor_failed;
1199         retval = rf69_disable_amplifier(spi, MASK_PALEVEL_PA2);
1200         if (retval < 0)
1201                 goto minor_failed;
1202         retval = rf69_set_output_power_level(spi, 13);
1203         if (retval < 0)
1204                 goto minor_failed;
1205         retval = rf69_set_antenna_impedance(spi, fifty_ohm);
1206         if (retval < 0)
1207                 goto minor_failed;
1208
1209         /* determ minor number */
1210         retval = pi433_get_minor(device);
1211         if (retval) {
1212                 dev_dbg(&spi->dev, "get of minor number failed");
1213                 goto minor_failed;
1214         }
1215
1216         /* create device */
1217         device->devt = MKDEV(MAJOR(pi433_dev), device->minor);
1218         device->dev = device_create(pi433_class,
1219                                     &spi->dev,
1220                                     device->devt,
1221                                     device,
1222                                     "pi433.%d",
1223                                     device->minor);
1224         if (IS_ERR(device->dev)) {
1225                 pr_err("pi433: device register failed\n");
1226                 retval = PTR_ERR(device->dev);
1227                 goto device_create_failed;
1228         } else {
1229                 dev_dbg(device->dev,
1230                         "created device for major %d, minor %d\n",
1231                         MAJOR(pi433_dev),
1232                         device->minor);
1233         }
1234
1235         /* start tx thread */
1236         device->tx_task_struct = kthread_run(pi433_tx_thread,
1237                                              device,
1238                                              "pi433.%d_tx_task",
1239                                              device->minor);
1240         if (IS_ERR(device->tx_task_struct)) {
1241                 dev_dbg(device->dev, "start of send thread failed");
1242                 retval = PTR_ERR(device->tx_task_struct);
1243                 goto send_thread_failed;
1244         }
1245
1246         /* create cdev */
1247         device->cdev = cdev_alloc();
1248         if (!device->cdev) {
1249                 dev_dbg(device->dev, "allocation of cdev failed");
1250                 goto cdev_failed;
1251         }
1252         device->cdev->owner = THIS_MODULE;
1253         cdev_init(device->cdev, &pi433_fops);
1254         retval = cdev_add(device->cdev, device->devt, 1);
1255         if (retval) {
1256                 dev_dbg(device->dev, "register of cdev failed");
1257                 goto del_cdev;
1258         }
1259
1260         /* spi setup */
1261         spi_set_drvdata(spi, device);
1262
1263         return 0;
1264
1265 del_cdev:
1266         cdev_del(device->cdev);
1267 cdev_failed:
1268         kthread_stop(device->tx_task_struct);
1269 send_thread_failed:
1270         device_destroy(pi433_class, device->devt);
1271 device_create_failed:
1272         pi433_free_minor(device);
1273 minor_failed:
1274         free_gpio(device);
1275 GPIO_failed:
1276         kfree(device->rx_buffer);
1277 RX_failed:
1278         kfree(device);
1279
1280         return retval;
1281 }
1282
1283 static int pi433_remove(struct spi_device *spi)
1284 {
1285         struct pi433_device     *device = spi_get_drvdata(spi);
1286
1287         /* free GPIOs */
1288         free_gpio(device);
1289
1290         /* make sure ops on existing fds can abort cleanly */
1291         device->spi = NULL;
1292
1293         kthread_stop(device->tx_task_struct);
1294
1295         device_destroy(pi433_class, device->devt);
1296
1297         cdev_del(device->cdev);
1298
1299         pi433_free_minor(device);
1300
1301         kfree(device->rx_buffer);
1302         kfree(device);
1303
1304         return 0;
1305 }
1306
1307 static const struct of_device_id pi433_dt_ids[] = {
1308         { .compatible = "Smarthome-Wolf,pi433" },
1309         {},
1310 };
1311
1312 MODULE_DEVICE_TABLE(of, pi433_dt_ids);
1313
1314 static struct spi_driver pi433_spi_driver = {
1315         .driver = {
1316                 .name =         "pi433",
1317                 .owner =        THIS_MODULE,
1318                 .of_match_table = of_match_ptr(pi433_dt_ids),
1319         },
1320         .probe =        pi433_probe,
1321         .remove =       pi433_remove,
1322
1323         /*
1324          * NOTE:  suspend/resume methods are not necessary here.
1325          * We don't do anything except pass the requests to/from
1326          * the underlying controller.  The refrigerator handles
1327          * most issues; the controller driver handles the rest.
1328          */
1329 };
1330
1331 /*-------------------------------------------------------------------------*/
1332
1333 static int __init pi433_init(void)
1334 {
1335         int status;
1336
1337         /*
1338          * If MAX_MSG_SIZE is smaller then FIFO_SIZE, the driver won't
1339          * work stable - risk of buffer overflow
1340          */
1341         if (MAX_MSG_SIZE < FIFO_SIZE)
1342                 return -EINVAL;
1343
1344         /*
1345          * Claim device numbers.  Then register a class
1346          * that will key udev/mdev to add/remove /dev nodes.  Last, register
1347          * Last, register the driver which manages those device numbers.
1348          */
1349         status = alloc_chrdev_region(&pi433_dev, 0, N_PI433_MINORS, "pi433");
1350         if (status < 0)
1351                 return status;
1352
1353         pi433_class = class_create(THIS_MODULE, "pi433");
1354         if (IS_ERR(pi433_class)) {
1355                 unregister_chrdev(MAJOR(pi433_dev),
1356                                   pi433_spi_driver.driver.name);
1357                 return PTR_ERR(pi433_class);
1358         }
1359
1360         status = spi_register_driver(&pi433_spi_driver);
1361         if (status < 0) {
1362                 class_destroy(pi433_class);
1363                 unregister_chrdev(MAJOR(pi433_dev),
1364                                   pi433_spi_driver.driver.name);
1365         }
1366
1367         return status;
1368 }
1369
1370 module_init(pi433_init);
1371
1372 static void __exit pi433_exit(void)
1373 {
1374         spi_unregister_driver(&pi433_spi_driver);
1375         class_destroy(pi433_class);
1376         unregister_chrdev(MAJOR(pi433_dev), pi433_spi_driver.driver.name);
1377 }
1378 module_exit(pi433_exit);
1379
1380 MODULE_AUTHOR("Marcus Wolf, <linux@wolf-entwicklungen.de>");
1381 MODULE_DESCRIPTION("Driver for Pi433");
1382 MODULE_LICENSE("GPL");
1383 MODULE_ALIAS("spi:pi433");