platform/surface: Move Surface Pro 3 Button driver to platform/surface

Move the Surface Pro 3 Button driver from platform/x86 to the newly
created platform/surface directory.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Chen Yu <yu.c.chen@intel.com>
Link: https://lore.kernel.org/r/20201009141128.683254-6-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

3 files changed, 275 insertions, 0 deletions

diff --git a/drivers/platform/surface/Kconfig b/drivers/platform/surface/Kconfig
index ac1c749a7a2f..10902ea43861 100644
--- a/drivers/platform/surface/Kconfig
+++ b/drivers/platform/surface/Kconfig
@@ -40,4 +40,10 @@ config SURFACE_3_POWER_OPREGION
 	  This driver provides support for ACPI operation
 	  region of the Surface 3 battery platform driver.
 
+config SURFACE_PRO3_BUTTON
+	tristate "Power/home/volume buttons driver for Microsoft Surface Pro 3/4 tablet"
+	depends on ACPI && INPUT
+	help
+	  This driver handles the power/home/volume buttons on the Microsoft Surface Pro 3/4 tablet.
+
 endif # SURFACE_PLATFORMS
diff --git a/drivers/platform/surface/Makefile b/drivers/platform/surface/Makefile
index 4940d4db58b2..dcb1df06d57a 100644
--- a/drivers/platform/surface/Makefile
+++ b/drivers/platform/surface/Makefile
@@ -7,3 +7,4 @@
 obj-$(CONFIG_SURFACE3_WMI)		+= surface3-wmi.o
 obj-$(CONFIG_SURFACE_3_BUTTON)		+= surface3_button.o
 obj-$(CONFIG_SURFACE_3_POWER_OPREGION)	+= surface3_power.o
+obj-$(CONFIG_SURFACE_PRO3_BUTTON)	+= surfacepro3_button.o
diff --git a/drivers/platform/surface/surfacepro3_button.c b/drivers/platform/surface/surfacepro3_button.c
new file mode 100644
index 000000000000..d8afed5db94c
--- /dev/null
+++ b/drivers/platform/surface/surfacepro3_button.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * power/home/volume button support for
+ * Microsoft Surface Pro 3/4 tablet.
+ *
+ * Copyright (c) 2015 Intel Corporation.
+ * All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/input.h>
+#include <linux/acpi.h>
+#include <acpi/button.h>
+
+#define SURFACE_PRO3_BUTTON_HID		"MSHW0028"
+#define SURFACE_PRO4_BUTTON_HID		"MSHW0040"
+#define SURFACE_BUTTON_OBJ_NAME		"VGBI"
+#define SURFACE_BUTTON_DEVICE_NAME	"Surface Pro 3/4 Buttons"
+
+#define MSHW0040_DSM_REVISION		0x01
+#define MSHW0040_DSM_GET_OMPR		0x02	// get OEM Platform Revision
+static const guid_t MSHW0040_DSM_UUID =
+	GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
+		  0x49, 0x80, 0x35);
+
+#define SURFACE_BUTTON_NOTIFY_TABLET_MODE	0xc8
+
+#define SURFACE_BUTTON_NOTIFY_PRESS_POWER	0xc6
+#define SURFACE_BUTTON_NOTIFY_RELEASE_POWER	0xc7
+
+#define SURFACE_BUTTON_NOTIFY_PRESS_HOME	0xc4
+#define SURFACE_BUTTON_NOTIFY_RELEASE_HOME	0xc5
+
+#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP	0xc0
+#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP	0xc1
+
+#define SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN		0xc2
+#define SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN	0xc3
+
+ACPI_MODULE_NAME("surface pro 3 button");
+
+MODULE_AUTHOR("Chen Yu");
+MODULE_DESCRIPTION("Surface Pro3 Button Driver");
+MODULE_LICENSE("GPL v2");
+
+/*
+ * Power button, Home button, Volume buttons support is supposed to
+ * be covered by drivers/input/misc/soc_button_array.c, which is implemented
+ * according to "Windows ACPI Design Guide for SoC Platforms".
+ * However surface pro3 seems not to obey the specs, instead it uses
+ * device VGBI(MSHW0028) for dispatching the events.
+ * We choose acpi_driver rather than platform_driver/i2c_driver because
+ * although VGBI has an i2c resource connected to i2c controller, it
+ * is not embedded in any i2c controller's scope, thus neither platform_device
+ * will be created, nor i2c_client will be enumerated, we have to use
+ * acpi_driver.
+ */
+static const struct acpi_device_id surface_button_device_ids[] = {
+	{SURFACE_PRO3_BUTTON_HID,    0},
+	{SURFACE_PRO4_BUTTON_HID,    0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, surface_button_device_ids);
+
+struct surface_button {
+	unsigned int type;
+	struct input_dev *input;
+	char phys[32];			/* for input device */
+	unsigned long pushed;
+	bool suspended;
+};
+
