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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /drivers/acpi/button.c
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/acpi/button.c')
-rw-r--r--drivers/acpi/button.c667
1 files changed, 667 insertions, 0 deletions
diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
new file mode 100644
index 000000000..4861aad1a
--- /dev/null
+++ b/drivers/acpi/button.c
@@ -0,0 +1,667 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * button.c - ACPI Button Driver
+ *
+ * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ */
+
+#define pr_fmt(fmt) "ACPI: button: " fmt
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/dmi.h>
+#include <acpi/button.h>
+
+#define PREFIX "ACPI: "
+
+#define ACPI_BUTTON_CLASS "button"
+#define ACPI_BUTTON_FILE_STATE "state"
+#define ACPI_BUTTON_TYPE_UNKNOWN 0x00
+#define ACPI_BUTTON_NOTIFY_STATUS 0x80
+
+#define ACPI_BUTTON_SUBCLASS_POWER "power"
+#define ACPI_BUTTON_DEVICE_NAME_POWER "Power Button"
+#define ACPI_BUTTON_TYPE_POWER 0x01
+
+#define ACPI_BUTTON_SUBCLASS_SLEEP "sleep"
+#define ACPI_BUTTON_DEVICE_NAME_SLEEP "Sleep Button"
+#define ACPI_BUTTON_TYPE_SLEEP 0x03
+
+#define ACPI_BUTTON_SUBCLASS_LID "lid"
+#define ACPI_BUTTON_DEVICE_NAME_LID "Lid Switch"
+#define ACPI_BUTTON_TYPE_LID 0x05
+
+enum {
+ ACPI_BUTTON_LID_INIT_IGNORE,
+ ACPI_BUTTON_LID_INIT_OPEN,
+ ACPI_BUTTON_LID_INIT_METHOD,
+ ACPI_BUTTON_LID_INIT_DISABLED,
+};
+
+static const char * const lid_init_state_str[] = {
+ [ACPI_BUTTON_LID_INIT_IGNORE] = "ignore",
+ [ACPI_BUTTON_LID_INIT_OPEN] = "open",
+ [ACPI_BUTTON_LID_INIT_METHOD] = "method",
+ [ACPI_BUTTON_LID_INIT_DISABLED] = "disabled",
+};
+
+#define _COMPONENT ACPI_BUTTON_COMPONENT
+ACPI_MODULE_NAME("button");
+
+MODULE_AUTHOR("Paul Diefenbaugh");
+MODULE_DESCRIPTION("ACPI Button Driver");
+MODULE_LICENSE("GPL");
+
+static const struct acpi_device_id button_device_ids[] = {
+ {ACPI_BUTTON_HID_LID, 0},
+ {ACPI_BUTTON_HID_SLEEP, 0},
+ {ACPI_BUTTON_HID_SLEEPF, 0},
+ {ACPI_BUTTON_HID_POWER, 0},
+ {ACPI_BUTTON_HID_POWERF, 0},
+ {"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, button_device_ids);
+
+/* Please keep this list sorted alphabetically by vendor and model */
+static const struct dmi_system_id dmi_lid_quirks[] = {
+ {
+ /* GP-electronic T701, _LID method points to a floating GPIO */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
+ DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
+ },
+ .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
+ },
+ {
+ /* Nextbook Ares 8A tablet, _LID device always reports lid closed */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "CherryTrail"),
+ DMI_MATCH(DMI_BIOS_VERSION, "M882"),
+ },
+ .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
+ },
+ {
+ /*
+ * Medion Akoya E2215T, notification of the LID device only
+ * happens on close, not on open and _LID always returns closed.
+ */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "E2215T"),
+ },
+ .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+ },
+ {
+ /*
+ * Medion Akoya E2228T, notification of the LID device only
+ * happens on close, not on open and _LID always returns closed.
+ */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "E2228T"),
+ },
+ .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+ },
+ {
+ /*
+ * Razer Blade Stealth 13 late 2019, notification of the LID device
+ * only happens on close, not on open and _LID always returns closed.
