/drivers/w1/masters/ds1wm.c

  1/*
  2 * 1-wire busmaster driver for DS1WM and ASICs with embedded DS1WMs
  3 * such as HP iPAQs (including h5xxx, h2200, and devices with ASIC3
  4 * like hx4700).
  5 *
  6 * Copyright (c) 2004-2005, Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
  7 * Copyright (c) 2004-2007, Matt Reimer <mreimer@vpop.net>
  8 *
  9 * Use consistent with the GNU GPL is permitted,
 10 * provided that this copyright notice is
 11 * preserved in its entirety in all copies and derived works.
 12 */
 13
 14#include <linux/module.h>
 15#include <linux/interrupt.h>
 16#include <linux/irq.h>
 17#include <linux/pm.h>
 18#include <linux/platform_device.h>
 19#include <linux/err.h>
 20#include <linux/delay.h>
 21#include <linux/mfd/core.h>
 22#include <linux/mfd/ds1wm.h>
 23#include <linux/slab.h>
 24
 25#include <asm/io.h>
 26
 27#include "../w1.h"
 28#include "../w1_int.h"
 29
 30
 31#define DS1WM_CMD	0x00	/* R/W 4 bits command */
 32#define DS1WM_DATA	0x01	/* R/W 8 bits, transmit/receive buffer */
 33#define DS1WM_INT	0x02	/* R/W interrupt status */
 34#define DS1WM_INT_EN	0x03	/* R/W interrupt enable */
 35#define DS1WM_CLKDIV	0x04	/* R/W 5 bits of divisor and pre-scale */
 36#define DS1WM_CNTRL	0x05	/* R/W master control register (not used yet) */
 37
 38#define DS1WM_CMD_1W_RESET  (1 << 0)	/* force reset on 1-wire bus */
 39#define DS1WM_CMD_SRA	    (1 << 1)	/* enable Search ROM accelerator mode */
 40#define DS1WM_CMD_DQ_OUTPUT (1 << 2)	/* write only - forces bus low */
 41#define DS1WM_CMD_DQ_INPUT  (1 << 3)	/* read only - reflects state of bus */
 42#define DS1WM_CMD_RST	    (1 << 5)	/* software reset */
 43#define DS1WM_CMD_OD	    (1 << 7)	/* overdrive */
 44
 45#define DS1WM_INT_PD	    (1 << 0)	/* presence detect */
 46#define DS1WM_INT_PDR	    (1 << 1)	/* presence detect result */
 47#define DS1WM_INT_TBE	    (1 << 2)	/* tx buffer empty */
 48#define DS1WM_INT_TSRE	    (1 << 3)	/* tx shift register empty */
 49#define DS1WM_INT_RBF	    (1 << 4)	/* rx buffer full */
 50#define DS1WM_INT_RSRF	    (1 << 5)	/* rx shift register full */
 51
 52#define DS1WM_INTEN_EPD	    (1 << 0)	/* enable presence detect int */
 53#define DS1WM_INTEN_IAS	    (1 << 1)	/* INTR active state */
 54#define DS1WM_INTEN_ETBE    (1 << 2)	/* enable tx buffer empty int */
 55#define DS1WM_INTEN_ETMT    (1 << 3)	/* enable tx shift register empty int */
 56#define DS1WM_INTEN_ERBF    (1 << 4)	/* enable rx buffer full int */
 57#define DS1WM_INTEN_ERSRF   (1 << 5)	/* enable rx shift register full int */
 58#define DS1WM_INTEN_DQO	    (1 << 6)	/* enable direct bus driving ops */
 59
 60#define DS1WM_INTEN_NOT_IAS (~DS1WM_INTEN_IAS)	/* all but INTR active state */
 61
 62#define DS1WM_TIMEOUT (HZ * 5)
 63
 64static struct {
 65	unsigned long freq;
 66	unsigned long divisor;
 67} freq[] = {
 68	{   1000000, 0x80 },
 69	{   2000000, 0x84 },
 70	{   3000000, 0x81 },
 71	{   4000000, 0x88 },
 72	{   5000000, 0x82 },
 73	{   6000000, 0x85 },
 74	{   7000000, 0x83 },
 75	{   8000000, 0x8c },
 76	{  10000000, 0x86 },
 77	{  12000000, 0x89 },
 78	{  14000000, 0x87 },
 79	{  16000000, 0x90 },
 80	{  20000000, 0x8a },
 81	{  24000000, 0x8d },
 82	{  28000000, 0x8b },
 83	{  32000000, 0x94 },
 84	{  40000000, 0x8e },
 85	{  48000000, 0x91 },
 86	{  56000000, 0x8f },
 87	{  64000000, 0x98 },
 88	{  80000000, 0x92 },
 89	{  96000000, 0x95 },
 90	{ 112000000, 0x93 },
 91	{ 128000000, 0x9c },
 92/* you can continue this table, consult the OPERATION - CLOCK DIVISOR
