xref: /openbmc/linux/drivers/acpi/acpi_lpss.c (revision 94cdda6b)
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 	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 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 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 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 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 struct lpss_device_desc byt_pwm_dev_desc = {
156 	.flags = LPSS_SAVE_CTX,
157 };
158 
159 static struct lpss_device_desc byt_uart_dev_desc = {
160 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
161 	.clk_con_id = "baudclk",
162 	.prv_offset = 0x800,
163 	.setup = lpss_uart_setup,
164 };
165 
166 static struct lpss_device_desc byt_spi_dev_desc = {
167 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
168 	.prv_offset = 0x400,
169 };
170 
171 static struct lpss_device_desc byt_sdio_dev_desc = {
172 	.flags = LPSS_CLK,
173 };
174 
175 static struct lpss_device_desc byt_i2c_dev_desc = {
176 	.flags = LPSS_CLK | LPSS_SAVE_CTX,
177 	.prv_offset = 0x800,
178 	.setup = byt_i2c_setup,
179 };
180 
181 static struct lpss_device_desc bsw_spi_dev_desc = {
182 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
183 	.prv_offset = 0x400,
184 	.setup = lpss_deassert_reset,
185 };
186 
187 #else
188 
189 #define LPSS_ADDR(desc) (0UL)
190 
191 #endif /* CONFIG_X86_INTEL_LPSS */
192 
193 static const struct acpi_device_id acpi_lpss_device_ids[] = {
194 	/* Generic LPSS devices */
195 	{ "INTL9C60", LPSS_ADDR(lpss_dma_desc) },
196 
197 	/* Lynxpoint LPSS devices */
198 	{ "INT33C0", LPSS_ADDR(lpt_dev_desc) },
199 	{ "INT33C1", LPSS_ADDR(lpt_dev_desc) },
200 	{ "INT33C2", LPSS_ADDR(lpt_i2c_dev_desc) },
201 	{ "INT33C3", LPSS_ADDR(lpt_i2c_dev_desc) },
202 	{ "INT33C4", LPSS_ADDR(lpt_uart_dev_desc) },
203 	{ "INT33C5", LPSS_ADDR(lpt_uart_dev_desc) },
204 	{ "INT33C6", LPSS_ADDR(lpt_sdio_dev_desc) },
205 	{ "INT33C7", },
206 
207 	/* BayTrail LPSS devices */
208 	{ "80860F09", LPSS_ADDR(byt_pwm_dev_desc) },
209 	{ "80860F0A", LPSS_ADDR(byt_uart_dev_desc) },
210 	{ "80860F0E", LPSS_ADDR(byt_spi_dev_desc) },
211 	{ "80860F14", LPSS_ADDR(byt_sdio_dev_desc) },
212 	{ "80860F41", LPSS_ADDR(byt_i2c_dev_desc) },
213 	{ "INT33B2", },
214 	{ "INT33FC", },
215 
216 	/* Braswell LPSS devices */
217 	{ "80862288", LPSS_ADDR(byt_pwm_dev_desc) },
218 	{ "8086228A", LPSS_ADDR(byt_uart_dev_desc) },
219 	{ "8086228E", LPSS_ADDR(bsw_spi_dev_desc) },
220 	{ "808622C1", LPSS_ADDR(byt_i2c_dev_desc) },
221 
222 	{ "INT3430", LPSS_ADDR(lpt_dev_desc) },
223 	{ "INT3431", LPSS_ADDR(lpt_dev_desc) },
224 	{ "INT3432", LPSS_ADDR(lpt_i2c_dev_desc) },
225 	{ "INT3433", LPSS_ADDR(lpt_i2c_dev_desc) },
226 	{ "INT3434", LPSS_ADDR(lpt_uart_dev_desc) },
227 	{ "INT3435", LPSS_ADDR(lpt_uart_dev_desc) },
228 	{ "INT3436", LPSS_ADDR(lpt_sdio_dev_desc) },
229 	{ "INT3437", },
230 
231 	/* Wildcat Point LPSS devices */
232 	{ "INT3438", LPSS_ADDR(lpt_dev_desc) },
233 
234 	{ }
235 };
236 
237 #ifdef CONFIG_X86_INTEL_LPSS
238 
239 static int is_memory(struct acpi_resource *res, void *not_used)
240 {
241 	struct resource r;
242 	return !acpi_dev_resource_memory(res, &r);
243 }
244 
245 /* LPSS main clock device. */
246 static struct platform_device *lpss_clk_dev;
247 
248 static inline void lpt_register_clock_device(void)
249 {
250 	lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
251 }
252 
253 static int register_device_clock(struct acpi_device *adev,
254 				 struct lpss_private_data *pdata)
255 {
256 	const struct lpss_device_desc *dev_desc = pdata->dev_desc;
257 	const char *devname = dev_name(&adev->dev);
