summaryrefslogtreecommitdiffstats
path: root/drivers/net/phy/sfp.c
blob: 6c7d9289078d3d27c4e6f7c425e3ae00d5733d85 (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
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

#include "mdio-i2c.h"
#include "sfp.h"
#include "swphy.h"

enum {
	GPIO_MODDEF0,
	GPIO_LOS,
	GPIO_TX_FAULT,
	GPIO_TX_DISABLE,
	GPIO_RATE_SELECT,
	GPIO_MAX,

	SFP_F_PRESENT = BIT(GPIO_MODDEF0),
	SFP_F_LOS = BIT(GPIO_LOS),
	SFP_F_TX_FAULT = BIT(GPIO_TX_FAULT),
	SFP_F_TX_DISABLE = BIT(GPIO_TX_DISABLE),
	SFP_F_RATE_SELECT = BIT(GPIO_RATE_SELECT),

	SFP_E_INSERT = 0,
	SFP_E_REMOVE,
	SFP_E_DEV_DOWN,
	SFP_E_DEV_UP,
	SFP_E_TX_FAULT,
	SFP_E_TX_CLEAR,
	SFP_E_LOS_HIGH,
	SFP_E_LOS_LOW,
	SFP_E_TIMEOUT,

	SFP_MOD_EMPTY = 0,
	SFP_MOD_PROBE,
	SFP_MOD_PRESENT,
	SFP_MOD_ERROR,

	SFP_DEV_DOWN = 0,
	SFP_DEV_UP,

	SFP_S_DOWN = 0,
	SFP_S_INIT,
	SFP_S_WAIT_LOS,
	SFP_S_LINK_UP,
	SFP_S_TX_FAULT,
	SFP_S_REINIT,
	SFP_S_TX_DISABLE,
};

static const char *gpio_of_names[] = {
	"mod-def0",
	"los",
	"tx-fault",
	"tx-disable",
	"rate-select0",
};

static const enum gpiod_flags gpio_flags[] = {
	GPIOD_IN,
	GPIOD_IN,
	GPIOD_IN,
	GPIOD_ASIS,
	GPIOD_ASIS,
};

#define T_INIT_JIFFIES	msecs_to_jiffies(300)
#define T_RESET_US	10
#define T_FAULT_RECOVER	msecs_to_jiffies(1000)

/* SFP module presence detection is poor: the three MOD DEF signals are
 * the same length on the PCB, which means it's possible for MOD DEF 0 to
 * connect before the I2C bus on MOD DEF 1/2.
 *
 * The SFP MSA specifies 300ms as t_init (the time taken for TX_FAULT to
 * be deasserted) but makes no mention of the earliest time before we can
 * access the I2C EEPROM.  However, Avago modules require 300ms.
 */
#define T_PROBE_INIT	msecs_to_jiffies(300)
#define T_PROBE_RETRY	msecs_to_jiffies(100)

/* SFP modules appear to always have their PHY configured for bus address
 * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
 */
#define SFP_PHY_ADDR	22

/* Give this long for the PHY to reset. */
#define T_PHY_RESET_MS	50

static DEFINE_MUTEX(sfp_mutex);

struct sff_data {
	unsigned int gpios;
	bool (*module_supported)(const struct sfp_eeprom_id *id);
};

struct sfp {
	struct device *dev;
	struct i2c_adapter *i2c;
	struct mii_bus *i2c_mii;
	struct sfp_bus *sfp_bus;
	struct phy_device *mod_phy;
	const struct sff_data *type;

	unsigned int (*get_state)(struct sfp *);
	void (*set_state)(struct sfp *, unsigned int);
	int (*read)(struct sfp *, bool, u8, void *, size_t);

	struct gpio_desc *gpio[GPIO_MAX];

	unsigned int state;
	struct delayed_work poll;
	struct delayed_work timeout;
	struct mutex sm_mutex;
	unsigned char sm_mod_state;
	unsigned char sm_dev_state;
	unsigned short sm_state;
	unsigned int sm_retries;