+ */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Razer Blade Stealth 13 Late 2019"),
+ },
+ .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
+ },
+ {}
+};
+
+static int acpi_button_add(struct acpi_device *device);
+static int acpi_button_remove(struct acpi_device *device);
+static void acpi_button_notify(struct acpi_device *device, u32 event);
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_button_suspend(struct device *dev);
+static int acpi_button_resume(struct device *dev);
+#else
+#define acpi_button_suspend NULL
+#define acpi_button_resume NULL
+#endif
+static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
+
+static struct acpi_driver acpi_button_driver = {
+ .name = "button",
+ .class = ACPI_BUTTON_CLASS,
+ .ids = button_device_ids,
+ .ops = {
+ .add = acpi_button_add,
+ .remove = acpi_button_remove,
+ .notify = acpi_button_notify,
+ },
+ .drv.pm = &acpi_button_pm,
+};
+
+struct acpi_button {
+ unsigned int type;
+ struct input_dev *input;
+ char phys[32]; /* for input device */
+ unsigned long pushed;
+ int last_state;
+ ktime_t last_time;
+ bool suspended;
+ bool lid_state_initialized;
+};
+
+static struct acpi_device *lid_device;
+static long lid_init_state = -1;
+
+static unsigned long lid_report_interval __read_mostly = 500;
+module_param(lid_report_interval, ulong, 0644);
+MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
+
+/* --------------------------------------------------------------------------
+ FS Interface (/proc)
+ -------------------------------------------------------------------------- */
+
+static struct proc_dir_entry *acpi_button_dir;
+static struct proc_dir_entry *acpi_lid_dir;
+
+static int acpi_lid_evaluate_state(struct acpi_device *device)
+{
+ unsigned long long lid_state;
+ acpi_status status;
+
+ status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ return lid_state ? 1 : 0;
+}
+
+static int acpi_lid_notify_state(struct acpi_device *device, int state)
+{
+ struct acpi_button *button = acpi_driver_data(device);
+ ktime_t next_report;
+ bool do_update;
+
+ /*
+ * In lid_init_state=ignore mode, if user opens/closes lid
+ * frequently with "open" missing, and "last_time" is also updated
+ * frequently, "close" cannot be delivered to the userspace.
+ * So "last_time" is only updated after a timeout or an actual
+ * switch.
+ */
+ if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
+ button->last_state != !!state)
+ do_update = true;
+ else
+ do_update = false;
+
+ next_report = ktime_add(button->last_time,
+ ms_to_ktime(lid_report_interval));
+ if (button->last_state == !!state &&
+ ktime_after(ktime_get(), next_report)) {
+ /* Complain the buggy firmware */
+ pr_warn_once("The lid device is not compliant to SW_LID.\n");
+
+ /*
+ * Send the unreliable complement switch event:
+ *
+ * On most platforms, the lid device is reliable. However
+ * there are exceptions:
+ * 1. Platforms returning initial lid state as "close" by
+ * default after booting/resuming:
+ * https://bugzilla.kernel.org/show_bug.cgi?id=89211
+ * https://bugzilla.kernel.org/show_bug.cgi?id=106151
+ * 2. Platforms never reporting "open" events:
+ * https://bugzilla.kernel.org/show_bug.cgi?id=106941
+ * On these buggy platforms, the usage model of the ACPI
+ * lid device actually is:
+ * 1. The initial returning value of _LID may not be
+ * reliable.
+ * 2. The open event may not be reliable.
+ * 3. The close event is reliable.
+ *
+ * But SW_LID is typed as input switch event, the input
+ * layer checks if the event is redundant. Hence if the
+ * state is not switched, the userspace cannot see this
+ * platform triggered reliable event. By inserting a
+ * complement switch event, it then is guaranteed that the
+ * platform triggered reliable one can always be seen by
+ * the userspace.
+ */
+ if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
+ do_update = true;
+ /*
+ * Do generate complement switch event for "close"
+ * as "close" is reliable and wrong "open" won't
+ * trigger unexpected behaviors.
