1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Supports for the button array on SoC tablets originally running
4  * Windows 8.
5  *
6  * (C) Copyright 2014 Intel Corporation
7  */
8 
9 #include <linux/module.h>
10 #include <linux/input.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/acpi.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/gpio_keys.h>
16 #include <linux/gpio.h>
17 #include <linux/platform_device.h>
18 
19 struct soc_button_info {
20 	const char *name;
21 	int acpi_index;
22 	unsigned int event_type;
23 	unsigned int event_code;
24 	bool autorepeat;
25 	bool wakeup;
26 };
27 
28 struct soc_device_data {
29 	const struct soc_button_info *button_info;
30 	int (*check)(struct device *dev);
31 };
32 
33 /*
34  * Some of the buttons like volume up/down are auto repeat, while others
35  * are not. To support both, we register two platform devices, and put
36  * buttons into them based on whether the key should be auto repeat.
37  */
38 #define BUTTON_TYPES	2
39 
40 struct soc_button_data {
41 	struct platform_device *children[BUTTON_TYPES];
42 };
43 
44 /*
45  * Get the Nth GPIO number from the ACPI object.
46  */
47 static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
48 {
49 	struct gpio_desc *desc;
50 	int gpio;
51 
52 	desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
53 	if (IS_ERR(desc))
54 		return PTR_ERR(desc);
55 
56 	gpio = desc_to_gpio(desc);
57 
58 	gpiod_put(desc);
59 
60 	return gpio;
61 }
62 
63 static struct platform_device *
64 soc_button_device_create(struct platform_device *pdev,
65 			 const struct soc_button_info *button_info,
66 			 bool autorepeat)
67 {
68 	const struct soc_button_info *info;
69 	struct platform_device *pd;
70 	struct gpio_keys_button *gpio_keys;
71 	struct gpio_keys_platform_data *gpio_keys_pdata;
72 	int n_buttons = 0;
73 	int gpio;
74 	int error;
75 
76 	for (info = button_info; info->name; info++)
77 		if (info->autorepeat == autorepeat)
78 			n_buttons++;
79 
80 	gpio_keys_pdata = devm_kzalloc(&pdev->dev,
81 				       sizeof(*gpio_keys_pdata) +
82 					sizeof(*gpio_keys) * n_buttons,
83 				       GFP_KERNEL);
84 	if (!gpio_keys_pdata)
85 		return ERR_PTR(-ENOMEM);
86 
87 	gpio_keys = (void *)(gpio_keys_pdata + 1);
88 	n_buttons = 0;
89 
90 	for (info = button_info; info->name; info++) {
91 		if (info->autorepeat != autorepeat)
92 			continue;
93 
94 		gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
95 		if (!gpio_is_valid(gpio)) {
96 			/*
97 			 * Skip GPIO if not present. Note we deliberately
98 			 * ignore -EPROBE_DEFER errors here. On some devices
99 			 * Intel is using so called virtual GPIOs which are not
100 			 * GPIOs at all but some way for AML code to check some
101 			 * random status bits without need a custom opregion.
102 			 * In some cases the resources table we parse points to
103 			 * such a virtual GPIO, since these are not real GPIOs
104 			 * we do not have a driver for these so they will never
105 			 * show up, therefore we ignore -EPROBE_DEFER.