258 	struct clk *clk = ERR_PTR(-ENODEV);
259 	struct lpss_clk_data *clk_data;
260 	const char *parent, *clk_name;
261 	void __iomem *prv_base;
262 
263 	if (!lpss_clk_dev)
264 		lpt_register_clock_device();
265 
266 	clk_data = platform_get_drvdata(lpss_clk_dev);
267 	if (!clk_data)
268 		return -ENODEV;
269 	clk = clk_data->clk;
270 
271 	if (!pdata->mmio_base
272 	    || pdata->mmio_size < dev_desc->prv_offset + LPSS_CLK_SIZE)
273 		return -ENODATA;
274 
275 	parent = clk_data->name;
276 	prv_base = pdata->mmio_base + dev_desc->prv_offset;
277 
278 	if (pdata->fixed_clk_rate) {
279 		clk = clk_register_fixed_rate(NULL, devname, parent, 0,
280 					      pdata->fixed_clk_rate);
281 		goto out;
282 	}
283 
284 	if (dev_desc->flags & LPSS_CLK_GATE) {
285 		clk = clk_register_gate(NULL, devname, parent, 0,
286 					prv_base, 0, 0, NULL);
287 		parent = devname;
288 	}
289 
290 	if (dev_desc->flags & LPSS_CLK_DIVIDER) {
291 		/* Prevent division by zero */
292 		if (!readl(prv_base))
293 			writel(LPSS_CLK_DIVIDER_DEF_MASK, prv_base);
294 
295 		clk_name = kasprintf(GFP_KERNEL, "%s-div", devname);
296 		if (!clk_name)
297 			return -ENOMEM;
298 		clk = clk_register_fractional_divider(NULL, clk_name, parent,
299 						      0, prv_base,
300 						      1, 15, 16, 15, 0, NULL);
301 		parent = clk_name;
302 
303 		clk_name = kasprintf(GFP_KERNEL, "%s-update", devname);
304 		if (!clk_name) {
305 			kfree(parent);
306 			return -ENOMEM;
307 		}
308 		clk = clk_register_gate(NULL, clk_name, parent,
309 					CLK_SET_RATE_PARENT | CLK_SET_RATE_GATE,
310 					prv_base, 31, 0, NULL);
311 		kfree(parent);
312 		kfree(clk_name);
313 	}
314 out:
315 	if (IS_ERR(clk))
316 		return PTR_ERR(clk);
317 
318 	pdata->clk = clk;
319 	clk_register_clkdev(clk, dev_desc->clk_con_id, devname);
320 	return 0;
321 }
322 
323 static int acpi_lpss_create_device(struct acpi_device *adev,
324 				   const struct acpi_device_id *id)
325 {
326 	struct lpss_device_desc *dev_desc;
327 	struct lpss_private_data *pdata;
328 	struct resource_entry *rentry;
329 	struct list_head resource_list;
330 	struct platform_device *pdev;
331 	int ret;
332 
333 	dev_desc = (struct lpss_device_desc *)id->driver_data;
334 	if (!dev_desc) {
335 		pdev = acpi_create_platform_device(adev);
336 		return IS_ERR_OR_NULL(pdev) ? PTR_ERR(pdev) : 1;
337 	}
338 	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
339 	if (!pdata)
340 		return -ENOMEM;
341 
342 	INIT_LIST_HEAD(&resource_list);
343 	ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
344 	if (ret < 0)
345 		goto err_out;
346 
347 	list_for_each_entry(rentry, &resource_list, node)
348 		if (resource_type(rentry->res) == IORESOURCE_MEM) {
349 			if (dev_desc->prv_size_override)
350 				pdata->mmio_size = dev_desc->prv_size_override;
351 			else
352 				pdata->mmio_size = resource_size(rentry->res);
353 			pdata->mmio_base = ioremap(rentry->res->start,
354 						   pdata->mmio_size);
355 			if (!pdata->mmio_base)
356 				goto err_out;
357 			break;
358 		}
359 
360 	acpi_dev_free_resource_list(&resource_list);
361 
362 	pdata->dev_desc = dev_desc;
363 
364 	if (dev_desc->setup)
365 		dev_desc->setup(pdata);
366 
367 	if (dev_desc->flags & LPSS_CLK) {
368 		ret = register_device_clock(adev, pdata);
369 		if (ret) {
370 			/* Skip the device, but continue the namespace scan. */
371 			ret = 0;
372 			goto err_out;
373 		}
374 	}
375 
376 	/*
377 	 * This works around a known issue in ACPI tables where LPSS devices
378 	 * have _PS0 and _PS3 without _PSC (and no power resources), so
379 	 * acpi_bus_init_power() will assume that the BIOS has put them into D0.
