Linux preempt-rt

Check our new training course

Real-Time Linux with PREEMPT_RT

Check our new training course
with Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
/* cc2520.c - IEEE 802.15.4 driver for TI CC2520 */

/*
 * Copyright (c) 2015 Intel Corporation.
 *
 * Copyright (c) 2011, Swedish Institute of Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2) Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3) Neither the name of Intel Corporation nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdint.h>

#include <nanokernel.h>

#include <errno.h>
#include <gpio.h>
#include <spi.h>

#include <board.h>
#include <init.h>
#include <sections.h>

#include <802.15.4/cc2520.h>

#include <net/l2_buf.h>
#include "packetbuf.h"
#include "net_driver_15_4.h"
#include "random.h"

#include "cc2520.h"
#include "cc2520_arch.h"

#ifndef CC2520_CONF_AUTOACK
#define CC2520_CONF_AUTOACK 0
#endif /* CC2520_CONF_AUTOACK */

#define WITH_SEND_CCA 1

#define FOOTER_LEN 2

#define AUTOCRC (1 << 6)
#define AUTOACK (1 << 5)
#define FRAME_MAX_VERSION ((1 << 3) | (1 << 2))
#define FRAME_FILTER_ENABLE (1 << 0)
#define CORR_THR(n) (((n) & 0x1f) << 6)
#define FIFOP_THR(n) ((n) & 0x7f)

#define FOOTER1_CRC_OK      0x80
#define FOOTER1_CORRELATION 0x7f

#define WAIT_100ms 100
#define WAIT_1000ms 1000
#define WAIT_500ms 500
#define WAIT_200ms 200
#define WAIT_10ms 10
#define WAIT_1ms 1

struct cc2520_gpio_config cc2520_gpio_config[CC2520_GPIO_IDX_LAST_ENTRY];
struct cc2520_config cc2520_config;

/* CC2520 is currently a singleton instance
 * This would be needed no get fixed. The main
 * issue is the gpio cb handler: it would need to
 * get access to the relevant instance of cc2520 driver
 */
struct device *cc2520_sgl_dev;

/* static int cc2520_authority_level_of_sender; */
static int cc2520_packets_seen;
static int cc2520_packets_read;

static uint8_t lock_on;
static uint8_t lock_off;
static uint8_t locked;
static bool init_ok;

/* max time is in millisecs */
#define BUSYWAIT_UNTIL(cond, max_time)					\
	do {								\
		uint32_t t0 = clock_get_cycle();			\
		uint32_t limit = t0 + CLOCK_MSEC_TO_CYCLES(max_time);	\
		while (!(cond) && CLOCK_CYCLE_LT(clock_get_cycle(),	\
							limit));	\
	} while (0)

#define CC2520_STROBE_PLUS_NOP(strobe) cc2520_strobe_plus_nop(strobe)
#define CC2520_ENABLE_FIFOP_INT() cc2520_enable_fifop_int(1)
#define CC2520_DISABLE_FIFOP_INT() cc2520_enable_fifop_int(0)
#define CC2520_FIFOP_INT_INIT() cc2520_init_fifop_int(cc2520_gpio_int_handler)
#define SET_VREG_ACTIVE() cc2520_set_vreg(1)
#define SET_VREG_INACTIVE() cc2520_set_vreg(0)
#define SET_RESET_ACTIVE() cc2520_set_reset(0)
#define SET_RESET_INACTIVE() cc2520_set_reset(1)

#define CC2520_FIFOP_IS_1 (cc2520_get_fifop() != 0)
#define CC2520_FIFO_IS_1 (cc2520_get_fifo() != 0)
#define CC2520_SFD_IS_1 (cc2520_get_sfd() != 0)
#define CC2520_CCA_IS_1 (cc2520_get_cca() != 0)

static volatile uint8_t cc2520_sfd_counter;
static volatile uint16_t cc2520_sfd_start_time;
static volatile uint16_t cc2520_sfd_end_time;

static volatile uint16_t last_packet_timestamp;

static signed char cc2520_last_rssi;
static uint8_t cc2520_last_correlation;

static uint8_t receive_on;
static int channel;
static bool cc2520_read_fifo_byte(uint8_t *byte)
{
	return cc2520_read_fifo_buf(byte, 1);
}

static uint8_t getreg(uint16_t regname)
{
	uint16_t reg = 0;

	if (!cc2520_read_reg(regname, &reg)) {
		DBG("%s: cannot read reg %d value\n", __func__,
		       regname);
	}
	return reg;
}

static void setreg(uint16_t regname, uint8_t value)
{
	if (!cc2520_write_reg(regname, value)) {
		DBG("%s: cannot set reg %d to %d\n", __func__,
		       regname, value);
	}
}

#ifdef CONFIG_TI_CC2520_DEBUG
static void print_radio_status(void)
{
	uint8_t value = getreg(CC2520_FSMSTAT1);

