xref: /openbmc/linux/drivers/acpi/acpi_lpss.c (revision 2c684d89)
1 /*
2  * ACPI support for Intel Lynxpoint LPSS.
3  *
4  * Copyright (C) 2013, Intel Corporation
5  * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
6  *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 
13 #include <linux/acpi.h>
14 #include <linux/clkdev.h>
15 #include <linux/clk-provider.h>
16 #include <linux/err.h>
17 #include <linux/io.h>
18 #include <linux/platform_device.h>
19 #include <linux/platform_data/clk-lpss.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/delay.h>
22 
23 #include "internal.h"
24 
25 ACPI_MODULE_NAME("acpi_lpss");
26 
27 #ifdef CONFIG_X86_INTEL_LPSS
28 
29 #define LPSS_ADDR(desc) ((unsigned long)&desc)
30 
31 #define LPSS_CLK_SIZE	0x04
32 #define LPSS_LTR_SIZE	0x18
33 
34 /* Offsets relative to LPSS_PRIVATE_OFFSET */
35 #define LPSS_CLK_DIVIDER_DEF_MASK	(BIT(1) | BIT(16))
36 #define LPSS_RESETS			0x04
37 #define LPSS_RESETS_RESET_FUNC		BIT(0)
38 #define LPSS_RESETS_RESET_APB		BIT(1)
39 #define LPSS_GENERAL			0x08
40 #define LPSS_GENERAL_LTR_MODE_SW	BIT(2)
41 #define LPSS_GENERAL_UART_RTS_OVRD	BIT(3)
42 #define LPSS_SW_LTR			0x10
43 #define LPSS_AUTO_LTR			0x14
44 #define LPSS_LTR_SNOOP_REQ		BIT(15)
45 #define LPSS_LTR_SNOOP_MASK		0x0000FFFF
46 #define LPSS_LTR_SNOOP_LAT_1US		0x800
47 #define LPSS_LTR_SNOOP_LAT_32US		0xC00
48 #define LPSS_LTR_SNOOP_LAT_SHIFT	5
49 #define LPSS_LTR_SNOOP_LAT_CUTOFF	3000
50 #define LPSS_LTR_MAX_VAL		0x3FF
51 #define LPSS_TX_INT			0x20
52 #define LPSS_TX_INT_MASK		BIT(1)
53 
54 #define LPSS_PRV_REG_COUNT		9
55 
56 /* LPSS Flags */
57 #define LPSS_CLK			BIT(0)
58 #define LPSS_CLK_GATE			BIT(1)
59 #define LPSS_CLK_DIVIDER		BIT(2)
60 #define LPSS_LTR			BIT(3)
61 #define LPSS_SAVE_CTX			BIT(4)
62 #define LPSS_NO_D3_DELAY		BIT(5)
63 
64 struct lpss_private_data;
65 
66 struct lpss_device_desc {
67 	unsigned int flags;
68 	const char *clk_con_id;
69 	unsigned int prv_offset;
70 	size_t prv_size_override;
71 	void (*setup)(struct lpss_private_data *pdata);
72 };
73 
74 static struct lpss_device_desc lpss_dma_desc = {
75 	.flags = LPSS_CLK,
76 };
77 
78 struct lpss_private_data {
79 	void __iomem *mmio_base;
80 	resource_size_t mmio_size;
81 	unsigned int fixed_clk_rate;
82 	struct clk *clk;
83 	const struct lpss_device_desc *dev_desc;
84 	u32 prv_reg_ctx[LPSS_PRV_REG_COUNT];
85 };
86 
87 /* UART Component Parameter Register */
88 #define LPSS_UART_CPR			0xF4
89 #define LPSS_UART_CPR_AFCE		BIT(4)
90 
91 static void lpss_uart_setup(struct lpss_private_data *pdata)
92 {
93 	unsigned int offset;
94 	u32 val;
95 
96 	offset = pdata->dev_desc->prv_offset + LPSS_TX_INT;
97 	val = readl(pdata->mmio_base + offset);
98 	writel(val | LPSS_TX_INT_MASK, pdata->mmio_base + offset);
99 
100 	val = readl(pdata->mmio_base + LPSS_UART_CPR);
101 	if (!(val & LPSS_UART_CPR_AFCE)) {
102 		offset = pdata->dev_desc->prv_offset + LPSS_GENERAL;
103 		val = readl(pdata->mmio_base + offset);
104 		val |= LPSS_GENERAL_UART_RTS_OVRD;