380 	 */
381 	ret = acpi_device_fix_up_power(adev);
382 	if (ret) {
383 		/* Skip the device, but continue the namespace scan. */
384 		ret = 0;
385 		goto err_out;
386 	}
387 
388 	adev->driver_data = pdata;
389 	pdev = acpi_create_platform_device(adev);
390 	if (!IS_ERR_OR_NULL(pdev)) {
391 		return 1;
392 	}
393 
394 	ret = PTR_ERR(pdev);
395 	adev->driver_data = NULL;
396 
397  err_out:
398 	kfree(pdata);
399 	return ret;
400 }
401 
402 static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
403 {
404 	return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
405 }
406 
407 static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
408 			     unsigned int reg)
409 {
410 	writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
411 }
412 
413 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
414 {
415 	struct acpi_device *adev;
416 	struct lpss_private_data *pdata;
417 	unsigned long flags;
418 	int ret;
419 
420 	ret = acpi_bus_get_device(ACPI_HANDLE(dev), &adev);
421 	if (WARN_ON(ret))
422 		return ret;
423 
424 	spin_lock_irqsave(&dev->power.lock, flags);
425 	if (pm_runtime_suspended(dev)) {
426 		ret = -EAGAIN;
427 		goto out;
428 	}
429 	pdata = acpi_driver_data(adev);
430 	if (WARN_ON(!pdata || !pdata->mmio_base)) {
431 		ret = -ENODEV;
432 		goto out;
433 	}
434 	*val = __lpss_reg_read(pdata, reg);
435 
436  out:
437 	spin_unlock_irqrestore(&dev->power.lock, flags);
438 	return ret;
439 }
440 
441 static ssize_t lpss_ltr_show(struct device *dev, struct device_attribute *attr,
442 			     char *buf)
443 {
444 	u32 ltr_value = 0;
445 	unsigned int reg;
446 	int ret;
447 
448 	reg = strcmp(attr->attr.name, "auto_ltr") ? LPSS_SW_LTR : LPSS_AUTO_LTR;
449 	ret = lpss_reg_read(dev, reg, &ltr_value);
450 	if (ret)
451 		return ret;
452 
453 	return snprintf(buf, PAGE_SIZE, "%08x\n", ltr_value);
454 }
455 
456 static ssize_t lpss_ltr_mode_show(struct device *dev,
457 				  struct device_attribute *attr, char *buf)
458 {
459 	u32 ltr_mode = 0;
460 	char *outstr;
461 	int ret;
462 
463 	ret = lpss_reg_read(dev, LPSS_GENERAL, &ltr_mode);
464 	if (ret)
465 		return ret;
466 
467 	outstr = (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) ? "sw" : "auto";
468 	return sprintf(buf, "%s\n", outstr);
469 }
470 
471 static DEVICE_ATTR(auto_ltr, S_IRUSR, lpss_ltr_show, NULL);
472 static DEVICE_ATTR(sw_ltr, S_IRUSR, lpss_ltr_show, NULL);
473 static DEVICE_ATTR(ltr_mode, S_IRUSR, lpss_ltr_mode_show, NULL);
474 
475 static struct attribute *lpss_attrs[] = {
476 	&dev_attr_auto_ltr.attr,
477 	&dev_attr_sw_ltr.attr,
478 	&dev_attr_ltr_mode.attr,
479 	NULL,
480 };
481 
482 static struct attribute_group lpss_attr_group = {
483 	.attrs = lpss_attrs,
484 	.name = "lpss_ltr",
485 };
486 
487 static void acpi_lpss_set_ltr(struct device *dev, s32 val)
488 {
489 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
490 	u32 ltr_mode, ltr_val;
491 
492 	ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
493 	if (val < 0) {
494 		if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
495 			ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
496 			__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
497 		}
498 		return;
499 	}
500 	ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
501 	if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
502 		ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
503 		val = LPSS_LTR_MAX_VAL;
504 	} else if (val > LPSS_LTR_MAX_VAL) {
505 		ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
