474 lines
12 KiB
C
474 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ACPI Time and Alarm (TAD) Device Driver
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*
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* Copyright (C) 2018 Intel Corporation
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* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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*
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* This driver is based on Section 9.18 of the ACPI 6.2 specification revision.
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*
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* It only supports the system wakeup capabilities of the TAD.
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*
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* Provided are sysfs attributes, available under the TAD platform device,
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* allowing user space to manage the AC and DC wakeup timers of the TAD:
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* set and read their values, set and check their expire timer wake policies,
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* check and clear their status and check the capabilities of the TAD reported
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* by AML. The DC timer attributes are only present if the TAD supports a
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* separate DC alarm timer.
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*
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* The wakeup events handling and power management of the TAD is expected to
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* be taken care of by the ACPI PM domain attached to its platform device.
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*/
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#include <linux/acpi.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/suspend.h>
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Rafael J. Wysocki");
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/* ACPI TAD capability flags (ACPI 6.2, Section 9.18.2) */
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#define ACPI_TAD_AC_WAKE BIT(0)
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#define ACPI_TAD_DC_WAKE BIT(1)
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#define ACPI_TAD_RT BIT(2)
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#define ACPI_TAD_RT_IN_MS BIT(3)
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#define ACPI_TAD_S4_S5__GWS BIT(4)
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#define ACPI_TAD_AC_S4_WAKE BIT(5)
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#define ACPI_TAD_AC_S5_WAKE BIT(6)
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#define ACPI_TAD_DC_S4_WAKE BIT(7)
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#define ACPI_TAD_DC_S5_WAKE BIT(8)
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/* ACPI TAD alarm timer selection */
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#define ACPI_TAD_AC_TIMER (u32)0
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#define ACPI_TAD_DC_TIMER (u32)1
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/* Special value for disabled timer or expired timer wake policy. */
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#define ACPI_TAD_WAKE_DISABLED (~(u32)0)
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struct acpi_tad_driver_data {
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u32 capabilities;
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};
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static int acpi_tad_wake_set(struct device *dev, char *method, u32 timer_id,
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u32 value)
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{
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acpi_handle handle = ACPI_HANDLE(dev);
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union acpi_object args[] = {
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{ .type = ACPI_TYPE_INTEGER, },
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{ .type = ACPI_TYPE_INTEGER, },
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};
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struct acpi_object_list arg_list = {
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.pointer = args,
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.count = ARRAY_SIZE(args),
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};
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unsigned long long retval;
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acpi_status status;
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args[0].integer.value = timer_id;
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args[1].integer.value = value;
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pm_runtime_get_sync(dev);
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status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
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pm_runtime_put_sync(dev);
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if (ACPI_FAILURE(status) || retval)
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return -EIO;
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return 0;
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}
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static int acpi_tad_wake_write(struct device *dev, const char *buf, char *method,
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u32 timer_id, const char *specval)
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{
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u32 value;
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if (sysfs_streq(buf, specval)) {
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value = ACPI_TAD_WAKE_DISABLED;
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} else {
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int ret = kstrtou32(buf, 0, &value);
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if (ret)
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return ret;
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if (value == ACPI_TAD_WAKE_DISABLED)
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return -EINVAL;
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}
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return acpi_tad_wake_set(dev, method, timer_id, value);
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}
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static ssize_t acpi_tad_wake_read(struct device *dev, char *buf, char *method,
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u32 timer_id, const char *specval)
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{
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acpi_handle handle = ACPI_HANDLE(dev);
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union acpi_object args[] = {
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{ .type = ACPI_TYPE_INTEGER, },
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};
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struct acpi_object_list arg_list = {
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.pointer = args,
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.count = ARRAY_SIZE(args),
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};
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unsigned long long retval;
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acpi_status status;
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args[0].integer.value = timer_id;
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pm_runtime_get_sync(dev);
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status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
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pm_runtime_put_sync(dev);
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if (ACPI_FAILURE(status))
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return -EIO;
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if ((u32)retval == ACPI_TAD_WAKE_DISABLED)
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return sprintf(buf, "%s\n", specval);
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return sprintf(buf, "%u\n", (u32)retval);
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}
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static const char *alarm_specval = "disabled";
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static int acpi_tad_alarm_write(struct device *dev, const char *buf,
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u32 timer_id)
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{
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return acpi_tad_wake_write(dev, buf, "_STV", timer_id, alarm_specval);
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}
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static ssize_t acpi_tad_alarm_read(struct device *dev, char *buf, u32 timer_id)
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{
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return acpi_tad_wake_read(dev, buf, "_TIV", timer_id, alarm_specval);
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}