+ * Do not generate complement switch event for
+ * "open" as "open" is not reliable and wrong
+ * "close" will trigger unexpected behaviors.
+ */
+ if (!state) {
+ input_report_switch(button->input,
+ SW_LID, state);
+ input_sync(button->input);
+ }
+ }
+ }
+ /* Send the platform triggered reliable event */
+ if (do_update) {
+ acpi_handle_debug(device->handle, "ACPI LID %s\n",
+ state ? "open" : "closed");
+ input_report_switch(button->input, SW_LID, !state);
+ input_sync(button->input);
+ button->last_state = !!state;
+ button->last_time = ktime_get();
+ }
+
+ return 0;
+}
+
+static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
+ void *offset)
+{
+ struct acpi_device *device = seq->private;
+ int state;
+
+ state = acpi_lid_evaluate_state(device);
+ seq_printf(seq, "state: %s\n",
+ state < 0 ? "unsupported" : (state ? "open" : "closed"));
+ return 0;
+}
+
+static int acpi_button_add_fs(struct acpi_device *device)
+{
+ struct acpi_button *button = acpi_driver_data(device);
+ struct proc_dir_entry *entry = NULL;
+ int ret = 0;
+
+ /* procfs I/F for ACPI lid device only */
+ if (button->type != ACPI_BUTTON_TYPE_LID)
+ return 0;
+
+ if (acpi_button_dir || acpi_lid_dir) {
+ printk(KERN_ERR PREFIX "More than one Lid device found!\n");
+ return -EEXIST;
+ }
+
+ /* create /proc/acpi/button */
+ acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
+ if (!acpi_button_dir)
+ return -ENODEV;
+
+ /* create /proc/acpi/button/lid */
+ acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+ if (!acpi_lid_dir) {
+ ret = -ENODEV;
+ goto remove_button_dir;
+ }
+
+ /* create /proc/acpi/button/lid/LID/ */
+ acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
+ if (!acpi_device_dir(device)) {
+ ret = -ENODEV;
+ goto remove_lid_dir;
+ }
+
+ /* create /proc/acpi/button/lid/LID/state */
+ entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
+ acpi_device_dir(device), acpi_button_state_seq_show,
+ device);
+ if (!entry) {
+ ret = -ENODEV;
+ goto remove_dev_dir;
+ }
+
+done:
+ return ret;
+
+remove_dev_dir:
+ remove_proc_entry(acpi_device_bid(device),
+ acpi_lid_dir);
+ acpi_device_dir(device) = NULL;
+remove_lid_dir:
+ remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+ acpi_lid_dir = NULL;
+remove_button_dir:
+ remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
+ acpi_button_dir = NULL;
+ goto done;
+}
+
+static int acpi_button_remove_fs(struct acpi_device *device)
+{
+ struct acpi_button *button = acpi_driver_data(device);
+
+ if (button->type != ACPI_BUTTON_TYPE_LID)
+ return 0;
+
+ remove_proc_entry(ACPI_BUTTON_FILE_STATE,
+ acpi_device_dir(device));
+ remove_proc_entry(acpi_device_bid(device),
+ acpi_lid_dir);
+ acpi_device_dir(device) = NULL;
+ remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
+ acpi_lid_dir = NULL;
+ remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
+ acpi_button_dir = NULL;
+
+ return 0;
+}
+
+/* --------------------------------------------------------------------------
+ Driver Interface
+ -------------------------------------------------------------------------- */
+int acpi_lid_open(void)
+{
+ if (!lid_device)
+ return -ENODEV;
+
+ return acpi_lid_evaluate_state(lid_device);
+}
+EXPORT_SYMBOL(acpi_lid_open);
+
+static int acpi_lid_update_state(struct acpi_device *device,
+ bool signal_wakeup)
+{
+ int state;
+
+ state = acpi_lid_evaluate_state(device);
+ if (state < 0)
+ return state;
+
+ if (state && signal_wakeup)
+ acpi_pm_wakeup_event(&device->dev);
+
+ return acpi_lid_notify_state(device, state);
+}
+
+static void acpi_lid_initialize_state(struct acpi_device *device)
