xref: /openbmc/linux/drivers/acpi/acpi_lpss.c (revision 92a2c6b2)
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/clk.h>
15 #include <linux/clkdev.h>
16 #include <linux/clk-provider.h>
17 #include <linux/err.h>
18 #include <linux/io.h>
19 #include <linux/platform_device.h>
20 #include <linux/platform_data/clk-lpss.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/delay.h>
23 
24 #include "internal.h"
25 
26 ACPI_MODULE_NAME("acpi_lpss");
27 
28 #ifdef CONFIG_X86_INTEL_LPSS
29 
30 #define LPSS_ADDR(desc) ((unsigned long)&desc)
31 
32 #define LPSS_CLK_SIZE	0x04
33 #define LPSS_LTR_SIZE	0x18
34 
35 /* Offsets relative to LPSS_PRIVATE_OFFSET */
36 #define LPSS_CLK_DIVIDER_DEF_MASK	(BIT(1) | BIT(16))
37 #define LPSS_RESETS			0x04
38 #define LPSS_RESETS_RESET_FUNC		BIT(0)
39 #define LPSS_RESETS_RESET_APB		BIT(1)
40 #define LPSS_GENERAL			0x08
41 #define LPSS_GENERAL_LTR_MODE_SW	BIT(2)
42 #define LPSS_GENERAL_UART_RTS_OVRD	BIT(3)
43 #define LPSS_SW_LTR			0x10
44 #define LPSS_AUTO_LTR			0x14
45 #define LPSS_LTR_SNOOP_REQ		BIT(15)
46 #define LPSS_LTR_SNOOP_MASK		0x0000FFFF
47 #define LPSS_LTR_SNOOP_LAT_1US		0x800
48 #define LPSS_LTR_SNOOP_LAT_32US		0xC00
49 #define LPSS_LTR_SNOOP_LAT_SHIFT	5
50 #define LPSS_LTR_SNOOP_LAT_CUTOFF	3000
51 #define LPSS_LTR_MAX_VAL		0x3FF
52 #define LPSS_TX_INT			0x20
53 #define LPSS_TX_INT_MASK		BIT(1)
54 
55 #define LPSS_PRV_REG_COUNT		9
56 
57 /* LPSS Flags */
58 #define LPSS_CLK			BIT(0)
59 #define LPSS_CLK_GATE			BIT(1)
60 #define LPSS_CLK_DIVIDER		BIT(2)
61 #define LPSS_LTR			BIT(3)
62 #define LPSS_SAVE_CTX			BIT(4)
63 
64 struct lpss_private_data;
65 
66 struct lpss_device_desc {
67 	unsigned int flags;
68 	unsigned int prv_offset;
69 	size_t prv_size_override;
70 	void (*setup)(struct lpss_private_data *pdata);
71 };
72 
73 static struct lpss_device_desc lpss_dma_desc = {
74 	.flags = LPSS_CLK,
75 };
76 
77 struct lpss_private_data {
78 	void __iomem *mmio_base;
79 	resource_size_t mmio_size;
80 	unsigned int fixed_clk_rate;
81 	struct clk *clk;
82 	const struct lpss_device_desc *dev_desc;
83 	u32 prv_reg_ctx[LPSS_PRV_REG_COUNT];
84 };
85 
86 /* UART Component Parameter Register */
87 #define LPSS_UART_CPR			0xF4
88 #define LPSS_UART_CPR_AFCE		BIT(4)
89 
90 static void lpss_uart_setup(struct lpss_private_data *pdata)
91 {
92 	unsigned int offset;
93 	u32 val;
94 
95 	offset = pdata->dev_desc->prv_offset + LPSS_TX_INT;
96 	val = readl(pdata->mmio_base + offset);
97 	writel(val | LPSS_TX_INT_MASK, pdata->mmio_base + offset);
98 
99 	val = readl(pdata->mmio_base + LPSS_UART_CPR);
100 	if (!(val & LPSS_UART_CPR_AFCE)) {
101 		offset = pdata->dev_desc->prv_offset + LPSS_GENERAL;
102 		val = readl(pdata->mmio_base + offset);
103 		val |= LPSS_GENERAL_UART_RTS_OVRD;
104 		writel(val, pdata->mmio_base + offset);
105 	}
106 }
107 
108 static void lpss_deassert_reset(struct lpss_private_data *pdata)
109 {
110 	unsigned int offset;
111 	u32 val;
112 
113 	offset = pdata->dev_desc->prv_offset + LPSS_RESETS;
114 	val = readl(pdata->mmio_base + offset);
115 	val |= LPSS_RESETS_RESET_APB | LPSS_RESETS_RESET_FUNC;
116 	writel(val, pdata->mmio_base + offset);
117 }
118 
119 #define LPSS_I2C_ENABLE			0x6c
120 
121 static void byt_i2c_setup(struct lpss_private_data *pdata)
122 {