506 		val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
507 	} else {
508 		ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
509 	}
510 	ltr_val |= val;
511 	__lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
512 	if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
513 		ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
514 		__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
515 	}
516 }
517 
518 #ifdef CONFIG_PM
519 /**
520  * acpi_lpss_save_ctx() - Save the private registers of LPSS device
521  * @dev: LPSS device
522  * @pdata: pointer to the private data of the LPSS device
523  *
524  * Most LPSS devices have private registers which may loose their context when
525  * the device is powered down. acpi_lpss_save_ctx() saves those registers into
526  * prv_reg_ctx array.
527  */
528 static void acpi_lpss_save_ctx(struct device *dev,
529 			       struct lpss_private_data *pdata)
530 {
531 	unsigned int i;
532 
533 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
534 		unsigned long offset = i * sizeof(u32);
535 
536 		pdata->prv_reg_ctx[i] = __lpss_reg_read(pdata, offset);
537 		dev_dbg(dev, "saving 0x%08x from LPSS reg at offset 0x%02lx\n",
538 			pdata->prv_reg_ctx[i], offset);
539 	}
540 }
541 
542 /**
543  * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device
544  * @dev: LPSS device
545  * @pdata: pointer to the private data of the LPSS device
546  *
547  * Restores the registers that were previously stored with acpi_lpss_save_ctx().
548  */
549 static void acpi_lpss_restore_ctx(struct device *dev,
550 				  struct lpss_private_data *pdata)
551 {
552 	unsigned int i;
553 
554 	/*
555 	 * The following delay is needed or the subsequent write operations may
556 	 * fail. The LPSS devices are actually PCI devices and the PCI spec
557 	 * expects 10ms delay before the device can be accessed after D3 to D0
558 	 * transition.
559 	 */
560 	msleep(10);
561 
562 	for (i = 0; i < LPSS_PRV_REG_COUNT; i++) {
563 		unsigned long offset = i * sizeof(u32);
564 
565 		__lpss_reg_write(pdata->prv_reg_ctx[i], pdata, offset);
566 		dev_dbg(dev, "restoring 0x%08x to LPSS reg at offset 0x%02lx\n",
567 			pdata->prv_reg_ctx[i], offset);
568 	}
569 }
570 
571 #ifdef CONFIG_PM_SLEEP
572 static int acpi_lpss_suspend_late(struct device *dev)
573 {
574 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
575 	int ret;
576 
577 	ret = pm_generic_suspend_late(dev);
578 	if (ret)
579 		return ret;
580 
581 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
582 		acpi_lpss_save_ctx(dev, pdata);
583 
584 	return acpi_dev_suspend_late(dev);
585 }
586 
587 static int acpi_lpss_resume_early(struct device *dev)
588 {
589 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
590 	int ret;
591 
592 	ret = acpi_dev_resume_early(dev);
593 	if (ret)
594 		return ret;
595 
596 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
597 		acpi_lpss_restore_ctx(dev, pdata);
598 
599 	return pm_generic_resume_early(dev);
600 }
601 #endif /* CONFIG_PM_SLEEP */
602 
603 static int acpi_lpss_runtime_suspend(struct device *dev)
604 {
605 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
606 	int ret;
607 
608 	ret = pm_generic_runtime_suspend(dev);
609 	if (ret)
610 		return ret;
611 
612 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
613 		acpi_lpss_save_ctx(dev, pdata);
614 
615 	return acpi_dev_runtime_suspend(dev);
616 }
617 
618 static int acpi_lpss_runtime_resume(struct device *dev)
619 {
620 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
