aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/w1/masters/ds1wm.c
blob: e0b8a4bc73df948aa45584ac4b2cdea4c13c30c1 (plain) (blame)
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
/*
 * 1-wire busmaster driver for DS1WM and ASICs with embedded DS1WMs
 * such as HP iPAQs (including h5xxx, h2200, and devices with ASIC3
 * like hx4700).
 *
 * Copyright (c) 2004-2005, Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
 * Copyright (c) 2004-2007, Matt Reimer <mreimer@vpop.net>
 *
 * Use consistent with the GNU GPL is permitted,
 * provided that this copyright notice is
 * preserved in its entirety in all copies and derived works.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/mfd/core.h>
#include <linux/mfd/ds1wm.h>
#include <linux/slab.h>

#include <asm/io.h>

#include "../w1.h"
#include "../w1_int.h"


#define DS1WM_CMD	0x00	/* R/W 4 bits command */
#define DS1WM_DATA	0x01	/* R/W 8 bits, transmit/receive buffer */
#define DS1WM_INT	0x02	/* R/W interrupt status */
#define DS1WM_INT_EN	0x03	/* R/W interrupt enable */
#define DS1WM_CLKDIV	0x04	/* R/W 5 bits of divisor and pre-scale */
#define DS1WM_CNTRL	0x05	/* R/W master control register (not used yet) */

#define DS1WM_CMD_1W_RESET  (1 << 0)	/* force reset on 1-wire bus */
#define DS1WM_CMD_SRA	    (1 << 1)	/* enable Search ROM accelerator mode */
#define DS1WM_CMD_DQ_OUTPUT (1 << 2)	/* write only - forces bus low */
#define DS1WM_CMD_DQ_INPUT  (1 << 3)	/* read only - reflects state of bus */
#define DS1WM_CMD_RST	    (1 << 5)	/* software reset */
#define DS1WM_CMD_OD	    (1 << 7)	/* overdrive */

#define DS1WM_INT_PD	    (1 << 0)	/* presence detect */
#define DS1WM_INT_PDR	    (1 << 1)	/* presence detect result */
#define DS1WM_INT_TBE	    (1 << 2)	/* tx buffer empty */
#define DS1WM_INT_TSRE	    (1 << 3)	/* tx shift register empty */
#define DS1WM_INT_RBF	    (1 << 4)	/* rx buffer full */
#define DS1WM_INT_RSRF	    (1 << 5)	/* rx shift register full */

#define DS1WM_INTEN_EPD	    (1 << 0)	/* enable presence detect int */
#define DS1WM_INTEN_IAS	    (1 << 1)	/* INTR active state */
#define DS1WM_INTEN_ETBE    (1 << 2)	/* enable tx buffer empty int */
#define DS1WM_INTEN_ETMT    (1 << 3)	/* enable tx shift register empty int */
#define DS1WM_INTEN_ERBF    (1 << 4)	/* enable rx buffer full int */
#define DS1WM_INTEN_ERSRF   (1 << 5)	/* enable rx shift register full int */
#define DS1WM_INTEN_DQO	    (1 << 6)	/* enable direct bus driving ops */

#define DS1WM_INTEN_NOT_IAS (~DS1WM_INTEN_IAS)	/* all but INTR active state */

#define DS1WM_TIMEOUT (HZ * 5)

static struct {
	unsigned long freq;
	unsigned long divisor;
} freq[] = {
	{   1000000, 0x80 },
	{   2000000, 0x84 },
	{   3000000, 0x81 },
	{   4000000, 0x88 },
	{   5000000, 0x82 },
	{   6000000, 0x85 },
	{   7000000, 0x83 },
	{   8000000, 0x8c },
	{  10000000, 0x86 },
	{  12000000, 0x89 },
	{  14000000, 0x87 },
	{  16000000, 0x90 },
	{  20000000, 0x8a },
	{  24000000, 0x8d },
	{  28000000, 0x8b },
	{  32000000, 0x94 },
	{  40000000, 0x8e },
	{  48000000, 0x91 },
	{  56000000, 0x8f },
	{  64000000, 0x98 },
	{  80000000, 0x92 },
	{  96000000, 0x95 },
	{ 112000000, 0x93 },
	{ 128000000, 0x9c },
/* you can continue this table, consult the OPERATION - CLOCK DIVISOR
   section of the ds1wm spec sheet. */
};

struct ds1wm_data {
	void     __iomem *map;
	int      bus_shift; /* # of shifts to calc register offsets */
	struct platform_device *pdev;
	const struct mfd_cell   *cell;
	int      irq;
	int      slave_present;
	void     *reset_complete;
	void     *read_complete;
	void     *write_complete;
	int      read_error;
	/* last byte received */
	u8       read_byte;
	/* byte to write that makes all intr disabled, */
	/* considering active_state (IAS) (optimization) */
	u8       int_en_reg_none;
	unsigned int reset_recover_delay; /* see ds1wm.h */
};

