intel-hid: new hid event driver for hotkeys

This driver supports various HID events including hotkeys.
Dell XPS 13 9350 requires it for the wireless hotkey.
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Reviewed-and-tested-by: Andy Lutomirski <luto@kernel.org>

[dvhart: Kconfig help typo fix and INPUT_SPARSEKMAP fix from Sedat Dilek]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

MAINTAINERS

@@ -5498,6 +5498,12 @@ T:	git git://git.code.sf.net/p/intel-sas/isci
 S:	Supported
 F:	drivers/scsi/isci/
 
+INTEL HID EVENT DRIVER
+M:	Alex Hung <alex.hung@canonical.com>
+L:	platform-driver-x86@vger.kernel.org
+S:	Maintained
+F:	drivers/platform/x86/intel-hid.c
+
 INTEL IDLE DRIVER
 M:	Len Brown <lenb@kernel.org>
 L:	linux-pm@vger.kernel.org

drivers/platform/x86/Kconfig

@@ -732,6 +732,18 @@ config ACPI_CMPC
 	  keys as input device, backlight device, tablet and accelerometer
 	  devices.
 
+config INTEL_HID_EVENT
+	tristate "INTEL HID Event"
+	depends on ACPI
+	depends on INPUT
+	select INPUT_SPARSEKMAP
+	help
+	  This driver provides support for the Intel HID Event hotkey interface.
+	  Some laptops require this driver for hotkey support.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called intel_hid.
+
 config INTEL_SCU_IPC
 	bool "Intel SCU IPC Support"
 	depends on X86_INTEL_MID

drivers/platform/x86/Makefile

@@ -41,6 +41,7 @@ obj-$(CONFIG_ACPI_TOSHIBA)	+= toshiba_acpi.o
 obj-$(CONFIG_TOSHIBA_BT_RFKILL)	+= toshiba_bluetooth.o
 obj-$(CONFIG_TOSHIBA_HAPS)	+= toshiba_haps.o
 obj-$(CONFIG_TOSHIBA_WMI)	+= toshiba-wmi.o
+obj-$(CONFIG_INTEL_HID_EVENT)	+= intel-hid.o
 obj-$(CONFIG_INTEL_SCU_IPC)	+= intel_scu_ipc.o
 obj-$(CONFIG_INTEL_SCU_IPC_UTIL) += intel_scu_ipcutil.o
 obj-$(CONFIG_INTEL_MFLD_THERMAL) += intel_mid_thermal.o

drivers/platform/x86/intel-hid.c

+/*
+ *  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);