dell-wmi: new driver for hotkey control

Add a WMI driver for Dell laptops. Currently it does nothing but send a
generic input event when a button with a picture of a battery on it is
pressed, but maybe other uses will appear over time.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

MAINTAINERS

@@ -1393,6 +1393,11 @@ P:	Doug Warzecha
 M:	Douglas_Warzecha@dell.com
 S:	Maintained
 
+DELL WMI EXTRAS DRIVER
+P:	Matthew Garrett
+M:	mjg59@srcf.ucam.org
+S:	Maintained
+
 DEVICE NUMBER REGISTRY
 P:	Torben Mathiasen
 M:	device@lanana.org

drivers/platform/x86/Kconfig

@@ -67,6 +67,16 @@ config DELL_LAPTOP
 	This driver adds support for rfkill and backlight control to Dell
 	laptops.
 
+config DELL_WMI
+	tristate "Dell WMI extras"
+	depends on ACPI_WMI
+	depends on INPUT
+	---help---
+	  Say Y here if you want to support WMI-based hotkeys on Dell laptops.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called dell-wmi.
+
 config FUJITSU_LAPTOP
 	tristate "Fujitsu Laptop Extras"
 	depends on ACPI

drivers/platform/x86/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_EEEPC_LAPTOP)	+= eeepc-laptop.o
 obj-$(CONFIG_MSI_LAPTOP)	+= msi-laptop.o
 obj-$(CONFIG_COMPAL_LAPTOP)	+= compal-laptop.o
 obj-$(CONFIG_DELL_LAPTOP)	+= dell-laptop.o
+obj-$(CONFIG_DELL_WMI)		+= dell-wmi.o
 obj-$(CONFIG_ACER_WMI)		+= acer-wmi.o
 obj-$(CONFIG_HP_WMI)		+= hp-wmi.o
 obj-$(CONFIG_TC1100_WMI)	+= tc1100-wmi.o

