1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * ACPI Time and Alarm (TAD) Device Driver
  4 *
  5 * Copyright (C) 2018 Intel Corporation
  6 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  7 *
  8 * This driver is based on Section 9.18 of the ACPI 6.2 specification revision.
  9 *
 10 * It only supports the system wakeup capabilities of the TAD.
 11 *
 12 * Provided are sysfs attributes, available under the TAD platform device,
 13 * allowing user space to manage the AC and DC wakeup timers of the TAD:
 14 * set and read their values, set and check their expire timer wake policies,
 15 * check and clear their status and check the capabilities of the TAD reported
 16 * by AML.  The DC timer attributes are only present if the TAD supports a
 17 * separate DC alarm timer.
 18 *
 19 * The wakeup events handling and power management of the TAD is expected to
 20 * be taken care of by the ACPI PM domain attached to its platform device.
 21 */
 22
 23#include <linux/acpi.h>
 24#include <linux/kernel.h>
 25#include <linux/module.h>
 26#include <linux/platform_device.h>
 27#include <linux/pm_runtime.h>
 28#include <linux/suspend.h>
 29
 30MODULE_LICENSE("GPL v2");
 31MODULE_AUTHOR("Rafael J. Wysocki");
 32
 33/* ACPI TAD capability flags (ACPI 6.2, Section 9.18.2) */
 34#define ACPI_TAD_AC_WAKE	BIT(0)
 35#define ACPI_TAD_DC_WAKE	BIT(1)
 36#define ACPI_TAD_RT		BIT(2)
 37#define ACPI_TAD_RT_IN_MS	BIT(3)
 38#define ACPI_TAD_S4_S5__GWS	BIT(4)
 39#define ACPI_TAD_AC_S4_WAKE	BIT(5)
 40#define ACPI_TAD_AC_S5_WAKE	BIT(6)
 41#define ACPI_TAD_DC_S4_WAKE	BIT(7)
 42#define ACPI_TAD_DC_S5_WAKE	BIT(8)
 43
 44/* ACPI TAD alarm timer selection */
 45#define ACPI_TAD_AC_TIMER	(u32)0
 46#define ACPI_TAD_DC_TIMER	(u32)1
 47
 48/* Special value for disabled timer or expired timer wake policy. */
 49#define ACPI_TAD_WAKE_DISABLED	(~(u32)0)
 50
 51struct acpi_tad_driver_data {
 52	u32 capabilities;
 53};
 54
 55static int acpi_tad_wake_set(struct device *dev, char *method, u32 timer_id,
 56			     u32 value)
 57{
 58	acpi_handle handle = ACPI_HANDLE(dev);
 59	union acpi_object args[] = {
 60		{ .type = ACPI_TYPE_INTEGER, },
 61		{ .type = ACPI_TYPE_INTEGER, },
 62	};
 63	struct acpi_object_list arg_list = {
 64		.pointer = args,
 65		.count = ARRAY_SIZE(args),
 66	};
 67	unsigned long long retval;
 68	acpi_status status;
 69
 70	args[0].integer.value = timer_id;
 71	args[1].integer.value = value;
 72
 73	pm_runtime_get_sync(dev);
 74
 75	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
 76
 77	pm_runtime_put_sync(dev);
 78
 79	if (ACPI_FAILURE(status) || retval)
 80		return -EIO;
 81
 82	return 0;
 83}
 84
 85static int acpi_tad_wake_write(struct device *dev, const char *buf, char *method,
 86			       u32 timer_id, const char *specval)
 87{
 88	u32 value;
 89
 90	if (sysfs_streq(buf, specval)) {
 91		value = ACPI_TAD_WAKE_DISABLED;
 92	} else {
 93		int ret = kstrtou32(buf, 0, &value);
 94
 95		if (ret)
 96			return ret;
 97
 98		if (value == ACPI_TAD_WAKE_DISABLED)
 99			return -EINVAL;
100	}
101
102	return acpi_tad_wake_set(dev, method, timer_id, value);
103}
104
105static ssize_t acpi_tad_wake_read(struct device *dev, char *buf, char *method,
106				  u32 timer_id, const char *specval)
107{
108	acpi_handle handle = ACPI_HANDLE(dev);
109	union acpi_object args[] = {
110		{ .type = ACPI_TYPE_INTEGER, },
