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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * ACPI Direct App Launch driver4 *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/pm_wakeup.h>24#include <linux/printk.h>25#include <linux/slab.h>26#include <linux/sysfs.h>27#include <linux/types.h>28 29#include <linux/unaligned.h>30 31#define DRIVER_NAME "quickstart"32 33/*34 * There will be two events:35 * 0x02 - Button was pressed while device was off/sleeping.36 * 0x80 - Button was pressed while device was up.37 */38#define QUICKSTART_EVENT_RUNTIME 0x8039 40struct quickstart_data {41 struct device *dev;42 struct mutex input_lock; /* Protects input sequence during notify */43 struct input_dev *input_device;44 char input_name[32];45 char phys[32];46 u32 id;47};48 49/*50 * Knowing what these buttons do require system specific knowledge.51 * This could be done by matching on DMI data in a long quirk table.52 * However, it is easier to leave it up to user space to figure this out.53 *54 * Using for example udev hwdb the scancode 0x1 can be remapped suitably.55 */56static const struct key_entry quickstart_keymap[] = {57 { KE_KEY, 0x1, { KEY_UNKNOWN } },58 { KE_END, 0 },59};60 61static ssize_t button_id_show(struct device *dev, struct device_attribute *attr, char *buf)62{63 struct quickstart_data *data = dev_get_drvdata(dev);64 65 return sysfs_emit(buf, "%u\n", data->id);66}67static DEVICE_ATTR_RO(button_id);68 69static struct attribute *quickstart_attrs[] = {70 &dev_attr_button_id.attr,71 NULL72};73ATTRIBUTE_GROUPS(quickstart);74 75static void quickstart_notify(acpi_handle handle, u32 event, void *context)76{77 struct quickstart_data *data = context;78 79 switch (event) {80 case QUICKSTART_EVENT_RUNTIME:81 mutex_lock(&data->input_lock);82 sparse_keymap_report_event(data->input_device, 0x1, 1, true);83 mutex_unlock(&data->input_lock);84 85 acpi_bus_generate_netlink_event(DRIVER_NAME, dev_name(data->dev), event, 0);86 break;87 default:88 dev_err(data->dev, FW_INFO "Unexpected ACPI notify event (%u)\n", event);89 break;90 }91}92 93/*94 * The GHID ACPI method is used to indicate the "role" of the button.95 * However, all the meanings of these values are vendor defined.96 *97 * We do however expose this value to user space.98 */99static int quickstart_get_ghid(struct quickstart_data *data)100{101 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };102 acpi_handle handle = ACPI_HANDLE(data->dev);103 union acpi_object *obj;104 acpi_status status;105 int ret = 0;106 107 /*108 * This returns a buffer telling the button usage ID,109 * and triggers pending notify events (The ones before booting).110 */111 status = acpi_evaluate_object_typed(handle, "GHID", NULL, &buffer, ACPI_TYPE_BUFFER);112 if (ACPI_FAILURE(status))113 return -EIO;114 115 obj = buffer.pointer;116 if (!obj)117 return -ENODATA;118 119 /*120 * Quoting the specification:121 * "The GHID method can return a BYTE, WORD, or DWORD.122 * The value must be encoded in little-endian byte123 * order (least significant byte first)."124 */125 switch (obj->buffer.length) {126 case 1:127 data->id = obj->buffer.pointer[0];128 break;129 case 2:130 data->id = get_unaligned_le16(obj->buffer.pointer);131 break;132 case 4:133 data->id = get_unaligned_le32(obj->buffer.pointer);134 break;135 default:136 dev_err(data->dev,137 FW_BUG "GHID method returned buffer of unexpected length %u\n",138 obj->buffer.length);139 ret = -EIO;140 break;141 }142 143 kfree(obj);144 145 return ret;146}147 148static void quickstart_notify_remove(void *context)149{150 struct quickstart_data *data = context;151 acpi_handle handle;152 153 handle = ACPI_HANDLE(data->dev);154 155 acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, quickstart_notify);156}157 158static void quickstart_mutex_destroy(void *data)159{160 struct mutex *lock = data;161 162 mutex_destroy(lock);163}164 165static int quickstart_probe(struct platform_device *pdev)166{167 struct quickstart_data *data;168 acpi_handle handle;169 acpi_status status;170 int ret;171 172 handle = ACPI_HANDLE(&pdev->dev);173 if (!handle)174 return -ENODEV;175 176 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);177 if (!data)178 return -ENOMEM;179 180 data->dev = &pdev->dev;181 dev_set_drvdata(&pdev->dev, data);182 183 mutex_init(&data->input_lock);184 ret = devm_add_action_or_reset(&pdev->dev, quickstart_mutex_destroy, &data->input_lock);185 if (ret < 0)186 return ret;187 188 /*189 * We have to initialize the device wakeup before evaluating GHID because190 * doing so will notify the device if the button was used to wake the machine191 * from S5.192 */193 device_init_wakeup(&pdev->dev, true);194 195 ret = quickstart_get_ghid(data);196 if (ret < 0)197 return ret;198 199 data->input_device = devm_input_allocate_device(&pdev->dev);200 if (!data->input_device)201 return -ENOMEM;202 203 ret = sparse_keymap_setup(data->input_device, quickstart_keymap, NULL);204 if (ret < 0)205 return ret;206 207 snprintf(data->input_name, sizeof(data->input_name), "Quickstart Button %u", data->id);208 snprintf(data->phys, sizeof(data->phys), DRIVER_NAME "/input%u", data->id);209 210 data->input_device->name = data->input_name;211 data->input_device->phys = data->phys;212 data->input_device->id.bustype = BUS_HOST;213 214 ret = input_register_device(data->input_device);215 if (ret < 0)216 return ret;217 218 status = acpi_install_notify_handler(handle, ACPI_DEVICE_NOTIFY, quickstart_notify, data);219 if (ACPI_FAILURE(status))220 return -EIO;221 222 return devm_add_action_or_reset(&pdev->dev, quickstart_notify_remove, data);223}224 225static const struct acpi_device_id quickstart_device_ids[] = {226 { "PNP0C32" },227 { }228};229MODULE_DEVICE_TABLE(acpi, quickstart_device_ids);230 231static struct platform_driver quickstart_platform_driver = {232 .driver = {233 .name = DRIVER_NAME,234 .dev_groups = quickstart_groups,235 .probe_type = PROBE_PREFER_ASYNCHRONOUS,236 .acpi_match_table = quickstart_device_ids,237 },238 .probe = quickstart_probe,239};240module_platform_driver(quickstart_platform_driver);241 242MODULE_AUTHOR("Armin Wolf <W_Armin@gmx.de>");243MODULE_AUTHOR("Arvid Norlander <lkml@vorpal.se>");244MODULE_AUTHOR("Angelo Arrifano");245MODULE_DESCRIPTION("ACPI Direct App Launch driver");246MODULE_LICENSE("GPL");247