105 		writel(val, pdata->mmio_base + offset);
106 	}
107 }
108 
109 static void lpss_deassert_reset(struct lpss_private_data *pdata)
110 {
111 	unsigned int offset;
112 	u32 val;
113 
114 	offset = pdata->dev_desc->prv_offset + LPSS_RESETS;
115 	val = readl(pdata->mmio_base + offset);
116 	val |= LPSS_RESETS_RESET_APB | LPSS_RESETS_RESET_FUNC;
117 	writel(val, pdata->mmio_base + offset);
118 }
119 
120 #define LPSS_I2C_ENABLE			0x6c
121 
122 static void byt_i2c_setup(struct lpss_private_data *pdata)
123 {
124 	lpss_deassert_reset(pdata);
125 
126 	if (readl(pdata->mmio_base + pdata->dev_desc->prv_offset))
127 		pdata->fixed_clk_rate = 133000000;
128 
129 	writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
130 }
131 
132 static const struct lpss_device_desc lpt_dev_desc = {
133 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
134 	.prv_offset = 0x800,
135 };
136 
137 static const struct lpss_device_desc lpt_i2c_dev_desc = {
138 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_LTR,
139 	.prv_offset = 0x800,
140 };
141 
142 static const struct lpss_device_desc lpt_uart_dev_desc = {
143 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
144 	.clk_con_id = "baudclk",
145 	.prv_offset = 0x800,
146 	.setup = lpss_uart_setup,
147 };
148 
149 static const struct lpss_device_desc lpt_sdio_dev_desc = {
150 	.flags = LPSS_LTR,
151 	.prv_offset = 0x1000,
152 	.prv_size_override = 0x1018,
153 };
154 
155 static const struct lpss_device_desc byt_pwm_dev_desc = {
156 	.flags = LPSS_SAVE_CTX,
157 };
158 
159 static const struct lpss_device_desc bsw_pwm_dev_desc = {
160 	.flags = LPSS_SAVE_CTX | LPSS_NO_D3_DELAY,
161 };
162 
163 static const struct lpss_device_desc byt_uart_dev_desc = {
164 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
165 	.clk_con_id = "baudclk",
166 	.prv_offset = 0x800,
167 	.setup = lpss_uart_setup,
168 };
169 
170 static const struct lpss_device_desc bsw_uart_dev_desc = {
171 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX
172 			| LPSS_NO_D3_DELAY,
173 	.clk_con_id = "baudclk",
174 	.prv_offset = 0x800,
175 	.setup = lpss_uart_setup,
176 };
177 
178 static const struct lpss_device_desc byt_spi_dev_desc = {
179 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
180 	.prv_offset = 0x400,
181 };
182 
183 static const struct lpss_device_desc byt_sdio_dev_desc = {
184 	.flags = LPSS_CLK,
185 };
186 
187 static const struct lpss_device_desc byt_i2c_dev_desc = {
188 	.flags = LPSS_CLK | LPSS_SAVE_CTX,
189 	.prv_offset = 0x800,
190 	.setup = byt_i2c_setup,
191 };
192 
193 static const struct lpss_device_desc bsw_i2c_dev_desc = {
194 	.flags = LPSS_CLK | LPSS_SAVE_CTX | LPSS_NO_D3_DELAY,
195 	.prv_offset = 0x800,
196 	.setup = byt_i2c_setup,
197 };
198 
199 static struct lpss_device_desc bsw_spi_dev_desc = {
200 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX
201 			| LPSS_NO_D3_DELAY,
202 	.prv_offset = 0x400,
203 	.setup = lpss_deassert_reset,
204 };
205 
206 #else
207 
208 #define LPSS_ADDR(desc) (0UL)