111	};
112	struct acpi_object_list arg_list = {
113		.pointer = args,
114		.count = ARRAY_SIZE(args),
115	};
116	unsigned long long retval;
117	acpi_status status;
118
119	args[0].integer.value = timer_id;
120
121	pm_runtime_get_sync(dev);
122
123	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
124
125	pm_runtime_put_sync(dev);
126
127	if (ACPI_FAILURE(status))
128		return -EIO;
129
130	if ((u32)retval == ACPI_TAD_WAKE_DISABLED)
131		return sprintf(buf, "%s\n", specval);
132
133	return sprintf(buf, "%u\n", (u32)retval);
134}
135
136static const char *alarm_specval = "disabled";
137
138static int acpi_tad_alarm_write(struct device *dev, const char *buf,
139				u32 timer_id)
140{
141	return acpi_tad_wake_write(dev, buf, "_STV", timer_id, alarm_specval);
142}
143
144static ssize_t acpi_tad_alarm_read(struct device *dev, char *buf, u32 timer_id)
145{
146	return acpi_tad_wake_read(dev, buf, "_TIV", timer_id, alarm_specval);
147}
148
149static const char *policy_specval = "never";
150
151static int acpi_tad_policy_write(struct device *dev, const char *buf,
152				 u32 timer_id)
153{
154	return acpi_tad_wake_write(dev, buf, "_STP", timer_id, policy_specval);
155}
156
157static ssize_t acpi_tad_policy_read(struct device *dev, char *buf, u32 timer_id)
158{
159	return acpi_tad_wake_read(dev, buf, "_TIP", timer_id, policy_specval);
160}
161
162static int acpi_tad_clear_status(struct device *dev, u32 timer_id)
163{
164	acpi_handle handle = ACPI_HANDLE(dev);
165	union acpi_object args[] = {
166		{ .type = ACPI_TYPE_INTEGER, },
167	};
168	struct acpi_object_list arg_list = {
169		.pointer = args,
170		.count = ARRAY_SIZE(args),
171	};
172	unsigned long long retval;
173	acpi_status status;
174
175	args[0].integer.value = timer_id;
176
177	pm_runtime_get_sync(dev);
178
179	status = acpi_evaluate_integer(handle, "_CWS", &arg_list, &retval);
180
181	pm_runtime_put_sync(dev);
182
183	if (ACPI_FAILURE(status) || retval)
184		return -EIO;
185
186	return 0;
187}
188
189static int acpi_tad_status_write(struct device *dev, const char *buf, u32 timer_id)
190{
191	int ret, value;
192
193	ret = kstrtoint(buf, 0, &value);
194	if (ret)
195		return ret;
196
197	if (value)
198		return -EINVAL;
199
200	return acpi_tad_clear_status(dev, timer_id);
201}
202
203static ssize_t acpi_tad_status_read(struct device *dev, char *buf, u32 timer_id)
204{
205	acpi_handle handle = ACPI_HANDLE(dev);
206	union acpi_object args[] = {
207		{ .type = ACPI_TYPE_INTEGER, },
208	};
209	struct acpi_object_list arg_list = {
210		.pointer = args,
211		.count = ARRAY_SIZE(args),
212	};
213	unsigned long long retval;
214	acpi_status status;
215
216	args[0].integer.value = timer_id;
217
218	pm_runtime_get_sync(dev);
219
220	status = acpi_evaluate_integer(handle, "_GWS", &arg_list, &retval);
221
222	pm_runtime_put_sync(dev);
223
224	if (ACPI_FAILURE(status))
225		return -EIO;
226
227	return sprintf(buf, "0x%02X\n", (u32)retval);
228}
229
230static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
231			 char *buf)
232{
233	struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
234
235	return sprintf(buf, "0x%02X\n", dd->capabilities);
236}
237
238static DEVICE_ATTR_RO(caps);
239
240static ssize_t ac_alarm_store(struct device *dev, struct device_attribute *attr,
241			      const char *buf, size_t count)
242{