	DBG("Radio status FSMSTAT1: ");
	if (value & BIT(CC2520_STATUS_FIFO)) {
		DBG("FIFO ");
	}
	if (value & BIT(CC2520_STATUS_FIFOP)) {
		DBG("FIFOP ");
	}
	if (value & BIT(CC2520_STATUS_SFD)) {
		DBG("SFD ");
	}
	if (value & BIT(CC2520_STATUS_CCA)) {
		DBG("CCA ");
	}
	if (value & BIT(CC2520_STATUS_SAMPLED_CCA)) {
		DBG("SAMPLED_CCA ");
	}
	if (value & BIT(CC2520_STATUS_LOCK_STATUS)) {
		DBG("LOCK_STATUS ");
	}
	if (value & BIT(CC2520_STATUS_TX_ACTIVE)) {
		DBG("TX_ACTIVE ");
	}
	if (value & BIT(CC2520_STATUS_RX_ACTIVE)) {
		DBG("RX_ACTIVE ");
	}
	DBG("\n");
}

static inline void print_exceptions_0(void)
{
	uint8_t flag = getreg(CC2520_EXCFLAG0);

	DBG("EXCFLAG0: ");
	if (flag & BIT(CC2520_EXCFLAGS0_RF_IDLE)) {
		DBG("RF_IDLE ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_TX_FRM_DONE)) {
		DBG("TX_FRM_DONE ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_TX_ACK_DONE)) {
		DBG("TX_ACK_DONE ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_TX_UNDERFLOW)) {
		DBG("TX_UNDERFLOW ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_TX_OVERFLOW)) {
		DBG("TX_OVERFLOW ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_RX_UNDERFLOW)) {
		DBG("RX_UNDERFLOW ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_RX_OVERFLOW)) {
		DBG("RX_OVERFLOW ");
	}
	if (flag & BIT(CC2520_EXCFLAGS0_RXENABLE_ZERO)) {
		DBG("RXENABLE_ZERO");
	}
	DBG("\n");

	setreg(CC2520_EXCFLAG0, 0);
}

static inline void print_exceptions_1(void)
{
	uint8_t flag = getreg(CC2520_EXCFLAG1);

	DBG("EXCFLAG1: ");
	if (flag & BIT(CC2520_EXCFLAGS1_RX_FRM_DONE)) {
		DBG("RX_FRM_DONE ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_RX_FRM_ACCEPTED)) {
		DBG("RX_FRM_ACCEPTED ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_SRC_MATCH_DONE)) {
		DBG("SRC_MATCH_DONE ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_SRC_MATCH_FOUND)) {
		DBG("SRC_MATCH_FOUND ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_FIFOP)) {
		DBG("FIFOP ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_SFD)) {
		DBG("SFD ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_DPU_DONE_L)) {
		DBG("DPU_DONE_L ");
	}
	if (flag & BIT(CC2520_EXCFLAGS1_DPU_DONE_H)) {
		DBG("DPU_DONE_H");
	}
	DBG("\n");
}

static inline void print_errors(void)
{
	uint8_t flag = getreg(CC2520_EXCFLAG2);

	DBG("EXCFLAG2: ");
	if (flag & BIT(CC2520_EXCFLAGS2_MEMADDR_ERROR)) {
		DBG("MEMADDR_ERROR ");
	}
	if (flag & BIT(CC2520_EXCFLAGS2_USAGE_ERROR)) {
		DBG("USAGE_ERROR ");
	}
	if (flag & BIT(CC2520_EXCFLAGS2_OPERAND_ERROR)) {
		DBG("OPERAND_ERROR ");
	}
	if (flag & BIT(CC2520_EXCFLAGS2_SPI_ERROR)) {
		DBG("SPI_ERROR ");
	}
	if (flag & BIT(CC2520_EXCFLAGS2_RF_NO_LOCK)) {
		DBG("RF_NO_LOCK ");
	}
	if (flag & BIT(CC2520_EXCFLAGS2_RX_FRM_ABORTED)) {
		DBG("RX_FRM_ABORTED ");
	}
	if (flag & BIT(CC2520_EXCFLAGS2_RFBUFMOV_TIMEOUT)) {
		DBG("RFBUFMOV_TIMEOUT");
	}
	DBG("\n");
}

static void clear_exceptions(void)
{
	DBG("Clearing up exceptions & errors\n");

	setreg(CC2520_EXCFLAG0, 0);
	setreg(CC2520_EXCFLAG1, 0);
	setreg(CC2520_EXCFLAG2, 0);
}

static void cc2520_print_gpio_config(void)
{
	DBG("GPIOCTRL0: 0x%x\n", getreg(CC2520_GPIOCTRL0));
	DBG("GPIOCTRL1: 0x%x\n", getreg(CC2520_GPIOCTRL1));
	DBG("GPIOCTRL2: 0x%x\n", getreg(CC2520_GPIOCTRL2));
	DBG("GPIOCTRL3: 0x%x\n", getreg(CC2520_GPIOCTRL3));
	DBG("GPIOCTRL4: 0x%x\n", getreg(CC2520_GPIOCTRL4));
	DBG("GPIOCTRL5: 0x%x\n", getreg(CC2520_GPIOCTRL5));
	DBG("GPIOPOLARITY: 0x%x\n", getreg(CC2520_GPIOPOLARITY));
	DBG("GPIOCTRL: 0x%x\n", getreg(CC2520_GPIOCTRL));
}