	struct sfp_eeprom_id id;
};

static bool sff_module_supported(const struct sfp_eeprom_id *id)
{
	return id->base.phys_id == SFP_PHYS_ID_SFF &&
	       id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP;
}

static const struct sff_data sff_data = {
	.gpios = SFP_F_LOS | SFP_F_TX_FAULT | SFP_F_TX_DISABLE,
	.module_supported = sff_module_supported,
};

static bool sfp_module_supported(const struct sfp_eeprom_id *id)
{
	return id->base.phys_id == SFP_PHYS_ID_SFP &&
	       id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP;
}

static const struct sff_data sfp_data = {
	.gpios = SFP_F_PRESENT | SFP_F_LOS | SFP_F_TX_FAULT |
		 SFP_F_TX_DISABLE | SFP_F_RATE_SELECT,
	.module_supported = sfp_module_supported,
};

static const struct of_device_id sfp_of_match[] = {
	{ .compatible = "sff,sff", .data = &sff_data, },
	{ .compatible = "sff,sfp", .data = &sfp_data, },
	{ },
};
MODULE_DEVICE_TABLE(of, sfp_of_match);

static unsigned long poll_jiffies;

static unsigned int sfp_gpio_get_state(struct sfp *sfp)
{
	unsigned int i, state, v;

	for (i = state = 0; i < GPIO_MAX; i++) {
		if (gpio_flags[i] != GPIOD_IN || !sfp->gpio[i])
			continue;

		v = gpiod_get_value_cansleep(sfp->gpio[i]);
		if (v)
			state |= BIT(i);
	}

	return state;
}

static unsigned int sff_gpio_get_state(struct sfp *sfp)
{
	return sfp_gpio_get_state(sfp) | SFP_F_PRESENT;
}

static void sfp_gpio_set_state(struct sfp *sfp, unsigned int state)
{
	if (state & SFP_F_PRESENT) {
		/* If the module is present, drive the signals */
		if (sfp->gpio[GPIO_TX_DISABLE])
			gpiod_direction_output(sfp->gpio[GPIO_TX_DISABLE],
					       state & SFP_F_TX_DISABLE);
		if (state & SFP_F_RATE_SELECT)
			gpiod_direction_output(sfp->gpio[GPIO_RATE_SELECT],
					       state & SFP_F_RATE_SELECT);
	} else {
		/* Otherwise, let them float to the pull-ups */
		if (sfp->gpio[GPIO_TX_DISABLE])
			gpiod_direction_input(sfp->gpio[GPIO_TX_DISABLE]);
		if (state & SFP_F_RATE_SELECT)
			gpiod_direction_input(sfp->gpio[GPIO_RATE_SELECT]);
	}
}

static int sfp__i2c_read(struct i2c_adapter *i2c, u8 bus_addr, u8 dev_addr,
			 void *buf, size_t len)
{
	struct i2c_msg msgs[2];
	int ret;

	msgs[0].addr = bus_addr;
	msgs[0].flags = 0;
	msgs[0].len = 1;
	msgs[0].buf = &dev_addr;
	msgs[1].addr = bus_addr;
	msgs[1].flags = I2C_M_RD;
	msgs[1].len = len;
	msgs[1].buf = buf;

	ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
		return ret;

	return ret == ARRAY_SIZE(msgs) ? len : 0;
}

static int sfp_i2c_read(struct sfp *sfp, bool a2, u8 addr, void *buf,
			size_t len)
{
	return sfp__i2c_read(sfp->i2c, a2 ? 0x51 : 0x50, addr, buf, len);
}

static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
{
	struct mii_bus *i2c_mii;
	int ret;

	if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
		return -EINVAL;

	sfp->i2c = i2c;
	sfp->read = sfp_i2c_read;

	i2c_mii = mdio_i2c_alloc(sfp->dev, i2c);
	if (IS_ERR(i2c_mii))
		return PTR_ERR(i2c_mii);

	i2c_mii->name = "SFP I2C Bus";
	i2c_mii->phy_mask = ~0;