+{
+ struct acpi_button *button = acpi_driver_data(device);
+
+ switch (lid_init_state) {
+ case ACPI_BUTTON_LID_INIT_OPEN:
+ (void)acpi_lid_notify_state(device, 1);
+ break;
+ case ACPI_BUTTON_LID_INIT_METHOD:
+ (void)acpi_lid_update_state(device, false);
+ break;
+ case ACPI_BUTTON_LID_INIT_IGNORE:
+ default:
+ break;
+ }
+
+ button->lid_state_initialized = true;
+}
+
+static void acpi_button_notify(struct acpi_device *device, u32 event)
+{
+ struct acpi_button *button = acpi_driver_data(device);
+ struct input_dev *input;
+
+ switch (event) {
+ case ACPI_FIXED_HARDWARE_EVENT:
+ event = ACPI_BUTTON_NOTIFY_STATUS;
+ fallthrough;
+ case ACPI_BUTTON_NOTIFY_STATUS:
+ input = button->input;
+ if (button->type == ACPI_BUTTON_TYPE_LID) {
+ if (button->lid_state_initialized)
+ acpi_lid_update_state(device, true);
+ } else {
+ int keycode;
+
+ acpi_pm_wakeup_event(&device->dev);
+ if (button->suspended)
+ break;
+
+ keycode = test_bit(KEY_SLEEP, input->keybit) ?
+ KEY_SLEEP : KEY_POWER;
+ input_report_key(input, keycode, 1);
+ input_sync(input);
+ input_report_key(input, keycode, 0);
+ input_sync(input);
+
+ acpi_bus_generate_netlink_event(
+ device->pnp.device_class,
+ dev_name(&device->dev),
+ event, ++button->pushed);
+ }
+ break;
+ default:
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+ "Unsupported event [0x%x]\n", event));
+ break;
+ }
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int acpi_button_suspend(struct device *dev)
+{
+ struct acpi_device *device = to_acpi_device(dev);
+ struct acpi_button *button = acpi_driver_data(device);
+
+ button->suspended = true;
+ return 0;
+}
+
+static int acpi_button_resume(struct device *dev)
+{
+ struct acpi_device *device = to_acpi_device(dev);
+ struct acpi_button *button = acpi_driver_data(device);
+
+ button->suspended = false;
+ if (button->type == ACPI_BUTTON_TYPE_LID) {
+ button->last_state = !!acpi_lid_evaluate_state(device);
+ button->last_time = ktime_get();
+ acpi_lid_initialize_state(device);
+ }
+ return 0;
+}
+#endif
+
+static int acpi_lid_input_open(struct input_dev *input)
+{
+ struct acpi_device *device = input_get_drvdata(input);
+ struct acpi_button *button = acpi_driver_data(device);
+
+ button->last_state = !!acpi_lid_evaluate_state(device);
+ button->last_time = ktime_get();
+ acpi_lid_initialize_state(device);
+
+ return 0;
+}
+
+static int acpi_button_add(struct acpi_device *device)
+{
+ struct acpi_button *button;
+ struct input_dev *input;
+ const char *hid = acpi_device_hid(device);
+ char *name, *class;
+ int error;
+
+ if (!strcmp(hid, ACPI_BUTTON_HID_LID) &&
+ lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
+ return -ENODEV;
+
+ button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
+ if (!button)
+ return -ENOMEM;
+
+ device->driver_data = button;
+
+ button->input = input = input_allocate_device();
+ if (!input) {
+ error = -ENOMEM;
+ goto err_free_button;
+ }
+
+ name = acpi_device_name(device);
+ class = acpi_device_class(device);
+
+ if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
+ !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
+ button->type = ACPI_BUTTON_TYPE_POWER;
+ strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
+ sprintf(class, "%s/%s",
+ ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
+ } else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
+ !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
+ button->type = ACPI_BUTTON_TYPE_SLEEP;
+ strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
+ sprintf(class, "%s/%s",
+ ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
