summaryrefslogtreecommitdiff
path: root/drivers/platform/surface/surface3_button.c
blob: 48d77e7aae76340d8f9a9745a75d46e3111899e8 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Supports for the button array on the Surface tablets.
 *
 * (C) Copyright 2016 Red Hat, Inc
 *
 * Based on soc_button_array.c:
 *
 * {C} Copyright 2014 Intel Corporation
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio_keys.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>


#define SURFACE_BUTTON_OBJ_NAME		"TEV2"
#define MAX_NBUTTONS			4

/*
 * 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

/*
 * Power button, Home button, Volume buttons support is supposed to
 * be covered by drivers/input/misc/soc_button_array.c, which is implemented
 * according to "Windows ACPI Design Guide for SoC Platforms".
 * However surface 3 seems not to obey the specs, instead it uses
 * device TEV2(MSHW0028) for declaring the GPIOs. The gpios are also slightly
 * different in which the Home button is active high.
 * Compared to surfacepro3_button.c which also handles MSHW0028, the Surface 3
 * is a reduce platform and thus uses GPIOs, not ACPI events.
 * We choose an I2C driver here because we need to access the resources
 * declared under the device node, while surfacepro3_button.c only needs
 * the ACPI companion node.
 */
static const struct acpi_device_id surface3_acpi_match[] = {
	{ "MSHW0028", 0 },
	{ }
};
MODULE_DEVICE_TABLE(acpi, surface3_acpi_match);

struct surface3_button_info {
	const char *name;
	int acpi_index;
	unsigned int event_type;
	unsigned int event_code;
	bool autorepeat;
	bool wakeup;
	bool active_low;
};

struct surface3_button_data {
	struct platform_device *children[BUTTON_TYPES];
};

/*
 * Get the Nth GPIO number from the ACPI object.
 */
static int surface3_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 *
surface3_button_device_create(struct i2c_client *client,
			      const struct surface3_button_info *button_info,
			      bool autorepeat)
{
	const struct surface3_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;

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

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

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

		gpio = surface3_button_lookup_gpio(&client->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 = info->active_low;
		gpio_keys[n_buttons].desc = info->name;
		gpio_keys[n_buttons].wakeup = info->wakeup;
		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(&client->dev, gpio_keys_pdata);
	return ERR_PTR(error);
}

static int surface3_button_remove(struct i2c_client *client)
{
	struct surface3_button_data *priv = i2c_get_clientdata(client);

	int i;

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

	return 0;
}

static struct surface3_button_info surface3_button_surface3[] = {
	{ "power", 0, EV_KEY, KEY_POWER, false, true, true },
	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true, false },
	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true },
	{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true },
	{ }
};

static int surface3_button_probe(struct i2c_client *client,
				 const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct surface3_button_data *priv;
	struct platform_device *pd;
	int i;
	int error;

	if (strncmp(acpi_device_bid(ACPI_COMPANION(&client->dev)),
		    SURFACE_BUTTON_OBJ_NAME,
		    strlen(SURFACE_BUTTON_OBJ_NAME)))
		return -ENODEV;

	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;

	i2c_set_clientdata(client, priv);

	for (i = 0; i < BUTTON_TYPES; i++) {
		pd = surface3_button_device_create(client,
						   surface3_button_surface3,
						   i == 0);
		if (IS_ERR(pd)) {
			error = PTR_ERR(pd);
			if (error != -ENODEV) {
				surface3_button_remove(client);
				return error;
			}
			continue;
		}

		priv->children[i] = pd;
	}

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

	return 0;
}

static const struct i2c_device_id surface3_id[] = {
	{ }
};
MODULE_DEVICE_TABLE(i2c, surface3_id);

static struct i2c_driver surface3_driver = {
	.probe = surface3_button_probe,
	.remove = surface3_button_remove,
	.id_table = surface3_id,
	.driver = {
		.name = "surface3",
		.acpi_match_table = ACPI_PTR(surface3_acpi_match),
	},
};
module_i2c_driver(surface3_driver);

MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_DESCRIPTION("surface3 button array driver");
MODULE_LICENSE("GPL v2");