209 
210 #endif /* CONFIG_X86_INTEL_LPSS */
211 
212 static const struct acpi_device_id acpi_lpss_device_ids[] = {
213 	/* Generic LPSS devices */
214 	{ "INTL9C60", LPSS_ADDR(lpss_dma_desc) },
215 
216 	/* Lynxpoint LPSS devices */
217 	{ "INT33C0", LPSS_ADDR(lpt_dev_desc) },
218 	{ "INT33C1", LPSS_ADDR(lpt_dev_desc) },
219 	{ "INT33C2", LPSS_ADDR(lpt_i2c_dev_desc) },
220 	{ "INT33C3", LPSS_ADDR(lpt_i2c_dev_desc) },
221 	{ "INT33C4", LPSS_ADDR(lpt_uart_dev_desc) },
222 	{ "INT33C5", LPSS_ADDR(lpt_uart_dev_desc) },
223 	{ "INT33C6", LPSS_ADDR(lpt_sdio_dev_desc) },
224 	{ "INT33C7", },
225 
226 	/* BayTrail LPSS devices */
227 	{ "80860F09", LPSS_ADDR(byt_pwm_dev_desc) },
228 	{ "80860F0A", LPSS_ADDR(byt_uart_dev_desc) },
229 	{ "80860F0E", LPSS_ADDR(byt_spi_dev_desc) },
230 	{ "80860F14", LPSS_ADDR(byt_sdio_dev_desc) },
231 	{ "80860F41", LPSS_ADDR(byt_i2c_dev_desc) },
232 	{ "INT33B2", },
233 	{ "INT33FC", },
234 
235 	/* Braswell LPSS devices */
236 	{ "80862288", LPSS_ADDR(bsw_pwm_dev_desc) },
237 	{ "8086228A", LPSS_ADDR(bsw_uart_dev_desc) },
238 	{ "8086228E", LPSS_ADDR(bsw_spi_dev_desc) },
239 	{ "808622C1", LPSS_ADDR(bsw_i2c_dev_desc) },
240 
241 	/* Broadwell LPSS devices */
242 	{ "INT3430", LPSS_ADDR(lpt_dev_desc) },
243 	{ "INT3431", LPSS_ADDR(lpt_dev_desc) },
244 	{ "INT3432", LPSS_ADDR(lpt_i2c_dev_desc) },
245 	{ "INT3433", LPSS_ADDR(lpt_i2c_dev_desc) },
246 	{ "INT3434", LPSS_ADDR(lpt_uart_dev_desc) },
247 	{ "INT3435", LPSS_ADDR(lpt_uart_dev_desc) },
248 	{ "INT3436", LPSS_ADDR(lpt_sdio_dev_desc) },
249 	{ "INT3437", },
250 
251 	/* Wildcat Point LPSS devices */
252 	{ "INT3438", LPSS_ADDR(lpt_dev_desc) },
253 
254 	{ }
255 };
256 
257 #ifdef CONFIG_X86_INTEL_LPSS
258 
259 static int is_memory(struct acpi_resource *res, void *not_used)
260 {
261 	struct resource r;
262 	return !acpi_dev_resource_memory(res, &r);
263 }
264 
265 /* LPSS main clock device. */
266 static struct platform_device *lpss_clk_dev;
267 
268 static inline void lpt_register_clock_device(void)
269 {
270 	lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
271 }
272 
273 static int register_device_clock(struct acpi_device *adev,
274 				 struct lpss_private_data *pdata)
275 {
276 	const struct lpss_device_desc *dev_desc = pdata->dev_desc;
277 	const char *devname = dev_name(&adev->dev);
278 	struct clk *clk = ERR_PTR(-ENODEV);
279 	struct lpss_clk_data *clk_data;
280 	const char *parent, *clk_name;
281 	void __iomem *prv_base;
282 
283 	if (!lpss_clk_dev)
284 		lpt_register_clock_device();
285 
286 	clk_data = platform_get_drvdata(lpss_clk_dev);
287 	if (!clk_data)
288 		return -ENODEV;
289 	clk = clk_data->clk;
290 
291 	if (!pdata->mmio_base
292 	    || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
293 		return -ENODATA;
294 
295 	parent = clk_data->name;
296 	prv_base = pdata->mmio_base + dev_desc->prv_offset;
297 
298 	if (pdata->fixed_clk_rate) {
299 		clk = clk_register_fixed_rate(NULL, devname, parent, 0,
300 					      pdata->fixed_clk_rate);