243	int ret = acpi_tad_alarm_write(dev, buf, ACPI_TAD_AC_TIMER);
244
245	return ret ? ret : count;
246}
247
248static ssize_t ac_alarm_show(struct device *dev, struct device_attribute *attr,
249			     char *buf)
250{
251	return acpi_tad_alarm_read(dev, buf, ACPI_TAD_AC_TIMER);
252}
253
254static DEVICE_ATTR(ac_alarm, S_IRUSR | S_IWUSR, ac_alarm_show, ac_alarm_store);
255
256static ssize_t ac_policy_store(struct device *dev, struct device_attribute *attr,
257			       const char *buf, size_t count)
258{
259	int ret = acpi_tad_policy_write(dev, buf, ACPI_TAD_AC_TIMER);
260
261	return ret ? ret : count;
262}
263
264static ssize_t ac_policy_show(struct device *dev, struct device_attribute *attr,
265			      char *buf)
266{
267	return acpi_tad_policy_read(dev, buf, ACPI_TAD_AC_TIMER);
268}
269
270static DEVICE_ATTR(ac_policy, S_IRUSR | S_IWUSR, ac_policy_show, ac_policy_store);
271
272static ssize_t ac_status_store(struct device *dev, struct device_attribute *attr,
273			       const char *buf, size_t count)
274{
275	int ret = acpi_tad_status_write(dev, buf, ACPI_TAD_AC_TIMER);
276
277	return ret ? ret : count;
278}
279
280static ssize_t ac_status_show(struct device *dev, struct device_attribute *attr,
281			      char *buf)
282{
283	return acpi_tad_status_read(dev, buf, ACPI_TAD_AC_TIMER);
284}
285
286static DEVICE_ATTR(ac_status, S_IRUSR | S_IWUSR, ac_status_show, ac_status_store);
287
288static struct attribute *acpi_tad_attrs[] = {
289	&dev_attr_caps.attr,
290	&dev_attr_ac_alarm.attr,
291	&dev_attr_ac_policy.attr,
292	&dev_attr_ac_status.attr,
293	NULL,
294};
295static const struct attribute_group acpi_tad_attr_group = {
296	.attrs	= acpi_tad_attrs,
297};
298
299static ssize_t dc_alarm_store(struct device *dev, struct device_attribute *attr,
300			      const char *buf, size_t count)
301{
302	int ret = acpi_tad_alarm_write(dev, buf, ACPI_TAD_DC_TIMER);
303
304	return ret ? ret : count;
305}
306
307static ssize_t dc_alarm_show(struct device *dev, struct device_attribute *attr,
308			     char *buf)
309{
310	return acpi_tad_alarm_read(dev, buf, ACPI_TAD_DC_TIMER);
311}
312
313static DEVICE_ATTR(dc_alarm, S_IRUSR | S_IWUSR, dc_alarm_show, dc_alarm_store);
314
315static ssize_t dc_policy_store(struct device *dev, struct device_attribute *attr,
316			       const char *buf, size_t count)
317{
318	int ret = acpi_tad_policy_write(dev, buf, ACPI_TAD_DC_TIMER);
319
320	return ret ? ret : count;
321}
322
323static ssize_t dc_policy_show(struct device *dev, struct device_attribute *attr,
324			      char *buf)
325{
326	return acpi_tad_policy_read(dev, buf, ACPI_TAD_DC_TIMER);
327}
328
329static DEVICE_ATTR(dc_policy, S_IRUSR | S_IWUSR, dc_policy_show, dc_policy_store);
330
331static ssize_t dc_status_store(struct device *dev, struct device_attribute *attr,
332			       const char *buf, size_t count)
333{
334	int ret = acpi_tad_status_write(dev, buf, ACPI_TAD_DC_TIMER);
335
336	return ret ? ret : count;
337}
338
339static ssize_t dc_status_show(struct device *dev, struct device_attribute *attr,
340			      char *buf)
341{
342	return acpi_tad_status_read(dev, buf, ACPI_TAD_DC_TIMER);
343}
344
345static DEVICE_ATTR(dc_status, S_IRUSR | S_IWUSR, dc_status_show, dc_status_store);
346
347static struct attribute *acpi_tad_dc_attrs[] = {
348	&dev_attr_dc_alarm.attr,
349	&dev_attr_dc_policy.attr,
350	&dev_attr_dc_status.attr,
