1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * ACPI Direct App Launch driver
4 *
5 * Copyright (C) 2024 Armin Wolf <[email protected]>
6 * Copyright (C) 2022 Arvid Norlander <[email protected]>
7 * Copyright (C) 2007-2010 Angelo Arrifano <[email protected]>
8 *
9 * Information gathered from disassembled dsdt and from here:
10 * <https://archive.org/details/microsoft-acpi-dirapplaunch>
11 */
12
13 #include <linux/acpi.h>
14 #include <linux/device.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/input.h>
18 #include <linux/input/sparse-keymap.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/platform_device.h>
23 #include <linux/printk.h>
24 #include <linux/slab.h>
25 #include <linux/sysfs.h>
26 #include <linux/types.h>
27
28 #include <linux/unaligned.h>
29
30 #define DRIVER_NAME "quickstart"
31
32 /*
33 * There will be two events:
34 * 0x02 - Button was pressed while device was off/sleeping.
35 * 0x80 - Button was pressed while device was up.
36 */
37 #define QUICKSTART_EVENT_RUNTIME 0x80
38
39 struct quickstart_data {
40 struct device *dev;
41 struct mutex input_lock; /* Protects input sequence during notify */
42 struct input_dev *input_device;
43 char input_name[32];
44 char phys[32];
45 u32 id;
46 };
47
48 /*
49 * Knowing what these buttons do require system specific knowledge.
50 * This could be done by matching on DMI data in a long quirk table.
51 * However, it is easier to leave it up to user space to figure this out.
52 *
53 * Using for example udev hwdb the scancode 0x1 can be remapped suitably.
54 */
55 static const struct key_entry quickstart_keymap[] = {
56 { KE_KEY, 0x1, { KEY_UNKNOWN } },
57 { KE_END, 0 },
58 };
59
button_id_show(struct device * dev,struct device_attribute * attr,char * buf)60 static ssize_t button_id_show(struct device *dev, struct device_attribute *attr, char *buf)
61 {
62 struct quickstart_data *data = dev_get_drvdata(dev);
63
64 return sysfs_emit(buf, "%u\n", data->id);
65 }
66 static DEVICE_ATTR_RO(button_id);
67
68 static struct attribute *quickstart_attrs[] = {
69 &dev_attr_button_id.attr,
70 NULL
71 };
72 ATTRIBUTE_GROUPS(quickstart);
73
quickstart_notify(acpi_handle handle,u32 event,void * context)74 static void quickstart_notify(acpi_handle handle, u32 event, void *context)
75 {
76 struct quickstart_data *data = context;
77
78 switch (event) {
79 case QUICKSTART_EVENT_RUNTIME:
80 mutex_lock(&data->input_lock);
81 sparse_keymap_report_event(data->input_device, 0x1, 1, true);
82 mutex_unlock(&data->input_lock);
83
84 acpi_bus_generate_netlink_event(DRIVER_NAME, dev_name(data->dev), event, 0);
85 break;
86 default:
87 dev_err(data->dev, FW_INFO "Unexpected ACPI notify event (%u)\n", event);
88 break;
89 }
90 }
91
92 /*
93 * The GHID ACPI method is used to indicate the "role" of the button.
94 * However, all the meanings of these values are vendor defined.
95 *
96 * We do however expose this value to user space.
97 */
quickstart_get_ghid(struct quickstart_data * data)98 static int quickstart_get_ghid(struct quickstart_data *data)
99 {
100 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
101 acpi_handle handle = ACPI_HANDLE(data->dev);
102 union acpi_object *obj;
103 acpi_status status;
104 int ret = 0;
105
106 /*
107 * This returns a buffer telling the button usage ID,
108 * and triggers pending notify events (The ones before booting).
109 */
110 status = acpi_evaluate_object_typed(handle, "GHID", NULL, &buffer, ACPI_TYPE_BUFFER);
111 if (ACPI_FAILURE(status))
112 return -EIO;
113
114 obj = buffer.pointer;
115 if (!obj)
116 return -ENODATA;
117
118 /*
119 * Quoting the specification:
120 * "The GHID method can return a BYTE, WORD, or DWORD.