static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
					u8 val)
{
	__raw_writeb(val, ds1wm_data->map + (reg << ds1wm_data->bus_shift));
}

static inline u8 ds1wm_read_register(struct ds1wm_data *ds1wm_data, u32 reg)
{
	return __raw_readb(ds1wm_data->map + (reg << ds1wm_data->bus_shift));
}


static irqreturn_t ds1wm_isr(int isr, void *data)
{
	struct ds1wm_data *ds1wm_data = data;
	u8 intr;
	u8 inten = ds1wm_read_register(ds1wm_data, DS1WM_INT_EN);
	/* if no bits are set in int enable register (except the IAS)
	than go no further, reading the regs below has side effects */
	if (!(inten & DS1WM_INTEN_NOT_IAS))
		return IRQ_NONE;

	ds1wm_write_register(ds1wm_data,
		DS1WM_INT_EN, ds1wm_data->int_en_reg_none);

	/* this read action clears the INTR and certain flags in ds1wm */
	intr = ds1wm_read_register(ds1wm_data, DS1WM_INT);

	ds1wm_data->slave_present = (intr & DS1WM_INT_PDR) ? 0 : 1;

	if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete) {
		inten &= ~DS1WM_INTEN_ETMT;
		complete(ds1wm_data->write_complete);
	}
	if (intr & DS1WM_INT_RBF) {
		/* this read clears the RBF flag */
		ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
		DS1WM_DATA);
		inten &= ~DS1WM_INTEN_ERBF;
		if (ds1wm_data->read_complete)
			complete(ds1wm_data->read_complete);
	}
	if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete) {
		inten &= ~DS1WM_INTEN_EPD;
		complete(ds1wm_data->reset_complete);
	}

	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, inten);
	return IRQ_HANDLED;
}

static int ds1wm_reset(struct ds1wm_data *ds1wm_data)
{
	unsigned long timeleft;
	DECLARE_COMPLETION_ONSTACK(reset_done);

	ds1wm_data->reset_complete = &reset_done;

	/* enable Presence detect only */
	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
	ds1wm_data->int_en_reg_none);

	ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_1W_RESET);

	timeleft = wait_for_completion_timeout(&reset_done, DS1WM_TIMEOUT);
	ds1wm_data->reset_complete = NULL;
	if (!timeleft) {
		dev_err(&ds1wm_data->pdev->dev, "reset failed, timed out\n");
		return 1;
	}

	if (!ds1wm_data->slave_present) {
		dev_dbg(&ds1wm_data->pdev->dev, "reset: no devices found\n");
		return 1;
	}

	if (ds1wm_data->reset_recover_delay)
		msleep(ds1wm_data->reset_recover_delay);

	return 0;
}

static int ds1wm_write(struct ds1wm_data *ds1wm_data, u8 data)
{
	unsigned long timeleft;
	DECLARE_COMPLETION_ONSTACK(write_done);
	ds1wm_data->write_complete = &write_done;

	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
	ds1wm_data->int_en_reg_none | DS1WM_INTEN_ETMT);

	ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);

	timeleft = wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);

	ds1wm_data->write_complete = NULL;
	if (!timeleft) {
		dev_err(&ds1wm_data->pdev->dev, "write failed, timed out\n");
		return -ETIMEDOUT;
	}

	return 0;
}

static u8 ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
{
	unsigned long timeleft;
	u8 intEnable = DS1WM_INTEN_ERBF | ds1wm_data->int_en_reg_none;
	DECLARE_COMPLETION_ONSTACK(read_done);

	ds1wm_read_register(ds1wm_data, DS1WM_DATA);

	ds1wm_data->read_complete = &read_done;
	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, intEnable);

	ds1wm_write_register(ds1wm_data, DS1WM_DATA, write_data);
	timeleft = wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);

	ds1wm_data->read_complete = NULL;
	if (!timeleft) {
		dev_err(&ds1wm_data->pdev->dev, "read failed, timed out\n");
		ds1wm_data->read_error = -ETIMEDOUT;
		return 0xFF;
	}
	ds1wm_data->read_error = 0;
	return ds1wm_data->read_byte;
}

static int ds1wm_find_divisor(int gclk)
{
	int i;

	for (i = ARRAY_SIZE(freq)-1; i >= 0; --i)
		if (gclk >= freq[i].freq)
			return freq[i].divisor;

	return 0;
}

static void ds1wm_up(struct ds1wm_data *ds1wm_data)
{
	int divisor;
	struct device *dev = &ds1wm_data->pdev->dev;
	struct ds1wm_driver_data *plat = dev_get_platdata(dev);

	if (ds1wm_data->cell->enable)
		ds1wm_data->cell->enable(ds1wm_data->pdev);

	divisor = ds1wm_find_divisor(plat->clock_rate);
	dev_dbg(dev, "found divisor 0x%x for clock %d\n",
		divisor, plat->clock_rate);
	if (divisor == 0) {
		dev_err(dev, "no suitable divisor for %dHz clock\n",
			plat->clock_rate);
		return;
	}
	ds1wm_write_register(ds1wm_data, DS1WM_CLKDIV, divisor);

