summaryrefslogtreecommitdiff
path: root/drivers/input/misc/soc_button_array.c
blob: 20c80f543d5e56fbe59f15403f2d64d9cb791cff (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
/*
 * 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/input.h>
#include <linux/platform_device.h>
#include <linux/pnp.h>

/*
 * 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"
 */
#define MAX_NBUTTONS	5

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, KBUILD_MODNAME, acpi_index);
	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 pnp_dev *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;

	gpio_keys_pdata = devm_kzalloc(&pdev->dev,
				       sizeof(*gpio_keys_pdata) +
					sizeof(*gpio_keys) * MAX_NBUTTONS,
				       GFP_KERNEL);
	gpio_keys = (void *)(gpio_keys_pdata + 1);

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

		gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
		if (gpio < 0)
			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;
		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 void soc_button_remove(struct pnp_dev *pdev)
{
	struct soc_button_data *priv = pnp_get_drvdata(pdev);
	int i;

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

static int soc_button_pnp_probe(struct pnp_dev *pdev,
				const struct pnp_device_id *id)
{
	const struct soc_button_info *button_info = (void *)id->driver_data;
	struct soc_button_data *priv;
	struct platform_device *pd;
	int i;
	int error;

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

	pnp_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;

	return 0;
}

static struct soc_button_info soc_button_PNP0C40[] = {
	{ "power", 0, EV_KEY, KEY_POWER, false, true },
	{ "home", 1, EV_KEY, KEY_HOME, 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 pnp_device_id soc_button_pnp_match[] = {
	{ .id = "PNP0C40", .driver_data = (long)soc_button_PNP0C40 },
	{ .id = "" }
};
MODULE_DEVICE_TABLE(pnp, soc_button_pnp_match);

static struct pnp_driver soc_button_pnp_driver = {
	.name		= KBUILD_MODNAME,
	.id_table	= soc_button_pnp_match,
	.probe          = soc_button_pnp_probe,
	.remove		= soc_button_remove,
};

static int __init soc_button_init(void)
{
	return pnp_register_driver(&soc_button_pnp_driver);
}

static void __exit soc_button_exit(void)
{
	pnp_unregister_driver(&soc_button_pnp_driver);
}

module_init(soc_button_init);
module_exit(soc_button_exit);

MODULE_LICENSE("GPL");