aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/lantiq/files-3.3/drivers/spi/spi-xway.c
blob: be5c25b1fe01ddcf6739c07a95ebc3aeee5e2b43 (plain)
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
/*
 * Lantiq SoC SPI controller
 *
 * Copyright (C) 2011 Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
 *
 * This program is free software; you can distribute it and/or modify it
 * under the terms of the GNU General Public License (Version 2) as
 * published by the Free Software Foundation.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>

#include <lantiq_soc.h>
#include <lantiq_platform.h>

#define LTQ_SPI_CLC		0x00	/* Clock control */
#define LTQ_SPI_PISEL		0x04	/* Port input select */
#define LTQ_SPI_ID		0x08	/* Identification */
#define LTQ_SPI_CON		0x10	/* Control */
#define LTQ_SPI_STAT		0x14	/* Status */
#define LTQ_SPI_WHBSTATE	0x18	/* Write HW modified state */
#define LTQ_SPI_TB		0x20	/* Transmit buffer */
#define LTQ_SPI_RB		0x24	/* Receive buffer */
#define LTQ_SPI_RXFCON		0x30	/* Receive FIFO control */
#define LTQ_SPI_TXFCON		0x34	/* Transmit FIFO control */
#define LTQ_SPI_FSTAT		0x38	/* FIFO status */
#define LTQ_SPI_BRT		0x40	/* Baudrate timer */
#define LTQ_SPI_BRSTAT		0x44	/* Baudrate timer status */
#define LTQ_SPI_SFCON		0x60	/* Serial frame control */
#define LTQ_SPI_SFSTAT		0x64	/* Serial frame status */
#define LTQ_SPI_GPOCON		0x70	/* General purpose output control */
#define LTQ_SPI_GPOSTAT		0x74	/* General purpose output status */
#define LTQ_SPI_FGPO		0x78	/* Forced general purpose output */
#define LTQ_SPI_RXREQ		0x80	/* Receive request */
#define LTQ_SPI_RXCNT		0x84	/* Receive count */
#define LTQ_SPI_DMACON		0xEC	/* DMA control */
#define LTQ_SPI_IRNEN		0xF4	/* Interrupt node enable */
#define LTQ_SPI_IRNICR		0xF8	/* Interrupt node interrupt capture */
#define LTQ_SPI_IRNCR		0xFC	/* Interrupt node control */

#define LTQ_SPI_CLC_SMC_SHIFT	16	/* Clock divider for sleep mode */
#define LTQ_SPI_CLC_SMC_MASK	0xFF
#define LTQ_SPI_CLC_RMC_SHIFT	8	/* Clock divider for normal run mode */
#define LTQ_SPI_CLC_RMC_MASK	0xFF
#define LTQ_SPI_CLC_DISS	BIT(1)	/* Disable status bit */
#define LTQ_SPI_CLC_DISR	BIT(0)	/* Disable request bit */

#define LTQ_SPI_ID_TXFS_SHIFT	24	/* Implemented TX FIFO size */
#define LTQ_SPI_ID_TXFS_MASK	0x3F
#define LTQ_SPI_ID_RXFS_SHIFT	16	/* Implemented RX FIFO size */
#define LTQ_SPI_ID_RXFS_MASK	0x3F
#define LTQ_SPI_ID_REV_MASK	0x1F	/* Hardware revision number */
#define LTQ_SPI_ID_CFG		BIT(5)	/* DMA interface support */

#define LTQ_SPI_CON_BM_SHIFT	16	/* Data width selection */
#define LTQ_SPI_CON_BM_MASK	0x1F
#define LTQ_SPI_CON_EM		BIT(24)	/* Echo mode */
#define LTQ_SPI_CON_IDLE	BIT(23)	/* Idle bit value */
#define LTQ_SPI_CON_ENBV	BIT(22)	/* Enable byte valid control */
#define LTQ_SPI_CON_RUEN	BIT(12)	/* Receive underflow error enable */
#define LTQ_SPI_CON_TUEN	BIT(11)	/* Transmit underflow error enable */
#define LTQ_SPI_CON_AEN		BIT(10)	/* Abort error enable */
#define LTQ_SPI_CON_REN		BIT(9)	/* Receive overflow error enable */
#define LTQ_SPI_CON_TEN		BIT(8)	/* Transmit overflow error enable */
#define LTQ_SPI_CON_LB		BIT(7)	/* Loopback control */
#define LTQ_SPI_CON_PO		BIT(6)	/* Clock polarity control */
#define LTQ_SPI_CON_PH		BIT(5)	/* Clock phase control */
#define LTQ_SPI_CON_HB		BIT(4)	/* Heading control */
#define LTQ_SPI_CON_RXOFF	BIT(1)	/* Switch receiver off */
#define LTQ_SPI_CON_TXOFF	BIT(0)	/* Switch transmitter off */

