projects/linux·blob cba3b00d · refs

223 lines · 5.1 KiB

1/*
2 * Supports for the button array on SoC tablets originally running
3 * Windows 8.
4 *
5 * (C) Copyright 2014 Intel Corporation
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; version 2
10 * of the License.
11 */
12
13#include <linux/module.h>
14#include <linux/input.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/acpi.h>
18#include <linux/gpio/consumer.h>
19#include <linux/gpio_keys.h>
20#include <linux/platform_device.h>
21#include <linux/acpi.h>
22
23/*
24 * Definition of buttons on the tablet. The ACPI index of each button
25 * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
26 * Platforms"
27 */
28#define MAX_NBUTTONS 5
29
30struct soc_button_info {
31 const char *name;
32 int acpi_index;
33 unsigned int event_type;
34 unsigned int event_code;
35 bool autorepeat;
36 bool wakeup;
37};
38
39/*
40 * Some of the buttons like volume up/down are auto repeat, while others
41 * are not. To support both, we register two platform devices, and put
42 * buttons into them based on whether the key should be auto repeat.
43 */
44#define BUTTON_TYPES 2
45
46struct soc_button_data {
47 struct platform_device *children[BUTTON_TYPES];
48};
49
50/*
51 * Get the Nth GPIO number from the ACPI object.
52 */
53static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
54{
55 struct gpio_desc *desc;
56 int gpio;
57
58 desc = gpiod_get_index(dev, KBUILD_MODNAME, acpi_index, GPIOD_ASIS);
59 if (IS_ERR(desc))
60 return PTR_ERR(desc);
61
62 gpio = desc_to_gpio(desc);
63
64 gpiod_put(desc);
65
66 return gpio;
67}
68
69static struct platform_device *
70soc_button_device_create(struct platform_device *pdev,
71 const struct soc_button_info *button_info,
72 bool autorepeat)
73{
74 const struct soc_button_info *info;
75 struct platform_device *pd;
76 struct gpio_keys_button *gpio_keys;
77 struct gpio_keys_platform_data *gpio_keys_pdata;
78 int n_buttons = 0;
79 int gpio;
80 int error;
81
82 gpio_keys_pdata = devm_kzalloc(&pdev->dev,
83 sizeof(*gpio_keys_pdata) +
84 sizeof(*gpio_keys) * MAX_NBUTTONS,
85 GFP_KERNEL);
86 if (!gpio_keys_pdata)
87 return ERR_PTR(-ENOMEM);
88
89 gpio_keys = (void *)(gpio_keys_pdata + 1);
90
91 for (info = button_info; info->name; info++) {
92 if (info->autorepeat != autorepeat)
93 continue;
94
95 gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
96 if (gpio < 0)
97 continue;
98
99 gpio_keys[n_buttons].type = info->event_type;
100 gpio_keys[n_buttons].code = info->event_code;
101 gpio_keys[n_buttons].gpio = gpio;
102 gpio_keys[n_buttons].active_low = 1;
103 gpio_keys[n_buttons].desc = info->name;
104 gpio_keys[n_buttons].wakeup = info->wakeup;
105 n_buttons++;
106 }
107
108 if (n_buttons == 0) {
109 error = -ENODEV;
110 goto err_free_mem;
111 }
112
113 gpio_keys_pdata->buttons = gpio_keys;
114 gpio_keys_pdata->nbuttons = n_buttons;
115 gpio_keys_pdata->rep = autorepeat;
116
117 pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
118 if (!pd) {
119 error = -ENOMEM;
120 goto err_free_mem;
121 }
122
123 error = platform_device_add_data(pd, gpio_keys_pdata,
124 sizeof(*gpio_keys_pdata));
125 if (error)
126 goto err_free_pdev;
127
128 error = platform_device_add(pd);
129 if (error)
130 goto err_free_pdev;
131
132 return pd;
133
134err_free_pdev:
135 platform_device_put(pd);
136err_free_mem:
137 devm_kfree(&pdev->dev, gpio_keys_pdata);
138 return ERR_PTR(error);
139}
140
141static int soc_button_remove(struct platform_device *pdev)
142{
143 struct soc_button_data *priv = platform_get_drvdata(pdev);
144
145 int i;
146
147 for (i = 0; i < BUTTON_TYPES; i++)
148 if (priv->children[i])
149 platform_device_unregister(priv->children[i]);
150
151 return 0;
152}
153
154static int soc_button_probe(struct platform_device *pdev)
155{
156 struct device *dev = &pdev->dev;
157 const struct acpi_device_id *id;
158 struct soc_button_info *button_info;
159 struct soc_button_data *priv;
160 struct platform_device *pd;
161 int i;
162 int error;
163
164 id = acpi_match_device(dev->driver->acpi_match_table, dev);
165 if (!id)
166 return -ENODEV;
167
168 button_info = (struct soc_button_info *)id->driver_data;
169
170 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
171 if (!priv)
172 return -ENOMEM;
173
174 platform_set_drvdata(pdev, priv);
175
176 for (i = 0; i < BUTTON_TYPES; i++) {
177 pd = soc_button_device_create(pdev, button_info, i == 0);
178 if (IS_ERR(pd)) {
179 error = PTR_ERR(pd);
180 if (error != -ENODEV) {
181 soc_button_remove(pdev);
182 return error;
183 }
184 continue;
185 }
186
187 priv->children[i] = pd;
188 }
189
190 if (!priv->children[0] && !priv->children[1])
191 return -ENODEV;
192
193 return 0;
194}
195
196static struct soc_button_info soc_button_PNP0C40[] = {
197 { "power", 0, EV_KEY, KEY_POWER, false, true },
198 { "home", 1, EV_KEY, KEY_HOME, false, true },
199 { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
200 { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
201 { "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false },
202 { }
203};
204
205static const struct acpi_device_id soc_button_acpi_match[] = {
206 { "PNP0C40", (unsigned long)soc_button_PNP0C40 },
207 { }
208};
209
210MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
211
212static struct platform_driver soc_button_driver = {
213 .probe = soc_button_probe,
214 .remove = soc_button_remove,
215 .driver = {
216 .name = KBUILD_MODNAME,
217 .owner = THIS_MODULE,
218 .acpi_match_table = ACPI_PTR(soc_button_acpi_match),
219 },
220};
221module_platform_driver(soc_button_driver);
222
223MODULE_LICENSE("GPL");