 93   section of the ds1wm spec sheet. */
 94};
 95
 96struct ds1wm_data {
 97	void     __iomem *map;
 98	int      bus_shift; /* # of shifts to calc register offsets */
 99	struct platform_device *pdev;
100	const struct mfd_cell   *cell;
101	int      irq;
102	int      slave_present;
103	void     *reset_complete;
104	void     *read_complete;
105	void     *write_complete;
106	int      read_error;
107	/* last byte received */
108	u8       read_byte;
109	/* byte to write that makes all intr disabled, */
110	/* considering active_state (IAS) (optimization) */
111	u8       int_en_reg_none;
112	unsigned int reset_recover_delay; /* see ds1wm.h */
113};
114
115static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
116					u8 val)
117{
118	__raw_writeb(val, ds1wm_data->map + (reg << ds1wm_data->bus_shift));
119}
120
121static inline u8 ds1wm_read_register(struct ds1wm_data *ds1wm_data, u32 reg)
122{
123	return __raw_readb(ds1wm_data->map + (reg << ds1wm_data->bus_shift));
124}
125
126
127static irqreturn_t ds1wm_isr(int isr, void *data)
128{
129	struct ds1wm_data *ds1wm_data = data;
130	u8 intr;
131	u8 inten = ds1wm_read_register(ds1wm_data, DS1WM_INT_EN);
132	/* if no bits are set in int enable register (except the IAS)
133	than go no further, reading the regs below has side effects */
134	if (!(inten & DS1WM_INTEN_NOT_IAS))
135		return IRQ_NONE;
136
137	ds1wm_write_register(ds1wm_data,
138		DS1WM_INT_EN, ds1wm_data->int_en_reg_none);
139
140	/* this read action clears the INTR and certain flags in ds1wm */
141	intr = ds1wm_read_register(ds1wm_data, DS1WM_INT);
142
143	ds1wm_data->slave_present = (intr & DS1WM_INT_PDR) ? 0 : 1;
144
145	if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete) {
146		inten &= ~DS1WM_INTEN_ETMT;
147		complete(ds1wm_data->write_complete);
148	}
149	if (intr & DS1WM_INT_RBF) {
150		/* this read clears the RBF flag */
151		ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
152		DS1WM_DATA);
153		inten &= ~DS1WM_INTEN_ERBF;
154		if (ds1wm_data->read_complete)
155			complete(ds1wm_data->read_complete);
156	}
157	if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete) {
158		inten &= ~DS1WM_INTEN_EPD;
159		complete(ds1wm_data->reset_complete);
160	}
161
162	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, inten);
163	return IRQ_HANDLED;
164}
165
166static int ds1wm_reset(struct ds1wm_data *ds1wm_data)
167{
168	unsigned long timeleft;
169	DECLARE_COMPLETION_ONSTACK(reset_done);
170
171	ds1wm_data->reset_complete = &reset_done;
172
173	/* enable Presence detect only */
174	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
175	ds1wm_data->int_en_reg_none);
176
177	ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_1W_RESET);
178
179	timeleft = wait_for_completion_timeout(&reset_done, DS1WM_TIMEOUT);
180	ds1wm_data->reset_complete = NULL;
181	if (!timeleft) {
182		dev_err(&ds1wm_data->pdev->dev, "reset failed, timed out\n");
183		return 1;
184	}
185
186	if (!ds1wm_data->slave_present) {
187		dev_dbg(&ds1wm_data->pdev->dev, "reset: no devices found\n");
188		return 1;
189	}
190
191	if (ds1wm_data->reset_recover_delay)
192		msleep(ds1wm_data->reset_recover_delay);
193
194	return 0;
195}
196
197static int ds1wm_write(struct ds1wm_data *ds1wm_data, u8 data)
198{
199	unsigned long timeleft;
200	DECLARE_COMPLETION_ONSTACK(write_done);
201	ds1wm_data->write_complete = &write_done;
202
203	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
204	ds1wm_data->int_en_reg_none | DS1WM_INTEN_ETMT);
205
