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