	/* Let the w1 clock stabilize. */
	msleep(1);

	ds1wm_reset(ds1wm_data);
}

static void ds1wm_down(struct ds1wm_data *ds1wm_data)
{
	ds1wm_reset(ds1wm_data);

	/* Disable interrupts. */
	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
		ds1wm_data->int_en_reg_none);

	if (ds1wm_data->cell->disable)
		ds1wm_data->cell->disable(ds1wm_data->pdev);
}

/* --------------------------------------------------------------------- */
/* w1 methods */

static u8 ds1wm_read_byte(void *data)
{
	struct ds1wm_data *ds1wm_data = data;

	return ds1wm_read(ds1wm_data, 0xff);
}

static void ds1wm_write_byte(void *data, u8 byte)
{
	struct ds1wm_data *ds1wm_data = data;

	ds1wm_write(ds1wm_data, byte);
}

static u8 ds1wm_reset_bus(void *data)
{
	struct ds1wm_data *ds1wm_data = data;

	ds1wm_reset(ds1wm_data);

	return 0;
}

static void ds1wm_search(void *data, struct w1_master *master_dev,
			u8 search_type, w1_slave_found_callback slave_found)
{
	struct ds1wm_data *ds1wm_data = data;
	int i;
	int ms_discrep_bit = -1;
	u64 r = 0; /* holds the progress of the search */
	u64 r_prime, d;
	unsigned slaves_found = 0;
	unsigned int pass = 0;

	dev_dbg(&ds1wm_data->pdev->dev, "search begin\n");
	while (true) {
		++pass;
		if (pass > 100) {
			dev_dbg(&ds1wm_data->pdev->dev,
				"too many attempts (100), search aborted\n");
			return;
		}

		mutex_lock(&master_dev->bus_mutex);
		if (ds1wm_reset(ds1wm_data)) {
			mutex_unlock(&master_dev->bus_mutex);
			dev_dbg(&ds1wm_data->pdev->dev,
				"pass: %d reset error (or no slaves)\n", pass);
			break;
		}

		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d r : %0#18llx writing SEARCH_ROM\n", pass, r);
		ds1wm_write(ds1wm_data, search_type);
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d entering ASM\n", pass);
		ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d beginning nibble loop\n", pass);

		r_prime = 0;
		d = 0;
		/* we work one nibble at a time */
		/* each nibble is interleaved to form a byte */
		for (i = 0; i < 16; i++) {

			unsigned char resp, _r, _r_prime, _d;

			_r = (r >> (4*i)) & 0xf;
			_r = ((_r & 0x1) << 1) |
			((_r & 0x2) << 2) |
			((_r & 0x4) << 3) |
			((_r & 0x8) << 4);

			/* writes _r, then reads back: */
			resp = ds1wm_read(ds1wm_data, _r);

			if (ds1wm_data->read_error) {
				dev_err(&ds1wm_data->pdev->dev,
				"pass: %d nibble: %d read error\n", pass, i);
				break;
			}

			_r_prime = ((resp & 0x02) >> 1) |
			((resp & 0x08) >> 2) |
			((resp & 0x20) >> 3) |
			((resp & 0x80) >> 4);

			_d = ((resp & 0x01) >> 0) |
			((resp & 0x04) >> 1) |
			((resp & 0x10) >> 2) |
			((resp & 0x40) >> 3);

			r_prime |= (unsigned long long) _r_prime << (i * 4);
			d |= (unsigned long long) _d << (i * 4);

		}
		if (ds1wm_data->read_error) {
			mutex_unlock(&master_dev->bus_mutex);
			dev_err(&ds1wm_data->pdev->dev,
				"pass: %d read error, retrying\n", pass);
			break;
		}
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d r\': %0#18llx d:%0#18llx\n",
			pass, r_prime, d);
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d nibble loop complete, exiting ASM\n", pass);
		ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d resetting bus\n", pass);
		ds1wm_reset(ds1wm_data);
		mutex_unlock(&master_dev->bus_mutex);
		if ((r_prime & ((u64)1 << 63)) && (d & ((u64)1 << 63))) {
			dev_err(&ds1wm_data->pdev->dev,
				"pass: %d bus error, retrying\n", pass);
			continue; /* start over */
		}


