summaryrefslogtreecommitdiffstats
path: root/drivers/input/misc/soc_button_array.c
blob: e37d37273182097d412f30a3878ea0303f9f7a5b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
/*
 * Supports for the button array on SoC tablets originally running
 * Windows 8.
 *
 * (C) Copyright 2014 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio_keys.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>

struct soc_button_info {
	const char *name;
	int acpi_index;
	unsigned int event_type;
	unsigned int event_code;
	bool autorepeat;
	bool wakeup;
};

/*
 * Some of the buttons like volume up/down are auto repeat, while others
 * are not. To support both, we register two platform devices, and put
 * buttons into them based on whether the key should be auto repeat.
 */
#define BUTTON_TYPES	2

struct soc_button_data {
	struct platform_device *children[BUTTON_TYPES];
};

/*
 * Get the Nth GPIO number from the ACPI object.
 */
static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
{
	struct gpio_desc *desc;
	int gpio;

	desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	gpio = desc_to_gpio(desc);

	gpiod_put(desc);

	return gpio;
}

static struct platform_device *
soc_button_device_create(struct platform_device *pdev,
			 const struct soc_button_info *button_info,
			 bool autorepeat)
{
	const struct soc_button_info *info;
	struct platform_device *pd;
	struct gpio_keys_button *gpio_keys;
	struct gpio_keys_platform_data *gpio_keys_pdata;
	int n_buttons = 0;
	int gpio;
	int error;

	for (info = button_info; info->name; info++)
		if (info->autorepeat == autorepeat)
			n_buttons++;

	gpio_keys_pdata = devm_kzalloc(&pdev->dev,
				       sizeof(*gpio_keys_pdata) +
					sizeof(*gpio_keys) * n_buttons,
				       GFP_KERNEL);
	if (!gpio_keys_pdata)
		return ERR_PTR(-ENOMEM);

	gpio_keys = (void *)(gpio_keys_pdata + 1);
	n_buttons = 0;

	for (info = button_info; info->name; info++) {
		if (info->autorepeat != autorepeat)
			continue;

		gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
		if (!gpio_is_valid(gpio))
			continue;

		gpio_keys[n_buttons].type = info->event_type;
		gpio_keys[n_buttons].code = info->event_code;
		gpio_keys[n_buttons].gpio = gpio;
		gpio_keys[n_buttons].active_low = 1;
		gpio_keys[n_buttons].desc = info->name;
		gpio_keys[n_buttons].wakeup = info->wakeup;
		/* These devices often use cheap buttons, use 50 ms debounce */
		gpio_keys[n_buttons].debounce_interval = 50;
		n_buttons++;
	}

	if (n_buttons == 0) {
		error = -ENODEV;
		goto err_free_mem;
	}

	gpio_keys_pdata->buttons = gpio_keys;
	gpio_keys_pdata->nbuttons = n_buttons;
	gpio_keys_pdata->rep = autorepeat;

	pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
	if (!pd) {
		error = -ENOMEM;
		goto err_free_mem;
	}

	error = platform_device_add_data(pd, gpio_keys_pdata,
					 sizeof(*gpio_keys_pdata));
	if (error)
		goto err_free_pdev;

	error = platform_device_add(pd);
	if (error)
		goto err_free_pdev;

	return pd;

err_free_pdev:
	platform_device_put(pd);
err_free_mem:
	devm_kfree(&pdev->dev, gpio_keys_pdata);
	return ERR_PTR(error);
}

static int soc_button_get_acpi_object_int(const union acpi_object *obj)
{
	if (obj->type != ACPI_TYPE_INTEGER)
		return -1;

	return obj->integer.value;
}

/* Parse a single ACPI0011 _DSD button descriptor */
static int soc_button_parse_btn_desc(struct device *dev,
				     const union acpi_object *desc,
				     int collection_uid,
				     struct soc_button_info *info)
{
	int upage, usage;

	if (desc->type != ACPI_TYPE_PACKAGE ||
	    desc->package.count != 5 ||
	    /* First byte should be 1 (control) */
	    soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
	    /* Third byte should be collection uid */
	    soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
							    collection_uid) {
		dev_err(dev, "Invalid ACPI Button Descriptor\n");
		return -ENODEV;
	}

	info->event_type = EV_KEY;
	info->acpi_index =
		soc_button_get_acpi_object_int(&desc->package.elements[1]);
	upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
	usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);

	/*
	 * The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
	 * usage page and usage codes, but otherwise the device is not HID
	 * compliant: it uses one irq per button instead of generating HID
	 * input reports and some buttons should generate wakeups where as
	 * others should not, so we cannot use the HID subsystem.
	 *
	 * Luckily all devices only use a few usage page + usage combinations,
	 * so we can simply check for the known combinations here.
	 */
	if (upage == 0x01 && usage == 0x81) {
		info->name = "power";
		info->event_code = KEY_POWER;
		info->wakeup = true;
	} else if (upage == 0x07 && usage == 0xe3) {
		info->name = "home";
		info->event_code = KEY_LEFTMETA;
		info->wakeup = true;
	} else if (upage == 0x0c && usage == 0xe9) {
		info->name = "volume_up";
		info->event_code = KEY_VOLUMEUP;
		info->autorepeat = true;
	} else if (upage == 0x0c && usage == 0xea) {
		info->name = "volume_down";
		info->event_code = KEY_VOLUMEDOWN;
		info->autorepeat = true;
	} else {
		dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n",
			 info->acpi_index, upage, usage);
		info->name = "unknown";
		info->event_code = KEY_RESERVED;
	}

	return 0;
}

/* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */
static const u8 btns_desc_uuid[16] = {
	0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47,
	0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e
};