#else
#define print_radio_status()
#define print_exceptions_0()
#define print_exceptions_1()
#define print_errors()
#define clear_exceptions()
#define cc2520_print_gpio_config()
#endif

static inline unsigned int status(void)
{
	uint8_t status = 0x00;

	if (!cc2520_get_status(&status)) {
		DBG("Reading status 0x%x failed\n", status);
		return 0x00;
	}

	return status;
}

static inline int cc2520_pending_packet(void)
{
	return CC2520_FIFOP_IS_1;
}

static void flushrx(void)
{
	cc2520_strobe(CC2520_INS_SFLUSHRX);
}

static void on(void)
{
	DBG("cc2520 radio on\n");

	CC2520_ENABLE_FIFOP_INT();
	cc2520_strobe(CC2520_INS_SRXON);

	BUSYWAIT_UNTIL(status() & (BIT(CC2520_XOSC16M_STABLE)), WAIT_10ms);
	if (!(status() & BIT(CC2520_XOSC16M_STABLE))) {
		DBG("Clock is not stabilized, radio is not on\n");
		return;
	}

	print_radio_status();

	receive_on = 1;
}

static void off(void)
{
	DBG("cc2520 radio off\n");
	receive_on = 0;

	/* Wait for transmission to end before turning radio off. */
	BUSYWAIT_UNTIL(!(status() & BIT(CC2520_TX_ACTIVE)), WAIT_100ms);

	cc2520_strobe(CC2520_INS_SRFOFF);
	CC2520_DISABLE_FIFOP_INT();

	if (!cc2520_pending_packet()) {
		flushrx();
	}
}

static inline void cc2520_radio_lock(void)
{
	struct cc2520_config *info = cc2520_sgl_dev->config->config_info;

	nano_fiber_sem_take(&info->radio_lock, TICKS_UNLIMITED);
	locked++;
}

static inline void cc2520_radio_unlock(void)
{
	struct cc2520_config *info = cc2520_sgl_dev->config->config_info;

	if (lock_on) {
		on();
		lock_on = 0;
	}

	if (lock_off) {
		off();
		lock_off = 0;
	}

	locked--;
	nano_fiber_sem_give(&info->radio_lock);
}

static int cc2520_off(void)
{
	/* Don't do anything if we are already turned off. */
	if (!receive_on) {
		return 1;
	}

	if (locked) {
		lock_off = 1;
		return 1;
	}

	cc2520_radio_lock();

	if (status() & BIT(CC2520_TX_ACTIVE)) {
		lock_off = 1;
	} else {
		off();
	}

	cc2520_radio_unlock();

	return 1;
}

int cc2520_on(void)
{
	if (!init_ok) {
		DBG("cc2520 not initialized, radio will stay off\n");
		return 0;
	}

	if (receive_on) {
		return 1;
	}

	if (locked) {
		lock_on = 1;
		return 1;
	}

	cc2520_radio_lock();

	on();

	cc2520_radio_unlock();

	return 1;
}

static radio_result_t cc2520_set_rx_mode(radio_value_t value)
{
	static radio_value_t old_value = -1;

	if (value == old_value) {
		return RADIO_RESULT_OK;
	}

#if CC2520_CONF_AUTOACK
	value |= RADIO_RX_MODE_AUTOACK;
#endif /* CC2520_CONF_AUTOACK */

	/*
	 * Writing RAM requires crystal oscillator to be stable.
	 */
	BUSYWAIT_UNTIL(status() & (BIT(CC2520_XOSC16M_STABLE)), WAIT_100ms);
	if (!(status() & (BIT(CC2520_XOSC16M_STABLE)))) {
		DBG("cc2520_set_rx_mode: CC2520_XOSC16M_STABLE not set\n");
	}

	/* Wait for any transmission to end. */
	BUSYWAIT_UNTIL(!(status() & BIT(CC2520_TX_ACTIVE)), WAIT_100ms);

	if ((value & RADIO_RX_MODE_AUTOACK) !=
	    (old_value & RADIO_RX_MODE_AUTOACK)) {
		if (value & RADIO_RX_MODE_AUTOACK) {
			setreg(CC2520_FRMCTRL0, AUTOCRC | AUTOACK);
		} else {
			setreg(CC2520_FRMCTRL0, AUTOCRC);
		}
	}

	if ((value & RADIO_RX_MODE_ADDRESS_FILTER) !=
	    (old_value & RADIO_RX_MODE_ADDRESS_FILTER)) {
		if (value & RADIO_RX_MODE_ADDRESS_FILTER) {
			setreg(CC2520_FRMFILT0,
			       FRAME_MAX_VERSION | FRAME_FILTER_ENABLE);
		} else {
			setreg(CC2520_FRMFILT0, FRAME_MAX_VERSION);
		}
	}
	old_value = value;

