[PATCH v7 2/3] x86: add support for Huawei WMI hotkeys.

[Ayman Bagabas]

This driver adds support for missing hotkeys on some Huawei laptops.
Currently, only Huawei Matebook X and Matebook X Pro is supported.

Signed-off-by: Ayman Bagabas <ayman.bagabas@xxxxxxxxx>
---
 drivers/platform/x86/Kconfig      |  15 ++
 drivers/platform/x86/Makefile     |   1 +
 drivers/platform/x86/huawei-wmi.c | 247 ++++++++++++++++++++++++++++++
 3 files changed, 263 insertions(+)
 create mode 100644 drivers/platform/x86/huawei-wmi.c

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 87f70e8f4dd0..0f9db4275fb4 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1292,6 +1292,21 @@ config INTEL_ATOMISP2_PM
 	  To compile this driver as a module, choose M here: the module
 	  will be called intel_atomisp2_pm.
 
+config HUAWEI_WMI
+	tristate "Huawei WMI hotkeys driver"
+	depends on ACPI_WMI
+	depends on INPUT
+	select INPUT_SPARSEKMAP
+	select LEDS_TRIGGERS
+	select LEDS_TRIGGER_AUDIO
+	help
+	  This driver provides support for Huawei WMI hotkeys.
+	  It enables the missing keys and adds support to the micmute
+	  LED found on some of these laptops.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called huawei-wmi.
+
 endif # X86_PLATFORM_DEVICES
 