206	ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);
207
208	timeleft = wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
209
210	ds1wm_data->write_complete = NULL;
211	if (!timeleft) {
212		dev_err(&ds1wm_data->pdev->dev, "write failed, timed out\n");
213		return -ETIMEDOUT;
214	}
215
216	return 0;
217}
218
219static u8 ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
220{
221	unsigned long timeleft;
222	u8 intEnable = DS1WM_INTEN_ERBF | ds1wm_data->int_en_reg_none;
223	DECLARE_COMPLETION_ONSTACK(read_done);
224
225	ds1wm_read_register(ds1wm_data, DS1WM_DATA);
226
227	ds1wm_data->read_complete = &read_done;
228	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, intEnable);
229
230	ds1wm_write_register(ds1wm_data, DS1WM_DATA, write_data);
231	timeleft = wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
232
233	ds1wm_data->read_complete = NULL;
234	if (!timeleft) {
235		dev_err(&ds1wm_data->pdev->dev, "read failed, timed out\n");
236		ds1wm_data->read_error = -ETIMEDOUT;
237		return 0xFF;
238	}
239	ds1wm_data->read_error = 0;
240	return ds1wm_data->read_byte;
241}
242
243static int ds1wm_find_divisor(int gclk)
244{
245	int i;
246
247	for (i = ARRAY_SIZE(freq)-1; i >= 0; --i)
248		if (gclk >= freq[i].freq)
249			return freq[i].divisor;
250
251	return 0;
252}
253
254static void ds1wm_up(struct ds1wm_data *ds1wm_data)
255{
256	int divisor;
257	struct ds1wm_driver_data *plat = ds1wm_data->pdev->dev.platform_data;
258
259	if (ds1wm_data->cell->enable)
260		ds1wm_data->cell->enable(ds1wm_data->pdev);
261
262	divisor = ds1wm_find_divisor(plat->clock_rate);
263	dev_dbg(&ds1wm_data->pdev->dev,
264		"found divisor 0x%x for clock %d\n", divisor, plat->clock_rate);
265	if (divisor == 0) {
266		dev_err(&ds1wm_data->pdev->dev,
267			"no suitable divisor for %dHz clock\n",
268			plat->clock_rate);
269		return;
270	}
271	ds1wm_write_register(ds1wm_data, DS1WM_CLKDIV, divisor);
272
273	/* Let the w1 clock stabilize. */
274	msleep(1);
275
276	ds1wm_reset(ds1wm_data);
277}
278
279static void ds1wm_down(struct ds1wm_data *ds1wm_data)
280{
281	ds1wm_reset(ds1wm_data);
282
283	/* Disable interrupts. */
284	ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
285		ds1wm_data->int_en_reg_none);
286
287	if (ds1wm_data->cell->disable)
288		ds1wm_data->cell->disable(ds1wm_data->pdev);
289}
290
291/* --------------------------------------------------------------------- */
292/* w1 methods */
293
294static u8 ds1wm_read_byte(void *data)
295{
296	struct ds1wm_data *ds1wm_data = data;
297
298	return ds1wm_read(ds1wm_data, 0xff);
299}
300
301static void ds1wm_write_byte(void *data, u8 byte)
302{
303	struct ds1wm_data *ds1wm_data = data;
304
305	ds1wm_write(ds1wm_data, byte);
306}
307
308static u8 ds1wm_reset_bus(void *data)
309{
310	struct ds1wm_data *ds1wm_data = data;
311
312	ds1wm_reset(ds1wm_data);
313
314	return 0;
315}
316
317static void ds1wm_search(void *data, struct w1_master *master_dev,
318			u8 search_type, w1_slave_found_callback slave_found)
319{
320	struct ds1wm_data *ds1wm_data = data;
321	int i;
322	int ms_discrep_bit = -1;
323	u64 r = 0; /* holds the progress of the search */
324	u64 r_prime, d;
325	unsigned slaves_found = 0;
326	unsigned int pass = 0;
327
328	dev_dbg(&ds1wm_data->pdev->dev, "search begin\n");
329	while (true) {
330		++pass;
331		if (pass > 100) {
332			dev_dbg(&ds1wm_data->pdev->dev,
333				"too many attempts (100), search aborted\n");
334			return;
335		}
336
337		if (ds1wm_reset(ds1wm_data)) {
338			dev_dbg(&ds1wm_data->pdev->dev,