#if 1
	if (receive_on) {
		cc2520_strobe(CC2520_INS_SRXON);

		BUSYWAIT_UNTIL((status() & BIT(CC2520_RSSI_VALID)), WAIT_100ms);
		if (!(status() & BIT(CC2520_RSSI_VALID))) {
			return RADIO_RESULT_ERROR;
		}
	}
#endif /* 1/0 */

	return RADIO_RESULT_OK;
}

radio_result_t cc2520_get_value(radio_param_t param, radio_value_t *value)
{
	if (!value) {
		return RADIO_RESULT_INVALID_VALUE;
	}

	switch (param) {
	case RADIO_PARAM_POWER_MODE:
		*value = receive_on ? RADIO_POWER_MODE_ON :
					RADIO_POWER_MODE_OFF;
		return RADIO_RESULT_OK;
	case RADIO_PARAM_CHANNEL:
		*value = cc2520_get_channel();
		return RADIO_RESULT_OK;
	case RADIO_CONST_CHANNEL_MIN:
		*value = 11;
		return RADIO_RESULT_OK;
	case RADIO_CONST_CHANNEL_MAX:
		*value = 26;
		return RADIO_RESULT_OK;
	default:
		return RADIO_RESULT_NOT_SUPPORTED;
	}
}

radio_result_t cc2520_set_value(radio_param_t param, radio_value_t value)
{
	switch (param) {
	case RADIO_PARAM_POWER_MODE:
		if (value == RADIO_POWER_MODE_ON) {
			cc2520_on();
			return RADIO_RESULT_OK;
		}
		if (value == RADIO_POWER_MODE_OFF) {
			cc2520_off();
			return RADIO_RESULT_OK;
		}
		return RADIO_RESULT_INVALID_VALUE;
	case RADIO_PARAM_CHANNEL:
		if (value < 11 || value > 26) {
			return RADIO_RESULT_INVALID_VALUE;
		}
		cc2520_set_channel(value);
		return RADIO_RESULT_OK;
	case RADIO_PARAM_PAN_ID:
		cc2520_set_pan_addr(value, 0x0000, NULL);
		return RADIO_RESULT_OK;
	case RADIO_PARAM_RX_MODE:
		return cc2520_set_rx_mode(value);
	default:
		return RADIO_RESULT_NOT_SUPPORTED;
	}
}

static void getrxdata(void *buf, int len)
{
	cc2520_read_fifo_buf(buf, len);
}

static void getrxbyte(uint8_t *byte)
{
	cc2520_read_fifo_byte(byte);

	/* Masking useless 7th bit
	 * Hardware does it for itself when filtering is on for instance
	 * See end of page 75 of datasheet.
	 */
	*byte &= 0x7f;
}

static inline bool strobe(uint8_t regname)
{
	return cc2520_strobe(regname);
}

static void set_txpower(uint8_t power)
{
	setreg(CC2520_TXPOWER, power);
}

static inline int cc2520_receiving_packet(void)
{
	return CC2520_SFD_IS_1;
}

static int cc2520_transmit(struct net_buf *buf, unsigned short payload_len)
{
	int txpower;
	uint32_t tx_start_wait;
	uint8_t sampled_cca;

	if (!init_ok) {
		return -EIO;
	}

	txpower = 0;

	if (packetbuf_attr(buf, PACKETBUF_ATTR_RADIO_TXPOWER) > 0) {
		/* Remember the current transmission power */
		txpower = cc2520_get_txpower();
		/* Set the specified transmission power */
		set_txpower(packetbuf_attr(buf, PACKETBUF_ATTR_RADIO_TXPOWER) - 1);
	}

	/* The TX FIFO can only hold one packet. Make sure to not overrun
	 * FIFO by waiting for transmission to start here and synchronizing
	 * with the CC2520_TX_ACTIVE check in cc2520_send.
	 *
	 * Note that we may have to wait up to 320 us (20 symbols) before
	 * transmission starts.
	 */

#if WITH_SEND_CCA
	strobe(CC2520_INS_SRXON);
	BUSYWAIT_UNTIL(status() & BIT(CC2520_RSSI_VALID), WAIT_100ms);
	strobe(CC2520_INS_STXONCCA);
	BUSYWAIT_UNTIL((sampled_cca = (getreg(CC2520_FSMSTAT1) &
					CC2520_FSMSTAT1_SAMPLED_CCA)),
			WAIT_10ms);
	if (sampled_cca == 0) {
		DBG("cc2520: sample_cca is 0, TX ERROR\n");
		return RADIO_TX_ERR;
	}
#else /* WITH_SEND_CCA */
	strobe(CC2520_INS_STXON);
#endif /* WITH_SEND_CCA */

	tx_start_wait = clock_get_cycle() + CLOCK_MSEC_TO_CYCLES(3000) + 1;
	while (CLOCK_CYCLE_LT(clock_get_cycle(), tx_start_wait)) {
		if (!CC2520_SFD_IS_1) {
			continue;
		}