	ret = mdiobus_register(i2c_mii);
	if (ret < 0) {
		mdiobus_free(i2c_mii);
		return ret;
	}

	sfp->i2c_mii = i2c_mii;

	return 0;
}

/* Interface */
static unsigned int sfp_get_state(struct sfp *sfp)
{
	return sfp->get_state(sfp);
}

static void sfp_set_state(struct sfp *sfp, unsigned int state)
{
	sfp->set_state(sfp, state);
}

static int sfp_read(struct sfp *sfp, bool a2, u8 addr, void *buf, size_t len)
{
	return sfp->read(sfp, a2, addr, buf, len);
}

static unsigned int sfp_check(void *buf, size_t len)
{
	u8 *p, check;

	for (p = buf, check = 0; len; p++, len--)
		check += *p;

	return check;
}

/* Helpers */
static void sfp_module_tx_disable(struct sfp *sfp)
{
	dev_dbg(sfp->dev, "tx disable %u -> %u\n",
		sfp->state & SFP_F_TX_DISABLE ? 1 : 0, 1);
	sfp->state |= SFP_F_TX_DISABLE;
	sfp_set_state(sfp, sfp->state);
}

static void sfp_module_tx_enable(struct sfp *sfp)
{
	dev_dbg(sfp->dev, "tx disable %u -> %u\n",
		sfp->state & SFP_F_TX_DISABLE ? 1 : 0, 0);
	sfp->state &= ~SFP_F_TX_DISABLE;
	sfp_set_state(sfp, sfp->state);
}

static void sfp_module_tx_fault_reset(struct sfp *sfp)
{
	unsigned int state = sfp->state;

	if (state & SFP_F_TX_DISABLE)
		return;

	sfp_set_state(sfp, state | SFP_F_TX_DISABLE);

	udelay(T_RESET_US);

	sfp_set_state(sfp, state);
}

/* SFP state machine */
static void sfp_sm_set_timer(struct sfp *sfp, unsigned int timeout)
{
	if (timeout)
		mod_delayed_work(system_power_efficient_wq, &sfp->timeout,
				 timeout);
	else
		cancel_delayed_work(&sfp->timeout);
}

static void sfp_sm_next(struct sfp *sfp, unsigned int state,
			unsigned int timeout)
{
	sfp->sm_state = state;
	sfp_sm_set_timer(sfp, timeout);
}

static void sfp_sm_ins_next(struct sfp *sfp, unsigned int state,
			    unsigned int timeout)
{
	sfp->sm_mod_state = state;
	sfp_sm_set_timer(sfp, timeout);
}

static void sfp_sm_phy_detach(struct sfp *sfp)
{
	phy_stop(sfp->mod_phy);
	sfp_remove_phy(sfp->sfp_bus);
	phy_device_remove(sfp->mod_phy);
	phy_device_free(sfp->mod_phy);
	sfp->mod_phy = NULL;
}

static void sfp_sm_probe_phy(struct sfp *sfp)
{
	struct phy_device *phy;
	int err;

	msleep(T_PHY_RESET_MS);

	phy = mdiobus_scan(sfp->i2c_mii, SFP_PHY_ADDR);
	if (phy == ERR_PTR(-ENODEV)) {
		dev_info(sfp->dev, "no PHY detected\n");
		return;
	}
	if (IS_ERR(phy)) {
		dev_err(sfp->dev, "mdiobus scan returned %ld\n", PTR_ERR(phy));
		return;
	}

	err = sfp_add_phy(sfp->sfp_bus, phy);
	if (err) {
		phy_device_remove(phy);
		phy_device_free(phy);
		dev_err(sfp->dev, "sfp_add_phy failed: %d\n", err);
		return;
	}

	sfp->mod_phy = phy;
	phy_start(phy);
}

static void sfp_sm_link_up(struct sfp *sfp)
{
	sfp_link_up(sfp->sfp_bus);
	sfp_sm_next(sfp, SFP_S_LINK_UP, 0);
}

static void sfp_sm_link_down(struct sfp *sfp)
{
	sfp_link_down(sfp->sfp_bus);
}

static void sfp_sm_link_check_los(struct sfp *sfp)
{
	unsigned int los = sfp->state & SFP_F_LOS;