106 			 */
107 			continue;
108 		}
109 
110 		gpio_keys[n_buttons].type = info->event_type;
111 		gpio_keys[n_buttons].code = info->event_code;
112 		gpio_keys[n_buttons].gpio = gpio;
113 		gpio_keys[n_buttons].active_low = 1;
114 		gpio_keys[n_buttons].desc = info->name;
115 		gpio_keys[n_buttons].wakeup = info->wakeup;
116 		/* These devices often use cheap buttons, use 50 ms debounce */
117 		gpio_keys[n_buttons].debounce_interval = 50;
118 		n_buttons++;
119 	}
120 
121 	if (n_buttons == 0) {
122 		error = -ENODEV;
123 		goto err_free_mem;
124 	}
125 
126 	gpio_keys_pdata->buttons = gpio_keys;
127 	gpio_keys_pdata->nbuttons = n_buttons;
128 	gpio_keys_pdata->rep = autorepeat;
129 
130 	pd = platform_device_register_resndata(&pdev->dev, "gpio-keys",
131 					       PLATFORM_DEVID_AUTO, NULL, 0,
132 					       gpio_keys_pdata,
133 					       sizeof(*gpio_keys_pdata));
134 	error = PTR_ERR_OR_ZERO(pd);
135 	if (error) {
136 		dev_err(&pdev->dev,
137 			"failed registering gpio-keys: %d\n", error);
138 		goto err_free_mem;
139 	}
140 
141 	return pd;
142 
143 err_free_mem:
144 	devm_kfree(&pdev->dev, gpio_keys_pdata);
145 	return ERR_PTR(error);
146 }
147 
148 static int soc_button_get_acpi_object_int(const union acpi_object *obj)
149 {
150 	if (obj->type != ACPI_TYPE_INTEGER)
151 		return -1;
152 
153 	return obj->integer.value;
154 }
155 
156 /* Parse a single ACPI0011 _DSD button descriptor */
157 static int soc_button_parse_btn_desc(struct device *dev,
158 				     const union acpi_object *desc,
159 				     int collection_uid,
160 				     struct soc_button_info *info)
161 {
162 	int upage, usage;
163 
164 	if (desc->type != ACPI_TYPE_PACKAGE ||
165 	    desc->package.count != 5 ||
166 	    /* First byte should be 1 (control) */
167 	    soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
168 	    /* Third byte should be collection uid */
169 	    soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
170 							    collection_uid) {
171 		dev_err(dev, "Invalid ACPI Button Descriptor\n");
172 		return -ENODEV;
173 	}
174 
175 	info->event_type = EV_KEY;
176 	info->acpi_index =
177 		soc_button_get_acpi_object_int(&desc->package.elements[1]);
178 	upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
179 	usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);
180 
181 	/*
182 	 * The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
183 	 * usage page and usage codes, but otherwise the device is not HID
184 	 * compliant: it uses one irq per button instead of generating HID
185 	 * input reports and some buttons should generate wakeups where as
186 	 * others should not, so we cannot use the HID subsystem.
187 	 *
188 	 * Luckily all devices only use a few usage page + usage combinations,
189 	 * so we can simply check for the known combinations here.
190 	 */
191 	if (upage == 0x01 && usage == 0x81) {
192 		info->name = "power";
193 		info->event_code = KEY_POWER;
194 		info->wakeup = true;
195 	} else if (upage == 0x01 && usage == 0xca) {
196 		info->name = "rotation lock switch";
197 		info->event_type = EV_SW;
198 		info->event_code = SW_ROTATE_LOCK;
199 	} else if (upage == 0x07 && usage == 0xe3) {
200 		info->name = "home";
201 		info->event_code = KEY_LEFTMETA;
202 		info->wakeup = true;
203 	} else if (upage == 0x0c && usage == 0xe9) {
204 		info->name = "volume_up";
205 		info->event_code = KEY_VOLUMEUP;
206 		info->autorepeat = true;
207 	} else if (upage == 0x0c && usage == 0xea) {
208 		info->name = "volume_down";
209 		info->event_code = KEY_VOLUMEDOWN;
210 		info->autorepeat = true;
211 	} else {
212 		dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n",
213 			 info->acpi_index, upage, usage);
214 		info->name = "unknown";
215 		info->event_code = KEY_RESERVED;
216 	}
217 
218 	return 0;
219 }
220 
221 /* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */
222 static const u8 btns_desc_uuid[16] = {
223 	0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47,
224 	0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e
225 };
226 
227 /* Parse ACPI0011 _DSD button descriptors */
228 static struct soc_button_info *soc_button_get_button_info(struct device *dev)
229 {
230 	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
231 	const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL;
232 	struct soc_button_info *button_info;
233 	acpi_status status;
234 	int i, btn, collection_uid = -1;
235 
236 	status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL,
237 					    &buf, ACPI_TYPE_PACKAGE);
238 	if (ACPI_FAILURE(status)) {
239 		dev_err(dev, "ACPI _DSD object not found\n");
240 		return ERR_PTR(-ENODEV);
