summaryrefslogtreecommitdiff
path: root/drivers/acpi/acpi_lpss.c
blob: 73f056a597a9dc2b0e87c27ac527ff7149fd9fb8 (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
/*
 * ACPI support for Intel Lynxpoint LPSS.
 *
 * Copyright (C) 2013, Intel Corporation
 * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
 *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 *
 * This program is free software; you can redistribute 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/acpi.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/platform_data/clk-lpss.h>
#include <linux/pm_runtime.h>
#include <linux/delay.h>

#include "internal.h"

ACPI_MODULE_NAME("acpi_lpss");

#ifdef CONFIG_X86_INTEL_LPSS

#define LPSS_ADDR(desc) ((unsigned long)&desc)

#define LPSS_CLK_SIZE	0x04
#define LPSS_LTR_SIZE	0x18

/* Offsets relative to LPSS_PRIVATE_OFFSET */
#define LPSS_CLK_DIVIDER_DEF_MASK	(BIT(1) | BIT(16))
#define LPSS_RESETS			0x04
#define LPSS_RESETS_RESET_FUNC		BIT(0)
#define LPSS_RESETS_RESET_APB		BIT(1)
#define LPSS_GENERAL			0x08
#define LPSS_GENERAL_LTR_MODE_SW	BIT(2)
#define LPSS_GENERAL_UART_RTS_OVRD	BIT(3)
#define LPSS_SW_LTR			0x10
#define LPSS_AUTO_LTR			0x14
#define LPSS_LTR_SNOOP_REQ		BIT(15)
#define LPSS_LTR_SNOOP_MASK		0x0000FFFF
#define LPSS_LTR_SNOOP_LAT_1US		0x800
#define LPSS_LTR_SNOOP_LAT_32US		0xC00
#define LPSS_LTR_SNOOP_LAT_SHIFT	5
#define LPSS_LTR_SNOOP_LAT_CUTOFF	3000
#define LPSS_LTR_MAX_VAL		0x3FF
#define LPSS_TX_INT			0x20
#define LPSS_TX_INT_MASK		BIT(1)

#define LPSS_PRV_REG_COUNT		9

/* LPSS Flags */
#define LPSS_CLK			BIT(0)
#define LPSS_CLK_GATE			BIT(1)
#define LPSS_CLK_DIVIDER		BIT(2)
#define LPSS_LTR			BIT(3)
#define LPSS_SAVE_CTX			BIT(4)

struct lpss_private_data;

struct lpss_device_desc {
	unsigned int flags;
	const char *clk_con_id;
	unsigned int prv_offset;
	size_t prv_size_override;
	void (*setup)(struct lpss_private_data *pdata);
};

static struct lpss_device_desc lpss_dma_desc = {
	.flags = LPSS_CLK,
};

struct lpss_private_data {
	void __iomem *mmio_base;
	resource_size_t mmio_size;
	unsigned int fixed_clk_rate;
	struct clk *clk;
	const struct lpss_device_desc *dev_desc;
	u32 prv_reg_ctx[LPSS_PRV_REG_COUNT];
};

/* UART Component Parameter Register */
#define LPSS_UART_CPR			0xF4
#define LPSS_UART_CPR_AFCE		BIT(4)

static void lpss_uart_setup(struct lpss_private_data *pdata)
{
	unsigned int offset;
	u32 val;

	offset = pdata->dev_desc->prv_offset + LPSS_TX_INT;
	val = readl(pdata->mmio_base + offset);
	writel(val | LPSS_TX_INT_MASK, pdata->mmio_base + offset);

	val = readl(pdata->mmio_base + LPSS_UART_CPR);
	if (!(val & LPSS_UART_CPR_AFCE)) {
		offset = pdata->dev_desc->prv_offset + LPSS_GENERAL;
		val = readl(pdata->mmio_base + offset);
		val |= LPSS_GENERAL_UART_RTS_OVRD;
		writel(val, pdata->mmio_base + offset);
	}
}

static void lpss_deassert_reset(struct lpss_private_data *pdata)
{
	unsigned int offset;
	u32 val;

	offset = pdata->dev_desc->prv_offset + LPSS_RESETS;
	val = readl(pdata->mmio_base + offset);
	val |= LPSS_RESETS_RESET_APB | LPSS_RESETS_RESET_FUNC;
	writel(val, pdata->mmio_base + offset);
}