301 		goto out;
302 	}
303 
304 	if (dev_desc->flags & LPSS_CLK_GATE) {
305 		clk = clk_register_gate(NULL, devname, parent, 0,
306 					prv_base, 0, 0, NULL);
307 		parent = devname;
308 	}
309 
310 	if (dev_desc->flags & LPSS_CLK_DIVIDER) {
311 		/* Prevent division by zero */
312 		if (!readl(prv_base))
313 			writel(LPSS_CLK_DIVIDER_DEF_MASK, prv_base);
314 
315 		clk_name = kasprintf(GFP_KERNEL, "%s-div", devname);
316 		if (!clk_name)
317 			return -ENOMEM;
318 		clk = clk_register_fractional_divider(NULL, clk_name, parent,
319 						      0, prv_base,
320 						      1, 15, 16, 15, 0, NULL);
321 		parent = clk_name;
322 
323 		clk_name = kasprintf(GFP_KERNEL, "%s-update", devname);
324 		if (!clk_name) {
325 			kfree(parent);
326 			return -ENOMEM;
327 		}
328 		clk = clk_register_gate(NULL, clk_name, parent,
329 					CLK_SET_RATE_PARENT | CLK_SET_RATE_GATE,
330 					prv_base, 31, 0, NULL);
331 		kfree(parent);
332 		kfree(clk_name);
333 	}
334 out:
335 	if (IS_ERR(clk))
336 		return PTR_ERR(clk);
337 
338 	pdata->clk = clk;
339 	clk_register_clkdev(clk, dev_desc->clk_con_id, devname);
340 	return 0;
341 }
342 
343 static int acpi_lpss_create_device(struct acpi_device *adev,
344 				   const struct acpi_device_id *id)
345 {
346 	const struct lpss_device_desc *dev_desc;
347 	struct lpss_private_data *pdata;
348 	struct resource_entry *rentry;
349 	struct list_head resource_list;
350 	struct platform_device *pdev;
351 	int ret;
352 
353 	dev_desc = (const struct lpss_device_desc *)id->driver_data;
354 	if (!dev_desc) {
355 		pdev = acpi_create_platform_device(adev);
356 		return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
357 	}
358 	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
359 	if (!pdata)
360 		return -ENOMEM;
361 
362 	INIT_LIST_HEAD(&resource_list);
363 	ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
364 	if (ret < 0)
365 		goto err_out;
366 
367 	list_for_each_entry(rentry, &resource_list, node)
368 		if (resource_type(rentry->res) == IORESOURCE_MEM) {
369 			if (dev_desc->prv_size_override)
370 				pdata->mmio_size = dev_desc->prv_size_override;
371 			else
372 				pdata->mmio_size = resource_size(rentry->res);
373 			pdata->mmio_base = ioremap(rentry->res->start,
374 						   pdata->mmio_size);
375 			break;
376 		}
377 
378 	acpi_dev_free_resource_list(&resource_list);
379 
380 	if (!pdata->mmio_base) {
381 		ret = -ENOMEM;
382 		goto err_out;
383 	}
384 
385 	pdata->dev_desc = dev_desc;
386 
387 	if (dev_desc->setup)
388 		dev_desc->setup(pdata);
389 
390 	if (dev_desc->flags & LPSS_CLK) {
391 		ret = register_device_clock(adev, pdata);
392 		if (ret) {
393 			/* Skip the device, but continue the namespace scan. */
394 			ret = 0;
395 			goto err_out;
396 		}
397 	}
398 
399 	/*
400 	 * This works around a known issue in ACPI tables where LPSS devices
401 	 * have _PS0 and _PS3 without _PSC (and no power resources), so
402 	 * acpi_bus_init_power() will assume that the BIOS has put them into D0.