+ } else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
+ button->type = ACPI_BUTTON_TYPE_LID;
+ strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
+ sprintf(class, "%s/%s",
+ ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
+ input->open = acpi_lid_input_open;
+ } else {
+ printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
+ error = -ENODEV;
+ goto err_free_input;
+ }
+
+ error = acpi_button_add_fs(device);
+ if (error)
+ goto err_free_input;
+
+ snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
+
+ input->name = name;
+ input->phys = button->phys;
+ input->id.bustype = BUS_HOST;
+ input->id.product = button->type;
+ input->dev.parent = &device->dev;
+
+ switch (button->type) {
+ case ACPI_BUTTON_TYPE_POWER:
+ input_set_capability(input, EV_KEY, KEY_POWER);
+ break;
+
+ case ACPI_BUTTON_TYPE_SLEEP:
+ input_set_capability(input, EV_KEY, KEY_SLEEP);
+ break;
+
+ case ACPI_BUTTON_TYPE_LID:
+ input_set_capability(input, EV_SW, SW_LID);
+ break;
+ }
+
+ input_set_drvdata(input, device);
+ error = input_register_device(input);
+ if (error)
+ goto err_remove_fs;
+ if (button->type == ACPI_BUTTON_TYPE_LID) {
+ /*
+ * This assumes there's only one lid device, or if there are
+ * more we only care about the last one...
+ */
+ lid_device = device;
+ }
+
+ device_init_wakeup(&device->dev, true);
+ printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
+ return 0;
+
+ err_remove_fs:
+ acpi_button_remove_fs(device);
+ err_free_input:
+ input_free_device(input);
+ err_free_button:
+ kfree(button);
+ return error;
+}
+
+static int acpi_button_remove(struct acpi_device *device)
+{
+ struct acpi_button *button = acpi_driver_data(device);
+
+ acpi_button_remove_fs(device);
+ input_unregister_device(button->input);
+ kfree(button);
+ return 0;
+}
+
+static int param_set_lid_init_state(const char *val,
+ const struct kernel_param *kp)
+{
+ int i;
+
+ i = sysfs_match_string(lid_init_state_str, val);
+ if (i < 0)
+ return i;
+
+ lid_init_state = i;
+ pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
+ return 0;
+}
+
+static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
+{
+ int i, c = 0;
+
+ for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
+ if (i == lid_init_state)
+ c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
+ else
+ c += sprintf(buf + c, "%s ", lid_init_state_str[i]);
+
+ buf[c - 1] = '\n'; /* Replace the final space with a newline */
+
+ return c;
+}
+
+module_param_call(lid_init_state,
+ param_set_lid_init_state, param_get_lid_init_state,
+ NULL, 0644);
+MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
+
+static int acpi_button_register_driver(struct acpi_driver *driver)
+{
+ const struct dmi_system_id *dmi_id;
+
+ if (lid_init_state == -1) {
+ dmi_id = dmi_first_match(dmi_lid_quirks);
+ if (dmi_id)
+ lid_init_state = (long)dmi_id->driver_data;
+ else
+ lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
+ }
+
+ /*
+ * Modules such as nouveau.ko and i915.ko have a link time dependency
+ * on acpi_lid_open(), and would therefore not be loadable on ACPI
+ * capable kernels booted in non-ACPI mode if the return value of
+ * acpi_bus_register_driver() is returned from here with ACPI disabled
+ * when this driver is built as a module.
+ */
+ if (acpi_disabled)
+ return 0;
+
+ return acpi_bus_register_driver(driver);
+}
+
+static void acpi_button_unregister_driver(struct acpi_driver *driver)
+{
+ if (!acpi_disabled)
+ acpi_bus_unregister_driver(driver);
+}
+
+module_driver(acpi_button_driver, acpi_button_register_driver,
+ acpi_button_unregister_driver);