Enable Dell All-In-One volume up/down keys

Enable volume up and down hotkeys on WMI events
GUID 284A0E6B-380E-472A-921F-E52786257FB4 and
GUID 02314822-307C-4F66-bf0E-48AEAEB26CC8.

Also works around a firmware bug where the _WED method
should return an integer containing the key code and in fact
the method returns the key code in element zero of a buffer.

BugLink: http://bugs.launchpad.net/bugs/701530
BugLink: http://bugs.launchpad.net/bugs/676997

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

3 files changed, 185 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 2822d8a8cdd2..f0ef757d9fde 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -101,6 +101,19 @@ config DELL_WMI
           To compile this driver as a module, choose M here: the module will
           be called dell-wmi.
 
+config DELL_WMI_AIO
+        tristate "WMI Hotkeys for Dell All-In-One series"
+        depends on ACPI_WMI
+        depends on INPUT
+        select INPUT_SPARSEKMAP
+        ---help---
+          Say Y here if you want to support WMI-based hotkeys on Dell
+          All-In-One machines.
+
+          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
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 3e14b18403e0..46f3fd2c8856 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_ACPI_CMPC)		+= classmate-laptop.o
 obj-$(CONFIG_COMPAL_LAPTOP)     += compal-laptop.o
 obj-$(CONFIG_DELL_LAPTOP)       += dell-laptop.o
 obj-$(CONFIG_DELL_WMI)          += dell-wmi.o
+obj-$(CONFIG_DELL_WMI_AIO)      += dell-wmi-aio.o
 obj-$(CONFIG_ACER_WMI)          += acer-wmi.o
 obj-$(CONFIG_ACERHDF)           += acerhdf.o
 obj-$(CONFIG_HP_ACCEL)          += hp_accel.o
diff --git a/drivers/platform/x86/dell-wmi-aio.c b/drivers/platform/x86/dell-wmi-aio.c
new file mode 100644
index 000000000000..0ed84573ae1f
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-aio.c
@@ -0,0 +1,171 @@
+/*
+ *  WMI hotkeys support for Dell All-In-One series
+ *
+ *  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
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/input.h>
+#include <linux/input/sparse-keymap.h>
+#include <acpi/acpi_drivers.h>
+#include <linux/acpi.h>
+#include <linux/string.h>
+
+MODULE_DESCRIPTION("WMI hotkeys driver for Dell All-In-One series");
+MODULE_LICENSE("GPL");
+
+#define EVENT_GUID1 "284A0E6B-380E-472A-921F-E52786257FB4"
+#define EVENT_GUID2 "02314822-307C-4F66-BF0E-48AEAEB26CC8"
+
+static const char *dell_wmi_aio_guids[] = {
+        EVENT_GUID1,
+        EVENT_GUID2,
+        NULL
+};
+
+MODULE_ALIAS("wmi:"EVENT_GUID1);
+MODULE_ALIAS("wmi:"EVENT_GUID2);
+
+static const struct key_entry dell_wmi_aio_keymap[] = {
+        { KE_KEY, 0xc0, { KEY_VOLUMEUP } },
+        { KE_KEY, 0xc1, { KEY_VOLUMEDOWN } },
+        { KE_END, 0 }
+};
+
+static struct input_dev *dell_wmi_aio_input_dev;
+
+static void dell_wmi_aio_notify(u32 value, void *context)
+{
+        struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
+        union acpi_object *obj;
+        acpi_status status;
+
+        status = wmi_get_event_data(value, &response);
+        if (status != AE_OK) {
+                pr_info("bad event status 0x%x\n", status);
+                return;
+        }
+
+        obj = (union acpi_object *)response.pointer;
+        if (obj) {
+                unsigned int scancode;
+
+                switch (obj->type) {
+                case ACPI_TYPE_INTEGER:
+                        /* Most All-In-One correctly return integer scancode */
+                        scancode = obj->integer.value;
+                        sparse_keymap_report_event(dell_wmi_aio_input_dev,
+                                scancode, 1, true);
+                        break;
+                case ACPI_TYPE_BUFFER:
+                        /* Broken machines return the scancode in a buffer */
+                        if (obj->buffer.pointer && obj->buffer.length > 0) {
+                                scancode = obj->buffer.pointer[0];
+                                sparse_keymap_report_event(
+                                        dell_wmi_aio_input_dev,
+                                        scancode, 1, true);
+                        }
+                        break;
+                }
+        }
+        kfree(obj);
+}
+
+static int __init dell_wmi_aio_input_setup(void)
+{
+        int err;
+
+        dell_wmi_aio_input_dev = input_allocate_device();
+
+        if (!dell_wmi_aio_input_dev)
+                return -ENOMEM;
+
+        dell_wmi_aio_input_dev->name = "Dell AIO WMI hotkeys";
+        dell_wmi_aio_input_dev->phys = "wmi/input0";
+        dell_wmi_aio_input_dev->id.bustype = BUS_HOST;
+
+        err = sparse_keymap_setup(dell_wmi_aio_input_dev,
+                        dell_wmi_aio_keymap, NULL);
+        if (err) {
+                pr_err("Unable to setup input device keymap\n");
+                goto err_free_dev;
+        }
+        err = input_register_device(dell_wmi_aio_input_dev);
+        if (err) {
+                pr_info("Unable to register input device\n");
+                goto err_free_keymap;
+        }
+        return 0;
+
+err_free_keymap:
+        sparse_keymap_free(dell_wmi_aio_input_dev);
+err_free_dev:
+        input_free_device(dell_wmi_aio_input_dev);
+        return err;
+}
+
+static const char *dell_wmi_aio_find(void)
+{
+        int i;
+
+        for (i = 0; dell_wmi_aio_guids[i] != NULL; i++)
+                if (wmi_has_guid(dell_wmi_aio_guids[i]))
+                        return dell_wmi_aio_guids[i];
+
+        return NULL;
+}
+
+static int __init dell_wmi_aio_init(void)
+{
+        int err;
+        const char *guid;
+
+        guid = dell_wmi_aio_find();
+        if (!guid) {
+                pr_warning("No known WMI GUID found\n");
+                return -ENXIO;
+        }
+
+        err = dell_wmi_aio_input_setup();
+        if (err)
+                return err;
+
+        err = wmi_install_notify_handler(guid, dell_wmi_aio_notify, NULL);
+        if (err) {
+                pr_err("Unable to register notify handler - %d\n", err);
+                sparse_keymap_free(dell_wmi_aio_input_dev);
+                input_unregister_device(dell_wmi_aio_input_dev);
+                return err;
+        }
+
+        return 0;
+}
+
+static void __exit dell_wmi_aio_exit(void)
+{
+        const char *guid;
+
+        guid = dell_wmi_aio_find();
+        wmi_remove_notify_handler(guid);
+        sparse_keymap_free(dell_wmi_aio_input_dev);
+        input_unregister_device(dell_wmi_aio_input_dev);
+}
+
+module_init(dell_wmi_aio_init);
+module_exit(dell_wmi_aio_exit);