#define LPSS_I2C_ENABLE			0x6c

static void byt_i2c_setup(struct lpss_private_data *pdata)
{
	lpss_deassert_reset(pdata);

	if (readl(pdata->mmio_base + pdata->dev_desc->prv_offset))
		pdata->fixed_clk_rate = 133000000;

	writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
}

static struct lpss_device_desc lpt_dev_desc = {
	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
	.prv_offset = 0x800,
};

static struct lpss_device_desc lpt_i2c_dev_desc = {
	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_LTR,
	.prv_offset = 0x800,
};

static struct lpss_device_desc lpt_uart_dev_desc = {
	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
	.clk_con_id = "baudclk",
	.prv_offset = 0x800,
	.setup = lpss_uart_setup,
};

static struct lpss_device_desc lpt_sdio_dev_desc = {
	.flags = LPSS_LTR,
	.prv_offset = 0x1000,
	.prv_size_override = 0x1018,
};

static struct lpss_device_desc byt_pwm_dev_desc = {
	.flags = LPSS_SAVE_CTX,
};

static struct lpss_device_desc byt_uart_dev_desc = {
	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
	.clk_con_id = "baudclk",
	.prv_offset = 0x800,
	.setup = lpss_uart_setup,
};

static struct lpss_device_desc byt_spi_dev_desc = {
	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
	.prv_offset = 0x400,
};

static struct lpss_device_desc byt_sdio_dev_desc = {
	.flags = LPSS_CLK,
};

static struct lpss_device_desc byt_i2c_dev_desc = {
	.flags = LPSS_CLK | LPSS_SAVE_CTX,
	.prv_offset = 0x800,
	.setup = byt_i2c_setup,
};

static struct lpss_device_desc bsw_spi_dev_desc = {
	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
	.prv_offset = 0x400,
	.setup = lpss_deassert_reset,
};

#else

#define LPSS_ADDR(desc) (0UL)

#endif /* CONFIG_X86_INTEL_LPSS */

static const struct acpi_device_id acpi_lpss_device_ids[] = {
	/* Generic LPSS devices */
	{ "INTL9C60", LPSS_ADDR(lpss_dma_desc) },

	/* Lynxpoint LPSS devices */
	{ "INT33C0", LPSS_ADDR(lpt_dev_desc) },
	{ "INT33C1", LPSS_ADDR(lpt_dev_desc) },
	{ "INT33C2", LPSS_ADDR(lpt_i2c_dev_desc) },
	{ "INT33C3", LPSS_ADDR(lpt_i2c_dev_desc) },
	{ "INT33C4", LPSS_ADDR(lpt_uart_dev_desc) },
	{ "INT33C5", LPSS_ADDR(lpt_uart_dev_desc) },
	{ "INT33C6", LPSS_ADDR(lpt_sdio_dev_desc) },
	{ "INT33C7", },

	/* BayTrail LPSS devices */
	{ "80860F09", LPSS_ADDR(byt_pwm_dev_desc) },
	{ "80860F0A", LPSS_ADDR(byt_uart_dev_desc) },
	{ "80860F0E", LPSS_ADDR(byt_spi_dev_desc) },
	{ "80860F14", LPSS_ADDR(byt_sdio_dev_desc) },
	{ "80860F41", LPSS_ADDR(byt_i2c_dev_desc) },
	{ "INT33B2", },
	{ "INT33FC", },

	/* Braswell LPSS devices */
	{ "80862288", LPSS_ADDR(byt_pwm_dev_desc) },
	{ "8086228A", LPSS_ADDR(byt_uart_dev_desc) },
	{ "8086228E", LPSS_ADDR(bsw_spi_dev_desc) },
	{ "808622C1", LPSS_ADDR(byt_i2c_dev_desc) },

	{ "INT3430", LPSS_ADDR(lpt_dev_desc) },
	{ "INT3431", LPSS_ADDR(lpt_dev_desc) },
	{ "INT3432", LPSS_ADDR(lpt_i2c_dev_desc) },
	{ "INT3433", LPSS_ADDR(lpt_i2c_dev_desc) },
	{ "INT3434", LPSS_ADDR(lpt_uart_dev_desc) },
	{ "INT3435", LPSS_ADDR(lpt_uart_dev_desc) },
	{ "INT3436", LPSS_ADDR(lpt_sdio_dev_desc) },
	{ "INT3437", },