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static const char *policy_specval = "never";
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static int acpi_tad_policy_write(struct device *dev, const char *buf,
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u32 timer_id)
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{
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return acpi_tad_wake_write(dev, buf, "_STP", timer_id, policy_specval);
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}
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static ssize_t acpi_tad_policy_read(struct device *dev, char *buf, u32 timer_id)
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{
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return acpi_tad_wake_read(dev, buf, "_TIP", timer_id, policy_specval);
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}
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static int acpi_tad_clear_status(struct device *dev, u32 timer_id)
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{
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acpi_handle handle = ACPI_HANDLE(dev);
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union acpi_object args[] = {
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{ .type = ACPI_TYPE_INTEGER, },
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};
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struct acpi_object_list arg_list = {
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.pointer = args,
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.count = ARRAY_SIZE(args),
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};
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unsigned long long retval;
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acpi_status status;
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args[0].integer.value = timer_id;
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pm_runtime_get_sync(dev);
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status = acpi_evaluate_integer(handle, "_CWS", &arg_list, &retval);
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pm_runtime_put_sync(dev);
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if (ACPI_FAILURE(status) || retval)
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return -EIO;
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return 0;
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}
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static int acpi_tad_status_write(struct device *dev, const char *buf, u32 timer_id)
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{
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int ret, value;
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ret = kstrtoint(buf, 0, &value);
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if (ret)
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return ret;
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if (value)
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return -EINVAL;
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return acpi_tad_clear_status(dev, timer_id);
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}
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static ssize_t acpi_tad_status_read(struct device *dev, char *buf, u32 timer_id)
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{
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acpi_handle handle = ACPI_HANDLE(dev);
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union acpi_object args[] = {
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{ .type = ACPI_TYPE_INTEGER, },
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};
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struct acpi_object_list arg_list = {
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.pointer = args,
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.count = ARRAY_SIZE(args),
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};
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unsigned long long retval;
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acpi_status status;
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args[0].integer.value = timer_id;
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pm_runtime_get_sync(dev);
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status = acpi_evaluate_integer(handle, "_GWS", &arg_list, &retval);
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pm_runtime_put_sync(dev);
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if (ACPI_FAILURE(status))
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return -EIO;
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return sprintf(buf, "0x%02X\n", (u32)retval);
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}
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static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
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return sprintf(buf, "0x%02X\n", dd->capabilities);
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}
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static DEVICE_ATTR_RO(caps);
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static ssize_t ac_alarm_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int ret = acpi_tad_alarm_write(dev, buf, ACPI_TAD_AC_TIMER);
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return ret ? ret : count;
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}
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static ssize_t ac_alarm_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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return acpi_tad_alarm_read(dev, buf, ACPI_TAD_AC_TIMER);
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}
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static DEVICE_ATTR(ac_alarm, S_IRUSR | S_IWUSR, ac_alarm_show, ac_alarm_store);
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static ssize_t ac_policy_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int ret = acpi_tad_policy_write(dev, buf, ACPI_TAD_AC_TIMER);
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return ret ? ret : count;
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}
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static ssize_t ac_policy_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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return acpi_tad_policy_read(dev, buf, ACPI_TAD_AC_TIMER);
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}
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static DEVICE_ATTR(ac_policy, S_IRUSR | S_IWUSR, ac_policy_show, ac_policy_store);
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static ssize_t ac_status_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int ret = acpi_tad_status_write(dev, buf, ACPI_TAD_AC_TIMER);
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return ret ? ret : count;
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}
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static ssize_t ac_status_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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return acpi_tad_status_read(dev, buf, ACPI_TAD_AC_TIMER);
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}
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static DEVICE_ATTR(ac_status, S_IRUSR | S_IWUSR, ac_status_show, ac_status_store);
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static struct attribute *acpi_tad_attrs[] = {
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&dev_attr_caps.attr,
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&dev_attr_ac_alarm.attr,
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&dev_attr_ac_policy.attr,
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&dev_attr_ac_status.attr,
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NULL,
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};
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static const struct attribute_group acpi_tad_attr_group = {
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.attrs = acpi_tad_attrs,
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};
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static ssize_t dc_alarm_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int ret = acpi_tad_alarm_write(dev, buf, ACPI_TAD_DC_TIMER);
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return ret ? ret : count;
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}
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static ssize_t dc_alarm_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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return acpi_tad_alarm_read(dev, buf, ACPI_TAD_DC_TIMER);
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}
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static DEVICE_ATTR(dc_alarm, S_IRUSR | S_IWUSR, dc_alarm_show, dc_alarm_store);
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static ssize_t dc_policy_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int ret = acpi_tad_policy_write(dev, buf, ACPI_TAD_DC_TIMER);
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return ret ? ret : count;
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}