339				"pass: %d reset error (or no slaves)\n", pass);
340			break;
341		}
342
343		dev_dbg(&ds1wm_data->pdev->dev,
344			"pass: %d r : %0#18llx writing SEARCH_ROM\n", pass, r);
345		ds1wm_write(ds1wm_data, search_type);
346		dev_dbg(&ds1wm_data->pdev->dev,
347			"pass: %d entering ASM\n", pass);
348		ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
349		dev_dbg(&ds1wm_data->pdev->dev,
350			"pass: %d begining nibble loop\n", pass);
351
352		r_prime = 0;
353		d = 0;
354		/* we work one nibble at a time */
355		/* each nibble is interleaved to form a byte */
356		for (i = 0; i < 16; i++) {
357
358			unsigned char resp, _r, _r_prime, _d;
359
360			_r = (r >> (4*i)) & 0xf;
361			_r = ((_r & 0x1) << 1) |
362			((_r & 0x2) << 2) |
363			((_r & 0x4) << 3) |
364			((_r & 0x8) << 4);
365
366			/* writes _r, then reads back: */
367			resp = ds1wm_read(ds1wm_data, _r);
368
369			if (ds1wm_data->read_error) {
370				dev_err(&ds1wm_data->pdev->dev,
371				"pass: %d nibble: %d read error\n", pass, i);
372				break;
373			}
374
375			_r_prime = ((resp & 0x02) >> 1) |
376			((resp & 0x08) >> 2) |
377			((resp & 0x20) >> 3) |
378			((resp & 0x80) >> 4);
379
380			_d = ((resp & 0x01) >> 0) |
381			((resp & 0x04) >> 1) |
382			((resp & 0x10) >> 2) |
383			((resp & 0x40) >> 3);
384
385			r_prime |= (unsigned long long) _r_prime << (i * 4);
386			d |= (unsigned long long) _d << (i * 4);
387
388		}
389		if (ds1wm_data->read_error) {
390			dev_err(&ds1wm_data->pdev->dev,
391				"pass: %d read error, retrying\n", pass);
392			break;
393		}
394		dev_dbg(&ds1wm_data->pdev->dev,
395			"pass: %d r\': %0#18llx d:%0#18llx\n",
396			pass, r_prime, d);
397		dev_dbg(&ds1wm_data->pdev->dev,
398			"pass: %d nibble loop complete, exiting ASM\n", pass);
399		ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
400		dev_dbg(&ds1wm_data->pdev->dev,
401			"pass: %d resetting bus\n", pass);
402		ds1wm_reset(ds1wm_data);
403		if ((r_prime & ((u64)1 << 63)) && (d & ((u64)1 << 63))) {
404			dev_err(&ds1wm_data->pdev->dev,
405				"pass: %d bus error, retrying\n", pass);
406			continue; /* start over */
407		}
408
409
410		dev_dbg(&ds1wm_data->pdev->dev,
411			"pass: %d found %0#18llx\n", pass, r_prime);
412		slave_found(master_dev, r_prime);
413		++slaves_found;
414		dev_dbg(&ds1wm_data->pdev->dev,
415			"pass: %d complete, preparing next pass\n", pass);
416
417		/* any discrepency found which we already choose the
418		   '1' branch is now is now irrelevant we reveal the
419		   next branch with this: */
420		d &= ~r;
421		/* find last bit set, i.e. the most signif. bit set */
422		ms_discrep_bit = fls64(d) - 1;
423		dev_dbg(&ds1wm_data->pdev->dev,
424			"pass: %d new d:%0#18llx MS discrep bit:%d\n",
425			pass, d, ms_discrep_bit);
426
427		/* prev_ms_discrep_bit = ms_discrep_bit;
428		   prepare for next ROM search:		    */
429		if (ms_discrep_bit == -1)
430			break;
431
432		r = (r &  ~(~0ull << (ms_discrep_bit))) | 1 << ms_discrep_bit;
433	} /* end while true */
434	dev_dbg(&ds1wm_data->pdev->dev,
435		"pass: %d total: %d search done ms d bit pos: %d\n", pass,
436		slaves_found, ms_discrep_bit);
437}
438
439/* --------------------------------------------------------------------- */
440
441static struct w1_bus_master ds1wm_master = {
442	.read_byte  = ds1wm_read_byte,
443	.write_byte = ds1wm_write_byte,
444	.reset_bus  = ds1wm_reset_bus,
445	.search	    = ds1wm_search,
446};
447
448static int ds1wm_probe(struct platform_device *pdev)
449{
450	struct ds1wm_data *ds1wm_data;
