--- /dev/null
+/*
+ * Intel HID event driver for Windows 8
+ *
+ * Copyright (C) 2015 Alex Hung <alex.hung@canonical.com>
+ * Copyright (C) 2015 Andrew Lutomirski <luto@kernel.org>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/input/sparse-keymap.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alex Hung");
+
+static const struct acpi_device_id intel_hid_ids[] = {
+ {"INT33D5", 0},
+ {"", 0},
+};
+
+/* In theory, these are HID usages. */
+static const struct key_entry intel_hid_keymap[] = {
+ /* 1: LSuper (Page 0x07, usage 0xE3) -- unclear what to do */
+ /* 2: Toggle SW_ROTATE_LOCK -- easy to implement if seen in wild */
+ { KE_KEY, 3, { KEY_NUMLOCK } },
+ { KE_KEY, 4, { KEY_HOME } },
+ { KE_KEY, 5, { KEY_END } },
+ { KE_KEY, 6, { KEY_PAGEUP } },
+ { KE_KEY, 4, { KEY_PAGEDOWN } },
+ { KE_KEY, 4, { KEY_HOME } },
+ { KE_KEY, 8, { KEY_RFKILL } },
+ { KE_KEY, 9, { KEY_POWER } },
+ { KE_KEY, 11, { KEY_SLEEP } },
+ /* 13 has two different meanings in the spec -- ignore it. */
+ { KE_KEY, 14, { KEY_STOPCD } },
+ { KE_KEY, 15, { KEY_PLAYPAUSE } },
+ { KE_KEY, 16, { KEY_MUTE } },
+ { KE_KEY, 17, { KEY_VOLUMEUP } },
+ { KE_KEY, 18, { KEY_VOLUMEDOWN } },
+ { KE_KEY, 19, { KEY_BRIGHTNESSUP } },
+ { KE_KEY, 20, { KEY_BRIGHTNESSDOWN } },
+ /* 27: wake -- needs special handling */
+ { KE_END },
+};
+
+struct intel_hid_priv {
+ struct input_dev *input_dev;
+};
+
+static int intel_hid_set_enable(struct device *device, int enable)
+{
+ union acpi_object arg0 = { ACPI_TYPE_INTEGER };
+ struct acpi_object_list args = { 1, &arg0 };
+ acpi_status status;
+
+ arg0.integer.value = enable;
+ status = acpi_evaluate_object(ACPI_HANDLE(device), "HDSM", &args, NULL);
+ if (!ACPI_SUCCESS(status)) {
+ dev_warn(device, "failed to %sable hotkeys\n",
+ enable ? "en" : "dis");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int intel_hid_pl_suspend_handler(struct device *device)
+{
+ intel_hid_set_enable(device, 0);
+ return 0;
+}
+
+static int intel_hid_pl_resume_handler(struct device *device)
+{
+ intel_hid_set_enable(device, 1);
+ return 0;
+}
+
+static const struct dev_pm_ops intel_hid_pl_pm_ops = {
+ .suspend = intel_hid_pl_suspend_handler,
+ .resume = intel_hid_pl_resume_handler,
+};
+
+static int intel_hid_input_setup(struct platform_device *device)
+{
+ struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
+ int ret;
+
+ priv->input_dev = input_allocate_device();
+ if (!priv->input_dev)
+ return -ENOMEM;
+
+ ret = sparse_keymap_setup(priv->input_dev, intel_hid_keymap, NULL);
+ if (ret)
+ goto err_free_device;
+
+ priv->input_dev->dev.parent = &device->dev;
+ priv->input_dev->name = "Intel HID events";
+ priv->input_dev->id.bustype = BUS_HOST;
+ set_bit(KEY_RFKILL, priv->input_dev->keybit);
+
+ ret = input_register_device(priv->input_dev);
+ if (ret)
+ goto err_free_device;
+
+ return 0;
+
+err_free_device:
+ input_free_device(priv->input_dev);
+ return ret;
+}
+
+static void intel_hid_input_destroy(struct platform_device *device)
+{
+ struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
+
+ input_unregister_device(priv->input_dev);
+}
+
+static void notify_handler(acpi_handle handle, u32 event, void *context)
+{
+ struct platform_device *device = context;
+ struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
+ unsigned long long ev_index;
+ acpi_status status;
+
+ /* The platform spec only defines one event code: 0xC0. */
+ if (event != 0xc0) {
+ dev_warn(&device->dev, "received unknown event (0x%x)\n",
+ event);
+ return;
+ }
+
+ status = acpi_evaluate_integer(handle, "HDEM", NULL, &ev_index);
+ if (!ACPI_SUCCESS(status)) {
+ dev_warn(&device->dev, "failed to get event index\n");
+ return;
+ }
+
+ if (!sparse_keymap_report_event(priv->input_dev, ev_index, 1, true))
+ dev_info(&device->dev, "unknown event index 0x%llx\n",
+ ev_index);
+}
+
+static int intel_hid_probe(struct platform_device *device)
+{
+ acpi_handle handle = ACPI_HANDLE(&device->dev);
+ struct intel_hid_priv *priv;
+ unsigned long long mode;
+ acpi_status status;
+ int err;
+
+ status = acpi_evaluate_integer(handle, "HDMM", NULL, &mode);
+ if (!ACPI_SUCCESS(status)) {
+ dev_warn(&device->dev, "failed to read mode\n");
+ return -ENODEV;
+ }
+
+ if (mode != 0) {
+ /*
+ * This driver only implements "simple" mode. There appear
+ * to be no other modes, but we should be paranoid and check
+ * for compatibility.