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static ssize_t dc_policy_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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return acpi_tad_policy_read(dev, buf, ACPI_TAD_DC_TIMER);
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}
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static DEVICE_ATTR(dc_policy, S_IRUSR | S_IWUSR, dc_policy_show, dc_policy_store);
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static ssize_t dc_status_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int ret = acpi_tad_status_write(dev, buf, ACPI_TAD_DC_TIMER);
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return ret ? ret : count;
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}
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static ssize_t dc_status_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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return acpi_tad_status_read(dev, buf, ACPI_TAD_DC_TIMER);
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}
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static DEVICE_ATTR(dc_status, S_IRUSR | S_IWUSR, dc_status_show, dc_status_store);
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static struct attribute *acpi_tad_dc_attrs[] = {
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&dev_attr_dc_alarm.attr,
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&dev_attr_dc_policy.attr,
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&dev_attr_dc_status.attr,
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NULL,
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};
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static const struct attribute_group acpi_tad_dc_attr_group = {
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.attrs = acpi_tad_dc_attrs,
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};
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static int acpi_tad_disable_timer(struct device *dev, u32 timer_id)
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{
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return acpi_tad_wake_set(dev, "_STV", timer_id, ACPI_TAD_WAKE_DISABLED);
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}
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static int acpi_tad_remove(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
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device_init_wakeup(dev, false);
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pm_runtime_get_sync(dev);
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if (dd->capabilities & ACPI_TAD_DC_WAKE)
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sysfs_remove_group(&dev->kobj, &acpi_tad_dc_attr_group);
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sysfs_remove_group(&dev->kobj, &acpi_tad_attr_group);
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acpi_tad_disable_timer(dev, ACPI_TAD_AC_TIMER);
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acpi_tad_clear_status(dev, ACPI_TAD_AC_TIMER);
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if (dd->capabilities & ACPI_TAD_DC_WAKE) {
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acpi_tad_disable_timer(dev, ACPI_TAD_DC_TIMER);
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acpi_tad_clear_status(dev, ACPI_TAD_DC_TIMER);
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}
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pm_runtime_put_sync(dev);
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pm_runtime_disable(dev);
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return 0;
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}
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static int acpi_tad_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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acpi_handle handle = ACPI_HANDLE(dev);
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struct acpi_tad_driver_data *dd;
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acpi_status status;
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unsigned long long caps;
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int ret;
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/*
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* Initialization failure messages are mostly about firmware issues, so
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* print them at the "info" level.
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*/
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status = acpi_evaluate_integer(handle, "_GCP", NULL, &caps);
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if (ACPI_FAILURE(status)) {
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dev_info(dev, "Unable to get capabilities\n");
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return -ENODEV;
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}
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if (!(caps & ACPI_TAD_AC_WAKE)) {
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dev_info(dev, "Unsupported capabilities\n");
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return -ENODEV;
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}
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if (!acpi_has_method(handle, "_PRW")) {
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dev_info(dev, "Missing _PRW\n");
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return -ENODEV;
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}
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dd = devm_kzalloc(dev, sizeof(*dd), GFP_KERNEL);
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if (!dd)
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return -ENOMEM;
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dd->capabilities = caps;
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dev_set_drvdata(dev, dd);
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/*
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* Assume that the ACPI PM domain has been attached to the device and
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* simply enable system wakeup and runtime PM and put the device into
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* runtime suspend. Everything else should be taken care of by the ACPI
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* PM domain callbacks.
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*/
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device_init_wakeup(dev, true);
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dev_pm_set_driver_flags(dev, DPM_FLAG_SMART_SUSPEND |
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DPM_FLAG_LEAVE_SUSPENDED);
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/*
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* The platform bus type layer tells the ACPI PM domain powers up the
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* device, so set the runtime PM status of it to "active".
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*/
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pm_runtime_set_active(dev);
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pm_runtime_enable(dev);
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pm_runtime_suspend(dev);
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ret = sysfs_create_group(&dev->kobj, &acpi_tad_attr_group);
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if (ret)
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goto fail;
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if (caps & ACPI_TAD_DC_WAKE) {
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ret = sysfs_create_group(&dev->kobj, &acpi_tad_dc_attr_group);
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if (ret)
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goto fail;
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}
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return 0;
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fail:
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acpi_tad_remove(pdev);
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return ret;
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}
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static const struct acpi_device_id acpi_tad_ids[] = {
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{"ACPI000E", 0},
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{}
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};
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static struct platform_driver acpi_tad_driver = {
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.driver = {
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.name = "acpi-tad",
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.acpi_match_table = acpi_tad_ids,
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},
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.probe = acpi_tad_probe,
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.remove = acpi_tad_remove,
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};
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MODULE_DEVICE_TABLE(acpi, acpi_tad_ids);
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module_platform_driver(acpi_tad_driver);
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