/* Parse ACPI0011 _DSD button descriptors */
static struct soc_button_info *soc_button_get_button_info(struct device *dev)
{
	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
	const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL;
	struct soc_button_info *button_info;
	acpi_status status;
	int i, btn, collection_uid = -1;

	status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL,
					    &buf, ACPI_TYPE_PACKAGE);
	if (ACPI_FAILURE(status)) {
		dev_err(dev, "ACPI _DSD object not found\n");
		return ERR_PTR(-ENODEV);
	}

	/* Look for the Button Descriptors UUID */
	desc = buf.pointer;
	for (i = 0; (i + 1) < desc->package.count; i += 2) {
		uuid = &desc->package.elements[i];

		if (uuid->type != ACPI_TYPE_BUFFER ||
		    uuid->buffer.length != 16 ||
		    desc->package.elements[i + 1].type != ACPI_TYPE_PACKAGE) {
			break;
		}

		if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) {
			btns_desc = &desc->package.elements[i + 1];
			break;
		}
	}

	if (!btns_desc) {
		dev_err(dev, "ACPI Button Descriptors not found\n");
		return ERR_PTR(-ENODEV);
	}

	/* The first package describes the collection */
	el0 = &btns_desc->package.elements[0];
	if (el0->type == ACPI_TYPE_PACKAGE &&
	    el0->package.count == 5 &&
	    /* First byte should be 0 (collection) */
	    soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 &&
	    /* Third byte should be 0 (top level collection) */
	    soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) {
		collection_uid = soc_button_get_acpi_object_int(
						&el0->package.elements[1]);
	}
	if (collection_uid == -1) {
		dev_err(dev, "Invalid Button Collection Descriptor\n");
		return ERR_PTR(-ENODEV);
	}

	/* There are package.count - 1 buttons + 1 terminating empty entry */
	button_info = devm_kcalloc(dev, btns_desc->package.count,
				   sizeof(*button_info), GFP_KERNEL);
	if (!button_info)
		return ERR_PTR(-ENOMEM);

	/* Parse the button descriptors */
	for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) {
		if (soc_button_parse_btn_desc(dev,
					      &btns_desc->package.elements[i],
					      collection_uid,
					      &button_info[btn]))
			return ERR_PTR(-ENODEV);
	}

	return button_info;
}

static int soc_button_remove(struct platform_device *pdev)
{
	struct soc_button_data *priv = platform_get_drvdata(pdev);

	int i;

	for (i = 0; i < BUTTON_TYPES; i++)
		if (priv->children[i])
			platform_device_unregister(priv->children[i]);

	return 0;
}

static int soc_button_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	const struct acpi_device_id *id;
	struct soc_button_info *button_info;
	struct soc_button_data *priv;
	struct platform_device *pd;
	int i;
	int error;

	id = acpi_match_device(dev->driver->acpi_match_table, dev);
	if (!id)
		return -ENODEV;

	if (!id->driver_data) {
		button_info = soc_button_get_button_info(dev);
		if (IS_ERR(button_info))
			return PTR_ERR(button_info);
	} else {
		button_info = (struct soc_button_info *)id->driver_data;
	}

	error = gpiod_count(dev, NULL);
	if (error < 0) {
		dev_dbg(dev, "no GPIO attached, ignoring...\n");
		return error;
	}

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	platform_set_drvdata(pdev, priv);

	for (i = 0; i < BUTTON_TYPES; i++) {
		pd = soc_button_device_create(pdev, button_info, i == 0);
		if (IS_ERR(pd)) {
			error = PTR_ERR(pd);
			if (error != -ENODEV) {
				soc_button_remove(pdev);
				return error;
			}
			continue;
		}

		priv->children[i] = pd;
	}

	if (!priv->children[0] && !priv->children[1])
		return -ENODEV;

	if (!id->driver_data)
		devm_kfree(dev, button_info);

	return 0;
}

/*
 * Definition of buttons on the tablet. The ACPI index of each button
 * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
 * Platforms"
 */
static struct soc_button_info soc_button_PNP0C40[] = {
	{ "power", 0, EV_KEY, KEY_POWER, false, true },
	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
	{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
	{ "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false },
	{ }
};

static const struct acpi_device_id soc_button_acpi_match[] = {
	{ "PNP0C40", (unsigned long)soc_button_PNP0C40 },
	{ "ACPI0011", 0 },
	{ }
};

MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);

static struct platform_driver soc_button_driver = {
	.probe          = soc_button_probe,
	.remove		= soc_button_remove,
	.driver		= {
		.name = KBUILD_MODNAME,
		.acpi_match_table = ACPI_PTR(soc_button_acpi_match),
	},
};
module_platform_driver(soc_button_driver);

MODULE_LICENSE("GPL");