		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d found %0#18llx\n", pass, r_prime);
		slave_found(master_dev, r_prime);
		++slaves_found;
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d complete, preparing next pass\n", pass);

		/* any discrepency found which we already choose the
		   '1' branch is now is now irrelevant we reveal the
		   next branch with this: */
		d &= ~r;
		/* find last bit set, i.e. the most signif. bit set */
		ms_discrep_bit = fls64(d) - 1;
		dev_dbg(&ds1wm_data->pdev->dev,
			"pass: %d new d:%0#18llx MS discrep bit:%d\n",
			pass, d, ms_discrep_bit);

		/* prev_ms_discrep_bit = ms_discrep_bit;
		   prepare for next ROM search:		    */
		if (ms_discrep_bit == -1)
			break;

		r = (r &  ~(~0ull << (ms_discrep_bit))) | 1 << ms_discrep_bit;
	} /* end while true */
	dev_dbg(&ds1wm_data->pdev->dev,
		"pass: %d total: %d search done ms d bit pos: %d\n", pass,
		slaves_found, ms_discrep_bit);
}

/* --------------------------------------------------------------------- */

static struct w1_bus_master ds1wm_master = {
	.read_byte  = ds1wm_read_byte,
	.write_byte = ds1wm_write_byte,
	.reset_bus  = ds1wm_reset_bus,
	.search	    = ds1wm_search,
};

static int ds1wm_probe(struct platform_device *pdev)
{
	struct ds1wm_data *ds1wm_data;
	struct ds1wm_driver_data *plat;
	struct resource *res;
	int ret;

	if (!pdev)
		return -ENODEV;

	ds1wm_data = devm_kzalloc(&pdev->dev, sizeof(*ds1wm_data), GFP_KERNEL);
	if (!ds1wm_data)
		return -ENOMEM;

	platform_set_drvdata(pdev, ds1wm_data);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENXIO;
	ds1wm_data->map = devm_ioremap(&pdev->dev, res->start,
				       resource_size(res));
	if (!ds1wm_data->map)
		return -ENOMEM;

	/* calculate bus shift from mem resource */
	ds1wm_data->bus_shift = resource_size(res) >> 3;

	ds1wm_data->pdev = pdev;
	ds1wm_data->cell = mfd_get_cell(pdev);
	if (!ds1wm_data->cell)
		return -ENODEV;
	plat = dev_get_platdata(&pdev->dev);
	if (!plat)
		return -ENODEV;

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res)
		return -ENXIO;
	ds1wm_data->irq = res->start;
	ds1wm_data->int_en_reg_none = (plat->active_high ? DS1WM_INTEN_IAS : 0);
	ds1wm_data->reset_recover_delay = plat->reset_recover_delay;

	if (res->flags & IORESOURCE_IRQ_HIGHEDGE)
		irq_set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_RISING);
	if (res->flags & IORESOURCE_IRQ_LOWEDGE)
		irq_set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_FALLING);

	ret = devm_request_irq(&pdev->dev, ds1wm_data->irq, ds1wm_isr,
			IRQF_SHARED, "ds1wm", ds1wm_data);
	if (ret)
		return ret;

	ds1wm_up(ds1wm_data);

	ds1wm_master.data = (void *)ds1wm_data;

	ret = w1_add_master_device(&ds1wm_master);
	if (ret)
		goto err;

	return 0;

err:
	ds1wm_down(ds1wm_data);

	return ret;
}

#ifdef CONFIG_PM
static int ds1wm_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);

	ds1wm_down(ds1wm_data);

	return 0;
}

static int ds1wm_resume(struct platform_device *pdev)
{
	struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);

	ds1wm_up(ds1wm_data);

	return 0;
}
#else
#define ds1wm_suspend NULL
#define ds1wm_resume NULL
#endif

static int ds1wm_remove(struct platform_device *pdev)
{
	struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);

	w1_remove_master_device(&ds1wm_master);
	ds1wm_down(ds1wm_data);

	return 0;
}

static struct platform_driver ds1wm_driver = {
	.driver   = {
		.name = "ds1wm",
	},
	.probe    = ds1wm_probe,
	.remove   = ds1wm_remove,
	.suspend  = ds1wm_suspend,
	.resume   = ds1wm_resume
};

static int __init ds1wm_init(void)
{
	pr_info("DS1WM w1 busmaster driver - (c) 2004 Szabolcs Gyurko\n");
	return platform_driver_register(&ds1wm_driver);
}

static void __exit ds1wm_exit(void)
{
	platform_driver_unregister(&ds1wm_driver);
}

module_init(ds1wm_init);
module_exit(ds1wm_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
	"Matt Reimer <mreimer@vpop.net>,"
	"Jean-Francois Dagenais <dagenaisj@sonatest.com>");
MODULE_DESCRIPTION("DS1WM w1 busmaster driver");