drivers/platform/x86/dell-wmi.c

+/*
+ * Dell WMI hotkeys
+ *
+ * Copyright (C) 2008 Red Hat <mjg@redhat.com>
+ *
+ * Portions based on wistron_btns.c:
+ * Copyright (C) 2005 Miloslav Trmac <mitr@volny.cz>
+ * Copyright (C) 2005 Bernhard Rosenkraenzer <bero@arklinux.org>
+ * Copyright (C) 2005 Dmitry Torokhov <dtor@mail.ru>
+ *
+ *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/input.h>
+#include <acpi/acpi_drivers.h>
+#include <linux/acpi.h>
+#include <linux/string.h>
+
+MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
+MODULE_DESCRIPTION("Dell laptop WMI hotkeys driver");
+MODULE_LICENSE("GPL");
+
+#define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"
+
+MODULE_ALIAS("wmi:"DELL_EVENT_GUID);
+
+struct key_entry {
+	char type;		/* See KE_* below */
+	u16 code;
+	u16 keycode;
+};
+
+enum { KE_KEY, KE_SW, KE_END };
+
+static struct key_entry dell_wmi_keymap[] = {
+	{KE_KEY, 0xe045, KEY_PROG1},
+	{KE_END, 0}
+};
+
+static struct input_dev *dell_wmi_input_dev;
+
+static struct key_entry *dell_wmi_get_entry_by_scancode(int code)
+{
+	struct key_entry *key;
+
+	for (key = dell_wmi_keymap; key->type != KE_END; key++)
+		if (code == key->code)
+			return key;
+
+	return NULL;
+}
+
+static struct key_entry *dell_wmi_get_entry_by_keycode(int keycode)
+{
+	struct key_entry *key;
+
+	for (key = dell_wmi_keymap; key->type != KE_END; key++)
+		if (key->type == KE_KEY && keycode == key->keycode)
+			return key;
+
+	return NULL;
+}
+
+static int dell_wmi_getkeycode(struct input_dev *dev, int scancode,
+			       int *keycode)
+{
+	struct key_entry *key = dell_wmi_get_entry_by_scancode(scancode);
+
+	if (key && key->type == KE_KEY) {
+		*keycode = key->keycode;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int dell_wmi_setkeycode(struct input_dev *dev, int scancode, int keycode)
+{
+	struct key_entry *key;
+	int old_keycode;
+
+	if (keycode < 0 || keycode > KEY_MAX)
+		return -EINVAL;
+
+	key = dell_wmi_get_entry_by_scancode(scancode);
+	if (key && key->type == KE_KEY) {
+		old_keycode = key->keycode;
+		key->keycode = keycode;
+		set_bit(keycode, dev->keybit);
+		if (!dell_wmi_get_entry_by_keycode(old_keycode))
+			clear_bit(old_keycode, dev->keybit);
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static void dell_wmi_notify(u32 value, void *context)
+{
+	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
+	static struct key_entry *key;
+	union acpi_object *obj;
+
+	wmi_get_event_data(value, &response);
+
+	obj = (union acpi_object *)response.pointer;
+
+	if (obj && obj->type == ACPI_TYPE_BUFFER) {
+		int *buffer = (int *)obj->buffer.pointer;
+		key = dell_wmi_get_entry_by_scancode(buffer[1]);
+		if (key) {
+			input_report_key(dell_wmi_input_dev, key->keycode, 1);
+			input_sync(dell_wmi_input_dev);
+			input_report_key(dell_wmi_input_dev, key->keycode, 0);
+			input_sync(dell_wmi_input_dev);
+		} else
+			printk(KERN_INFO "dell-wmi: Unknown key %x pressed\n",
+			       buffer[1]);
+	}
+}
+
+static int __init dell_wmi_input_setup(void)
+{
+	struct key_entry *key;
+	int err;
+
+	dell_wmi_input_dev = input_allocate_device();
+
+	if (!dell_wmi_input_dev)
+		return -ENOMEM;
+
+	dell_wmi_input_dev->name = "Dell WMI hotkeys";
+	dell_wmi_input_dev->phys = "wmi/input0";
+	dell_wmi_input_dev->id.bustype = BUS_HOST;
+	dell_wmi_input_dev->getkeycode = dell_wmi_getkeycode;
+	dell_wmi_input_dev->setkeycode = dell_wmi_setkeycode;
+
+	for (key = dell_wmi_keymap; key->type != KE_END; key++) {
+		switch (key->type) {
+		case KE_KEY:
+			set_bit(EV_KEY, dell_wmi_input_dev->evbit);
+			set_bit(key->keycode, dell_wmi_input_dev->keybit);
+			break;
+		case KE_SW:
+			set_bit(EV_SW, dell_wmi_input_dev->evbit);
+			set_bit(key->keycode, dell_wmi_input_dev->swbit);
+			break;
+		}
+	}
+
+	err = input_register_device(dell_wmi_input_dev);
+
+	if (err) {
+		input_free_device(dell_wmi_input_dev);
+		return err;
+	}
+
+	return 0;
+}
+
+static int __init dell_wmi_init(void)
+{
+	int err;
+
+	if (wmi_has_guid(DELL_EVENT_GUID)) {
+		err = dell_wmi_input_setup();
+
+		if (err)
+			return err;
+
+		err = wmi_install_notify_handler(DELL_EVENT_GUID,
+						 dell_wmi_notify, NULL);
+		if (err) {
+			input_unregister_device(dell_wmi_input_dev);
+			printk(KERN_ERR "dell-wmi: Unable to register"
+			       " notify handler - %d\n", err);
+			return err;
+		}
+
+	} else
+		printk(KERN_WARNING "dell-wmi: No known WMI GUID found\n");
+
+	return 0;
+}
+
+static void __exit dell_wmi_exit(void)
+{
+	if (wmi_has_guid(DELL_EVENT_GUID)) {
+		wmi_remove_notify_handler(DELL_EVENT_GUID);
+		input_unregister_device(dell_wmi_input_dev);
+	}
+}
+
+module_init(dell_wmi_init);
+module_exit(dell_wmi_exit);