platform/x86: Add Asus Wireless Radio Control driver

Some Asus notebooks like the Asus E202SA and the Asus X555UB have a
separate ACPI device for notifications from the airplane mode hotkey.
This device is called "Wireless Radio Control" in Asus websites and ASHS
in the DSDT, and its ACPI _HID is ATK4002 in the two models mentioned
above.

For these models, when the airplane mode hotkey (Fn+F2) is pressed, a
query 0x0B is started in the Embedded Controller, and all this query does
is a notify ASHS with the value 0x88 (for acpi_osi >= "Windows 2012"):

	Scope (_SB.PCI0.SBRG.EC0)
	{
		(...)
		Method (_Q0B, 0, NotSerialized)  // _Qxx: EC Query
		{
			If ((MSOS () >= OSW8))
			{
				Notify (ASHS, 0x88) // Device-Specific
			}
			Else
			{
				(...)
			}
		}
	}

Signed-off-by: João Paulo Rechi Vita <jprvita@endlessm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

3 files changed, 98 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 9d7704e51366..f37821f004f9 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -587,6 +587,20 @@ config EEEPC_WMI
           If you have an ACPI-WMI compatible Eee PC laptop (>= 1000), say Y or M
           here.
 
+config ASUS_WIRELESS
+        tristate "Asus Wireless Radio Control Driver"
+        depends on ACPI
+        depends on INPUT
+        ---help---
+          The Asus Wireless Radio Control handles the airplane mode hotkey
+          present on some Asus laptops.
+
+          Say Y or M here if you have an ASUS notebook with an airplane mode
+          hotkey.
+
+          If you choose to compile this driver as a module the module will be
+          called asus-wireless.
+
 config ACPI_WMI
         tristate "WMI"
         depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 4410e91627ac..8b8df29dc502 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -5,6 +5,7 @@
 obj-$(CONFIG_ASUS_LAPTOP)       += asus-laptop.o
 obj-$(CONFIG_ASUS_WMI)          += asus-wmi.o
 obj-$(CONFIG_ASUS_NB_WMI)       += asus-nb-wmi.o
+obj-$(CONFIG_ASUS_WIRELESS)     += asus-wireless.o
 obj-$(CONFIG_EEEPC_LAPTOP)      += eeepc-laptop.o
 obj-$(CONFIG_EEEPC_WMI)         += eeepc-wmi.o
 obj-$(CONFIG_MSI_LAPTOP)        += msi-laptop.o
diff --git a/drivers/platform/x86/asus-wireless.c b/drivers/platform/x86/asus-wireless.c
new file mode 100644
index 000000000000..5058d48f2909
--- /dev/null
+++ b/drivers/platform/x86/asus-wireless.c
@@ -0,0 +1,83 @@
+/*
+ * Asus Wireless Radio Control Driver
+ *
+ * Copyright (C) 2015-2016 Endless Mobile, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/acpi.h>
+#include <linux/input.h>
+#include <linux/pci_ids.h>
+
+struct asus_wireless_data {
+        struct input_dev *idev;
+};
+
+static void asus_wireless_notify(struct acpi_device *adev, u32 event)
+{
+        struct asus_wireless_data *data = acpi_driver_data(adev);
+
+        dev_dbg(&adev->dev, "event=%#x\n", event);
+        if (event != 0x88) {
+                dev_notice(&adev->dev, "Unknown ASHS event: %#x\n", event);
+                return;
+        }
+        input_report_key(data->idev, KEY_RFKILL, 1);
+        input_report_key(data->idev, KEY_RFKILL, 0);
+        input_sync(data->idev);
+}
+
+static int asus_wireless_add(struct acpi_device *adev)
+{
+        struct asus_wireless_data *data;
+
+        data = devm_kzalloc(&adev->dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+        adev->driver_data = data;
+
+        data->idev = devm_input_allocate_device(&adev->dev);
+        if (!data->idev)
+                return -ENOMEM;
+        data->idev->name = "Asus Wireless Radio Control";
+        data->idev->phys = "asus-wireless/input0";
+        data->idev->id.bustype = BUS_HOST;
+        data->idev->id.vendor = PCI_VENDOR_ID_ASUSTEK;
+        set_bit(EV_KEY, data->idev->evbit);
+        set_bit(KEY_RFKILL, data->idev->keybit);
+        return input_register_device(data->idev);
+}
+
+static int asus_wireless_remove(struct acpi_device *adev)
+{
+        return 0;
+}
+
+static const struct acpi_device_id device_ids[] = {
+        {"ATK4002", 0},
+        {"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, device_ids);
+
+static struct acpi_driver asus_wireless_driver = {
+        .name = "Asus Wireless Radio Control Driver",
+        .class = "hotkey",
+        .ids = device_ids,
+        .ops = {
+                .add = asus_wireless_add,
+                .remove = asus_wireless_remove,
+                .notify = asus_wireless_notify,
+        },
+};
+module_acpi_driver(asus_wireless_driver);
+
+MODULE_DESCRIPTION("Asus Wireless Radio Control Driver");
+MODULE_AUTHOR("João Paulo Rechi Vita <jprvita@gmail.com>");
+MODULE_LICENSE("GPL");