351	NULL,
352};
353static const struct attribute_group acpi_tad_dc_attr_group = {
354	.attrs	= acpi_tad_dc_attrs,
355};
356
357static int acpi_tad_disable_timer(struct device *dev, u32 timer_id)
358{
359	return acpi_tad_wake_set(dev, "_STV", timer_id, ACPI_TAD_WAKE_DISABLED);
360}
361
362static int acpi_tad_remove(struct platform_device *pdev)
363{
364	struct device *dev = &pdev->dev;
365	struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
366
367	device_init_wakeup(dev, false);
368
369	pm_runtime_get_sync(dev);
370
371	if (dd->capabilities & ACPI_TAD_DC_WAKE)
372		sysfs_remove_group(&dev->kobj, &acpi_tad_dc_attr_group);
373
374	sysfs_remove_group(&dev->kobj, &acpi_tad_attr_group);
375
376	acpi_tad_disable_timer(dev, ACPI_TAD_AC_TIMER);
377	acpi_tad_clear_status(dev, ACPI_TAD_AC_TIMER);
378	if (dd->capabilities & ACPI_TAD_DC_WAKE) {
379		acpi_tad_disable_timer(dev, ACPI_TAD_DC_TIMER);
380		acpi_tad_clear_status(dev, ACPI_TAD_DC_TIMER);
381	}
382
383	pm_runtime_put_sync(dev);
384	pm_runtime_disable(dev);
385	return 0;
386}
387
388static int acpi_tad_probe(struct platform_device *pdev)
389{
390	struct device *dev = &pdev->dev;
391	acpi_handle handle = ACPI_HANDLE(dev);
392	struct acpi_tad_driver_data *dd;
393	acpi_status status;
394	unsigned long long caps;
395	int ret;
396
397	/*
398	 * Initialization failure messages are mostly about firmware issues, so
399	 * print them at the "info" level.
400	 */
401	status = acpi_evaluate_integer(handle, "_GCP", NULL, &caps);
402	if (ACPI_FAILURE(status)) {
403		dev_info(dev, "Unable to get capabilities\n");
404		return -ENODEV;
405	}
406
407	if (!(caps & ACPI_TAD_AC_WAKE)) {
408		dev_info(dev, "Unsupported capabilities\n");
409		return -ENODEV;
410	}
411
412	if (!acpi_has_method(handle, "_PRW")) {
413		dev_info(dev, "Missing _PRW\n");
414		return -ENODEV;
415	}
416
417	dd = devm_kzalloc(dev, sizeof(*dd), GFP_KERNEL);
418	if (!dd)
419		return -ENOMEM;
420
421	dd->capabilities = caps;
422	dev_set_drvdata(dev, dd);
423
424	/*
425	 * Assume that the ACPI PM domain has been attached to the device and
426	 * simply enable system wakeup and runtime PM and put the device into
427	 * runtime suspend.  Everything else should be taken care of by the ACPI
428	 * PM domain callbacks.
429	 */
430	device_init_wakeup(dev, true);
431	dev_pm_set_driver_flags(dev, DPM_FLAG_SMART_SUSPEND |
432				     DPM_FLAG_LEAVE_SUSPENDED);
433	/*
434	 * The platform bus type layer tells the ACPI PM domain powers up the
435	 * device, so set the runtime PM status of it to "active".
436	 */
437	pm_runtime_set_active(dev);
438	pm_runtime_enable(dev);
439	pm_runtime_suspend(dev);
440
441	ret = sysfs_create_group(&dev->kobj, &acpi_tad_attr_group);
442	if (ret)
443		goto fail;
444
445	if (caps & ACPI_TAD_DC_WAKE) {
446		ret = sysfs_create_group(&dev->kobj, &acpi_tad_dc_attr_group);
447		if (ret)
448			goto fail;
449	}
450
451	return 0;
452
453fail:
454	acpi_tad_remove(pdev);
455	return ret;
456}
457
458static const struct acpi_device_id acpi_tad_ids[] = {
459	{"ACPI000E", 0},
460	{}
461};
462
463static struct platform_driver acpi_tad_driver = {
464	.driver = {
465		.name = "acpi-tad",
466		.acpi_match_table = acpi_tad_ids,
467	},
468	.probe = acpi_tad_probe,
469	.remove = acpi_tad_remove,
470};
471MODULE_DEVICE_TABLE(acpi, acpi_tad_ids);
472
473module_platform_driver(acpi_tad_driver);