	/* Wildcat Point LPSS devices */
	{ "INT3438", LPSS_ADDR(lpt_dev_desc) },

	{ }
};

#ifdef CONFIG_X86_INTEL_LPSS

static int is_memory(struct acpi_resource *res, void *not_used)
{
	struct resource r;
	return !acpi_dev_resource_memory(res, &r);
}

/* LPSS main clock device. */
static struct platform_device *lpss_clk_dev;

static inline void lpt_register_clock_device(void)
{
	lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
}

static int register_device_clock(struct acpi_device *adev,
				 struct lpss_private_data *pdata)
{
	const struct lpss_device_desc *dev_desc = pdata->dev_desc;
	const char *devname = dev_name(&adev->dev);
	struct clk *clk = ERR_PTR(-ENODEV);
	struct lpss_clk_data *clk_data;
	const char *parent, *clk_name;
	void __iomem *prv_base;

	if (!lpss_clk_dev)
		lpt_register_clock_device();

	clk_data = platform_get_drvdata(lpss_clk_dev);
	if (!clk_data)
		return -ENODEV;
	clk = clk_data->clk;

	if (!pdata->mmio_base
	    || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
		return -ENODATA;

	parent = clk_data->name;
	prv_base = pdata->mmio_base + dev_desc->prv_offset;

	if (pdata->fixed_clk_rate) {
		clk = clk_register_fixed_rate(NULL, devname, parent, 0,
					      pdata->fixed_clk_rate);
		goto out;
	}

	if (dev_desc->flags & LPSS_CLK_GATE) {
		clk = clk_register_gate(NULL, devname, parent, 0,
					prv_base, 0, 0, NULL);
		parent = devname;
	}

	if (dev_desc->flags & LPSS_CLK_DIVIDER) {
		/* Prevent division by zero */
		if (!readl(prv_base))
			writel(LPSS_CLK_DIVIDER_DEF_MASK, prv_base);

		clk_name = kasprintf(GFP_KERNEL, "%s-div", devname);
		if (!clk_name)
			return -ENOMEM;
		clk = clk_register_fractional_divider(NULL, clk_name, parent,
						      0, prv_base,
						      1, 15, 16, 15, 0, NULL);
		parent = clk_name;

		clk_name = kasprintf(GFP_KERNEL, "%s-update", devname);
		if (!clk_name) {
			kfree(parent);
			return -ENOMEM;
		}
		clk = clk_register_gate(NULL, clk_name, parent,
					CLK_SET_RATE_PARENT | CLK_SET_RATE_GATE,
					prv_base, 31, 0, NULL);
		kfree(parent);
		kfree(clk_name);
	}
out:
	if (IS_ERR(clk))
		return PTR_ERR(clk);

	pdata->clk = clk;
	clk_register_clkdev(clk, dev_desc->clk_con_id, devname);
	return 0;
}

static int acpi_lpss_create_device(struct acpi_device *adev,
				   const struct acpi_device_id *id)
{
	struct lpss_device_desc *dev_desc;
	struct lpss_private_data *pdata;
	struct resource_entry *rentry;
	struct list_head resource_list;
	struct platform_device *pdev;
	int ret;

	dev_desc = (struct lpss_device_desc *)id->driver_data;
	if (!dev_desc) {
		pdev = acpi_create_platform_device(adev);
		return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
	}
	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;

	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
	if (ret < 0)
		goto err_out;

	list_for_each_entry(rentry, &resource_list, node)
		if (resource_type(rentry->res) == IORESOURCE_MEM) {
			if (dev_desc->prv_size_override)
				pdata->mmio_size = dev_desc->prv_size_override;
			else
				pdata->mmio_size = resource_size(rentry->res);
			pdata->mmio_base = ioremap(rentry->res->start,
						   pdata->mmio_size);
			break;
		}

	acpi_dev_free_resource_list(&resource_list);

	if (!pdata->mmio_base) {
		ret = -ENOMEM;
		goto err_out;
	}

	pdata->dev_desc = dev_desc;

	if (dev_desc->setup)
		dev_desc->setup(pdata);

	if (dev_desc->flags & LPSS_CLK) {
		ret = register_device_clock(adev, pdata);
		if (ret) {
			/* Skip the device, but continue the namespace scan. */
			ret = 0;
			goto err_out;
		}
	}

