summaryrefslogtreecommitdiffstats
path: root/drivers/w1/masters/ds1wm.c
blob: ea894bf181136d79053222eb102a383748c2e13f (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
/*
 * 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/irq.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/ds1wm.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_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_TIMEOUT (HZ * 5)

static struct {
	unsigned long freq;
	unsigned long divisor;
} freq[] = {
	{ 4000000, 0x8 },
	{ 5000000, 0x2 },
	{ 6000000, 0x5 },
	{ 7000000, 0x3 },
	{ 8000000, 0xc },
	{ 10000000, 0x6 },
	{ 12000000, 0x9 },
	{ 14000000, 0x7 },
	{ 16000000, 0x10 },
	{ 20000000, 0xa },
	{ 24000000, 0xd },
	{ 28000000, 0xb },
	{ 32000000, 0x14 },
	{ 40000000, 0xe },
	{ 48000000, 0x11 },
	{ 56000000, 0xf },
	{ 64000000, 0x18 },
	{ 80000000, 0x12 },
	{ 96000000, 0x15 },
	{ 112000000, 0x13 },
	{ 128000000, 0x1c },
};

struct ds1wm_data {
	void		__iomem *map;
	int		bus_shift; /* # of shifts to calc register offsets */
	struct platform_device *pdev;
	struct ds1wm_platform_data *pdata;
	int		irq;
	int		active_high;
	struct clk	*clk;
	int		slave_present;
	void		*reset_complete;
	void		*read_complete;
	void		*write_complete;
	u8		read_byte; /* last byte received */
};

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 = ds1wm_read_register(ds1wm_data, DS1WM_INT);

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

	if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete)
		complete(ds1wm_data->reset_complete);

	if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete)
		complete(ds1wm_data->write_complete);

	if (intr & DS1WM_INT_RBF) {
		ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
							    DS1WM_DATA);
		if (ds1wm_data->read_complete)
			complete(ds1wm_data->read_complete);
	}

	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;

	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
		(ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));

	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\n");
		return 1;
	}

	/* Wait for the end of the reset. According to the specs, the time
	 * from when the interrupt is asserted to the end of the reset is:
	 *     tRSTH  - tPDH  - tPDL - tPDI
	 *     625 us - 60 us - 240 us - 100 ns = 324.9 us
	 *
	 * We'll wait a bit longer just to be sure.
	 */
	udelay(500);

	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
		DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD |
		(ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));

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

	return 0;
}

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

	ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);

	wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
	ds1wm_data->write_complete = NULL;

	return 0;
}

static int ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
{
	DECLARE_COMPLETION_ONSTACK(read_done);
	ds1wm_data->read_complete = &read_done;

	ds1wm_write(ds1wm_data, write_data);
	wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
	ds1wm_data->read_complete = NULL;

	return ds1wm_data->read_byte;
}

static int ds1wm_find_divisor(int gclk)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(freq); i++)
		if (gclk <= freq[i].freq)
			return freq[i].divisor;

	return 0;
}

static void ds1wm_up(struct ds1wm_data *ds1wm_data)
{
	int gclk, divisor;

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

	gclk = clk_get_rate(ds1wm_data->clk);
	clk_enable(ds1wm_data->clk);
	divisor = ds1wm_find_divisor(gclk);
	if (divisor == 0) {
		dev_err(&ds1wm_data->pdev->dev,
			"no suitable divisor for %dHz clock\n", gclk);
		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->active_high ? DS1WM_INTEN_IAS : 0);

	if (ds1wm_data->pdata->disable)
		ds1wm_data->pdata->disable(ds1wm_data->pdev);

	clk_disable(ds1wm_data->clk);
}

/* --------------------------------------------------------------------- */
/* 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;
	unsigned long long rom_id;

	/* XXX We need to iterate for multiple devices per the DS1WM docs.
	 * See http://www.maxim-ic.com/appnotes.cfm/appnote_number/120. */
	if (ds1wm_reset(ds1wm_data))
		return;

	ds1wm_write(ds1wm_data, search_type);
	ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);

	for (rom_id = 0, i = 0; i < 16; i++) {

		unsigned char resp, r, d;

		resp = ds1wm_read(ds1wm_data, 0x00);

		r = ((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);

		rom_id |= (unsigned long long) r << (i * 4);

	}
	dev_dbg(&ds1wm_data->pdev->dev, "found 0x%08llX\n", rom_id);

	ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
	ds1wm_reset(ds1wm_data);

	slave_found(master_dev, rom_id);
}

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

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_platform_data *plat;
	struct resource *res;
	int ret;

	if (!pdev)
		return -ENODEV;

	ds1wm_data = kzalloc(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) {
		ret = -ENXIO;
		goto err0;
	}
	ds1wm_data->map = ioremap(res->start, res->end - res->start + 1);
	if (!ds1wm_data->map) {
		ret = -ENOMEM;
		goto err0;
	}
	plat = pdev->dev.platform_data;
	ds1wm_data->bus_shift = plat->bus_shift;
	ds1wm_data->pdev = pdev;
	ds1wm_data->pdata = plat;

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res) {
		ret = -ENXIO;
		goto err1;
	}
	ds1wm_data->irq = res->start;
	ds1wm_data->active_high = plat->active_high;

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

	ret = request_irq(ds1wm_data->irq, ds1wm_isr, IRQF_DISABLED,
			  "ds1wm", ds1wm_data);
	if (ret)
		goto err1;

	ds1wm_data->clk = clk_get(&pdev->dev, "ds1wm");
	if (IS_ERR(ds1wm_data->clk)) {
		ret = PTR_ERR(ds1wm_data->clk);
		goto err2;
	}

	ds1wm_up(ds1wm_data);

	ds1wm_master.data = (void *)ds1wm_data;

	ret = w1_add_master_device(&ds1wm_master);
	if (ret)
		goto err3;

	return 0;

err3:
	ds1wm_down(ds1wm_data);
	clk_put(ds1wm_data->clk);
err2:
	free_irq(ds1wm_data->irq, ds1wm_data);
err1:
	iounmap(ds1wm_data->map);
err0:
	kfree(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);
	clk_put(ds1wm_data->clk);
	free_irq(ds1wm_data->irq, ds1wm_data);
	iounmap(ds1wm_data->map);
	kfree(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)
{
	printk("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>");
MODULE_DESCRIPTION("DS1WM w1 busmaster driver");