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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1a64b719 BT |
2 | /* |
3 | * Supports for the button array on the Surface tablets. | |
4 | * | |
5 | * (C) Copyright 2016 Red Hat, Inc | |
6 | * | |
7 | * Based on soc_button_array.c: | |
8 | * | |
9 | * {C} Copyright 2014 Intel Corporation | |
1a64b719 BT |
10 | */ |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/input.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/i2c.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/acpi.h> | |
19 | #include <linux/gpio/consumer.h> | |
20 | #include <linux/gpio_keys.h> | |
21 | #include <linux/gpio.h> | |
22 | #include <linux/platform_device.h> | |
23 | ||
24 | ||
25 | #define SURFACE_BUTTON_OBJ_NAME "TEV2" | |
26 | #define MAX_NBUTTONS 4 | |
27 | ||
28 | /* | |
29 | * Some of the buttons like volume up/down are auto repeat, while others | |
30 | * are not. To support both, we register two platform devices, and put | |
31 | * buttons into them based on whether the key should be auto repeat. | |
32 | */ | |
33 | #define BUTTON_TYPES 2 | |
34 | ||
35 | /* | |
36 | * Power button, Home button, Volume buttons support is supposed to | |
37 | * be covered by drivers/input/misc/soc_button_array.c, which is implemented | |
38 | * according to "Windows ACPI Design Guide for SoC Platforms". | |
39 | * However surface 3 seems not to obey the specs, instead it uses | |
40 | * device TEV2(MSHW0028) for declaring the GPIOs. The gpios are also slightly | |
41 | * different in which the Home button is active high. | |
42 | * Compared to surfacepro3_button.c which also handles MSHW0028, the Surface 3 | |
43 | * is a reduce platform and thus uses GPIOs, not ACPI events. | |
44 | * We choose an I2C driver here because we need to access the resources | |
45 | * declared under the device node, while surfacepro3_button.c only needs | |
46 | * the ACPI companion node. | |
47 | */ | |
48 | static const struct acpi_device_id surface3_acpi_match[] = { | |
49 | { "MSHW0028", 0 }, | |
50 | { } | |
51 | }; | |
52 | MODULE_DEVICE_TABLE(acpi, surface3_acpi_match); | |
53 | ||
54 | struct surface3_button_info { | |
55 | const char *name; | |
56 | int acpi_index; | |
57 | unsigned int event_type; | |
58 | unsigned int event_code; | |
59 | bool autorepeat; | |
60 | bool wakeup; | |
61 | bool active_low; | |
62 | }; | |
63 | ||
64 | struct surface3_button_data { | |
65 | struct platform_device *children[BUTTON_TYPES]; | |
66 | }; | |
67 | ||
68 | /* | |
69 | * Get the Nth GPIO number from the ACPI object. | |
70 | */ | |
71 | static int surface3_button_lookup_gpio(struct device *dev, int acpi_index) | |
72 | { | |
73 | struct gpio_desc *desc; | |
74 | int gpio; | |
75 | ||
76 | desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS); | |
77 | if (IS_ERR(desc)) | |
78 | return PTR_ERR(desc); | |
79 | ||
80 | gpio = desc_to_gpio(desc); | |
81 | ||
82 | gpiod_put(desc); | |
83 | ||
84 | return gpio; | |
85 | } | |
86 | ||
87 | static struct platform_device * | |
88 | surface3_button_device_create(struct i2c_client *client, | |
89 | const struct surface3_button_info *button_info, | |
90 | bool autorepeat) | |
91 | { | |
92 | const struct surface3_button_info *info; | |
93 | struct platform_device *pd; | |
94 | struct gpio_keys_button *gpio_keys; | |
95 | struct gpio_keys_platform_data *gpio_keys_pdata; | |
96 | int n_buttons = 0; | |
97 | int gpio; | |
98 | int error; | |
99 | ||
100 | gpio_keys_pdata = devm_kzalloc(&client->dev, | |
101 | sizeof(*gpio_keys_pdata) + | |
102 | sizeof(*gpio_keys) * MAX_NBUTTONS, | |
103 | GFP_KERNEL); | |
104 | if (!gpio_keys_pdata) | |
105 | return ERR_PTR(-ENOMEM); | |
106 | ||
107 | gpio_keys = (void *)(gpio_keys_pdata + 1); | |
108 | ||
109 | for (info = button_info; info->name; info++) { | |
110 | if (info->autorepeat != autorepeat) | |
111 | continue; | |
112 | ||
113 | gpio = surface3_button_lookup_gpio(&client->dev, | |
114 | info->acpi_index); | |
115 | if (!gpio_is_valid(gpio)) | |
116 | continue; | |
117 | ||
118 | gpio_keys[n_buttons].type = info->event_type; | |