123 	lpss_deassert_reset(pdata);
124 
125 	if (readl(pdata->mmio_base + pdata->dev_desc->prv_offset))
126 		pdata->fixed_clk_rate = 133000000;
127 
128 	writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
129 }
130 
131 static struct lpss_device_desc lpt_dev_desc = {
132 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
133 	.prv_offset = 0x800,
134 };
135 
136 static struct lpss_device_desc lpt_i2c_dev_desc = {
137 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_LTR,
138 	.prv_offset = 0x800,
139 };
140 
141 static struct lpss_device_desc lpt_uart_dev_desc = {
142 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
143 	.prv_offset = 0x800,
144 	.setup = lpss_uart_setup,
145 };
146 
147 static struct lpss_device_desc lpt_sdio_dev_desc = {
148 	.flags = LPSS_LTR,
149 	.prv_offset = 0x1000,
150 	.prv_size_override = 0x1018,
151 };
152 
153 static struct lpss_device_desc byt_pwm_dev_desc = {
154 	.flags = LPSS_SAVE_CTX,
155 };
156 
157 static struct lpss_device_desc byt_uart_dev_desc = {
158 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
159 	.prv_offset = 0x800,
160 	.setup = lpss_uart_setup,
161 };
162 
163 static struct lpss_device_desc byt_spi_dev_desc = {
164 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
165 	.prv_offset = 0x400,
166 };
167 
168 static struct lpss_device_desc byt_sdio_dev_desc = {
169 	.flags = LPSS_CLK,
170 };
171 
172 static struct lpss_device_desc byt_i2c_dev_desc = {
173 	.flags = LPSS_CLK | LPSS_SAVE_CTX,
174 	.prv_offset = 0x800,
175 	.setup = byt_i2c_setup,
176 };
177 
178 static struct lpss_device_desc bsw_spi_dev_desc = {
179 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
180 	.prv_offset = 0x400,
181 	.setup = lpss_deassert_reset,
182 };
183 
184 #else
185 
186 #define LPSS_ADDR(desc) (0UL)
187 
188 #endif /* CONFIG_X86_INTEL_LPSS */
189 
190 static const struct acpi_device_id acpi_lpss_device_ids[] = {
191 	/* Generic LPSS devices */
192 	{ "INTL9C60", LPSS_ADDR(lpss_dma_desc) },
193 
194 	/* Lynxpoint LPSS devices */
195 	{ "INT33C0", LPSS_ADDR(lpt_dev_desc) },
196 	{ "INT33C1", LPSS_ADDR(lpt_dev_desc) },
197 	{ "INT33C2", LPSS_ADDR(lpt_i2c_dev_desc) },
198 	{ "INT33C3", LPSS_ADDR(lpt_i2c_dev_desc) },
199 	{ "INT33C4", LPSS_ADDR(lpt_uart_dev_desc) },
200 	{ "INT33C5", LPSS_ADDR(lpt_uart_dev_desc) },
201 	{ "INT33C6", LPSS_ADDR(lpt_sdio_dev_desc) },
202 	{ "INT33C7", },
203 
204 	/* BayTrail LPSS devices */
205 	{ "80860F09", LPSS_ADDR(byt_pwm_dev_desc) },
206 	{ "80860F0A", LPSS_ADDR(byt_uart_dev_desc) },
207 	{ "80860F0E", LPSS_ADDR(byt_spi_dev_desc) },
208 	{ "80860F14", LPSS_ADDR(byt_sdio_dev_desc) },
209 	{ "80860F41", LPSS_ADDR(byt_i2c_dev_desc) },
210 	{ "INT33B2", },
211 	{ "INT33FC", },
212 
213 	/* Braswell LPSS devices */
214 	{ "80862288", LPSS_ADDR(byt_pwm_dev_desc) },
215 	{ "8086228A", LPSS_ADDR(byt_uart_dev_desc) },
216 	{ "8086228E", LPSS_ADDR(bsw_spi_dev_desc) },
217 	{ "808622C1", LPSS_ADDR(byt_i2c_dev_desc) },
218 
219 	{ "INT3430", LPSS_ADDR(lpt_dev_desc) },
220 	{ "INT3431", LPSS_ADDR(lpt_dev_desc) },
221 	{ "INT3432", LPSS_ADDR(lpt_i2c_dev_desc) },
222 	{ "INT3433", LPSS_ADDR(lpt_i2c_dev_desc) },
223 	{ "INT3434", LPSS_ADDR(lpt_uart_dev_desc) },
224 	{ "INT3435", LPSS_ADDR(lpt_uart_dev_desc) },