#if PACKETBUF_WITH_PACKET_TYPE
		{
			uint32_t sfd_timestamp;

			sfd_timestamp = cc2520_sfd_start_time;
			if (packetbuf_attr(buf, PACKETBUF_ATTR_PACKET_TYPE) ==
					PACKETBUF_ATTR_PACKET_TYPE_TIMESTAMP) {
				/* Write timestamp to last two bytes of packet
				 * in TXFIFO.
				 */
				cc2520_write_ram(&sfd_timestamp,
					CC2520RAM_TXFIFO + payload_len - 1, 2);
			}
		}
#endif

		if (!(status() & BIT(CC2520_TX_ACTIVE))) {
			/* SFD went high but we are not transmitting.
			 * This means that we just started receiving a packet,
			 * so we drop the transmission.
			 */
			DBG("TX collision 0x%x\n", status());
			return RADIO_TX_COLLISION;
		}

		/* We wait until transmission has ended so that we get an
		 * accurate measurement of the transmission time.
		 */
		BUSYWAIT_UNTIL(!(status() & BIT(CC2520_TX_ACTIVE)), WAIT_500ms);

		DBG("status 0x%x\n", status());

		if (!receive_on) {
			/* We need to explicitly turn off the radio,
			 * since STXON[CCA] -> TX_ACTIVE -> RX_ACTIVE
			 */
			off();
		}

		if (packetbuf_attr(buf, PACKETBUF_ATTR_RADIO_TXPOWER) > 0) {
			/* Restore the transmission power */
			set_txpower(txpower & 0xff);
		}

		return RADIO_TX_OK;
	}

	/* If we are using WITH_SEND_CCA, we get here if the packet wasn't
	 * transmitted because of other channel activity.
	 */
	DBG("cc2520: transmission never started\n");

	print_exceptions_0();
	print_exceptions_1();

	if (packetbuf_attr(buf, PACKETBUF_ATTR_RADIO_TXPOWER) > 0) {
		/* Restore the transmission power */
		set_txpower(txpower & 0xff);
	}

	return RADIO_TX_COLLISION;
}

static int cc2520_prepare(const void *payload, unsigned short payload_len)
{
	uint8_t *buf = (uint8_t *)payload;
	uint8_t total_len;

	if (!init_ok) {
		return -EIO;
	}

	DBG("cc2520: sending %d bytes\n", payload_len);

	clear_exceptions();

	/* Write packet to TX FIFO. */
	strobe(CC2520_INS_SFLUSHTX);

	total_len = payload_len + FOOTER_LEN;
	DBG("TX FIFO has %u bytes\n", getreg(CC2520_TXFIFOCNT));
	cc2520_write_fifo_buf(&total_len, 1);
	cc2520_write_fifo_buf(buf, payload_len);
	DBG("TX FIFO has %u bytes\n", getreg(CC2520_TXFIFOCNT));

	print_errors();

	return 0;
}

static int cc2520_send(struct net_buf *buf, const void *payload,
		       unsigned short payload_len)
{
	int ret;

	cc2520_radio_lock();

	cc2520_prepare(payload, payload_len);
	ret = cc2520_transmit(buf, payload_len);

	cc2520_radio_unlock();

	return ret;
}

int cc2520_get_channel(void)
{
	return channel;
}

int cc2520_set_channel(int c)
{
	int ret = RADIO_RESULT_OK;
	uint16_t f;

	cc2520_radio_lock();

	/*
	 * Subtract the base channel (11), multiply by 5, which is the
	 * channel spacing. 357 is 2405-2048 and 0x4000 is LOCK_THR = 1.
	 */
	channel = c;

	f = MIN_CHANNEL + ((channel - MIN_CHANNEL) * CHANNEL_SPACING);
	/*
	 * Writing RAM requires crystal oscillator to be stable.
	 */
	BUSYWAIT_UNTIL((status() & (BIT(CC2520_XOSC16M_STABLE))), WAIT_100ms);

	/* Wait for any transmission to end. */
	BUSYWAIT_UNTIL(!(status() & BIT(CC2520_TX_ACTIVE)), WAIT_100ms);

	/* Define radio channel (between 11 and 25) */
	setreg(CC2520_FREQCTRL, f);

