https://github.com/torvalds/linux
Tip revision: 6a8b55ed4056ea5559ebe4f6a4b247f627870d4c authored by Linus Torvalds on 26 April 2020, 20:51:02 UTC
Linux 5.7-rc3
Linux 5.7-rc3
Tip revision: 6a8b55e
dell-rbtn.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
Dell Airplane Mode Switch driver
Copyright (C) 2014-2015 Pali Rohár <pali@kernel.org>
*/
#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/rfkill.h>
#include <linux/input.h>
#include "dell-rbtn.h"
enum rbtn_type {
RBTN_UNKNOWN,
RBTN_TOGGLE,
RBTN_SLIDER,
};
struct rbtn_data {
enum rbtn_type type;
struct rfkill *rfkill;
struct input_dev *input_dev;
bool suspended;
};
/*
* acpi functions
*/
static enum rbtn_type rbtn_check(struct acpi_device *device)
{
unsigned long long output;
acpi_status status;
status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
if (ACPI_FAILURE(status))
return RBTN_UNKNOWN;
switch (output) {
case 0:
case 1:
return RBTN_TOGGLE;
case 2:
case 3:
return RBTN_SLIDER;
default:
return RBTN_UNKNOWN;
}
}
static int rbtn_get(struct acpi_device *device)
{
unsigned long long output;
acpi_status status;
status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
if (ACPI_FAILURE(status))
return -EINVAL;
return !output;
}
static int rbtn_acquire(struct acpi_device *device, bool enable)
{
struct acpi_object_list input;
union acpi_object param;
acpi_status status;
param.type = ACPI_TYPE_INTEGER;
param.integer.value = enable;
input.count = 1;
input.pointer = ¶m;
status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
if (ACPI_FAILURE(status))
return -EINVAL;
return 0;
}
/*
* rfkill device
*/
static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
{
struct acpi_device *device = data;
int state;
state = rbtn_get(device);
if (state < 0)
return;
rfkill_set_states(rfkill, state, state);
}
static int rbtn_rfkill_set_block(void *data, bool blocked)
{
/* NOTE: setting soft rfkill state is not supported */
return -EINVAL;
}
static const struct rfkill_ops rbtn_ops = {
.query = rbtn_rfkill_query,
.set_block = rbtn_rfkill_set_block,
};
static int rbtn_rfkill_init(struct acpi_device *device)
{
struct rbtn_data *rbtn_data = device->driver_data;
int ret;
if (rbtn_data->rfkill)
return 0;
/*
* NOTE: rbtn controls all radio devices, not only WLAN
* but rfkill interface does not support "ANY" type
* so "WLAN" type is used
*/
rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
RFKILL_TYPE_WLAN, &rbtn_ops, device);
if (!rbtn_data->rfkill)
return -ENOMEM;
ret = rfkill_register(rbtn_data->rfkill);
if (ret) {
rfkill_destroy(rbtn_data->rfkill);
rbtn_data->rfkill = NULL;
return ret;
}
return 0;
}
static void rbtn_rfkill_exit(struct acpi_device *device)
{
struct rbtn_data *rbtn_data = device->driver_data;
if (!rbtn_data->rfkill)
return;
rfkill_unregister(rbtn_data->rfkill);
rfkill_destroy(rbtn_data->rfkill);
rbtn_data->rfkill = NULL;
}
static void rbtn_rfkill_event(struct acpi_device *device)
{
struct rbtn_data *rbtn_data = device->driver_data;
if (rbtn_data->rfkill)
rbtn_rfkill_query(rbtn_data->rfkill, device);
}
/*
* input device
*/
static int rbtn_input_init(struct rbtn_data *rbtn_data)
{
int ret;
rbtn_data->input_dev = input_allocate_device();
if (!rbtn_data->input_dev)
return -ENOMEM;
rbtn_data->input_dev->name = "DELL Wireless hotkeys";
rbtn_data->input_dev->phys = "dellabce/input0";
rbtn_data->input_dev->id.bustype = BUS_HOST;
rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);
ret = input_register_device(rbtn_data->input_dev);
if (ret) {
input_free_device(rbtn_data->input_dev);
rbtn_data->input_dev = NULL;
return ret;
}
return 0;
}
static void rbtn_input_exit(struct rbtn_data *rbtn_data)
{
input_unregister_device(rbtn_data->input_dev);
rbtn_data->input_dev = NULL;
}
static void rbtn_input_event(struct rbtn_data *rbtn_data)
{
input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
input_sync(rbtn_data->input_dev);
input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
input_sync(rbtn_data->input_dev);
}
/*
* acpi driver
*/
static int rbtn_add(struct acpi_device *device);
static int rbtn_remove(struct acpi_device *device);
static void rbtn_notify(struct acpi_device *device, u32 event);
static const struct acpi_device_id rbtn_ids[] = {
{ "DELRBTN", 0 },
{ "DELLABCE", 0 },
/*
* This driver can also handle the "DELLABC6" device that
* appears on the XPS 13 9350, but that device is disabled by
* the DSDT unless booted with acpi_osi="!Windows 2012"
* acpi_osi="!Windows 2013".
*
* According to Mario at Dell:
*
* DELLABC6 is a custom interface that was created solely to
* have airplane mode support for Windows 7. For Windows 10
* the proper interface is to use that which is handled by
* intel-hid. A OEM airplane mode driver is not used.
*
* Since the kernel doesn't identify as Windows 7 it would be
* incorrect to do attempt to use that interface.
*
* Even if we override _OSI and bind to DELLABC6, we end up with
* inconsistent behavior in which userspace can get out of sync
* with the rfkill state as it conflicts with events from
* intel-hid.
*
* The upshot is that it is better to just ignore DELLABC6
* devices.