	/* If neither SFP_OPTIONS_LOS_INVERTED nor SFP_OPTIONS_LOS_NORMAL
	 * are set, we assume that no LOS signal is available.
	 */
	if (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_INVERTED))
		los ^= SFP_F_LOS;
	else if (!(sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_NORMAL)))
		los = 0;

	if (los)
		sfp_sm_next(sfp, SFP_S_WAIT_LOS, 0);
	else
		sfp_sm_link_up(sfp);
}

static bool sfp_los_event_active(struct sfp *sfp, unsigned int event)
{
	return (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_INVERTED) &&
		event == SFP_E_LOS_LOW) ||
	       (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_NORMAL) &&
		event == SFP_E_LOS_HIGH);
}

static bool sfp_los_event_inactive(struct sfp *sfp, unsigned int event)
{
	return (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_INVERTED) &&
		event == SFP_E_LOS_HIGH) ||
	       (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_LOS_NORMAL) &&
		event == SFP_E_LOS_LOW);
}

static void sfp_sm_fault(struct sfp *sfp, bool warn)
{
	if (sfp->sm_retries && !--sfp->sm_retries) {
		dev_err(sfp->dev,
			"module persistently indicates fault, disabling\n");
		sfp_sm_next(sfp, SFP_S_TX_DISABLE, 0);
	} else {
		if (warn)
			dev_err(sfp->dev, "module transmit fault indicated\n");

		sfp_sm_next(sfp, SFP_S_TX_FAULT, T_FAULT_RECOVER);
	}
}

static void sfp_sm_mod_init(struct sfp *sfp)
{
	sfp_module_tx_enable(sfp);

	/* Wait t_init before indicating that the link is up, provided the
	 * current state indicates no TX_FAULT.  If TX_FAULT clears before
	 * this time, that's fine too.
	 */
	sfp_sm_next(sfp, SFP_S_INIT, T_INIT_JIFFIES);
	sfp->sm_retries = 5;

	/* Setting the serdes link mode is guesswork: there's no
	 * field in the EEPROM which indicates what mode should
	 * be used.
	 *
	 * If it's a gigabit-only fiber module, it probably does
	 * not have a PHY, so switch to 802.3z negotiation mode.
	 * Otherwise, switch to SGMII mode (which is required to
	 * support non-gigabit speeds) and probe for a PHY.
	 */
	if (sfp->id.base.e1000_base_t ||
	    sfp->id.base.e100_base_lx ||
	    sfp->id.base.e100_base_fx)
		sfp_sm_probe_phy(sfp);
}

static int sfp_sm_mod_probe(struct sfp *sfp)
{
	/* SFP module inserted - read I2C data */
	struct sfp_eeprom_id id;
	u8 check;
	int err;

	err = sfp_read(sfp, false, 0, &id, sizeof(id));
	if (err < 0) {
		dev_err(sfp->dev, "failed to read EEPROM: %d\n", err);
		return -EAGAIN;
	}

	if (err != sizeof(id)) {
		dev_err(sfp->dev, "EEPROM short read: %d\n", err);
		return -EAGAIN;
	}

	/* Validate the checksum over the base structure */
	check = sfp_check(&id.base, sizeof(id.base) - 1);
	if (check != id.base.cc_base) {
		dev_err(sfp->dev,
			"EEPROM base structure checksum failure: 0x%02x\n",
			check);
		print_hex_dump(KERN_ERR, "sfp EE: ", DUMP_PREFIX_OFFSET,
			       16, 1, &id, sizeof(id.base) - 1, true);
		return -EINVAL;
	}

	check = sfp_check(&id.ext, sizeof(id.ext) - 1);
	if (check != id.ext.cc_ext) {
		dev_err(sfp->dev,
			"EEPROM extended structure checksum failure: 0x%02x\n",
			check);
		memset(&id.ext, 0, sizeof(id.ext));
	}