225 	{ "INT3436", LPSS_ADDR(lpt_sdio_dev_desc) },
226 	{ "INT3437", },
227 
228 	/* Wildcat Point LPSS devices */
229 	{ "INT3438", LPSS_ADDR(lpt_dev_desc) },
230 
231 	{ }
232 };
233 
234 #ifdef CONFIG_X86_INTEL_LPSS
235 
236 static int is_memory(struct acpi_resource *res, void *not_used)
237 {
238 	struct resource r;
239 	return !acpi_dev_resource_memory(res, &r);
240 }
241 
242 /* LPSS main clock device. */
243 static struct platform_device *lpss_clk_dev;
244 
245 static inline void lpt_register_clock_device(void)
246 {
247 	lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
248 }
249 
250 static int register_device_clock(struct acpi_device *adev,
251 				 struct lpss_private_data *pdata)
252 {
253 	const struct lpss_device_desc *dev_desc = pdata->dev_desc;
254 	const char *devname = dev_name(&adev->dev);
255 	struct clk *clk = ERR_PTR(-ENODEV);
256 	struct lpss_clk_data *clk_data;
257 	const char *parent, *clk_name;
258 	void __iomem *prv_base;
259 
260 	if (!lpss_clk_dev)
261 		lpt_register_clock_device();
262 
263 	clk_data = platform_get_drvdata(lpss_clk_dev);
264 	if (!clk_data)
265 		return -ENODEV;
266 	clk = clk_data->clk;
267 
268 	if (!pdata->mmio_base
269 	    || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
270 		return -ENODATA;
271 
272 	parent = clk_data->name;
273 	prv_base = pdata->mmio_base + dev_desc->prv_offset;
274 
275 	if (pdata->fixed_clk_rate) {
276 		clk = clk_register_fixed_rate(NULL, devname, parent, 0,
277 					      pdata->fixed_clk_rate);
278 		goto out;
279 	}
280 
281 	if (dev_desc->flags & LPSS_CLK_GATE) {
282 		clk = clk_register_gate(NULL, devname, parent, 0,
283 					prv_base, 0, 0, NULL);
284 		parent = devname;
285 	}
286 
287 	if (dev_desc->flags & LPSS_CLK_DIVIDER) {
288 		/* Prevent division by zero */
289 		if (!readl(prv_base))
290 			writel(LPSS_CLK_DIVIDER_DEF_MASK, prv_base);
291 
292 		clk_name = kasprintf(GFP_KERNEL, "%s-div", devname);
293 		if (!clk_name)
294 			return -ENOMEM;
295 		clk = clk_register_fractional_divider(NULL, clk_name, parent,
296 						      0, prv_base,
297 						      1, 15, 16, 15, 0, NULL);
298 		parent = clk_name;
299 
300 		clk_name = kasprintf(GFP_KERNEL, "%s-update", devname);
301 		if (!clk_name) {
302 			kfree(parent);
303 			return -ENOMEM;
304 		}
305 		clk = clk_register_gate(NULL, clk_name, parent,
306 					CLK_SET_RATE_PARENT | CLK_SET_RATE_GATE,
307 					prv_base, 31, 0, NULL);
308 		kfree(parent);
309 		kfree(clk_name);
310 	}
311 out:
312 	if (IS_ERR(clk))
313 		return PTR_ERR(clk);
314 
315 	pdata->clk = clk;
316 	clk_register_clkdev(clk, NULL, devname);
317 	return 0;
318 }
319 
320 static int acpi_lpss_create_device(struct acpi_device *adev,
321 				   const struct acpi_device_id *id)
322 {
323 	struct lpss_device_desc *dev_desc;
324 	struct lpss_private_data *pdata;
325 	struct resource_entry *rentry;
326 	struct list_head resource_list;
327 	struct platform_device *pdev;
328 	int ret;
329 
330 	dev_desc = (struct lpss_device_desc *)id->driver_data;
331 	if (!dev_desc) {
332 		pdev = acpi_create_platform_device(adev);
333 		return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
334 	}
335 	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
336 	if (!pdata)
337 		return -ENOMEM;
338 
339 	INIT_LIST_HEAD(&resource_list);