 config PMC_ATOM
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 39ae94135406..d841c550e3cc 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -32,6 +32,7 @@ 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-$(CONFIG_HUAWEI_WMI)		+= huawei-wmi.o
 obj-$(CONFIG_AMILO_RFKILL)	+= amilo-rfkill.o
 obj-$(CONFIG_GPD_POCKET_FAN)	+= gpd-pocket-fan.o
 obj-$(CONFIG_TC1100_WMI)	+= tc1100-wmi.o
diff --git a/drivers/platform/x86/huawei-wmi.c b/drivers/platform/x86/huawei-wmi.c
new file mode 100644
index 000000000000..b6157c5b7f4a
--- /dev/null
+++ b/drivers/platform/x86/huawei-wmi.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Huawei WMI hotkeys
+ *
+ *  Copyright (C) 2018	      Ayman Bagabas <ayman.bagabas@xxxxxxxxx>
+ */
+
+#include <linux/acpi.h>
+#include <linux/input.h>
+#include <linux/input/sparse-keymap.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+
+MODULE_AUTHOR("Ayman Bagabas <ayman.bagabas@xxxxxxxxx>");
+MODULE_DESCRIPTION("Huawei WMI hotkeys");
+MODULE_LICENSE("GPL v2");
+
+/*
+ * Huawei WMI Events GUIDs
+ */
+#define MBX_EVENT_GUID "59142400-C6A3-40fa-BADB-8A2652834100"
+#define MBXP_EVENT_GUID "ABBC0F5C-8EA1-11D1-A000-C90629100000"
+
+MODULE_ALIAS("wmi:"MBX_EVENT_GUID);
+MODULE_ALIAS("wmi:"MBXP_EVENT_GUID);
+
+static const struct key_entry huawei_wmi_keymap[] __initconst = {
+		{ KE_KEY,    0x281, { KEY_BRIGHTNESSDOWN } },
+		{ KE_KEY,    0x282, { KEY_BRIGHTNESSUP } },
+		{ KE_KEY,    0x284, { KEY_MUTE } },
+		{ KE_KEY,    0x285, { KEY_VOLUMEDOWN } },
+		{ KE_KEY,    0x286, { KEY_VOLUMEUP } },
+		{ KE_KEY,    0x287, { KEY_MICMUTE } },
+		{ KE_KEY,    0x289, { KEY_WLAN } },
+		// Huawei |M| button
+		{ KE_KEY,    0x28a, { KEY_CONFIG } },
+		// Keyboard light
+		{ KE_IGNORE, 0x293, { KEY_KBDILLUMTOGGLE } },
+		{ KE_IGNORE, 0x294, { KEY_KBDILLUMUP } },
+		{ KE_IGNORE, 0x295, { KEY_KBDILLUMUP } },
+		{ KE_END,    0 }
+};
+
+static char *event_guid;
+static struct input_dev *inputdev;
+
+static int huawei_wmi_micmute_led_set(bool on)
+{
+	acpi_handle handle;
+	char *method;
+	union acpi_object args[3];
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+
+	handle = ACPI_HANDLE(&inputdev->dev);
+	args[0].type = args[1].type = args[2].type = ACPI_TYPE_INTEGER;
+	args[1].integer.value = 0x04;
+
+	if (acpi_has_method(handle, method = "\\_SB.PCI0.LPCB.EC0.SPIN")) {
+		args[0].integer.value = 0;
+		args[2].integer.value = on ? 1 : 0;
+	} else if (acpi_has_method(handle, method = "\\_SB.PCI0.LPCB.EC0.WPIN")) {
+		args[0].integer.value = 1;
+		args[2].integer.value = on ? 0 : 1;
+	} else {
+		dev_err(&inputdev->dev, "Unable to find ACPI method\n");
+		return -ENOSYS;
+	}
+
+	acpi_evaluate_object(handle, method, &arg_list, NULL);
+
+	return 0;
+}
+
+static int micmute_led_set(struct led_classdev *led_cdev,
+		enum led_brightness brightness)
+{
+	int state = brightness != LED_OFF;
+	int err;
+
+	err = huawei_wmi_micmute_led_set(state);
+	return err < 0 ? err : 0;
+}
+
+static struct led_classdev micmute_led_cdev = {
+	.name = "huawei::micmute",
+	.max_brightness = 1,
+	.brightness_set_blocking = micmute_led_set,
+	.default_trigger = "audio-micmute",
+};
+
+static void huawei_wmi_process_key(struct input_dev *inputdev, int code)
+{
+	const struct key_entry *key;
+
+	/*
+	 * MBX uses code 0x80 to indicate a hotkey event.
+	 * The actual key is fetched from the method WQ00.
+	 */
+	if (code == 0x80) {
+		acpi_status status;
+		unsigned long long result;
+		const char *method = "\\WMI0.WQ00";
+		union acpi_object args[1];
+		struct acpi_object_list arg_list = {
+			.pointer = args,
+			.count = ARRAY_SIZE(args),
+		};
+
+		args[0].type = ACPI_TYPE_INTEGER;
+		args[0].integer.value = 0;
+
+		status = acpi_evaluate_integer(ACPI_HANDLE(&inputdev->dev), (char *)method, &arg_list, &result);
+		if (ACPI_FAILURE(status)) {
+			dev_err(&inputdev->dev, "Unable to evaluate ACPI method %s\n", method);
+			return;
+		}
+
+		code = result;
+	}
+
+	key = sparse_keymap_entry_from_scancode(inputdev, code);
+	if (!key) {
+		dev_info(&inputdev->dev, "Unknown key pressed, code: 0x%04x\n", code);
+		return;
+	}
+
+	/*
+	 * The MBXP handles backlight natively using ACPI,
+	 * but not the MBX. If MBXP is being used, skip reporting event.
+	 */
+	if ((key->sw.code == KEY_BRIGHTNESSUP || key->sw.code == KEY_BRIGHTNESSDOWN)
+			&& strcmp(event_guid, MBXP_EVENT_GUID) == 0)
+		return;
+
+	sparse_keymap_report_entry(inputdev, key, 1, true);
+}
+
+static void huawei_wmi_notify(u32 value, void *context)
+{
+	struct input_dev *inputdev = context;
+	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	acpi_status status;
+
+	status = wmi_get_event_data(value, &response);
+	if (ACPI_FAILURE(status)) {
+		dev_err(&inputdev->dev, "Bad event status 0x%x\n", status);
+		return;
+	}
+
+	obj = (union acpi_object *)response.pointer;
+	if (!obj)
+		return;
+
+	if (obj->type == ACPI_TYPE_INTEGER)
+		huawei_wmi_process_key(inputdev, obj->integer.value);
+	else
+		dev_info(&inputdev->dev, "Unknown response received %d\n", obj->type);
+
+	kfree(response.pointer);
+}
+
+static int huawei_wmi_input_init(void)
+{
+	acpi_status status;
+	int err;
+
+	inputdev = input_allocate_device();
+	if (!inputdev)
+		return -ENOMEM;
+
+	inputdev->name = "Huawei WMI hotkeys";
+	inputdev->phys = "wmi/input0";
+	inputdev->id.bustype = BUS_HOST;
+
+	err = sparse_keymap_setup(inputdev, huawei_wmi_keymap, NULL);
+	if (err)
+		goto err_free_dev;
+
+	status = wmi_install_notify_handler(event_guid,
+			huawei_wmi_notify,
+			inputdev);
+	if (ACPI_FAILURE(status)) {
+		err = -EIO;
+		goto err_free_dev;
+	}
+
+	err = input_register_device(inputdev);
+	if (err)
+		goto err_remove_notifier;
+
+	return 0;
+
+err_remove_notifier:
+	wmi_remove_notify_handler(event_guid);
+err_free_dev:
+	input_free_device(inputdev);
+	return err;
+}
+
+static void huawei_wmi_input_exit(void)
+{
+	wmi_remove_notify_handler(event_guid);
+	input_unregister_device(inputdev);
+}
+
+static int __init huawei_wmi_init(void)
+{
+	int err;
+
+	if (wmi_has_guid(MBX_EVENT_GUID)) {
+		event_guid = MBX_EVENT_GUID;
+	} else if (wmi_has_guid(MBXP_EVENT_GUID)) {
+		event_guid = MBXP_EVENT_GUID;
+	} else {
+		pr_warn("Compatible WMI GUID not found\n");
+		return -ENODEV;
+	}
+
+	err = huawei_wmi_input_init();
+	if (err)
+		goto err_input;
+
+	micmute_led_cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
+	err = led_classdev_register(&inputdev->dev, &micmute_led_cdev);
+	if (err)
+		goto err_leds;
+
+	return 0;
+
+err_leds:
+	huawei_wmi_input_exit();
+err_input:
+	return err;
+}
+
+static void __exit huawei_wmi_exit(void)
+{
+	led_classdev_unregister(&micmute_led_cdev);
+	huawei_wmi_input_exit();
+}
+
+module_init(huawei_wmi_init);
+module_exit(huawei_wmi_exit);
-- 
2.19.1