#define LTQ_SPI_STAT_RXBV_MASK	0x7
#define LTQ_SPI_STAT_RXBV_SHIFT	28
#define LTQ_SPI_STAT_BSY	BIT(13)	/* Busy flag */
#define LTQ_SPI_STAT_RUE	BIT(12)	/* Receive underflow error flag */
#define LTQ_SPI_STAT_TUE	BIT(11)	/* Transmit underflow error flag */
#define LTQ_SPI_STAT_AE		BIT(10)	/* Abort error flag */
#define LTQ_SPI_STAT_RE		BIT(9)	/* Receive error flag */
#define LTQ_SPI_STAT_TE		BIT(8)	/* Transmit error flag */
#define LTQ_SPI_STAT_MS		BIT(1)	/* Master/slave select bit */
#define LTQ_SPI_STAT_EN		BIT(0)	/* Enable bit */

#define LTQ_SPI_WHBSTATE_SETTUE	BIT(15)	/* Set transmit underflow error flag */
#define LTQ_SPI_WHBSTATE_SETAE	BIT(14)	/* Set abort error flag */
#define LTQ_SPI_WHBSTATE_SETRE	BIT(13)	/* Set receive error flag */
#define LTQ_SPI_WHBSTATE_SETTE	BIT(12)	/* Set transmit error flag */
#define LTQ_SPI_WHBSTATE_CLRTUE	BIT(11)	/* Clear transmit underflow error flag */
#define LTQ_SPI_WHBSTATE_CLRAE	BIT(10)	/* Clear abort error flag */
#define LTQ_SPI_WHBSTATE_CLRRE	BIT(9)	/* Clear receive error flag */
#define LTQ_SPI_WHBSTATE_CLRTE	BIT(8)	/* Clear transmit error flag */
#define LTQ_SPI_WHBSTATE_SETME	BIT(7)	/* Set mode error flag */
#define LTQ_SPI_WHBSTATE_CLRME	BIT(6)	/* Clear mode error flag */
#define LTQ_SPI_WHBSTATE_SETRUE	BIT(5)	/* Set receive underflow error flag */
#define LTQ_SPI_WHBSTATE_CLRRUE	BIT(4)	/* Clear receive underflow error flag */
#define LTQ_SPI_WHBSTATE_SETMS	BIT(3)	/* Set master select bit */
#define LTQ_SPI_WHBSTATE_CLRMS	BIT(2)	/* Clear master select bit */
#define LTQ_SPI_WHBSTATE_SETEN	BIT(1)	/* Set enable bit (operational mode) */
#define LTQ_SPI_WHBSTATE_CLREN	BIT(0)	/* Clear enable bit (config mode */
#define LTQ_SPI_WHBSTATE_CLR_ERRORS	0x0F50

#define LTQ_SPI_RXFCON_RXFITL_SHIFT	8	/* FIFO interrupt trigger level */
#define LTQ_SPI_RXFCON_RXFITL_MASK	0x3F
#define LTQ_SPI_RXFCON_RXFLU		BIT(1)	/* FIFO flush */
#define LTQ_SPI_RXFCON_RXFEN		BIT(0)	/* FIFO enable */

#define LTQ_SPI_TXFCON_TXFITL_SHIFT	8	/* FIFO interrupt trigger level */
#define LTQ_SPI_TXFCON_TXFITL_MASK	0x3F
#define LTQ_SPI_TXFCON_TXFLU		BIT(1)	/* FIFO flush */
#define LTQ_SPI_TXFCON_TXFEN		BIT(0)	/* FIFO enable */

#define LTQ_SPI_FSTAT_RXFFL_MASK	0x3f
#define LTQ_SPI_FSTAT_RXFFL_SHIFT	0
#define LTQ_SPI_FSTAT_TXFFL_MASK	0x3f
#define LTQ_SPI_FSTAT_TXFFL_SHIFT	8

#define LTQ_SPI_GPOCON_ISCSBN_SHIFT	8
#define LTQ_SPI_GPOCON_INVOUTN_SHIFT	0

#define LTQ_SPI_FGPO_SETOUTN_SHIFT	8
#define LTQ_SPI_FGPO_CLROUTN_SHIFT	0

#define LTQ_SPI_RXREQ_RXCNT_MASK	0xFFFF	/* Receive count value */
#define LTQ_SPI_RXCNT_TODO_MASK		0xFFFF	/* Recevie to-do value */

#define LTQ_SPI_IRNEN_F		BIT(3)	/* Frame end interrupt request */
#define LTQ_SPI_IRNEN_E		BIT(2)	/* Error end interrupt request */
#define LTQ_SPI_IRNEN_T		BIT(1)	/* Transmit end interrupt request */
#define LTQ_SPI_IRNEN_R		BIT(0)	/* Receive end interrupt request */
#define LTQ_SPI_IRNEN_ALL	0xF