340 	ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
341 	if (ret < 0)
342 		goto err_out;
343 
344 	list_for_each_entry(rentry, &resource_list, node)
345 		if (resource_type(rentry->res) == IORESOURCE_MEM) {
346 			if (dev_desc->prv_size_override)
347 				pdata->mmio_size = dev_desc->prv_size_override;
348 			else
349 				pdata->mmio_size = resource_size(rentry->res);
350 			pdata->mmio_base = ioremap(rentry->res->start,
351 						   pdata->mmio_size);
352 			if (!pdata->mmio_base)
353 				goto err_out;
354 			break;
355 		}
356 
357 	acpi_dev_free_resource_list(&resource_list);
358 
359 	pdata->dev_desc = dev_desc;
360 
361 	if (dev_desc->setup)
362 		dev_desc->setup(pdata);
363 
364 	if (dev_desc->flags & LPSS_CLK) {
365 		ret = register_device_clock(adev, pdata);
366 		if (ret) {
367 			/* Skip the device, but continue the namespace scan. */
368 			ret = 0;
369 			goto err_out;
370 		}
371 	}
372 
373 	/*
374 	 * This works around a known issue in ACPI tables where LPSS devices
375 	 * have _PS0 and _PS3 without _PSC (and no power resources), so
376 	 * acpi_bus_init_power() will assume that the BIOS has put them into D0.
377 	 */
378 	ret = acpi_device_fix_up_power(adev);
379 	if (ret) {
380 		/* Skip the device, but continue the namespace scan. */
381 		ret = 0;
382 		goto err_out;
383 	}
384 
385 	adev->driver_data = pdata;
386 	pdev = acpi_create_platform_device(adev);
387 	if (!IS_ERR_OR_NULL(pdev)) {
388 		return 1;
389 	}
390 
391 	ret = PTR_ERR(pdev);
392 	adev->driver_data = NULL;
393 
394  err_out:
395 	kfree(pdata);
396 	return ret;
397 }
398 
399 static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
400 {
401 	return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
402 }
403 
404 static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
405 			     unsigned int reg)
406 {
407 	writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
408 }
409 
410 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
411 {
412 	struct acpi_device *adev;
413 	struct lpss_private_data *pdata;
414 	unsigned long flags;
415 	int ret;
416 
417 	ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
418 	if (WARN_ON(ret))
419 		return ret;
420 
421 	spin_lock_irqsave(&dev->power.lock, flags);
422 	if (pm_runtime_suspended(dev)) {
423 		ret = -EAGAIN;
424 		goto out;
425 	}
426 	pdata = acpi_driver_data(adev);
427 	if (WARN_ON(!pdata || !pdata->mmio_base)) {
428 		ret = -ENODEV;
429 		goto out;
430 	}
431 	*val = __lpss_reg_read(pdata, reg);
432 
433  out:
434 	spin_unlock_irqrestore(&dev->power.lock, flags);
435 	return ret;
436 }
437 
438 static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
439 			     char *buf)
440 {
441 	u32 ltr_value = 0;
442 	unsigned int reg;
443 	int ret;
444 
445 	reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
446 	ret = lpss_reg_read(dev, reg, &ltr_value);
447 	if (ret)
448 		return ret;
449 
450 	return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
451 }
452 
453 static ssize_t lpss_ltr_mode_show(struct device *dev,
454 				  struct device_attribute *attr, char *buf)
455 {
456 	u32 ltr_mode = 0;
457 	char *outstr;
458 	int ret;
459 
460 	ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
461 	if (ret)
462 		return ret;