403 	 */
404 	ret = acpi_device_fix_up_power(adev);
405 	if (ret) {
406 		/* Skip the device, but continue the namespace scan. */
407 		ret = 0;
408 		goto err_out;
409 	}
410 
411 	adev->driver_data = pdata;
412 	pdev = acpi_create_platform_device(adev);
413 	if (!IS_ERR_OR_NULL(pdev)) {
414 		return 1;
415 	}
416 
417 	ret = PTR_ERR(pdev);
418 	adev->driver_data = NULL;
419 
420  err_out:
421 	kfree(pdata);
422 	return ret;
423 }
424 
425 static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
426 {
427 	return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
428 }
429 
430 static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
431 			     unsigned int reg)
432 {
433 	writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
434 }
435 
436 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
437 {
438 	struct acpi_device *adev;
439 	struct lpss_private_data *pdata;
440 	unsigned long flags;
441 	int ret;
442 
443 	ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
444 	if (WARN_ON(ret))
445 		return ret;
446 
447 	spin_lock_irqsave(&dev->power.lock, flags);
448 	if (pm_runtime_suspended(dev)) {
449 		ret = -EAGAIN;
450 		goto out;
451 	}
452 	pdata = acpi_driver_data(adev);
453 	if (WARN_ON(!pdata || !pdata->mmio_base)) {
454 		ret = -ENODEV;
455 		goto out;
456 	}
457 	*val = __lpss_reg_read(pdata, reg);
458 
459  out:
460 	spin_unlock_irqrestore(&dev->power.lock, flags);
461 	return ret;
462 }
463 
464 static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
465 			     char *buf)
466 {
467 	u32 ltr_value = 0;
468 	unsigned int reg;
469 	int ret;
470 
471 	reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
472 	ret = lpss_reg_read(dev, reg, &ltr_value);
473 	if (ret)
474 		return ret;
475 
476 	return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
477 }
478 
479 static ssize_t lpss_ltr_mode_show(struct device *dev,
480 				  struct device_attribute *attr, char *buf)
481 {
482 	u32 ltr_mode = 0;
483 	char *outstr;
484 	int ret;
485 
486 	ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
487 	if (ret)
488 		return ret;
489 
490 	outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
491 	return sprintf(buf, "%s\n", outstr);
492 }
493 
494 static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
495 static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
496 static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
497 
498 static struct attribute *lpss_attrs[] = {
499 	&dev_attr_auto_ltr.attr,
500 	&dev_attr_sw_ltr.attr,
501 	&dev_attr_ltr_mode.attr,
502 	NULL,
503 };
504 
505 static struct attribute_group lpss_attr_group = {
506 	.attrs = lpss_attrs,
507 	.name = "lpss_ltr",
508 };
509 
510 static void acpi_lpss_set_ltr(struct device *dev, s32 val)
511 {
512 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
513 	u32 ltr_mode, ltr_val;
514 
515 	ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
516 	if (val < 0) {
517 		if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
518 			ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
519 			__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
520 		}
521 		return;
522 	}
523 	ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
524 	if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
525 		ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
526 		val = LPSS_LTR_MAX_VAL;
527 	} else if (val > LPSS_LTR_MAX_VAL) {
528 		ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
529 		val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
530 	} else {
531 		ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
532 	}
533 	ltr_val |= val;
534 	__lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
535 	if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
536 		ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
537 		__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
538 	}
539 }
540 
541 #ifdef CONFIG_PM
542 /**
543  * acpi_lpss_save_ctx() - Save the private registers of LPSS device
544  * @dev: LPSS device
545  * @pdata: pointer to the private data of the LPSS device
546  *
547  * Most LPSS devices have private registers which may loose their context when
548  * the device is powered down. acpi_lpss_save_ctx() saves those registers into
549  * prv_reg_ctx array.
