[PATCH v2] platform/x86: add lenovo generic wmi driver

[Ai Chao]

Add lenovo generic wmi driver to support camera button.

Signed-off-by: Ai Chao <aichao@xxxxxxxxxx>
---
v2: Adjust GPL v2 to GPL, adjust sprintf to sysfs_emit.

 drivers/platform/x86/Kconfig      |  10 +++
 drivers/platform/x86/Makefile     |   1 +
 drivers/platform/x86/lenovo-wmi.c | 121 ++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+)
 create mode 100644 drivers/platform/x86/lenovo-wmi.c

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index bdd302274b9a..fbbb8fb843d7 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1001,6 +1001,16 @@ config INSPUR_PLATFORM_PROFILE
 	To compile this driver as a module, choose M here: the module
 	will be called inspur-platform-profile.
 
+config LENOVO_WMI
+	tristate "Lenovo Geneirc WMI driver"
+	depends on ACPI_WMI
+	depends on INPUT
+	help
+	This driver provides support for Lenovo WMI driver.
+
+	To compile this driver as a module, choose M here: the module
+	will be called lenovo-wmi.
+
 source "drivers/platform/x86/x86-android-tablets/Kconfig"
 
 config FW_ATTR_CLASS
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 1de432e8861e..d51086552192 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
 obj-$(CONFIG_THINKPAD_LMI)	+= think-lmi.o
 obj-$(CONFIG_YOGABOOK)		+= lenovo-yogabook.o
+obj-$(CONFIG_LENOVO_WMI)	+= lenovo-wmi.o
 
 # Intel
 obj-y				+= intel/
diff --git a/drivers/platform/x86/lenovo-wmi.c b/drivers/platform/x86/lenovo-wmi.c
new file mode 100644
index 000000000000..aa7519d64d9b
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Lenovo Generic WMI Driver
+ *
+ *  Copyright (C) 2018	      Ai Chao <aichao@xxxxxxxxxx>
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/wmi.h>
+
+#define WMI_LENOVO_CAMERABUTTON_EVENT_GUID "50C76F1F-D8E4-D895-0A3D-62F4EA400013"
+
+static u8 camera_mode;
+
+struct lenovo_wmi_priv {
+	struct input_dev *idev;
+};
+
+static ssize_t camerabutton_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%u\n", camera_mode);
+}
+
+DEVICE_ATTR_RO(camerabutton);
+
+static struct attribute *lenovo_wmi_attrs[] = {
+	&dev_attr_camerabutton.attr,
+	NULL,
+};
+
+static const struct attribute_group lenovo_wmi_group = {
+	.attrs = lenovo_wmi_attrs,
+};
+
+const struct attribute_group *lenovo_wmi_groups[] = {
+	&lenovo_wmi_group,
+	NULL,
+};
+
+static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
+{
+	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+
+	if (obj->type == ACPI_TYPE_BUFFER) {
+		camera_mode = obj->buffer.pointer[0];
+		input_report_key(priv->idev, KEY_CAMERA, 1);
+		input_sync(priv->idev);
+		input_report_key(priv->idev, KEY_CAMERA, 0);
+		input_sync(priv->idev);
+	} else {
+		dev_info(&wdev->dev, "Bad response type %d\n", obj->type);
+	}
+}
+
+static int lenovo_wmi_input_setup(struct wmi_device *wdev)
+{
+	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+
+	priv->idev = devm_input_allocate_device(&wdev->dev);
+	if (!priv->idev)
+		return -ENOMEM;
+
+	priv->idev->name = "Lenovo WMI Camera Button";
+	priv->idev->phys = "wmi/input0";
+	priv->idev->id.bustype = BUS_HOST;
+	priv->idev->dev.parent = &wdev->dev;
+	priv->idev->evbit[0] = BIT_MASK(EV_KEY);
+	priv->idev->keybit[BIT_WORD(KEY_CAMERA)] = BIT_MASK(KEY_CAMERA);
+
+	return input_register_device(priv->idev);
+}
+
+static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
+{
+	struct lenovo_wmi_priv *priv;
+	int err;
+
+	priv = devm_kzalloc(&wdev->dev, sizeof(struct lenovo_wmi_priv),
+			    GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dev_set_drvdata(&wdev->dev, priv);
+
+	err = lenovo_wmi_input_setup(wdev);
+	return err;
+}
+
+static void lenovo_wmi_remove(struct wmi_device *wdev)
+{
+	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+
+	input_unregister_device(priv->idev);
+}
+
+static const struct wmi_device_id lenovo_wmi_id_table[] = {
+	{ .guid_string = WMI_LENOVO_CAMERABUTTON_EVENT_GUID },
+	{  }
+};
+
+static struct wmi_driver lenovo_wmi_driver = {
+	.driver = {
+		.name = "lenovo-wmi",
+		.dev_groups = lenovo_wmi_groups,
+	},
+	.id_table = lenovo_wmi_id_table,
+	.probe = lenovo_wmi_probe,
+	.notify = lenovo_wmi_notify,
+	.remove = lenovo_wmi_remove,
+};
+
+module_wmi_driver(lenovo_wmi_driver);
+
+MODULE_DEVICE_TABLE(wmi, lenovo_wmi_id_table);
+MODULE_AUTHOR("Ai Chao <aichao@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Lenovo Generic WMI Driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1