	/*
	 * This works around a known issue in ACPI tables where LPSS devices
	 * have _PS0 and _PS3 without _PSC (and no power resources), so
	 * acpi_bus_init_power() will assume that the BIOS has put them into D0.
	 */
	ret = acpi_device_fix_up_power(adev);
	if (ret) {
		/* Skip the device, but continue the namespace scan. */
		ret = 0;
		goto err_out;
	}

	adev->driver_data = pdata;
	pdev = acpi_create_platform_device(adev);
	if (!IS_ERR_OR_NULL(pdev)) {
		return 1;
	}

	ret = PTR_ERR(pdev);
	adev->driver_data = NULL;

 err_out:
	kfree(pdata);
	return ret;
}

static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
{
	return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
}

static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
			     unsigned int reg)
{
	writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
}

static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
{
	struct acpi_device *adev;
	struct lpss_private_data *pdata;
	unsigned long flags;
	int ret;

	ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
	if (WARN_ON(ret))
		return ret;

	spin_lock_irqsave(&dev->power.lock, flags);
	if (pm_runtime_suspended(dev)) {
		ret = -EAGAIN;
		goto out;
	}
	pdata = acpi_driver_data(adev);
	if (WARN_ON(!pdata || !pdata->mmio_base)) {
		ret = -ENODEV;
		goto out;
	}
	*val = __lpss_reg_read(pdata, reg);

 out:
	spin_unlock_irqrestore(&dev->power.lock, flags);
	return ret;
}

static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	u32 ltr_value = 0;
	unsigned int reg;
	int ret;

	reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
	ret = lpss_reg_read(dev, reg, &ltr_value);
	if (ret)
		return ret;

	return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
}

static ssize_t lpss_ltr_mode_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	u32 ltr_mode = 0;
	char *outstr;
	int ret;

	ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
	if (ret)
		return ret;

	outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
	return sprintf(buf, "%s\n", outstr);
}

static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);

static struct attribute *lpss_attrs[] = {
	&dev_attr_auto_ltr.attr,
	&dev_attr_sw_ltr.attr,
	&dev_attr_ltr_mode.attr,
	NULL,
};

static struct attribute_group lpss_attr_group = {
	.attrs = lpss_attrs,
	.name = "lpss_ltr",
};

static void acpi_lpss_set_ltr(struct device *dev, s32 val)
{
	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
	u32 ltr_mode, ltr_val;

	ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
	if (val < 0) {
		if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
			ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
			__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
		}
		return;
	}
	ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
	if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
		ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
		val = LPSS_LTR_MAX_VAL;
	} else if (val > LPSS_LTR_MAX_VAL) {
		ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
		val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
	} else {
		ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
	}
	ltr_val |= val;
	__lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
	if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
		ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
		__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
	}
}

#ifdef CONFIG_PM
/**
 * acpi_lpss_save_ctx() - Save the private registers of LPSS device
 * @dev: LPSS device
 * @pdata: pointer to the private data of the LPSS device
 *
 * Most LPSS devices have private registers which may loose their context when
 * the device is powered down. acpi_lpss_save_ctx() saves those registers into
 * prv_reg_ctx array.
 */
static void acpi_lpss_save_ctx(struct device *dev,
			       struct lpss_private_data *pdata)
{
	unsigned int i;

	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
		unsigned long offset = i * sizeof(u32);

		pdata->prv_reg_ctx[i] = __lpss_reg_read(pdata, offset);
		dev_dbg(dev, "saving 0x%08x from LPSS reg at offset 0x%02lx\n",
			pdata->prv_reg_ctx[i], offset);
	}
}

/**
 * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device
 * @dev: LPSS device
 * @pdata: pointer to the private data of the LPSS device
 *
 * Restores the registers that were previously stored with acpi_lpss_save_ctx().
 */
static void acpi_lpss_restore_ctx(struct device *dev,
				  struct lpss_private_data *pdata)
{
	unsigned int i;

	/*
	 * The following delay is needed or the subsequent write operations may
	 * fail. The LPSS devices are actually PCI devices and the PCI spec
	 * expects 10ms delay before the device can be accessed after D3 to D0
	 * transition.
	 */
	msleep(10);

	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
		unsigned long offset = i * sizeof(u32);

		__lpss_reg_write(pdata->prv_reg_ctx[i], pdata, offset);
		dev_dbg(dev, "restoring 0x%08x to LPSS reg at offset 0x%02lx\n",
			pdata->prv_reg_ctx[i], offset);
	}
}