/* Hard-wired GPIOs used by SPI controller */
#define LTQ_SPI_GPIO_DI 	(ltq_is_ase()?  8 : 16)
#define LTQ_SPI_GPIO_DO 	(ltq_is_ase()?  9 : 17)
#define LTQ_SPI_GPIO_CLK	(ltq_is_ase()? 10 : 18)

struct ltq_spi {
	struct spi_bitbang	bitbang;
	struct completion	done;
	spinlock_t		lock;

	struct device		*dev;
	void __iomem		*base;
	struct clk		*fpiclk;
	struct clk		*spiclk;

	int			status;
	int			irq[3];

	const u8		*tx;
	u8			*rx;
	u32			tx_cnt;
	u32			rx_cnt;
	u32			len;
	struct spi_transfer	*curr_transfer;

	u32 (*get_tx) (struct ltq_spi *);

	u16			txfs;
	u16			rxfs;
	unsigned		dma_support:1;
	unsigned		cfg_mode:1;

};

struct ltq_spi_controller_state {
	void (*cs_activate) (struct spi_device *);
	void (*cs_deactivate) (struct spi_device *);
};

struct ltq_spi_irq_map {
	char		*name;
	irq_handler_t	handler;
};

struct ltq_spi_cs_gpio_map {
	unsigned	gpio;
	unsigned	mux;
};

static inline struct ltq_spi *ltq_spi_to_hw(struct spi_device *spi)
{
	return spi_master_get_devdata(spi->master);
}

static inline u32 ltq_spi_reg_read(struct ltq_spi *hw, u32 reg)
{
	return ioread32be(hw->base + reg);
}

static inline void ltq_spi_reg_write(struct ltq_spi *hw, u32 val, u32 reg)
{
	iowrite32be(val, hw->base + reg);
}

static inline void ltq_spi_reg_setbit(struct ltq_spi *hw, u32 bits, u32 reg)
{
	u32 val;

	val = ltq_spi_reg_read(hw, reg);
	val |= bits;
	ltq_spi_reg_write(hw, val, reg);
}

static inline void ltq_spi_reg_clearbit(struct ltq_spi *hw, u32 bits, u32 reg)
{
	u32 val;

	val = ltq_spi_reg_read(hw, reg);
	val &= ~bits;
	ltq_spi_reg_write(hw, val, reg);
}

static void ltq_spi_hw_enable(struct ltq_spi *hw)
{
	u32 clc;

	/* Power-up mdule */
	clk_enable(hw->spiclk);

	/*
	 * Set clock divider for run mode to 1 to
	 * run at same frequency as FPI bus
	 */
	clc = (1 << LTQ_SPI_CLC_RMC_SHIFT);
	ltq_spi_reg_write(hw, clc, LTQ_SPI_CLC);
}

static void ltq_spi_hw_disable(struct ltq_spi *hw)
{
	/* Set clock divider to 0 and set module disable bit */
	ltq_spi_reg_write(hw, LTQ_SPI_CLC_DISS, LTQ_SPI_CLC);

	/* Power-down mdule */
	clk_disable(hw->spiclk);
}

static void ltq_spi_reset_fifos(struct ltq_spi *hw)
{
	u32 val;

	/*
	 * Enable and flush FIFOs. Set interrupt trigger level to
	 * half of FIFO count implemented in hardware.
	 */
	if (hw->txfs > 1) {
		val = hw->txfs << (LTQ_SPI_TXFCON_TXFITL_SHIFT - 1);
		val |= LTQ_SPI_TXFCON_TXFEN | LTQ_SPI_TXFCON_TXFLU;
		ltq_spi_reg_write(hw, val, LTQ_SPI_TXFCON);
	}

	if (hw->rxfs > 1) {
		val = hw->rxfs << (LTQ_SPI_RXFCON_RXFITL_SHIFT - 1);
		val |= LTQ_SPI_RXFCON_RXFEN | LTQ_SPI_RXFCON_RXFLU;
		ltq_spi_reg_write(hw, val, LTQ_SPI_RXFCON);
	}
}

static inline int ltq_spi_wait_ready(struct ltq_spi *hw)
{
	u32 stat;
	unsigned long timeout;

	timeout = jiffies + msecs_to_jiffies(200);

	do {
		stat = ltq_spi_reg_read(hw, LTQ_SPI_STAT);
		if (!(stat & LTQ_SPI_STAT_BSY))
			return 0;

		cond_resched();
	} while (!time_after_eq(jiffies, timeout));

	dev_err(hw->dev, "SPI wait ready timed out stat: %x\n", stat);

	return -ETIMEDOUT;
}

static void ltq_spi_config_mode_set(struct ltq_spi *hw)
{
	if (hw->cfg_mode)
		return;

	/*
	 * Putting the SPI module in config mode is only safe if no
	 * transfer is in progress as indicated by busy flag STATE.BSY.
	 */
	if (ltq_spi_wait_ready(hw)) {
		ltq_spi_reset_fifos(hw);
		hw->status = -ETIMEDOUT;
	}
	ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_CLREN, LTQ_SPI_WHBSTATE);

	hw->cfg_mode = 1;
}

static void ltq_spi_run_mode_set(struct ltq_spi *hw)
{
	if (!hw->cfg_mode)
		return;

	ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_SETEN, LTQ_SPI_WHBSTATE);

	hw->cfg_mode = 0;
}

static u32 ltq_spi_tx_word_u8(struct ltq_spi *hw)
{
	const u8 *tx = hw->tx;
	u32 data = *tx++;

	hw->tx_cnt++;
	hw->tx++;

	return data;
}

static u32 ltq_spi_tx_word_u16(struct ltq_spi *hw)
{
	const u16 *tx = (u16 *) hw->tx;
	u32 data = *tx++;

	hw->tx_cnt += 2;
	hw->tx += 2;

	return data;
}

static u32 ltq_spi_tx_word_u32(struct ltq_spi *hw)
{
	const u32 *tx = (u32 *) hw->tx;
	u32 data = *tx++;

	hw->tx_cnt += 4;
	hw->tx += 4;

	return data;
}

static void ltq_spi_bits_per_word_set(struct spi_device *spi)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u32 bm;
	u8 bits_per_word = spi->bits_per_word;

	/*
	 * Use either default value of SPI device or value
	 * from current transfer.
	 */
	if (hw->curr_transfer && hw->curr_transfer->bits_per_word)
		bits_per_word = hw->curr_transfer->bits_per_word;

	if (bits_per_word <= 8)
		hw->get_tx = ltq_spi_tx_word_u8;
	else if (bits_per_word <= 16)
		hw->get_tx = ltq_spi_tx_word_u16;
	else if (bits_per_word <= 32)
		hw->get_tx = ltq_spi_tx_word_u32;

	/* CON.BM value = bits_per_word - 1 */
	bm = (bits_per_word - 1) << LTQ_SPI_CON_BM_SHIFT;

	ltq_spi_reg_clearbit(hw, LTQ_SPI_CON_BM_MASK <<
			     LTQ_SPI_CON_BM_SHIFT, LTQ_SPI_CON);
	ltq_spi_reg_setbit(hw, bm, LTQ_SPI_CON);
}

static void ltq_spi_speed_set(struct spi_device *spi)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u32 br, max_speed_hz, spi_clk;
	u32 speed_hz = spi->max_speed_hz;

	/*
	 * Use either default value of SPI device or value
	 * from current transfer.
	 */
	if (hw->curr_transfer && hw->curr_transfer->speed_hz)
		speed_hz = hw->curr_transfer->speed_hz;

	/*
	 * SPI module clock is derived from FPI bus clock dependent on
	 * divider value in CLC.RMS which is always set to 1.
	 */
	spi_clk = clk_get_rate(hw->fpiclk);

	/*
	 * Maximum SPI clock frequency in master mode is half of
	 * SPI module clock frequency. Maximum reload value of
	 * baudrate generator BR is 2^16.
	 */
	max_speed_hz = spi_clk / 2;
	if (speed_hz >= max_speed_hz)
		br = 0;
	else
		br = (max_speed_hz / speed_hz) - 1;

	if (br > 0xFFFF)
		br = 0xFFFF;

	ltq_spi_reg_write(hw, br, LTQ_SPI_BRT);
}

static void ltq_spi_clockmode_set(struct spi_device *spi)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u32 con;

	con = ltq_spi_reg_read(hw, LTQ_SPI_CON);

	/*
	 * SPI mode mapping in CON register:
	 * Mode CPOL CPHA CON.PO CON.PH
	 *  0    0    0      0      1
	 *  1    0    1      0      0
	 *  2    1    0      1      1
	 *  3    1    1      1      0
	 */
	if (spi->mode & SPI_CPHA)
		con &= ~LTQ_SPI_CON_PH;
	else
		con |= LTQ_SPI_CON_PH;

	if (spi->mode & SPI_CPOL)
		con |= LTQ_SPI_CON_PO;
	else
		con &= ~LTQ_SPI_CON_PO;

	/* Set heading control */
	if (spi->mode & SPI_LSB_FIRST)
		con &= ~LTQ_SPI_CON_HB;
	else
		con |= LTQ_SPI_CON_HB;

	ltq_spi_reg_write(hw, con, LTQ_SPI_CON);
}

static void ltq_spi_xmit_set(struct ltq_spi *hw, struct spi_transfer *t)
{
	u32 con;

	con = ltq_spi_reg_read(hw, LTQ_SPI_CON);

	if (t) {
		if (t->tx_buf && t->rx_buf) {
			con &= ~(LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF);
		} else if (t->rx_buf) {
			con &= ~LTQ_SPI_CON_RXOFF;
			con |= LTQ_SPI_CON_TXOFF;
		} else if (t->tx_buf) {
			con &= ~LTQ_SPI_CON_TXOFF;
			con |= LTQ_SPI_CON_RXOFF;
		}
	} else
		con |= (LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF);

	ltq_spi_reg_write(hw, con, LTQ_SPI_CON);
}

static void ltq_spi_gpio_cs_activate(struct spi_device *spi)
{
	struct ltq_spi_controller_data *cdata = spi->controller_data;
	int val = spi->mode & SPI_CS_HIGH ? 1 : 0;