	sfp->id = id;

	dev_info(sfp->dev, "module %.*s %.*s rev %.*s sn %.*s dc %.*s\n",
		 (int)sizeof(id.base.vendor_name), id.base.vendor_name,
		 (int)sizeof(id.base.vendor_pn), id.base.vendor_pn,
		 (int)sizeof(id.base.vendor_rev), id.base.vendor_rev,
		 (int)sizeof(id.ext.vendor_sn), id.ext.vendor_sn,
		 (int)sizeof(id.ext.datecode), id.ext.datecode);

	/* Check whether we support this module */
	if (!sfp->type->module_supported(&sfp->id)) {
		dev_err(sfp->dev,
			"module is not supported - phys id 0x%02x 0x%02x\n",
			sfp->id.base.phys_id, sfp->id.base.phys_ext_id);
		return -EINVAL;
	}

	/* If the module requires address swap mode, warn about it */
	if (sfp->id.ext.diagmon & SFP_DIAGMON_ADDRMODE)
		dev_warn(sfp->dev,
			 "module address swap to access page 0xA2 is not supported.\n");

	return sfp_module_insert(sfp->sfp_bus, &sfp->id);
}

static void sfp_sm_mod_remove(struct sfp *sfp)
{
	sfp_module_remove(sfp->sfp_bus);

	if (sfp->mod_phy)
		sfp_sm_phy_detach(sfp);

	sfp_module_tx_disable(sfp);

	memset(&sfp->id, 0, sizeof(sfp->id));

	dev_info(sfp->dev, "module removed\n");
}

static void sfp_sm_event(struct sfp *sfp, unsigned int event)
{
	mutex_lock(&sfp->sm_mutex);

	dev_dbg(sfp->dev, "SM: enter %u:%u:%u event %u\n",
		sfp->sm_mod_state, sfp->sm_dev_state, sfp->sm_state, event);

	/* This state machine tracks the insert/remove state of
	 * the module, and handles probing the on-board EEPROM.
	 */
	switch (sfp->sm_mod_state) {
	default:
		if (event == SFP_E_INSERT) {
			sfp_module_tx_disable(sfp);
			sfp_sm_ins_next(sfp, SFP_MOD_PROBE, T_PROBE_INIT);
		}
		break;

	case SFP_MOD_PROBE:
		if (event == SFP_E_REMOVE) {
			sfp_sm_ins_next(sfp, SFP_MOD_EMPTY, 0);
		} else if (event == SFP_E_TIMEOUT) {
			int err = sfp_sm_mod_probe(sfp);

			if (err == 0)
				sfp_sm_ins_next(sfp, SFP_MOD_PRESENT, 0);
			else if (err == -EAGAIN)
				sfp_sm_set_timer(sfp, T_PROBE_RETRY);
			else
				sfp_sm_ins_next(sfp, SFP_MOD_ERROR, 0);
		}
		break;

	case SFP_MOD_PRESENT:
	case SFP_MOD_ERROR:
		if (event == SFP_E_REMOVE) {
			sfp_sm_mod_remove(sfp);
			sfp_sm_ins_next(sfp, SFP_MOD_EMPTY, 0);
		}
		break;
	}

	/* This state machine tracks the netdev up/down state */
	switch (sfp->sm_dev_state) {
	default:
		if (event == SFP_E_DEV_UP)
			sfp->sm_dev_state = SFP_DEV_UP;
		break;

	case SFP_DEV_UP:
		if (event == SFP_E_DEV_DOWN) {
			/* If the module has a PHY, avoid raising TX disable
			 * as this resets the PHY. Otherwise, raise it to
			 * turn the laser off.
			 */
			if (!sfp->mod_phy)
				sfp_module_tx_disable(sfp);
			sfp->sm_dev_state = SFP_DEV_DOWN;
		}
		break;
	}