463 
464 	outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
465 	return sprintf(buf, "%s\n", outstr);
466 }
467 
468 static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
469 static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
470 static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
471 
472 static struct attribute *lpss_attrs[] = {
473 	&dev_attr_auto_ltr.attr,
474 	&dev_attr_sw_ltr.attr,
475 	&dev_attr_ltr_mode.attr,
476 	NULL,
477 };
478 
479 static struct attribute_group lpss_attr_group = {
480 	.attrs = lpss_attrs,
481 	.name = "lpss_ltr",
482 };
483 
484 static void acpi_lpss_set_ltr(struct device *dev, s32 val)
485 {
486 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
487 	u32 ltr_mode, ltr_val;
488 
489 	ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
490 	if (val < 0) {
491 		if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
492 			ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
493 			__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
494 		}
495 		return;
496 	}
497 	ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
498 	if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
499 		ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
500 		val = LPSS_LTR_MAX_VAL;
501 	} else if (val > LPSS_LTR_MAX_VAL) {
502 		ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
503 		val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
504 	} else {
505 		ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
506 	}
507 	ltr_val |= val;
508 	__lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
509 	if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
510 		ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
511 		__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
512 	}
513 }
514 
515 #ifdef CONFIG_PM
516 /**
517  * acpi_lpss_save_ctx() - Save the private registers of LPSS device
518  * @dev: LPSS device
519  * @pdata: pointer to the private data of the LPSS device
520  *
521  * Most LPSS devices have private registers which may loose their context when
522  * the device is powered down. acpi_lpss_save_ctx() saves those registers into
523  * prv_reg_ctx array.
524  */
525 static void acpi_lpss_save_ctx(struct device *dev,
526 			       struct lpss_private_data *pdata)
527 {
528 	unsigned int i;
529 
530 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
531 		unsigned long offset = i * sizeof(u32);
532 
533 		pdata->prv_reg_ctx[i] = __lpss_reg_read(pdata, offset);
534 		dev_dbg(dev, "saving 0x%08x from LPSS reg at offset 0x%02lx\n",
535 			pdata->prv_reg_ctx[i], offset);
536 	}
537 }
538 
539 /**
540  * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device
541  * @dev: LPSS device
542  * @pdata: pointer to the private data of the LPSS device
543  *
544  * Restores the registers that were previously stored with acpi_lpss_save_ctx().
545  */
546 static void acpi_lpss_restore_ctx(struct device *dev,
547 				  struct lpss_private_data *pdata)
548 {
549 	unsigned int i;
550 
551 	/*
552 	 * The following delay is needed or the subsequent write operations may
553 	 * fail. The LPSS devices are actually PCI devices and the PCI spec
554 	 * expects 10ms delay before the device can be accessed after D3 to D0
555 	 * transition.