550  */
551 static void acpi_lpss_save_ctx(struct device *dev,
552 			       struct lpss_private_data *pdata)
553 {
554 	unsigned int i;
555 
556 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
557 		unsigned long offset = i * sizeof(u32);
558 
559 		pdata->prv_reg_ctx[i] = __lpss_reg_read(pdata, offset);
560 		dev_dbg(dev, "saving 0x%08x from LPSS reg at offset 0x%02lx\n",
561 			pdata->prv_reg_ctx[i], offset);
562 	}
563 }
564 
565 /**
566  * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device
567  * @dev: LPSS device
568  * @pdata: pointer to the private data of the LPSS device
569  *
570  * Restores the registers that were previously stored with acpi_lpss_save_ctx().
571  */
572 static void acpi_lpss_restore_ctx(struct device *dev,
573 				  struct lpss_private_data *pdata)
574 {
575 	unsigned int i;
576 
577 	/*
578 	 * The following delay is needed or the subsequent write operations may
579 	 * fail. The LPSS devices are actually PCI devices and the PCI spec
580 	 * expects 10ms delay before the device can be accessed after D3 to D0
581 	 * transition. However some platforms like BSW does not need this delay.
582 	 */
583 	unsigned int delay = 10;	/* default 10ms delay */
584 
585 	if (pdata->dev_desc->flags & LPSS_NO_D3_DELAY)
586 		delay = 0;
587 
588 	msleep(delay);
589 
590 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
591 		unsigned long offset = i * sizeof(u32);
592 
593 		__lpss_reg_write(pdata->prv_reg_ctx[i], pdata, offset);
594 		dev_dbg(dev, "restoring 0x%08x to LPSS reg at offset 0x%02lx\n",
595 			pdata->prv_reg_ctx[i], offset);
596 	}
597 }
598 
599 #ifdef CONFIG_PM_SLEEP
600 static int acpi_lpss_suspend_late(struct device *dev)
601 {
602 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
603 	int ret;
604 
605 	ret = pm_generic_suspend_late(dev);
606 	if (ret)
607 		return ret;
608 
609 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
610 		acpi_lpss_save_ctx(dev, pdata);
611 
612 	return acpi_dev_suspend_late(dev);
613 }
614 
615 static int acpi_lpss_resume_early(struct device *dev)
616 {
617 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
618 	int ret;
619 
620 	ret = acpi_dev_resume_early(dev);
621 	if (ret)
622 		return ret;
623 
624 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
625 		acpi_lpss_restore_ctx(dev, pdata);
626 
627 	return pm_generic_resume_early(dev);
628 }
629 #endif /* CONFIG_PM_SLEEP */
630 
631 static int acpi_lpss_runtime_suspend(struct device *dev)
632 {
633 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
634 	int ret;
635 
636 	ret = pm_generic_runtime_suspend(dev);
637 	if (ret)
638 		return ret;
639 
640 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
641 		acpi_lpss_save_ctx(dev, pdata);
642 
643 	return acpi_dev_runtime_suspend(dev);
644 }
645 
646 static int acpi_lpss_runtime_resume(struct device *dev)
647 {
648 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
649 	int ret;
650 
651 	ret = acpi_dev_runtime_resume(dev);
652 	if (ret)
653 		return ret;
654 
655 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
656 		acpi_lpss_restore_ctx(dev, pdata);
657 
658 	return pm_generic_runtime_resume(dev);
659 }
660 #endif /* CONFIG_PM */
661 