+ */
+ dev_info(&device->dev, "platform is not in simple mode\n");
+ return -ENODEV;
+ }
+
+ priv = devm_kzalloc(&device->dev,
+ sizeof(struct intel_hid_priv *), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ dev_set_drvdata(&device->dev, priv);
+
+ err = intel_hid_input_setup(device);
+ if (err) {
+ pr_err("Failed to setup Intel HID hotkeys\n");
+ return err;
+ }
+
+ status = acpi_install_notify_handler(handle,
+ ACPI_DEVICE_NOTIFY,
+ notify_handler,
+ device);
+ if (ACPI_FAILURE(status)) {
+ err = -EBUSY;
+ goto err_remove_input;
+ }
+
+ err = intel_hid_set_enable(&device->dev, 1);
+ if (err)
+ goto err_remove_notify;
+
+ return 0;
+
+err_remove_notify:
+ acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
+
+err_remove_input:
+ intel_hid_input_destroy(device);
+
+ return err;
+}
+
+static int intel_hid_remove(struct platform_device *device)
+{
+ acpi_handle handle = ACPI_HANDLE(&device->dev);
+
+ acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
+ intel_hid_input_destroy(device);
+ intel_hid_set_enable(&device->dev, 0);
+ acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
+
+ /*
+ * Even if we failed to shut off the event stream, we can still
+ * safely detach from the device.
+ */
+ return 0;
+}
+
+static struct platform_driver intel_hid_pl_driver = {
+ .driver = {
+ .name = "intel-hid",
+ .acpi_match_table = intel_hid_ids,
+ .pm = &intel_hid_pl_pm_ops,
+ },
+ .probe = intel_hid_probe,
+ .remove = intel_hid_remove,
+};
+MODULE_DEVICE_TABLE(acpi, intel_hid_ids);
+
+/*
+ * Unfortunately, some laptops provide a _HID="INT33D5" device with
+ * _CID="PNP0C02". This causes the pnpacpi scan driver to claim the
+ * ACPI node, so no platform device will be created. The pnpacpi
+ * driver rejects this device in subsequent processing, so no physical
+ * node is created at all.
+ *
+ * As a workaround until the ACPI core figures out how to handle
+ * this corner case, manually ask the ACPI platform device code to
+ * claim the ACPI node.
+ */
+static acpi_status __init
+check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+ const struct acpi_device_id *ids = context;
+ struct acpi_device *dev;
+
+ if (acpi_bus_get_device(handle, &dev) != 0)
+ return AE_OK;
+
+ if (acpi_match_device_ids(dev, ids) == 0)
+ if (acpi_create_platform_device(dev))
+ dev_info(&dev->dev,
+ "intel-hid: created platform device\n");
+
+ return AE_OK;
+}
+
+static int __init intel_hid_init(void)
+{
+ acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+ ACPI_UINT32_MAX, check_acpi_dev, NULL,
+ (void *)intel_hid_ids, NULL);
+
+ return platform_driver_register(&intel_hid_pl_driver);
+}
+module_init(intel_hid_init);
+
+static void __exit intel_hid_exit(void)
+{
+ platform_driver_unregister(&intel_hid_pl_driver);
+}
+module_exit(intel_hid_exit);