	/* Some events are global */
	if (sfp->sm_state != SFP_S_DOWN &&
	    (sfp->sm_mod_state != SFP_MOD_PRESENT ||
	     sfp->sm_dev_state != SFP_DEV_UP)) {
		if (sfp->sm_state == SFP_S_LINK_UP &&
		    sfp->sm_dev_state == SFP_DEV_UP)
			sfp_sm_link_down(sfp);
		if (sfp->mod_phy)
			sfp_sm_phy_detach(sfp);
		sfp_sm_next(sfp, SFP_S_DOWN, 0);
		mutex_unlock(&sfp->sm_mutex);
		return;
	}

	/* The main state machine */
	switch (sfp->sm_state) {
	case SFP_S_DOWN:
		if (sfp->sm_mod_state == SFP_MOD_PRESENT &&
		    sfp->sm_dev_state == SFP_DEV_UP)
			sfp_sm_mod_init(sfp);
		break;

	case SFP_S_INIT:
		if (event == SFP_E_TIMEOUT && sfp->state & SFP_F_TX_FAULT)
			sfp_sm_fault(sfp, true);
		else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR)
			sfp_sm_link_check_los(sfp);
		break;

	case SFP_S_WAIT_LOS:
		if (event == SFP_E_TX_FAULT)
			sfp_sm_fault(sfp, true);
		else if (sfp_los_event_inactive(sfp, event))
			sfp_sm_link_up(sfp);
		break;

	case SFP_S_LINK_UP:
		if (event == SFP_E_TX_FAULT) {
			sfp_sm_link_down(sfp);
			sfp_sm_fault(sfp, true);
		} else if (sfp_los_event_active(sfp, event)) {
			sfp_sm_link_down(sfp);
			sfp_sm_next(sfp, SFP_S_WAIT_LOS, 0);
		}
		break;

	case SFP_S_TX_FAULT:
		if (event == SFP_E_TIMEOUT) {
			sfp_module_tx_fault_reset(sfp);
			sfp_sm_next(sfp, SFP_S_REINIT, T_INIT_JIFFIES);
		}
		break;

	case SFP_S_REINIT:
		if (event == SFP_E_TIMEOUT && sfp->state & SFP_F_TX_FAULT) {
			sfp_sm_fault(sfp, false);
		} else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR) {
			dev_info(sfp->dev, "module transmit fault recovered\n");
			sfp_sm_link_check_los(sfp);
		}
		break;

	case SFP_S_TX_DISABLE:
		break;
	}

	dev_dbg(sfp->dev, "SM: exit %u:%u:%u\n",
		sfp->sm_mod_state, sfp->sm_dev_state, sfp->sm_state);

	mutex_unlock(&sfp->sm_mutex);
}

static void sfp_start(struct sfp *sfp)
{
	sfp_sm_event(sfp, SFP_E_DEV_UP);
}

static void sfp_stop(struct sfp *sfp)
{
	sfp_sm_event(sfp, SFP_E_DEV_DOWN);
}

static int sfp_module_info(struct sfp *sfp, struct ethtool_modinfo *modinfo)
{
	/* locking... and check module is present */

	if (sfp->id.ext.sff8472_compliance &&
	    !(sfp->id.ext.diagmon & SFP_DIAGMON_ADDRMODE)) {
		modinfo->type = ETH_MODULE_SFF_8472;
		modinfo->eeprom_len = ETH_MODULE_SFF_8472_LEN;
	} else {
		modinfo->type = ETH_MODULE_SFF_8079;
		modinfo->eeprom_len = ETH_MODULE_SFF_8079_LEN;
	}
	return 0;
}

static int sfp_module_eeprom(struct sfp *sfp, struct ethtool_eeprom *ee,
			     u8 *data)
{
	unsigned int first, last, len;
	int ret;

	if (ee->len == 0)
		return -EINVAL;

	first = ee->offset;
	last = ee->offset + ee->len;
	if (first < ETH_MODULE_SFF_8079_LEN) {
		len = min_t(unsigned int, last, ETH_MODULE_SFF_8079_LEN);
		len -= first;