	gpio_set_value(cdata->gpio, val);
}

static void ltq_spi_gpio_cs_deactivate(struct spi_device *spi)
{
	struct ltq_spi_controller_data *cdata = spi->controller_data;
	int val = spi->mode & SPI_CS_HIGH ? 0 : 1;

	gpio_set_value(cdata->gpio, val);
}

static void ltq_spi_internal_cs_activate(struct spi_device *spi)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u32 fgpo;

	fgpo = (1 << (spi->chip_select + LTQ_SPI_FGPO_CLROUTN_SHIFT));
	ltq_spi_reg_setbit(hw, fgpo, LTQ_SPI_FGPO);
}

static void ltq_spi_internal_cs_deactivate(struct spi_device *spi)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u32 fgpo;

	fgpo = (1 << (spi->chip_select + LTQ_SPI_FGPO_SETOUTN_SHIFT));
	ltq_spi_reg_setbit(hw, fgpo, LTQ_SPI_FGPO);
}

static void ltq_spi_chipselect(struct spi_device *spi, int cs)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	struct ltq_spi_controller_state *cstate = spi->controller_state;

	switch (cs) {
	case BITBANG_CS_ACTIVE:
		ltq_spi_bits_per_word_set(spi);
		ltq_spi_speed_set(spi);
		ltq_spi_clockmode_set(spi);
		ltq_spi_run_mode_set(hw);

		cstate->cs_activate(spi);
		break;

	case BITBANG_CS_INACTIVE:
		cstate->cs_deactivate(spi);

		ltq_spi_config_mode_set(hw);

		break;
	}
}

static int ltq_spi_setup_transfer(struct spi_device *spi,
				  struct spi_transfer *t)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u8 bits_per_word = spi->bits_per_word;

	hw->curr_transfer = t;

	if (t && t->bits_per_word)
		bits_per_word = t->bits_per_word;

	if (bits_per_word > 32)
		return -EINVAL;

	ltq_spi_config_mode_set(hw);

	return 0;
}

static const struct ltq_spi_cs_gpio_map ltq_spi_cs[] = {
	{ 15, 2 },
	{ 22, 2 },
	{ 13, 1 },
	{ 10, 1 },
	{  9, 1 },
	{ 11, 3 },
};

static const struct ltq_spi_cs_gpio_map ltq_spi_cs_ase[] = {
	{  7, 2 },
	{ 15, 1 },
	{ 14, 1 },
};

static int ltq_spi_setup(struct spi_device *spi)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	struct ltq_spi_controller_data *cdata = spi->controller_data;
	struct ltq_spi_controller_state *cstate;
	u32 gpocon, fgpo;
	int ret;

	/* Set default word length to 8 if not set */
	if (!spi->bits_per_word)
		spi->bits_per_word = 8;

	if (spi->bits_per_word > 32)
		return -EINVAL;

	if (!spi->controller_state) {
		cstate = kzalloc(sizeof(struct ltq_spi_controller_state),
				 GFP_KERNEL);
		if (!cstate)
			return -ENOMEM;

		spi->controller_state = cstate;
	} else
		return 0;

	/*
	 * Up to six GPIOs can be connected to the SPI module
	 * via GPIO alternate function to control the chip select lines.
	 * For more flexibility in board layout this driver can also control
	 * the CS lines via GPIO API. If GPIOs should be used, board setup code
	 * have to register the SPI device with struct ltq_spi_controller_data
	 * attached.
	 */
	if (cdata && cdata->gpio) {
		ret = gpio_request(cdata->gpio, "spi-cs");
		if (ret)
			return -EBUSY;

		ret = spi->mode & SPI_CS_HIGH ? 0 : 1;
		gpio_direction_output(cdata->gpio, ret);

		cstate->cs_activate = ltq_spi_gpio_cs_activate;
		cstate->cs_deactivate = ltq_spi_gpio_cs_deactivate;
	} else {
		struct ltq_spi_cs_gpio_map *cs_map =
				ltq_is_ase() ? ltq_spi_cs_ase : ltq_spi_cs;
		ret = ltq_gpio_request(&spi->dev, cs_map[spi->chip_select].gpio,
				cs_map[spi->chip_select].mux,
				1, "spi-cs");
		if (ret)
			return -EBUSY;

		gpocon = (1 << (spi->chip_select +
				LTQ_SPI_GPOCON_ISCSBN_SHIFT));

		if (spi->mode & SPI_CS_HIGH)
			gpocon |= (1 << spi->chip_select);

		fgpo = (1 << (spi->chip_select + LTQ_SPI_FGPO_SETOUTN_SHIFT));

		ltq_spi_reg_setbit(hw, gpocon, LTQ_SPI_GPOCON);
		ltq_spi_reg_setbit(hw, fgpo, LTQ_SPI_FGPO);

		cstate->cs_activate = ltq_spi_internal_cs_activate;
		cstate->cs_deactivate = ltq_spi_internal_cs_deactivate;
	}

	return 0;
}

static void ltq_spi_cleanup(struct spi_device *spi)
{
	struct ltq_spi_controller_data *cdata = spi->controller_data;
	struct ltq_spi_controller_state *cstate = spi->controller_state;
	unsigned gpio;

	if (cdata && cdata->gpio)
		gpio = cdata->gpio;
	else
		gpio = ltq_is_ase() ? ltq_spi_cs_ase[spi->chip_select].gpio :
					 ltq_spi_cs[spi->chip_select].gpio;

	gpio_free(gpio);
	kfree(cstate);
}

static void ltq_spi_txfifo_write(struct ltq_spi *hw)
{
	u32 fstat, data;
	u16 fifo_space;