121 * The value must be encoded in little-endian byte
122 * order (least significant byte first)."
123 */
124 switch (obj->buffer.length) {
125 case 1:
126 data->id = obj->buffer.pointer[0];
127 break;
128 case 2:
129 data->id = get_unaligned_le16(obj->buffer.pointer);
130 break;
131 case 4:
132 data->id = get_unaligned_le32(obj->buffer.pointer);
133 break;
134 default:
135 dev_err(data->dev,
136 FW_BUG "GHID method returned buffer of unexpected length %u\n",
137 obj->buffer.length);
138 ret = -EIO;
139 break;
140 }
141
142 kfree(obj);
143
144 return ret;
145 }
146
quickstart_notify_remove(void * context)147 static void quickstart_notify_remove(void *context)
148 {
149 struct quickstart_data *data = context;
150 acpi_handle handle;
151
152 handle = ACPI_HANDLE(data->dev);
153
154 acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, quickstart_notify);
155 }
156
quickstart_mutex_destroy(void * data)157 static void quickstart_mutex_destroy(void *data)
158 {
159 struct mutex *lock = data;
160
161 mutex_destroy(lock);
162 }
163
quickstart_probe(struct platform_device * pdev)164 static int quickstart_probe(struct platform_device *pdev)
165 {
166 struct quickstart_data *data;
167 acpi_handle handle;
168 acpi_status status;
169 int ret;
170
171 handle = ACPI_HANDLE(&pdev->dev);
172 if (!handle)
173 return -ENODEV;
174
175 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
176 if (!data)
177 return -ENOMEM;
178
179 data->dev = &pdev->dev;
180 dev_set_drvdata(&pdev->dev, data);
181
182 mutex_init(&data->input_lock);
183 ret = devm_add_action_or_reset(&pdev->dev, quickstart_mutex_destroy, &data->input_lock);
184 if (ret < 0)
185 return ret;
186
187 /*
188 * We have to initialize the device wakeup before evaluating GHID because
189 * doing so will notify the device if the button was used to wake the machine
190 * from S5.
191 */
192 device_init_wakeup(&pdev->dev, true);
193
194 ret = quickstart_get_ghid(data);
195 if (ret < 0)
196 return ret;
197
198 data->input_device = devm_input_allocate_device(&pdev->dev);
199 if (!data->input_device)
200 return -ENOMEM;
201
202 ret = sparse_keymap_setup(data->input_device, quickstart_keymap, NULL);
203 if (ret < 0)
204 return ret;
205
206 snprintf(data->input_name, sizeof(data->input_name), "Quickstart Button %u", data->id);
207 snprintf(data->phys, sizeof(data->phys), DRIVER_NAME "/input%u", data->id);
208
209 data->input_device->name = data->input_name;
210 data->input_device->phys = data->phys;
211 data->input_device->id.bustype = BUS_HOST;
212
213 ret = input_register_device(data->input_device);
214 if (ret < 0)
215 return ret;
216
217 status = acpi_install_notify_handler(handle, ACPI_DEVICE_NOTIFY, quickstart_notify, data);
218 if (ACPI_FAILURE(status))
219 return -EIO;
220
221 return devm_add_action_or_reset(&pdev->dev, quickstart_notify_remove, data);
222 }
223
224 static const struct acpi_device_id quickstart_device_ids[] = {
225 { "PNP0C32" },
226 { }
227 };
228 MODULE_DEVICE_TABLE(acpi, quickstart_device_ids);
229
230 static struct platform_driver quickstart_platform_driver = {
231 .driver = {
232 .name = DRIVER_NAME,
233 .dev_groups = quickstart_groups,
234 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
235 .acpi_match_table = quickstart_device_ids,
236 },
237 .probe = quickstart_probe,
238 };
239 module_platform_driver(quickstart_platform_driver);
240
241 MODULE_AUTHOR("Armin Wolf <[email protected]>");
242 MODULE_AUTHOR("Arvid Norlander <[email protected]>");
243 MODULE_AUTHOR("Angelo Arrifano");
244 MODULE_DESCRIPTION("ACPI Direct App Launch driver");
245 MODULE_LICENSE("GPL");
246