	/* If we are in receive mode, we issue an SRXON command to ensure
	 * that the VCO is calibrated.
	 */
	if (receive_on) {
		strobe(CC2520_INS_SRXON);
		BUSYWAIT_UNTIL((status() & BIT(CC2520_RSSI_VALID)), \
								WAIT_100ms);
		if (!(status() & BIT(CC2520_RSSI_VALID))) {
			ret = RADIO_RESULT_ERROR;
		}
	}

	cc2520_radio_unlock();

	return ret;
}

bool cc2520_set_pan_addr(unsigned pan, unsigned addr,
			 const uint8_t *ieee_addr)
{
	uint8_t tmp[2];

	cc2520_radio_lock();

	/*
	 * Writing RAM requires crystal oscillator to be stable.
	 */
	BUSYWAIT_UNTIL((status()) & (BIT(CC2520_XOSC16M_STABLE)), WAIT_1000ms);

	tmp[0] = pan & 0xff;
	tmp[1] = pan >> 8;
	cc2520_write_ram(tmp, CC2520RAM_PANID, 2);

	tmp[0] = addr & 0xff;
	tmp[1] = addr >> 8;
	cc2520_write_ram(tmp, CC2520RAM_SHORTADDR, 2);

	if (ieee_addr) {
		uint8_t tmp_addr[8];
		int f;

		/* LSB first, MSB last for 802.15.4 addresses in CC2520 */
		for (f = 0; f < 8; f++) {
			tmp_addr[7 - f] = ieee_addr[f];
		}

		cc2520_write_ram(tmp_addr, CC2520RAM_IEEEADDR, 8);
	}

	cc2520_radio_unlock();

	return true;
}

static int cc2520_read(void *buf, unsigned short bufsize)
{
	struct cc2520_config *info = cc2520_sgl_dev->config->config_info;
	uint8_t footer[2];
	uint8_t len;

	if (!init_ok) {
		return -EIO;
	}

	if (!cc2520_pending_packet()) {
		return -EAGAIN;
	}

	cc2520_packets_read++;

	getrxbyte(&len);

	DBG("%s: Incoming packet length: %d\n", __func__, len);

	if ((len - FOOTER_LEN > bufsize) ||
	    (len <= FOOTER_LEN)) {
		goto error;
	}

	getrxdata(buf, len - FOOTER_LEN);
	getrxdata(footer, FOOTER_LEN);

	if (footer[1] & FOOTER1_CRC_OK) {
		cc2520_last_rssi = footer[0];
		cc2520_last_correlation = footer[1] & FOOTER1_CORRELATION;
	} else {
		goto error;
	}

	if (cc2520_pending_packet()) {
		if (!CC2520_FIFO_IS_1) {
			/* Clean up in case of FIFO overflow!  This happens
			 * for every full length frame and is signaled by
			 * FIFOP = 1 and FIFO = 0
			 */
			flushrx();
		} else {
			/* Another packet might be waiting
			 * Let's unlock reading_packet_fiber()
			 */
			nano_fiber_sem_give(&info->read_lock);
		}
	}

	return len - FOOTER_LEN;

error:
	print_exceptions_0();
	print_exceptions_1();
	print_errors();

	flushrx();
	return -EINVAL;
}

static void read_packet(void)
{
	struct net_buf *buf;
	int len;

	buf = l2_buf_get_reserve(0);
	if (!buf) {
		DBG("%s: Could not allocate buffer\n", __func__);
		return;
	}

	packetbuf_set_attr(buf, PACKETBUF_ATTR_TIMESTAMP,
			   last_packet_timestamp);

	len = cc2520_read(packetbuf_dataptr(buf), PACKETBUF_SIZE);
	if (len < 0) {
		goto out;
	}

	packetbuf_set_attr(buf, PACKETBUF_ATTR_RSSI, cc2520_last_rssi);
	packetbuf_set_attr(buf, PACKETBUF_ATTR_LINK_QUALITY,
			   cc2520_last_correlation);
	packetbuf_set_datalen(buf, len);

	DBG("%s: received %d bytes\n", __func__, len);

	if (net_driver_15_4_recv_from_hw(buf) < 0) {
		DBG("%s: rdc input failed, packet discarded\n", __func__);
		goto out;
	}

	return;
out:
	l2_buf_unref(buf);
}

/* Reading incoming packet, so through SPI, cannot be done directly
 * the gpio callback since it's running in ISR context. Thus doing
 * it in an internal fiber
 */
static char __noinit __stack cc2520_read_stack[CC2520_READING_STACK_SIZE];

static void reading_packet_fiber(int unused1, int unused2)
{
	struct cc2520_config *info = cc2520_sgl_dev->config->config_info;

	while (1) {
		nano_fiber_sem_take(&info->read_lock, TICKS_UNLIMITED);

		cc2520_radio_lock();
		read_packet();
		cc2520_radio_unlock();

		last_packet_timestamp = cc2520_sfd_start_time;
		cc2520_packets_seen++;

		net_analyze_stack("CC2520 Rx Fiber stack", cc2520_read_stack,
				  CC2520_READING_STACK_SIZE);
	}
}

static void cc2520_gpio_int_handler(struct device *port, uint32_t pin)
{
	struct cc2520_config *info = cc2520_sgl_dev->config->config_info;