	/* Determine how much FIFOs are free for TX data */
	fstat = ltq_spi_reg_read(hw, LTQ_SPI_FSTAT);
	fifo_space = hw->txfs - ((fstat >> LTQ_SPI_FSTAT_TXFFL_SHIFT) &
					LTQ_SPI_FSTAT_TXFFL_MASK);

	if (!fifo_space)
		return;

	while (hw->tx_cnt < hw->len && fifo_space) {
		data = hw->get_tx(hw);
		ltq_spi_reg_write(hw, data, LTQ_SPI_TB);
		fifo_space--;
	}
}

static void ltq_spi_rxfifo_read(struct ltq_spi *hw)
{
	u32 fstat, data, *rx32;
	u16 fifo_fill;
	u8 rxbv, shift, *rx8;

	/* Determine how much FIFOs are filled with RX data */
	fstat = ltq_spi_reg_read(hw, LTQ_SPI_FSTAT);
	fifo_fill = ((fstat >> LTQ_SPI_FSTAT_RXFFL_SHIFT)
			& LTQ_SPI_FSTAT_RXFFL_MASK);

	if (!fifo_fill)
		return;

	/*
	 * The 32 bit FIFO is always used completely independent from the
	 * bits_per_word value. Thus four bytes have to be read at once
	 * per FIFO.
	 */
	rx32 = (u32 *) hw->rx;
	while (hw->len - hw->rx_cnt >= 4 && fifo_fill) {
		*rx32++ = ltq_spi_reg_read(hw, LTQ_SPI_RB);
		hw->rx_cnt += 4;
		hw->rx += 4;
		fifo_fill--;
	}

	/*
	 * If there are remaining bytes, read byte count from STAT.RXBV
	 * register and read the data byte-wise.
	 */
	while (fifo_fill && hw->rx_cnt < hw->len) {
		rxbv = (ltq_spi_reg_read(hw, LTQ_SPI_STAT) >>
			LTQ_SPI_STAT_RXBV_SHIFT) & LTQ_SPI_STAT_RXBV_MASK;
		data = ltq_spi_reg_read(hw, LTQ_SPI_RB);

		shift = (rxbv - 1) * 8;
		rx8 = hw->rx;

		while (rxbv) {
			*rx8++ = (data >> shift) & 0xFF;
			rxbv--;
			shift -= 8;
			hw->rx_cnt++;
			hw->rx++;
		}

		fifo_fill--;
	}
}

static void ltq_spi_rxreq_set(struct ltq_spi *hw)
{
	u32 rxreq, rxreq_max, rxtodo;

	rxtodo = ltq_spi_reg_read(hw, LTQ_SPI_RXCNT) & LTQ_SPI_RXCNT_TODO_MASK;

	/*
	 * In RX-only mode the serial clock is activated only after writing
	 * the expected amount of RX bytes into RXREQ register.
	 * To avoid receive overflows at high clocks it is better to request
	 * only the amount of bytes that fits into all FIFOs. This value
	 * depends on the FIFO size implemented in hardware.
	 */
	rxreq = hw->len - hw->rx_cnt;
	rxreq_max = hw->rxfs << 2;
	rxreq = min(rxreq_max, rxreq);

	if (!rxtodo && rxreq)
		ltq_spi_reg_write(hw, rxreq, LTQ_SPI_RXREQ);
}

static inline void ltq_spi_complete(struct ltq_spi *hw)
{
	complete(&hw->done);
}

irqreturn_t ltq_spi_tx_irq(int irq, void *data)
{
	struct ltq_spi *hw = data;
	unsigned long flags;
	int completed = 0;

	spin_lock_irqsave(&hw->lock, flags);

	if (hw->tx_cnt < hw->len)
		ltq_spi_txfifo_write(hw);

	if (hw->tx_cnt == hw->len)
		completed = 1;

	spin_unlock_irqrestore(&hw->lock, flags);

	if (completed)
		ltq_spi_complete(hw);

	return IRQ_HANDLED;
}

irqreturn_t ltq_spi_rx_irq(int irq, void *data)
{
	struct ltq_spi *hw = data;
	unsigned long flags;
	int completed = 0;

	spin_lock_irqsave(&hw->lock, flags);

	if (hw->rx_cnt < hw->len) {
		ltq_spi_rxfifo_read(hw);

		if (hw->tx && hw->tx_cnt < hw->len)
			ltq_spi_txfifo_write(hw);
	}

	if (hw->rx_cnt == hw->len)
		completed = 1;
	else if (!hw->tx)
		ltq_spi_rxreq_set(hw);

	spin_unlock_irqrestore(&hw->lock, flags);

	if (completed)
		ltq_spi_complete(hw);

	return IRQ_HANDLED;
}

irqreturn_t ltq_spi_err_irq(int irq, void *data)
{
	struct ltq_spi *hw = data;
	unsigned long flags;

	spin_lock_irqsave(&hw->lock, flags);