556 	 */
557 	msleep(10);
558 
559 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
560 		unsigned long offset = i * sizeof(u32);
561 
562 		__lpss_reg_write(pdata->prv_reg_ctx[i], pdata, offset);
563 		dev_dbg(dev, "restoring 0x%08x to LPSS reg at offset 0x%02lx\n",
564 			pdata->prv_reg_ctx[i], offset);
565 	}
566 }
567 
568 #ifdef CONFIG_PM_SLEEP
569 static int acpi_lpss_suspend_late(struct device *dev)
570 {
571 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
572 	int ret;
573 
574 	ret = pm_generic_suspend_late(dev);
575 	if (ret)
576 		return ret;
577 
578 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
579 		acpi_lpss_save_ctx(dev, pdata);
580 
581 	return acpi_dev_suspend_late(dev);
582 }
583 
584 static int acpi_lpss_resume_early(struct device *dev)
585 {
586 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
587 	int ret;
588 
589 	ret = acpi_dev_resume_early(dev);
590 	if (ret)
591 		return ret;
592 
593 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
594 		acpi_lpss_restore_ctx(dev, pdata);
595 
596 	return pm_generic_resume_early(dev);
597 }
598 #endif /* CONFIG_PM_SLEEP */
599 
600 static int acpi_lpss_runtime_suspend(struct device *dev)
601 {
602 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
603 	int ret;
604 
605 	ret = pm_generic_runtime_suspend(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_runtime_suspend(dev);
613 }
614 
615 static int acpi_lpss_runtime_resume(struct device *dev)
616 {
617 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
618 	int ret;
619 
620 	ret = acpi_dev_runtime_resume(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_runtime_resume(dev);
628 }
629 #endif /* CONFIG_PM */
630 
631 static struct dev_pm_domain acpi_lpss_pm_domain = {
632 	.ops = {
633 #ifdef CONFIG_PM
634 #ifdef CONFIG_PM_SLEEP
635 		.prepare = acpi_subsys_prepare,
636 		.complete = acpi_subsys_complete,
637 		.suspend = acpi_subsys_suspend,
638 		.suspend_late = acpi_lpss_suspend_late,
639 		.resume_early = acpi_lpss_resume_early,
640 		.freeze = acpi_subsys_freeze,
641 		.poweroff = acpi_subsys_suspend,
642 		.poweroff_late = acpi_lpss_suspend_late,
643 		.restore_early = acpi_lpss_resume_early,
644 #endif
645 		.runtime_suspend = acpi_lpss_runtime_suspend,
646 		.runtime_resume = acpi_lpss_runtime_resume,
647 #endif
648 	},
649 };
650 
651 static int acpi_lpss_platform_notify(struct notifier_block *nb,
652 				     unsigned long action, void *data)
653 {
654 	struct platform_device *pdev = to_platform_device(data);
655 	struct lpss_private_data *pdata;
656 	struct acpi_device *adev;
657 	const struct acpi_device_id *id;
658 
659 	id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
660 	if (!id || !id->driver_data)
661 		return 0;
662 
663 	if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
664 		return 0;
665 
666 	pdata = acpi_driver_data(adev);
667 	if (!pdata)
668 		return 0;
669 
670 	if (pdata->mmio_base &&
671 	    pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
672 		dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
673 		return 0;
674 	}
675 
676 	switch (action) {
677 	case BUS_NOTIFY_ADD_DEVICE:
678 		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
679 		if (pdata->dev_desc->flags & LPSS_LTR)
680 			return sysfs_create_group(&pdev->dev.kobj,
681 						  &lpss_attr_group);
682 		break;
683 	case BUS_NOTIFY_DEL_DEVICE:
684 		if (pdata->dev_desc->flags & LPSS_LTR)
685 			sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
686 		pdev->dev.pm_domain = NULL;
687 		break;
688 	default:
689 		break;
690 	}
691 
692 	return 0;
693 }
694 
695 static struct notifier_block acpi_lpss_nb = {
696 	.notifier_call = acpi_lpss_platform_notify,
697 };
698 
699 static void acpi_lpss_bind(struct device *dev)
700 {
701 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
702 
703 	if (!pdata || !pdata->mmio_base || !(pdata->dev_desc->flags & LPSS_LTR))
704 		return;
705 
706 	if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
707 		dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
708 	else
709 		dev_err(dev, "MMIO size insufficient to access LTR\n");
710 }
711 
712 static void acpi_lpss_unbind(struct device *dev)
713 {
714 	dev->power.set_latency_tolerance = NULL;
715 }
716 
717 static struct acpi_scan_handler lpss_handler = {
718 	.ids = acpi_lpss_device_ids,
719 	.attach = acpi_lpss_create_device,
720 	.bind = acpi_lpss_bind,
721 	.unbind = acpi_lpss_unbind,
722 };
723 
724 void __init acpi_lpss_init(void)
725 {
726 	if (!lpt_clk_init()) {
727 		bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
728 		acpi_scan_add_handler(&lpss_handler);
729 	}
730 }
731 
732 #else
733 
734 static struct acpi_scan_handler lpss_handler = {
735 	.ids = acpi_lpss_device_ids,
736 };
737 
738 void __init acpi_lpss_init(void)
739 {
740 	acpi_scan_add_handler(&lpss_handler);
741 }
742 
743 #endif /* CONFIG_X86_INTEL_LPSS */
744