	DBG("%s: RX interrupt in pin %lu\n", __func__, pin);

	/* In order to make this driver available for 2+ instances
	 * it would require this handler to get access to the concerned
	 * instance
	 */

	nano_isr_sem_give(&info->read_lock);
}

void cc2520_set_txpower(uint8_t power)
{
	cc2520_radio_lock();
	set_txpower(power);
	cc2520_radio_unlock();
}

int cc2520_get_txpower(void)
{
	uint8_t power;

	cc2520_radio_lock();
	power = getreg(CC2520_TXPOWER);
	cc2520_radio_unlock();

	return power;
}

int cc2520_rssi(void)
{
	int radio_was_off = 0;
	int rssi;

	if (!locked) {
		return 0;
	}

	cc2520_radio_lock();

	if (!receive_on) {
		radio_was_off = 1;
		cc2520_on();
	}
	BUSYWAIT_UNTIL(status() & BIT(CC2520_RSSI_VALID), WAIT_10ms);

	rssi = (int)((signed char)getreg(CC2520_RSSI));

	if (radio_was_off) {
		cc2520_off();
	}

	cc2520_radio_unlock();

	return rssi;
}

int cc2520_cca_valid(void)
{
	int valid;

	if (locked) {
		return 0;
	}

	cc2520_radio_lock();
	valid = !!(status() & BIT(CC2520_RSSI_VALID));
	cc2520_radio_unlock();

	return valid;
}

static int cc2520_cca(void)
{
	int radio_was_off = 0;
	int cca = 1;

	if (locked) {
		return 1;
	}

	cc2520_radio_lock();

	if (!receive_on) {
		radio_was_off = 1;
		cc2520_on();
	}

	/* Make sure that the radio really got turned on. */
	if (receive_on) {
		BUSYWAIT_UNTIL(status() & BIT(CC2520_RSSI_VALID), WAIT_10ms);
		cca = CC2520_CCA_IS_1;
	}

	cc2520_radio_unlock();

	if (radio_was_off) {
		cc2520_off();
	}

	return cca;
}

void cc2520_set_cca_threshold(int value)
{
	cc2520_radio_lock();
	setreg(CC2520_CCACTRL0, value & 0xff);
	cc2520_radio_unlock();
}

static struct device *cc2520_spi_configure(void)
{
	struct device *spi;
	struct spi_config spi_conf = {
		.config = (8 << 4),
		.max_sys_freq = CONFIG_TI_CC2520_SPI_FREQ,
	};

	spi = device_get_binding(CONFIG_TI_CC2520_SPI_DRV_NAME);
	spi_configure(spi, &spi_conf);

	return spi;
}

static void cc2520_set_mac_address(void)
{
	static unsigned char mac[8];
	int i;

	/* TI OUI */
	mac[0] = 0x00;
	mac[1] = 0x12;
	mac[2] = 0x4b;

	for (i = 3; i < 8; i++) {
		mac[i] = random_rand();
	}

	/* clear the group bit, and set the locally administered bit */
	mac[7] &= ~0x01;
	mac[7] |= 0x02;

	net_set_mac(mac, 8);
}

static void cc2520_configure(struct device *dev)
{
	CC2520_DISABLE_FIFOP_INT();
	CC2520_FIFOP_INT_INIT();

	/* Initially reset must be set */
	SET_RESET_ACTIVE();
	SET_VREG_INACTIVE();
	clock_delay_usec_busywait(250);

	/* Turn on voltage regulator. */
	SET_VREG_ACTIVE();
	clock_delay_usec_busywait(400);

	/* Release reset */
	SET_RESET_INACTIVE();
	clock_delay_usec_busywait(800);

	/* Turn on the crystal oscillator. */
	if (!CC2520_STROBE_PLUS_NOP(CC2520_INS_SXOSCON)) {
		DBG("Strobe SXOSCON sending failed\n");
		return;
	}

	clock_delay_usec_busywait(800);

	BUSYWAIT_UNTIL((status() & BIT(CC2520_XOSC16M_STABLE)),	WAIT_10ms);
	if (!(status() & BIT(CC2520_XOSC16M_STABLE))) {
		DBG("Clock is not stabilized.\n");
		return;
	}

	/* Change default values as recommended in the data sheet, */
	/* correlation threshold = 20, RX bandpass filter = 1.3uA.*/

	setreg(CC2520_TXCTRL, 0x94);
	setreg(CC2520_TXPOWER, 0x13); /* Output power 1 dBm */