119 | gpio_keys[n_buttons].code = info->event_code; | |
120 | gpio_keys[n_buttons].gpio = gpio; | |
121 | gpio_keys[n_buttons].active_low = info->active_low; | |
122 | gpio_keys[n_buttons].desc = info->name; | |
123 | gpio_keys[n_buttons].wakeup = info->wakeup; | |
124 | n_buttons++; | |
125 | } | |
126 | ||
127 | if (n_buttons == 0) { | |
128 | error = -ENODEV; | |
129 | goto err_free_mem; | |
130 | } | |
131 | ||
132 | gpio_keys_pdata->buttons = gpio_keys; | |
133 | gpio_keys_pdata->nbuttons = n_buttons; | |
134 | gpio_keys_pdata->rep = autorepeat; | |
135 | ||
136 | pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO); | |
137 | if (!pd) { | |
138 | error = -ENOMEM; | |
139 | goto err_free_mem; | |
140 | } | |
141 | ||
142 | error = platform_device_add_data(pd, gpio_keys_pdata, | |
143 | sizeof(*gpio_keys_pdata)); | |
144 | if (error) | |
145 | goto err_free_pdev; | |
146 | ||
147 | error = platform_device_add(pd); | |
148 | if (error) | |
149 | goto err_free_pdev; | |
150 | ||
151 | return pd; | |
152 | ||
153 | err_free_pdev: | |
154 | platform_device_put(pd); | |
155 | err_free_mem: | |
156 | devm_kfree(&client->dev, gpio_keys_pdata); | |
157 | return ERR_PTR(error); | |
158 | } | |
159 | ||
160 | static int surface3_button_remove(struct i2c_client *client) | |
161 | { | |
162 | struct surface3_button_data *priv = i2c_get_clientdata(client); | |
163 | ||
164 | int i; | |
165 | ||
166 | for (i = 0; i < BUTTON_TYPES; i++) | |
167 | if (priv->children[i]) | |
168 | platform_device_unregister(priv->children[i]); | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
173 | static struct surface3_button_info surface3_button_surface3[] = { | |
174 | { "power", 0, EV_KEY, KEY_POWER, false, true, true }, | |
175 | { "home", 1, EV_KEY, KEY_LEFTMETA, false, true, false }, | |
176 | { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true }, | |
177 | { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true }, | |
178 | { } | |
179 | }; | |
180 | ||
181 | static int surface3_button_probe(struct i2c_client *client, | |
182 | const struct i2c_device_id *id) | |
183 | { | |
184 | struct device *dev = &client->dev; | |
185 | struct surface3_button_data *priv; | |
186 | struct platform_device *pd; | |
187 | int i; | |
188 | int error; | |
189 | ||
190 | if (strncmp(acpi_device_bid(ACPI_COMPANION(&client->dev)), | |
191 | SURFACE_BUTTON_OBJ_NAME, | |
192 | strlen(SURFACE_BUTTON_OBJ_NAME))) | |
193 | return -ENODEV; | |
194 | ||
562e7a40 AS |
195 | error = gpiod_count(dev, NULL); |
196 | if (error < 0) { | |
1a64b719 | 197 | dev_dbg(dev, "no GPIO attached, ignoring...\n"); |
562e7a40 | 198 | return error; |
1a64b719 BT |
199 | } |
200 | ||
201 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); | |
202 | if (!priv) | |
203 | return -ENOMEM; | |
204 | ||
205 | i2c_set_clientdata(client, priv); | |
206 | ||
207 | for (i = 0; i < BUTTON_TYPES; i++) { | |
208 | pd = surface3_button_device_create(client, | |
209 | surface3_button_surface3, | |
210 | i == 0); | |
211 | if (IS_ERR(pd)) { | |
212 | error = PTR_ERR(pd); | |
213 | if (error != -ENODEV) { | |
214 | surface3_button_remove(client); | |
215 | return error; | |
216 | } | |
217 | continue; | |
218 | } | |
219 | ||
220 | priv->children[i] = pd; | |
221 | } | |
222 | ||
223 | if (!priv->children[0] && !priv->children[1]) | |
224 | return -ENODEV; | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static const struct i2c_device_id surface3_id[] = { | |
230 | { } | |
231 | }; | |
232 | MODULE_DEVICE_TABLE(i2c, surface3_id); | |
233 | ||
234 | static struct i2c_driver surface3_driver = { | |
235 | .probe = surface3_button_probe, | |
236 | .remove = surface3_button_remove, | |
237 | .id_table = surface3_id, | |
238 | .driver = { | |
239 | .name = "surface3", | |
240 | .acpi_match_table = ACPI_PTR(surface3_acpi_match), | |
241 | }, | |
242 | }; | |
243 | module_i2c_driver(surface3_driver); | |
244 | ||
245 | MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>"); | |
246 | MODULE_DESCRIPTION("surface3 button array driver"); | |
247 | MODULE_LICENSE("GPL v2"); |