241 	}
242 
243 	/* Look for the Button Descriptors UUID */
244 	desc = buf.pointer;
245 	for (i = 0; (i + 1) < desc->package.count; i += 2) {
246 		uuid = &desc->package.elements[i];
247 
248 		if (uuid->type != ACPI_TYPE_BUFFER ||
249 		    uuid->buffer.length != 16 ||
250 		    desc->package.elements[i + 1].type != ACPI_TYPE_PACKAGE) {
251 			break;
252 		}
253 
254 		if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) {
255 			btns_desc = &desc->package.elements[i + 1];
256 			break;
257 		}
258 	}
259 
260 	if (!btns_desc) {
261 		dev_err(dev, "ACPI Button Descriptors not found\n");
262 		button_info = ERR_PTR(-ENODEV);
263 		goto out;
264 	}
265 
266 	/* The first package describes the collection */
267 	el0 = &btns_desc->package.elements[0];
268 	if (el0->type == ACPI_TYPE_PACKAGE &&
269 	    el0->package.count == 5 &&
270 	    /* First byte should be 0 (collection) */
271 	    soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 &&
272 	    /* Third byte should be 0 (top level collection) */
273 	    soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) {
274 		collection_uid = soc_button_get_acpi_object_int(
275 						&el0->package.elements[1]);
276 	}
277 	if (collection_uid == -1) {
278 		dev_err(dev, "Invalid Button Collection Descriptor\n");
279 		button_info = ERR_PTR(-ENODEV);
280 		goto out;
281 	}
282 
283 	/* There are package.count - 1 buttons + 1 terminating empty entry */
284 	button_info = devm_kcalloc(dev, btns_desc->package.count,
285 				   sizeof(*button_info), GFP_KERNEL);
286 	if (!button_info) {
287 		button_info = ERR_PTR(-ENOMEM);
288 		goto out;
289 	}
290 
291 	/* Parse the button descriptors */
292 	for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) {
293 		if (soc_button_parse_btn_desc(dev,
294 					      &btns_desc->package.elements[i],
295 					      collection_uid,
296 					      &button_info[btn])) {
297 			button_info = ERR_PTR(-ENODEV);
298 			goto out;
299 		}
300 	}
301 
302 out:
303 	kfree(buf.pointer);
304 	return button_info;
305 }
306 
307 static int soc_button_remove(struct platform_device *pdev)
308 {
309 	struct soc_button_data *priv = platform_get_drvdata(pdev);
310 
311 	int i;
312 
313 	for (i = 0; i < BUTTON_TYPES; i++)
314 		if (priv->children[i])
315 			platform_device_unregister(priv->children[i]);
316 
317 	return 0;
318 }
319 
320 static int soc_button_probe(struct platform_device *pdev)
321 {
322 	struct device *dev = &pdev->dev;
323 	const struct soc_device_data *device_data;
324 	const struct soc_button_info *button_info;
325 	struct soc_button_data *priv;
326 	struct platform_device *pd;
327 	int i;
328 	int error;
329 
330 	device_data = acpi_device_get_match_data(dev);
331 	if (device_data && device_data->check) {
332 		error = device_data->check(dev);
333 		if (error)
334 			return error;
335 	}
336 
337 	if (device_data && device_data->button_info) {
338 		button_info = device_data->button_info;
339 	} else {
340 		button_info = soc_button_get_button_info(dev);
341 		if (IS_ERR(button_info))
342 			return PTR_ERR(button_info);
343 	}
344 
345 	error = gpiod_count(dev, NULL);
346 	if (error < 0) {
347 		dev_dbg(dev, "no GPIO attached, ignoring...\n");
348 		return -ENODEV;
349 	}
350 
351 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
352 	if (!priv)
353 		return -ENOMEM;
354 
355 	platform_set_drvdata(pdev, priv);
356 
357 	for (i = 0; i < BUTTON_TYPES; i++) {
358 		pd = soc_button_device_create(pdev, button_info, i == 0);
359 		if (IS_ERR(pd)) {
360 			error = PTR_ERR(pd);
361 			if (error != -ENODEV) {
362 				soc_button_remove(pdev);
363 				return error;
364 			}
365 			continue;
366 		}
367 
368 		priv->children[i] = pd;
369 	}
370 
371 	if (!priv->children[0] && !priv->children[1])
372 		return -ENODEV;
373 
374 	if (!device_data || !device_data->button_info)
375 		devm_kfree(dev, button_info);
376 
377 	return 0;
378 }
379 
380 /*
381  * Definition of buttons on the tablet. The ACPI index of each button
382  * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
383  * Platforms"
384  */
385 static const struct soc_button_info soc_button_PNP0C40[] = {
386 	{ "power", 0, EV_KEY, KEY_POWER, false, true },
387 	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
388 	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
389 	{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
390 	{ "rotation_lock", 4, EV_KEY, KEY_ROTATE_LOCK_TOGGLE, false, false },
391 	{ }
392 };
393 
394 static const struct soc_device_data soc_device_PNP0C40 = {
395 	.button_info = soc_button_PNP0C40,
396 };
397 
398 /*
399  * Special device check for Surface Book 2 and Surface Pro (2017).