	/* TXPOWER values
	 * 0x03 -> -18 dBm
	 * 0x2C -> -7 dBm
	 * 0x88 -> -4 dBm
	 * 0x81 -> -2 dBm
	 * 0x32 -> 0 dBm
	 * 0x13 -> 1 dBm
	 * 0x32 -> 0 dBm
	 * 0x13 -> 1 dBm
	 * 0xAB -> 2 dBm
	 * 0xF2 -> 3 dBm
	 * 0xF7 -> 5 dBm
	 */
	setreg(CC2520_CCACTRL0, 0xF8); /* CCA threshold -80dBm */

	/* Recommended RX settings */
	setreg(CC2520_MDMCTRL0, 0x84); /* Controls modem */
	setreg(CC2520_MDMCTRL1, 0x14); /* Controls modem */
	setreg(CC2520_RXCTRL, 0x3F); /* Adjust currents in RX analog */
	setreg(CC2520_FSCTRL, 0x5A); /* Adjust currents in synt. */
	setreg(CC2520_FSCAL1, 0x2B); /* Adjust currents in VCO */
	setreg(CC2520_AGCCTRL1, 0x11); /* Adjust target for AGC ctrl loop */
	setreg(CC2520_AGCCTRL2, 0xEB);

	/*  Disable external clock */
	setreg(CC2520_EXTCLOCK, 0x00);

	/*  Tune ADC performance */
	setreg(CC2520_ADCTEST0, 0x10);
	setreg(CC2520_ADCTEST1, 0x0E);
	setreg(CC2520_ADCTEST2, 0x03);

	/* Set auto CRC on frame. */
#if CC2520_CONF_AUTOACK
	setreg(CC2520_FRMCTRL0, AUTOCRC | AUTOACK);
	setreg(CC2520_FRMFILT0, FRAME_MAX_VERSION|FRAME_FILTER_ENABLE);
#else
	/* setreg(CC2520_FRMCTRL0,    0x60); */
	setreg(CC2520_FRMCTRL0, AUTOCRC);
	/* Disable filter on @ (remove if you want to address specific wismote) */
	setreg(CC2520_FRMFILT0, 0x00);
#endif /* CC2520_CONF_AUTOACK */
	/* SET_RXENMASK_ON_TX */
	setreg(CC2520_FRMCTRL1, 1);
	/* Set FIFOP threshold to maximum .*/
	setreg(CC2520_FIFOPCTRL, FIFOP_THR(0x7F));

	if (!cc2520_set_pan_addr(0xffff, 0x0000, NULL)) {
		return;
	}

	cc2520_set_channel(CONFIG_TI_CC2520_CHANNEL);

	cc2520_set_mac_address();

	flushrx();

	cc2520_print_gpio_config();

	init_ok = true;
}

static radio_result_t get_object(radio_param_t param,
				 void *dest, size_t size)
{
	return RADIO_RESULT_NOT_SUPPORTED;
}

static radio_result_t set_object(radio_param_t param,
				 const void *src, size_t size)
{
	return RADIO_RESULT_NOT_SUPPORTED;
}

static int cc2520_contiki_init(void)
{
	return init_ok;
}

/* Contiki IP stack needs radio driver that it uses to deal with the
 * hardware. This driver API acts as a middle man between Contiki and
 * the Zephyr CC2520 driver. This api needs to external so that
 * Contiki stack can call the API functions.
 */
cc2520_driver_api_t cc2520_15_4_radio_driver = {
	.init = cc2520_contiki_init,
	.prepare = cc2520_prepare,
	.transmit = cc2520_transmit,
	.send = cc2520_send,
	.read = cc2520_read,
	.channel_clear = cc2520_cca,
	.receiving_packet = cc2520_receiving_packet,
	.pending_packet = cc2520_pending_packet,
	.on = cc2520_on,
	.off = cc2520_off,
	.get_value = cc2520_get_value,
	.set_value = cc2520_set_value,
	.get_object = get_object,
	.set_object = set_object,
};

static int cc2520_init(struct device *dev)
{
	struct cc2520_config *info = dev->config->config_info;

	DBG("%s setup\n", DRIVER_STR);

	dev->driver_api = &cc2520_15_4_radio_driver;
	cc2520_sgl_dev = dev;

	info->gpios = cc2520_gpio_configure();
	info->spi = cc2520_spi_configure();
	info->spi_slave = CONFIG_TI_CC2520_SPI_SLAVE;
	nano_sem_init(&info->read_lock);
	nano_sem_init(&info->radio_lock);

	cc2520_configure(dev);

	if (init_ok) {
		DBG("%s initialized on device: %p\n", DRIVER_STR, dev);

		nano_sem_give(&info->radio_lock);
		task_fiber_start(cc2520_read_stack, CC2520_READING_STACK_SIZE,
				 reading_packet_fiber, 0, 0, 0, 0);
	} else {
		cc2520_sgl_dev = NULL;
		DBG("%s initialization failed\n", DRIVER_STR);

		return -EIO;
	}

	return 0;
}

DEVICE_INIT(cc2520, CONFIG_CC2520_DRV_NAME,
	    cc2520_init, NULL, &cc2520_config,
	    APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);