621 	int ret;
622 
623 	ret = acpi_dev_runtime_resume(dev);
624 	if (ret)
625 		return ret;
626 
627 	if (pdata->dev_desc->flags & LPSS_SAVE_CTX)
628 		acpi_lpss_restore_ctx(dev, pdata);
629 
630 	return pm_generic_runtime_resume(dev);
631 }
632 #endif /* CONFIG_PM */
633 
634 static struct dev_pm_domain acpi_lpss_pm_domain = {
635 	.ops = {
636 #ifdef CONFIG_PM
637 #ifdef CONFIG_PM_SLEEP
638 		.prepare = acpi_subsys_prepare,
639 		.complete = acpi_subsys_complete,
640 		.suspend = acpi_subsys_suspend,
641 		.suspend_late = acpi_lpss_suspend_late,
642 		.resume_early = acpi_lpss_resume_early,
643 		.freeze = acpi_subsys_freeze,
644 		.poweroff = acpi_subsys_suspend,
645 		.poweroff_late = acpi_lpss_suspend_late,
646 		.restore_early = acpi_lpss_resume_early,
647 #endif
648 		.runtime_suspend = acpi_lpss_runtime_suspend,
649 		.runtime_resume = acpi_lpss_runtime_resume,
650 #endif
651 	},
652 };
653 
654 static int acpi_lpss_platform_notify(struct notifier_block *nb,
655 				     unsigned long action, void *data)
656 {
657 	struct platform_device *pdev = to_platform_device(data);
658 	struct lpss_private_data *pdata;
659 	struct acpi_device *adev;
660 	const struct acpi_device_id *id;
661 
662 	id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev);
663 	if (!id || !id->driver_data)
664 		return 0;
665 
666 	if (acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev))
667 		return 0;
668 
669 	pdata = acpi_driver_data(adev);
670 	if (!pdata)
671 		return 0;
672 
673 	if (pdata->mmio_base &&
674 	    pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) {
675 		dev_err(&pdev->dev, "MMIO size insufficient to access LTR\n");
676 		return 0;
677 	}
678 
679 	switch (action) {
680 	case BUS_NOTIFY_ADD_DEVICE:
681 		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
682 		if (pdata->dev_desc->flags & LPSS_LTR)
683 			return sysfs_create_group(&pdev->dev.kobj,
684 						  &lpss_attr_group);
685 		break;
686 	case BUS_NOTIFY_DEL_DEVICE:
687 		if (pdata->dev_desc->flags & LPSS_LTR)
688 			sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
689 		pdev->dev.pm_domain = NULL;
690 		break;
691 	default:
692 		break;
693 	}
694 
695 	return 0;
696 }
697 
698 static struct notifier_block acpi_lpss_nb = {
699 	.notifier_call = acpi_lpss_platform_notify,
700 };
701 
702 static void acpi_lpss_bind(struct device *dev)
703 {
704 	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
705 
706 	if (!pdata || !pdata->mmio_base || !(pdata->dev_desc->flags & LPSS_LTR))
707 		return;
708 
709 	if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
710 		dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
711 	else
712 		dev_err(dev, "MMIO size insufficient to access LTR\n");
713 }
714 
715 static void acpi_lpss_unbind(struct device *dev)
716 {
717 	dev->power.set_latency_tolerance = NULL;
718 }
719 
720 static struct acpi_scan_handler lpss_handler = {
721 	.ids = acpi_lpss_device_ids,
722 	.attach = acpi_lpss_create_device,
723 	.bind = acpi_lpss_bind,
724 	.unbind = acpi_lpss_unbind,
725 };
726 
727 void __init acpi_lpss_init(void)
728 {
729 	if (!lpt_clk_init()) {
730 		bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
731 		acpi_scan_add_handler(&lpss_handler);
732 	}
733 }
734 
735 #else
736 
737 static struct acpi_scan_handler lpss_handler = {
738 	.ids = acpi_lpss_device_ids,
739 };
740 
741 void __init acpi_lpss_init(void)
742 {
743 	acpi_scan_add_handler(&lpss_handler);
744 }
745 
746 #endif /* CONFIG_X86_INTEL_LPSS */
747