1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * ACPI Direct App Launch driver 4 * 5 * Copyright (C) 2024 Armin Wolf <W_Armin@gmx.de> 6 * Copyright (C) 2022 Arvid Norlander <lkml@vorapal.se> 7 * Copyright (C) 2007-2010 Angelo Arrifano <miknix@gmail.com> 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 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 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 */ 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 } 146 147 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 } 156 157 static void quickstart_mutex_destroy(void *data) 158 { 159 struct mutex *lock = data; 160 161 mutex_destroy(lock); 162 } 163 164 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 <W_Armin@gmx.de>"); 242 MODULE_AUTHOR("Arvid Norlander <lkml@vorpal.se>"); 243 MODULE_AUTHOR("Angelo Arrifano"); 244 MODULE_DESCRIPTION("ACPI Direct App Launch driver"); 245 MODULE_LICENSE("GPL"); 246