	/* Disable all interrupts */
	ltq_spi_reg_clearbit(hw, LTQ_SPI_IRNEN_ALL, LTQ_SPI_IRNEN);

	/* Clear all error flags */
	ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);

	/* Flush FIFOs */
	ltq_spi_reg_setbit(hw, LTQ_SPI_RXFCON_RXFLU, LTQ_SPI_RXFCON);
	ltq_spi_reg_setbit(hw, LTQ_SPI_TXFCON_TXFLU, LTQ_SPI_TXFCON);

	hw->status = -EIO;
	spin_unlock_irqrestore(&hw->lock, flags);

	ltq_spi_complete(hw);

	return IRQ_HANDLED;
}

static int ltq_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
	struct ltq_spi *hw = ltq_spi_to_hw(spi);
	u32 irq_flags = 0;

	hw->tx = t->tx_buf;
	hw->rx = t->rx_buf;
	hw->len = t->len;
	hw->tx_cnt = 0;
	hw->rx_cnt = 0;
	hw->status = 0;
	INIT_COMPLETION(hw->done);

	ltq_spi_xmit_set(hw, t);

	/* Enable error interrupts */
	ltq_spi_reg_setbit(hw, LTQ_SPI_IRNEN_E, LTQ_SPI_IRNEN);

	if (hw->tx) {
		/* Initially fill TX FIFO with as much data as possible */
		ltq_spi_txfifo_write(hw);
		irq_flags |= LTQ_SPI_IRNEN_T;

		/* Always enable RX interrupt in Full Duplex mode */
		if (hw->rx)
			irq_flags |= LTQ_SPI_IRNEN_R;
	} else if (hw->rx) {
		/* Start RX clock */
		ltq_spi_rxreq_set(hw);

		/* Enable RX interrupt to receive data from RX FIFOs */
		irq_flags |= LTQ_SPI_IRNEN_R;
	}

	/* Enable TX or RX interrupts */
	ltq_spi_reg_setbit(hw, irq_flags, LTQ_SPI_IRNEN);
	wait_for_completion_interruptible(&hw->done);

	/* Disable all interrupts */
	ltq_spi_reg_clearbit(hw, LTQ_SPI_IRNEN_ALL, LTQ_SPI_IRNEN);

	/*
	 * Return length of current transfer for bitbang utility code if
	 * no errors occured during transmission.
	 */
	if (!hw->status)
		hw->status = hw->len;

	return hw->status;
}

static const struct ltq_spi_irq_map ltq_spi_irqs[] = {
	{ "spi_tx", ltq_spi_tx_irq },
	{ "spi_rx", ltq_spi_rx_irq },
	{ "spi_err", ltq_spi_err_irq },
};

static int __devinit
ltq_spi_probe(struct platform_device *pdev)
{
	struct spi_master *master;
	struct resource *r;
	struct ltq_spi *hw;
	struct ltq_spi_platform_data *pdata = pdev->dev.platform_data;
	int ret, i;
	u32 data, id;

	master = spi_alloc_master(&pdev->dev, sizeof(struct ltq_spi));
	if (!master) {
		dev_err(&pdev->dev, "spi_alloc_master\n");
		ret = -ENOMEM;
		goto err;
	}

	hw = spi_master_get_devdata(master);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (r == NULL) {
		dev_err(&pdev->dev, "platform_get_resource\n");
		ret = -ENOENT;
		goto err_master;
	}

	r = devm_request_mem_region(&pdev->dev, r->start, resource_size(r),
			pdev->name);
	if (!r) {
		dev_err(&pdev->dev, "devm_request_mem_region\n");
		ret = -ENXIO;
		goto err_master;
	}

	hw->base = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
	if (!hw->base) {
		dev_err(&pdev->dev, "devm_ioremap_nocache\n");
		ret = -ENXIO;
		goto err_master;
	}

	hw->fpiclk = clk_get_fpi();
	if (IS_ERR(hw->fpiclk)) {
		dev_err(&pdev->dev, "fpi clk\n");
		ret = PTR_ERR(hw->fpiclk);
		goto err_master;
	}

	hw->spiclk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(hw->spiclk)) {
		dev_err(&pdev->dev, "spi clk\n");
		ret = PTR_ERR(hw->spiclk);
		goto err_master;
	}