451	struct ds1wm_driver_data *plat;
452	struct resource *res;
453	int ret;
454
455	if (!pdev)
456		return -ENODEV;
457
458	ds1wm_data = kzalloc(sizeof(*ds1wm_data), GFP_KERNEL);
459	if (!ds1wm_data)
460		return -ENOMEM;
461
462	platform_set_drvdata(pdev, ds1wm_data);
463
464	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
465	if (!res) {
466		ret = -ENXIO;
467		goto err0;
468	}
469	ds1wm_data->map = ioremap(res->start, resource_size(res));
470	if (!ds1wm_data->map) {
471		ret = -ENOMEM;
472		goto err0;
473	}
474
475	/* calculate bus shift from mem resource */
476	ds1wm_data->bus_shift = resource_size(res) >> 3;
477
478	ds1wm_data->pdev = pdev;
479	ds1wm_data->cell = mfd_get_cell(pdev);
480	if (!ds1wm_data->cell) {
481		ret = -ENODEV;
482		goto err1;
483	}
484	plat = pdev->dev.platform_data;
485	if (!plat) {
486		ret = -ENODEV;
487		goto err1;
488	}
489
490	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
491	if (!res) {
492		ret = -ENXIO;
493		goto err1;
494	}
495	ds1wm_data->irq = res->start;
496	ds1wm_data->int_en_reg_none = (plat->active_high ? DS1WM_INTEN_IAS : 0);
497	ds1wm_data->reset_recover_delay = plat->reset_recover_delay;
498
499	if (res->flags & IORESOURCE_IRQ_HIGHEDGE)
500		irq_set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_RISING);
501	if (res->flags & IORESOURCE_IRQ_LOWEDGE)
502		irq_set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_FALLING);
503
504	ret = request_irq(ds1wm_data->irq, ds1wm_isr,
505			IRQF_DISABLED | IRQF_SHARED, "ds1wm", ds1wm_data);
506	if (ret)
507		goto err1;
508
509	ds1wm_up(ds1wm_data);
510
511	ds1wm_master.data = (void *)ds1wm_data;
512
513	ret = w1_add_master_device(&ds1wm_master);
514	if (ret)
515		goto err2;
516
517	return 0;
518
519err2:
520	ds1wm_down(ds1wm_data);
521	free_irq(ds1wm_data->irq, ds1wm_data);
522err1:
523	iounmap(ds1wm_data->map);
524err0:
525	kfree(ds1wm_data);
526
527	return ret;
528}
529
530#ifdef CONFIG_PM
531static int ds1wm_suspend(struct platform_device *pdev, pm_message_t state)
532{
533	struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
534
535	ds1wm_down(ds1wm_data);
536
537	return 0;
538}
539
540static int ds1wm_resume(struct platform_device *pdev)
541{
542	struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
543
544	ds1wm_up(ds1wm_data);
545
546	return 0;
547}
548#else
549#define ds1wm_suspend NULL
550#define ds1wm_resume NULL
551#endif
552
553static int ds1wm_remove(struct platform_device *pdev)
554{
555	struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
556
557	w1_remove_master_device(&ds1wm_master);
558	ds1wm_down(ds1wm_data);
559	free_irq(ds1wm_data->irq, ds1wm_data);
560	iounmap(ds1wm_data->map);
561	kfree(ds1wm_data);
562
563	return 0;
564}
565
566static struct platform_driver ds1wm_driver = {
567	.driver   = {
568		.name = "ds1wm",
569	},
570	.probe    = ds1wm_probe,
571	.remove   = ds1wm_remove,
572	.suspend  = ds1wm_suspend,
573	.resume   = ds1wm_resume
574};
575
576static int __init ds1wm_init(void)
577{
578	printk("DS1WM w1 busmaster driver - (c) 2004 Szabolcs Gyurko\n");
579	return platform_driver_register(&ds1wm_driver);
580}
581
582static void __exit ds1wm_exit(void)
583{
584	platform_driver_unregister(&ds1wm_driver);
585}
586
587module_init(ds1wm_init);
588module_exit(ds1wm_exit);
589
590MODULE_LICENSE("GPL");
591MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
592	"Matt Reimer <mreimer@vpop.net>,"
593	"Jean-Francois Dagenais <dagenaisj@sonatest.com>");
594MODULE_DESCRIPTION("DS1WM w1 busmaster driver");