		ret = sfp_read(sfp, false, first, data, len);
		if (ret < 0)
			return ret;

		first += len;
		data += len;
	}
	if (first < ETH_MODULE_SFF_8472_LEN && last > ETH_MODULE_SFF_8079_LEN) {
		len = min_t(unsigned int, last, ETH_MODULE_SFF_8472_LEN);
		len -= first;
		first -= ETH_MODULE_SFF_8079_LEN;

		ret = sfp_read(sfp, true, first, data, len);
		if (ret < 0)
			return ret;
	}
	return 0;
}

static const struct sfp_socket_ops sfp_module_ops = {
	.start = sfp_start,
	.stop = sfp_stop,
	.module_info = sfp_module_info,
	.module_eeprom = sfp_module_eeprom,
};

static void sfp_timeout(struct work_struct *work)
{
	struct sfp *sfp = container_of(work, struct sfp, timeout.work);

	rtnl_lock();
	sfp_sm_event(sfp, SFP_E_TIMEOUT);
	rtnl_unlock();
}

static void sfp_check_state(struct sfp *sfp)
{
	unsigned int state, i, changed;

	state = sfp_get_state(sfp);
	changed = state ^ sfp->state;
	changed &= SFP_F_PRESENT | SFP_F_LOS | SFP_F_TX_FAULT;

	for (i = 0; i < GPIO_MAX; i++)
		if (changed & BIT(i))
			dev_dbg(sfp->dev, "%s %u -> %u\n", gpio_of_names[i],
				!!(sfp->state & BIT(i)), !!(state & BIT(i)));

	state |= sfp->state & (SFP_F_TX_DISABLE | SFP_F_RATE_SELECT);
	sfp->state = state;

	rtnl_lock();
	if (changed & SFP_F_PRESENT)
		sfp_sm_event(sfp, state & SFP_F_PRESENT ?
				SFP_E_INSERT : SFP_E_REMOVE);

	if (changed & SFP_F_TX_FAULT)
		sfp_sm_event(sfp, state & SFP_F_TX_FAULT ?
				SFP_E_TX_FAULT : SFP_E_TX_CLEAR);

	if (changed & SFP_F_LOS)
		sfp_sm_event(sfp, state & SFP_F_LOS ?
				SFP_E_LOS_HIGH : SFP_E_LOS_LOW);
	rtnl_unlock();
}

static irqreturn_t sfp_irq(int irq, void *data)
{
	struct sfp *sfp = data;

	sfp_check_state(sfp);

	return IRQ_HANDLED;
}

static void sfp_poll(struct work_struct *work)
{
	struct sfp *sfp = container_of(work, struct sfp, poll.work);

	sfp_check_state(sfp);
	mod_delayed_work(system_wq, &sfp->poll, poll_jiffies);
}

static struct sfp *sfp_alloc(struct device *dev)
{
	struct sfp *sfp;

	sfp = kzalloc(sizeof(*sfp), GFP_KERNEL);
	if (!sfp)
		return ERR_PTR(-ENOMEM);

	sfp->dev = dev;

	mutex_init(&sfp->sm_mutex);
	INIT_DELAYED_WORK(&sfp->poll, sfp_poll);
	INIT_DELAYED_WORK(&sfp->timeout, sfp_timeout);

	return sfp;
}

static void sfp_cleanup(void *data)
{
	struct sfp *sfp = data;

	cancel_delayed_work_sync(&sfp->poll);
	cancel_delayed_work_sync(&sfp->timeout);
	if (sfp->i2c_mii) {
		mdiobus_unregister(sfp->i2c_mii);
		mdiobus_free(sfp->i2c_mii);
	}
	if (sfp->i2c)
		i2c_put_adapter(sfp->i2c);
	kfree(sfp);
}

static int sfp_probe(struct platform_device *pdev)
{
	const struct sff_data *sff;
	struct sfp *sfp;
	bool poll = false;
	int irq, err, i;

	sfp = sfp_alloc(&pdev->dev);
	if (IS_ERR(sfp))
		return PTR_ERR(sfp);