#ifdef CONFIG_PM_SLEEP
static int acpi_lpss_suspend_late(struct device *dev)
{
	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
	int ret;

	ret = pm_generic_suspend_late(dev);
	if (ret)
		return ret;

	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
		acpi_lpss_save_ctx(dev, pdata);

	return acpi_dev_suspend_late(dev);
}

static int acpi_lpss_resume_early(struct device *dev)
{
	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
	int ret;

	ret = acpi_dev_resume_early(dev);
	if (ret)
		return ret;

	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
		acpi_lpss_restore_ctx(dev, pdata);

	return pm_generic_resume_early(dev);
}
#endif /* CONFIG_PM_SLEEP */

static int acpi_lpss_runtime_suspend(struct device *dev)
{
	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
	int ret;

	ret = pm_generic_runtime_suspend(dev);
	if (ret)
		return ret;

	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
		acpi_lpss_save_ctx(dev, pdata);

	return acpi_dev_runtime_suspend(dev);
}

static int acpi_lpss_runtime_resume(struct device *dev)
{
	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
	int ret;

	ret = acpi_dev_runtime_resume(dev);
	if (ret)
		return ret;

	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
		acpi_lpss_restore_ctx(dev, pdata);

	return pm_generic_runtime_resume(dev);
}
#endif /* CONFIG_PM */

static struct dev_pm_domain acpi_lpss_pm_domain = {
	.ops = {
#ifdef CONFIG_PM
#ifdef CONFIG_PM_SLEEP
		.prepare = acpi_subsys_prepare,
		.complete = acpi_subsys_complete,
		.suspend = acpi_subsys_suspend,
		.suspend_late = acpi_lpss_suspend_late,
		.resume_early = acpi_lpss_resume_early,
		.freeze = acpi_subsys_freeze,
		.poweroff = acpi_subsys_suspend,
		.poweroff_late = acpi_lpss_suspend_late,
		.restore_early = acpi_lpss_resume_early,
#endif
		.runtime_suspend = acpi_lpss_runtime_suspend,
		.runtime_resume = acpi_lpss_runtime_resume,
#endif
	},
};

static int acpi_lpss_platform_notify(struct notifier_block *nb,
				     unsigned long action, void *data)
{
	struct platform_device *pdev = to_platform_device(data);
	struct lpss_private_data *pdata;
	struct acpi_device *adev;
	const struct acpi_device_id *id;

	id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
	if (!id || !id->driver_data)
		return 0;

	if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
		return 0;

	pdata = acpi_driver_data(adev);
	if (!pdata)
		return 0;

	if (pdata->mmio_base &&
	    pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
		dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
		return 0;
	}

	switch (action) {
	case BUS_NOTIFY_ADD_DEVICE:
		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
		if (pdata->dev_desc->flags & LPSS_LTR)
			return sysfs_create_group(&pdev->dev.kobj,
						  &lpss_attr_group);
		break;
	case BUS_NOTIFY_DEL_DEVICE:
		if (pdata->dev_desc->flags & LPSS_LTR)
			sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
		pdev->dev.pm_domain = NULL;
		break;
	default:
		break;
	}

	return 0;
}

static struct notifier_block acpi_lpss_nb = {
	.notifier_call = acpi_lpss_platform_notify,
};

static void acpi_lpss_bind(struct device *dev)
{
	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));

	if (!pdata || !pdata->mmio_base || !(pdata->dev_desc->flags & LPSS_LTR))
		return;

	if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
		dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
	else
		dev_err(dev, "MMIO size insufficient to access LTR\n");
}

static void acpi_lpss_unbind(struct device *dev)
{
	dev->power.set_latency_tolerance = NULL;
}

static struct acpi_scan_handler lpss_handler = {
	.ids = acpi_lpss_device_ids,
	.attach = acpi_lpss_create_device,
	.bind = acpi_lpss_bind,
	.unbind = acpi_lpss_unbind,
};

void __init acpi_lpss_init(void)
{
	if (!lpt_clk_init()) {
		bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
		acpi_scan_add_handler(&lpss_handler);
	}
}

#else

static struct acpi_scan_handler lpss_handler = {
	.ids = acpi_lpss_device_ids,
};

void __init acpi_lpss_init(void)
{
	acpi_scan_add_handler(&lpss_handler);
}

#endif /* CONFIG_X86_INTEL_LPSS */