400  * Both, the Surface Pro 4 (surfacepro3_button.c) and the above mentioned
401  * devices use MSHW0040 for power and volume buttons, however the way they
402  * have to be addressed differs. Make sure that we only load this drivers
403  * for the correct devices by checking the OEM Platform Revision provided by
404  * the _DSM method.
405  */
406 #define MSHW0040_DSM_REVISION		0x01
407 #define MSHW0040_DSM_GET_OMPR		0x02	// get OEM Platform Revision
408 static const guid_t MSHW0040_DSM_UUID =
409 	GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
410 		  0x49, 0x80, 0x35);
411 
412 static int soc_device_check_MSHW0040(struct device *dev)
413 {
414 	acpi_handle handle = ACPI_HANDLE(dev);
415 	union acpi_object *result;
416 	u64 oem_platform_rev = 0;	// valid revisions are nonzero
417 
418 	// get OEM platform revision
419 	result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
420 					 MSHW0040_DSM_REVISION,
421 					 MSHW0040_DSM_GET_OMPR, NULL,
422 					 ACPI_TYPE_INTEGER);
423 
424 	if (result) {
425 		oem_platform_rev = result->integer.value;
426 		ACPI_FREE(result);
427 	}
428 
429 	/*
430 	 * If the revision is zero here, the _DSM evaluation has failed. This
431 	 * indicates that we have a Pro 4 or Book 1 and this driver should not
432 	 * be used.
433 	 */
434 	if (oem_platform_rev == 0)
435 		return -ENODEV;
436 
437 	dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev);
438 
439 	return 0;
440 }
441 
442 /*
443  * Button infos for Microsoft Surface Book 2 and Surface Pro (2017).
444  * Obtained from DSDT/testing.
445  */
446 static const struct soc_button_info soc_button_MSHW0040[] = {
447 	{ "power", 0, EV_KEY, KEY_POWER, false, true },
448 	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
449 	{ "volume_down", 4, EV_KEY, KEY_VOLUMEDOWN, true, false },
450 	{ }
451 };
452 
453 static const struct soc_device_data soc_device_MSHW0040 = {
454 	.button_info = soc_button_MSHW0040,
455 	.check = soc_device_check_MSHW0040,
456 };
457 
458 static const struct acpi_device_id soc_button_acpi_match[] = {
459 	{ "PNP0C40", (unsigned long)&soc_device_PNP0C40 },
460 	{ "ACPI0011", 0 },
461 
462 	/* Microsoft Surface Devices (5th and 6th generation) */
463 	{ "MSHW0040", (unsigned long)&soc_device_MSHW0040 },
464 
465 	{ }
466 };
467 
468 MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
469 
470 static struct platform_driver soc_button_driver = {
471 	.probe          = soc_button_probe,
472 	.remove		= soc_button_remove,
473 	.driver		= {
474 		.name = KBUILD_MODNAME,
475 		.acpi_match_table = ACPI_PTR(soc_button_acpi_match),
476 	},
477 };
478 module_platform_driver(soc_button_driver);
479 
480 MODULE_LICENSE("GPL");
481