	platform_set_drvdata(pdev, sfp);

	err = devm_add_action(sfp->dev, sfp_cleanup, sfp);
	if (err < 0)
		return err;

	sff = sfp->type = &sfp_data;

	if (pdev->dev.of_node) {
		struct device_node *node = pdev->dev.of_node;
		const struct of_device_id *id;
		struct device_node *np;

		id = of_match_node(sfp_of_match, node);
		if (WARN_ON(!id))
			return -EINVAL;

		sff = sfp->type = id->data;

		np = of_parse_phandle(node, "i2c-bus", 0);
		if (np) {
			struct i2c_adapter *i2c;

			i2c = of_find_i2c_adapter_by_node(np);
			of_node_put(np);
			if (!i2c)
				return -EPROBE_DEFER;

			err = sfp_i2c_configure(sfp, i2c);
			if (err < 0) {
				i2c_put_adapter(i2c);
				return err;
			}
		}
	}

	for (i = 0; i < GPIO_MAX; i++)
		if (sff->gpios & BIT(i)) {
			sfp->gpio[i] = devm_gpiod_get_optional(sfp->dev,
					   gpio_of_names[i], gpio_flags[i]);
			if (IS_ERR(sfp->gpio[i]))
				return PTR_ERR(sfp->gpio[i]);
		}

	sfp->get_state = sfp_gpio_get_state;
	sfp->set_state = sfp_gpio_set_state;

	/* Modules that have no detect signal are always present */
	if (!(sfp->gpio[GPIO_MODDEF0]))
		sfp->get_state = sff_gpio_get_state;

	sfp->sfp_bus = sfp_register_socket(sfp->dev, sfp, &sfp_module_ops);
	if (!sfp->sfp_bus)
		return -ENOMEM;

	/* Get the initial state, and always signal TX disable,
	 * since the network interface will not be up.
	 */
	sfp->state = sfp_get_state(sfp) | SFP_F_TX_DISABLE;

	if (sfp->gpio[GPIO_RATE_SELECT] &&
	    gpiod_get_value_cansleep(sfp->gpio[GPIO_RATE_SELECT]))
		sfp->state |= SFP_F_RATE_SELECT;
	sfp_set_state(sfp, sfp->state);
	sfp_module_tx_disable(sfp);
	rtnl_lock();
	if (sfp->state & SFP_F_PRESENT)
		sfp_sm_event(sfp, SFP_E_INSERT);
	rtnl_unlock();

	for (i = 0; i < GPIO_MAX; i++) {
		if (gpio_flags[i] != GPIOD_IN || !sfp->gpio[i])
			continue;

		irq = gpiod_to_irq(sfp->gpio[i]);
		if (!irq) {
			poll = true;
			continue;
		}

		err = devm_request_threaded_irq(sfp->dev, irq, NULL, sfp_irq,
						IRQF_ONESHOT |
						IRQF_TRIGGER_RISING |
						IRQF_TRIGGER_FALLING,
						dev_name(sfp->dev), sfp);
		if (err)
			poll = true;
	}

	if (poll)
		mod_delayed_work(system_wq, &sfp->poll, poll_jiffies);

	return 0;
}

static int sfp_remove(struct platform_device *pdev)
{
	struct sfp *sfp = platform_get_drvdata(pdev);

	sfp_unregister_socket(sfp->sfp_bus);

	return 0;
}

static struct platform_driver sfp_driver = {
	.probe = sfp_probe,
	.remove = sfp_remove,
	.driver = {
		.name = "sfp",
		.of_match_table = sfp_of_match,
	},
};

static int sfp_init(void)
{
	poll_jiffies = msecs_to_jiffies(100);

	return platform_driver_register(&sfp_driver);
}
module_init(sfp_init);

static void sfp_exit(void)
{
	platform_driver_unregister(&sfp_driver);
}
module_exit(sfp_exit);

MODULE_ALIAS("platform:sfp");
MODULE_AUTHOR("Russell King");
MODULE_LICENSE("GPL v2");