	memset(hw->irq, 0, sizeof(hw->irq));
	for (i = 0; i < ARRAY_SIZE(ltq_spi_irqs); i++) {
		ret = platform_get_irq_byname(pdev, ltq_spi_irqs[i].name);
		if (0 > ret) {
			dev_err(&pdev->dev, "platform_get_irq_byname\n");
			goto err_irq;
		}

		hw->irq[i] = ret;
		ret = request_irq(hw->irq[i], ltq_spi_irqs[i].handler,
				  0, ltq_spi_irqs[i].name, hw);
		if (ret) {
			dev_err(&pdev->dev, "request_irq\n");
			goto err_irq;
		}
	}

	hw->bitbang.master = spi_master_get(master);
	hw->bitbang.chipselect = ltq_spi_chipselect;
	hw->bitbang.setup_transfer = ltq_spi_setup_transfer;
	hw->bitbang.txrx_bufs = ltq_spi_txrx_bufs;

	master->bus_num = pdev->id;
	master->num_chipselect = pdata->num_chipselect;
	master->setup = ltq_spi_setup;
	master->cleanup = ltq_spi_cleanup;

	hw->dev = &pdev->dev;
	init_completion(&hw->done);
	spin_lock_init(&hw->lock);

	/* Set GPIO alternate functions to SPI */
	ltq_gpio_request(&pdev->dev, LTQ_SPI_GPIO_DI, 2, 0, "spi-di");
	ltq_gpio_request(&pdev->dev, LTQ_SPI_GPIO_DO, 2, 1, "spi-do");
	ltq_gpio_request(&pdev->dev, LTQ_SPI_GPIO_CLK, 2, 1, "spi-clk");

	ltq_spi_hw_enable(hw);

	/* Read module capabilities */
	id = ltq_spi_reg_read(hw, LTQ_SPI_ID);
	hw->txfs = (id >> LTQ_SPI_ID_TXFS_SHIFT) & LTQ_SPI_ID_TXFS_MASK;
	hw->rxfs = (id >> LTQ_SPI_ID_TXFS_SHIFT) & LTQ_SPI_ID_TXFS_MASK;
	hw->dma_support = (id & LTQ_SPI_ID_CFG) ? 1 : 0;

	ltq_spi_config_mode_set(hw);

	/* Enable error checking, disable TX/RX, set idle value high */
	data = LTQ_SPI_CON_RUEN | LTQ_SPI_CON_AEN |
	    LTQ_SPI_CON_TEN | LTQ_SPI_CON_REN |
	    LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF | LTQ_SPI_CON_IDLE;
	ltq_spi_reg_write(hw, data, LTQ_SPI_CON);

	/* Enable master mode and clear error flags */
	ltq_spi_reg_write(hw, LTQ_SPI_WHBSTATE_SETMS |
			  LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);

	/* Reset GPIO/CS registers */
	ltq_spi_reg_write(hw, 0x0, LTQ_SPI_GPOCON);
	ltq_spi_reg_write(hw, 0xFF00, LTQ_SPI_FGPO);

	/* Enable and flush FIFOs */
	ltq_spi_reset_fifos(hw);

	ret = spi_bitbang_start(&hw->bitbang);
	if (ret) {
		dev_err(&pdev->dev, "spi_bitbang_start\n");
		goto err_bitbang;
	}

	platform_set_drvdata(pdev, hw);

	pr_info("Lantiq SoC SPI controller rev %u (TXFS %u, RXFS %u, DMA %u)\n",
		id & LTQ_SPI_ID_REV_MASK, hw->txfs, hw->rxfs, hw->dma_support);

	return 0;

err_bitbang:
	ltq_spi_hw_disable(hw);

err_irq:
	clk_put(hw->fpiclk);

	for (; i > 0; i--)
		free_irq(hw->irq[i], hw);

err_master:
	spi_master_put(master);

err:
	return ret;
}

static int __devexit
ltq_spi_remove(struct platform_device *pdev)
{
	struct ltq_spi *hw = platform_get_drvdata(pdev);
	int ret, i;

	ret = spi_bitbang_stop(&hw->bitbang);
	if (ret)
		return ret;

	platform_set_drvdata(pdev, NULL);

	ltq_spi_config_mode_set(hw);
	ltq_spi_hw_disable(hw);

	for (i = 0; i < ARRAY_SIZE(hw->irq); i++)
		if (0 < hw->irq[i])
			free_irq(hw->irq[i], hw);

	gpio_free(LTQ_SPI_GPIO_DI);
	gpio_free(LTQ_SPI_GPIO_DO);
	gpio_free(LTQ_SPI_GPIO_CLK);

	clk_put(hw->fpiclk);
	spi_master_put(hw->bitbang.master);

	return 0;
}

static struct platform_driver ltq_spi_driver = {
	.probe = ltq_spi_probe,
	.remove = __devexit_p(ltq_spi_remove),
	.driver = {
		.name = "ltq_spi",
		.owner = THIS_MODULE,
		},
};

module_platform_driver(ltq_spi_driver);

MODULE_DESCRIPTION("Lantiq SoC SPI controller driver");
MODULE_AUTHOR("Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ltq-spi");