662 static struct dev_pm_domain acpi_lpss_pm_domain = {
663 	.ops = {
664 #ifdef CONFIG_PM
665 #ifdef CONFIG_PM_SLEEP
666 		.prepare = acpi_subsys_prepare,
667 		.complete = pm_complete_with_resume_check,
668 		.suspend = acpi_subsys_suspend,
669 		.suspend_late = acpi_lpss_suspend_late,
670 		.resume_early = acpi_lpss_resume_early,
671 		.freeze = acpi_subsys_freeze,
672 		.poweroff = acpi_subsys_suspend,
673 		.poweroff_late = acpi_lpss_suspend_late,
674 		.restore_early = acpi_lpss_resume_early,
675 #endif
676 		.runtime_suspend = acpi_lpss_runtime_suspend,
677 		.runtime_resume = acpi_lpss_runtime_resume,
678 #endif
679 	},
680 };
681 
682 static int acpi_lpss_platform_notify(struct notifier_block *nb,
683 				     unsigned long action, void *data)
684 {
685 	struct platform_device *pdev = to_platform_device(data);
686 	struct lpss_private_data *pdata;
687 	struct acpi_device *adev;
688 	const struct acpi_device_id *id;
689 
690 	id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
691 	if (!id || !id->driver_data)
692 		return 0;
693 
694 	if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
695 		return 0;
696 
697 	pdata = acpi_driver_data(adev);
698 	if (!pdata)
699 		return 0;
700 
701 	if (pdata->mmio_base &&
702 	    pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
703 		dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
704 		return 0;
705 	}
706 
707 	switch (action) {
708 	case BUS_NOTIFY_ADD_DEVICE:
709 		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
710 		if (pdata->dev_desc->flags & LPSS_LTR)
711 			return sysfs_create_group(&pdev->dev.kobj,
712 						  &lpss_attr_group);
713 		break;
714 	case BUS_NOTIFY_DEL_DEVICE:
715 		if (pdata->dev_desc->flags & LPSS_LTR)
716 			sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
717 		pdev->dev.pm_domain = NULL;
718 		break;
719 	default:
720 		break;
721 	}
722 
723 	return 0;
724 }
725 
726 static struct notifier_block acpi_lpss_nb = {
727 	.notifier_call = acpi_lpss_platform_notify,
728 };
729 
730 static void acpi_lpss_bind(struct device *dev)
731 {
732 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
733 
734 	if (!pdata || !pdata->mmio_base || !(pdata->dev_desc->flags & LPSS_LTR))
735 		return;
736 
737 	if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
738 		dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
739 	else
740 		dev_err(dev, "MMIO size insufficient to access LTR\n");
741 }
742 
743 static void acpi_lpss_unbind(struct device *dev)
744 {
745 	dev->power.set_latency_tolerance = NULL;
746 }
747 
748 static struct acpi_scan_handler lpss_handler = {
749 	.ids = acpi_lpss_device_ids,
750 	.attach = acpi_lpss_create_device,
751 	.bind = acpi_lpss_bind,
752 	.unbind = acpi_lpss_unbind,
753 };
754 
755 void __init acpi_lpss_init(void)
756 {
757 	if (!lpt_clk_init()) {
758 		bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
759 		acpi_scan_add_handler(&lpss_handler);
760 	}
761 }
762 
763 #else
764 
765 static struct acpi_scan_handler lpss_handler = {
766 	.ids = acpi_lpss_device_ids,
767 };
768 
769 void __init acpi_lpss_init(void)
770 {
771 	acpi_scan_add_handler(&lpss_handler);
772 }
773 
774 #endif /* CONFIG_X86_INTEL_LPSS */
775