hp-wireless: new driver for hp wireless button for Windows 8

Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

drivers/platform/x86/Kconfig

@@ -197,6 +197,17 @@ config HP_ACCEL
 	  To compile this driver as a module, choose M here: the module will
 	  be called hp_accel.
 
+config HP_WIRELESS
+	tristate "HP WIRELESS"
+	depends on ACPI
+	depends on INPUT
+	help
+	 This driver provides supports for new HP wireless button for Windows 8.
+	 On such systems the driver should load automatically (via ACPI alias).
+
+	 To compile this driver as a module, choose M here: the module will
+	 be called hp-wireless.
+
 config HP_WMI
 	tristate "HP WMI extras"
 	depends on ACPI_WMI

drivers/platform/x86/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_DELL_WMI_AIO)	+= dell-wmi-aio.o
 obj-$(CONFIG_ACER_WMI)		+= acer-wmi.o
 obj-$(CONFIG_ACERHDF)		+= acerhdf.o
 obj-$(CONFIG_HP_ACCEL)		+= hp_accel.o
+obj-$(CONFIG_HP_WIRELESS)	+= hp-wireless.o
 obj-$(CONFIG_HP_WMI)		+= hp-wmi.o
 obj-$(CONFIG_AMILO_RFKILL)	+= amilo-rfkill.o
 obj-$(CONFIG_TC1100_WMI)	+= tc1100-wmi.o

drivers/platform/x86/hp-wireless.c

@@ -0,0 +1,132 @@
+/*
+ *  hp-wireless button for Windows 8
+ *
+ *  Copyright (C) 2014 Alex Hung <alex.hung@canonical.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alex Hung");
+MODULE_ALIAS("acpi*:HPQ6001:*");
+
+static struct input_dev *hpwl_input_dev;
+
+static const struct acpi_device_id hpwl_ids[] = {
+	{"HPQ6001", 0},
+	{"", 0},
+};
+
+static int hp_wireless_input_setup(void)
+{
+	int err;
+
+	hpwl_input_dev = input_allocate_device();
+	if (!hpwl_input_dev)
+		return -ENOMEM;
+
+	hpwl_input_dev->name = "HP Wireless hotkeys";
+	hpwl_input_dev->phys = "hpq6001/input0";
+	hpwl_input_dev->id.bustype = BUS_HOST;
+	hpwl_input_dev->evbit[0] = BIT(EV_KEY);
+	set_bit(KEY_RFKILL, hpwl_input_dev->keybit);
+
+	err = input_register_device(hpwl_input_dev);
+	if (err)
+		goto err_free_dev;
+
+	return 0;
+
+err_free_dev:
+	input_free_device(hpwl_input_dev);
+	return err;
+}
+
+static void hp_wireless_input_destroy(void)
+{
+	input_unregister_device(hpwl_input_dev);
+}
+
+static void hpwl_notify(struct acpi_device *acpi_dev, u32 event)
+{
+	if (event != 0x80) {
+		pr_info("Received unknown event (0x%x)\n", event);
+		return;
+	}
+
+	input_report_key(hpwl_input_dev, KEY_RFKILL, 1);
+	input_sync(hpwl_input_dev);
+	input_report_key(hpwl_input_dev, KEY_RFKILL, 0);
+	input_sync(hpwl_input_dev);
+}
+
+static int hpwl_add(struct acpi_device *device)
+{
+	int err;
+
+	err = hp_wireless_input_setup();
+	return err;
+}
+
+static int hpwl_remove(struct acpi_device *device)
+{
+	hp_wireless_input_destroy();
+	return 0;
+}
+
+static struct acpi_driver hpwl_driver = {
+	.name	= "hp-wireless",
+	.owner	= THIS_MODULE,
+	.ids	= hpwl_ids,
+	.ops	= {
+		.add	= hpwl_add,
+		.remove	= hpwl_remove,
+		.notify	= hpwl_notify,
+	},
+};
+
+static int __init hpwl_init(void)
+{
+	int err;
+
+	pr_info("Initializing HPQ6001 module\n");
+	err = acpi_bus_register_driver(&hpwl_driver);
+	if (err) {
+		pr_err("Unable to register HP wireless control driver.\n");
+		goto error_acpi_register;
+	}
+
+	return 0;
+
+error_acpi_register:
+	return err;
+}
+
+static void __exit hpwl_exit(void)
+{
+	pr_info("Exiting HPQ6001 module\n");
+	acpi_bus_unregister_driver(&hpwl_driver);
+}
+
+module_init(hpwl_init);
+module_exit(hpwl_exit);