*/
{ "", 0 },
};
#ifdef CONFIG_PM_SLEEP
static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
{
struct rbtn_data *rbtn_data = context;
rbtn_data->suspended = false;
}
static int rbtn_suspend(struct device *dev)
{
struct acpi_device *device = to_acpi_device(dev);
struct rbtn_data *rbtn_data = acpi_driver_data(device);
rbtn_data->suspended = true;
return 0;
}
static int rbtn_resume(struct device *dev)
{
struct acpi_device *device = to_acpi_device(dev);
struct rbtn_data *rbtn_data = acpi_driver_data(device);
acpi_status status;
/*
* Upon resume, some BIOSes send an ACPI notification thet triggers
* an unwanted input event. In order to ignore it, we use a flag
* that we set at suspend and clear once we have received the extra
* ACPI notification. Since ACPI notifications are delivered
* asynchronously to drivers, we clear the flag from the workqueue
* used to deliver the notifications. This should be enough
* to have the flag cleared only after we received the extra
* notification, if any.
*/
status = acpi_os_execute(OSL_NOTIFY_HANDLER,
rbtn_clear_suspended_flag, rbtn_data);
if (ACPI_FAILURE(status))
rbtn_clear_suspended_flag(rbtn_data);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
static struct acpi_driver rbtn_driver = {
.name = "dell-rbtn",
.ids = rbtn_ids,
.drv.pm = &rbtn_pm_ops,
.ops = {
.add = rbtn_add,
.remove = rbtn_remove,
.notify = rbtn_notify,
},
.owner = THIS_MODULE,
};
/*
* notifier export functions
*/
static bool auto_remove_rfkill = true;
static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
static int rbtn_inc_count(struct device *dev, void *data)
{
struct acpi_device *device = to_acpi_device(dev);
struct rbtn_data *rbtn_data = device->driver_data;
int *count = data;
if (rbtn_data->type == RBTN_SLIDER)
(*count)++;
return 0;
}
static int rbtn_switch_dev(struct device *dev, void *data)
{
struct acpi_device *device = to_acpi_device(dev);
struct rbtn_data *rbtn_data = device->driver_data;
bool enable = data;
if (rbtn_data->type != RBTN_SLIDER)
return 0;
if (enable)
rbtn_rfkill_init(device);
else
rbtn_rfkill_exit(device);
return 0;
}
int dell_rbtn_notifier_register(struct notifier_block *nb)
{
bool first;
int count;
int ret;
count = 0;
ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
rbtn_inc_count);
if (ret || count == 0)
return -ENODEV;
first = !rbtn_chain_head.head;
ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
if (ret != 0)
return ret;
if (auto_remove_rfkill && first)
ret = driver_for_each_device(&rbtn_driver.drv, NULL,
(void *)false, rbtn_switch_dev);
return ret;
}
EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
int dell_rbtn_notifier_unregister(struct notifier_block *nb)
{
int ret;
ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
if (ret != 0)
return ret;
if (auto_remove_rfkill && !rbtn_chain_head.head)
ret = driver_for_each_device(&rbtn_driver.drv, NULL,
(void *)true, rbtn_switch_dev);
return ret;
}
EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
/*
* acpi driver functions
*/
static int rbtn_add(struct acpi_device *device)
{
struct rbtn_data *rbtn_data;
enum rbtn_type type;
int ret = 0;
type = rbtn_check(device);
if (type == RBTN_UNKNOWN) {
dev_info(&device->dev, "Unknown device type\n");
return -EINVAL;
}
ret = rbtn_acquire(device, true);
if (ret < 0) {
dev_err(&device->dev, "Cannot enable device\n");
return ret;
}
rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
if (!rbtn_data)
return -ENOMEM;
rbtn_data->type = type;
device->driver_data = rbtn_data;
switch (rbtn_data->type) {
case RBTN_TOGGLE:
ret = rbtn_input_init(rbtn_data);
break;
case RBTN_SLIDER:
if (auto_remove_rfkill && rbtn_chain_head.head)
ret = 0;
else
ret = rbtn_rfkill_init(device);
break;
default:
ret = -EINVAL;
}
return ret;
}
static int rbtn_remove(struct acpi_device *device)
{
struct rbtn_data *rbtn_data = device->driver_data;
switch (rbtn_data->type) {
case RBTN_TOGGLE:
rbtn_input_exit(rbtn_data);
break;
case RBTN_SLIDER:
rbtn_rfkill_exit(device);
break;
default:
break;
}
rbtn_acquire(device, false);
device->driver_data = NULL;
return 0;
}
static void rbtn_notify(struct acpi_device *device, u32 event)
{
struct rbtn_data *rbtn_data = device->driver_data;
/*
* Some BIOSes send a notification at resume.
* Ignore it to prevent unwanted input events.
*/
if (rbtn_data->suspended) {
dev_dbg(&device->dev, "ACPI notification ignored\n");
return;
}
if (event != 0x80) {
dev_info(&device->dev, "Received unknown event (0x%x)\n",
event);
return;
}
switch (rbtn_data->type) {
case RBTN_TOGGLE:
rbtn_input_event(rbtn_data);
break;
case RBTN_SLIDER:
rbtn_rfkill_event(device);
atomic_notifier_call_chain(&rbtn_chain_head, event, device);
break;
default:
break;
}
}
/*
* module functions
*/
module_acpi_driver(rbtn_driver);
module_param(auto_remove_rfkill, bool, 0444);
MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
"other modules start receiving events "
"from this module and re-add them when "
"the last module stops receiving events "
"(default true)");
MODULE_DEVICE_TABLE(acpi, rbtn_ids);
MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
MODULE_LICENSE("GPL");