+static void surface_button_notify(struct acpi_device *device, u32 event)
+{
+	struct surface_button *button = acpi_driver_data(device);
+	struct input_dev *input;
+	int key_code = KEY_RESERVED;
+	bool pressed = false;
+
+	switch (event) {
+	/* Power button press,release handle */
+	case SURFACE_BUTTON_NOTIFY_PRESS_POWER:
+		pressed = true;
+		fallthrough;
+	case SURFACE_BUTTON_NOTIFY_RELEASE_POWER:
+		key_code = KEY_POWER;
+		break;
+	/* Home button press,release handle */
+	case SURFACE_BUTTON_NOTIFY_PRESS_HOME:
+		pressed = true;
+		fallthrough;
+	case SURFACE_BUTTON_NOTIFY_RELEASE_HOME:
+		key_code = KEY_LEFTMETA;
+		break;
+	/* Volume up button press,release handle */
+	case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_UP:
+		pressed = true;
+		fallthrough;
+	case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_UP:
+		key_code = KEY_VOLUMEUP;
+		break;
+	/* Volume down button press,release handle */
+	case SURFACE_BUTTON_NOTIFY_PRESS_VOLUME_DOWN:
+		pressed = true;
+		fallthrough;
+	case SURFACE_BUTTON_NOTIFY_RELEASE_VOLUME_DOWN:
+		key_code = KEY_VOLUMEDOWN;
+		break;
+	case SURFACE_BUTTON_NOTIFY_TABLET_MODE:
+		dev_warn_once(&device->dev, "Tablet mode is not supported\n");
+		break;
+	default:
+		dev_info_ratelimited(&device->dev,
+				     "Unsupported event [0x%x]\n", event);
+		break;
+	}
+	input = button->input;
+	if (key_code == KEY_RESERVED)
+		return;
+	if (pressed)
+		pm_wakeup_dev_event(&device->dev, 0, button->suspended);
+	if (button->suspended)
+		return;
+	input_report_key(input, key_code, pressed?1:0);
+	input_sync(input);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int surface_button_suspend(struct device *dev)
+{
+	struct acpi_device *device = to_acpi_device(dev);
+	struct surface_button *button = acpi_driver_data(device);
+
+	button->suspended = true;
+	return 0;
+}
+
+static int surface_button_resume(struct device *dev)
+{
+	struct acpi_device *device = to_acpi_device(dev);
+	struct surface_button *button = acpi_driver_data(device);
+
+	button->suspended = false;
+	return 0;
+}
+#endif
+
+/*
+ * Surface Pro 4 and Surface Book 2 / Surface Pro 2017 use the same device
+ * ID (MSHW0040) for the power/volume buttons. Make sure this is the right
+ * device by checking for the _DSM method and OEM Platform Revision.
+ *
+ * Returns true if the driver should bind to this device, i.e. the device is
+ * either MSWH0028 (Pro 3) or MSHW0040 on a Pro 4 or Book 1.
+ */
+static bool surface_button_check_MSHW0040(struct acpi_device *dev)
+{
+	acpi_handle handle = dev->handle;
+	union acpi_object *result;
+	u64 oem_platform_rev = 0;	// valid revisions are nonzero
+
+	// get OEM platform revision
+	result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
+					 MSHW0040_DSM_REVISION,
+					 MSHW0040_DSM_GET_OMPR,
+					 NULL, ACPI_TYPE_INTEGER);
+
+	/*
+	 * If evaluating the _DSM fails, the method is not present. This means
+	 * that we have either MSHW0028 or MSHW0040 on Pro 4 or Book 1, so we
+	 * should use this driver. We use revision 0 indicating it is
+	 * unavailable.
+	 */
+
+	if (result) {
+		oem_platform_rev = result->integer.value;
+		ACPI_FREE(result);
+	}
+
+	dev_dbg(&dev->dev, "OEM Platform Revision %llu\n", oem_platform_rev);
+
+	return oem_platform_rev == 0;
+}
+
+
+static int surface_button_add(struct acpi_device *device)
+{
+	struct surface_button *button;
+	struct input_dev *input;
+	const char *hid = acpi_device_hid(device);
+	char *name;
+	int error;
+
+	if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
+	    strlen(SURFACE_BUTTON_OBJ_NAME)))
+		return -ENODEV;
+
+	if (!surface_button_check_MSHW0040(device))
+		return -ENODEV;
+
+	button = kzalloc(sizeof(struct surface_button), GFP_KERNEL);
+	if (!button)
+		return -ENOMEM;
+
+	device->driver_data = button;
+	button->input = input = input_allocate_device();
+	if (!input) {
+		error = -ENOMEM;
+		goto err_free_button;
+	}
+
+	name = acpi_device_name(device);
+	strcpy(name, SURFACE_BUTTON_DEVICE_NAME);
+	snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
+
+	input->name = name;
+	input->phys = button->phys;
+	input->id.bustype = BUS_HOST;
+	input->dev.parent = &device->dev;
+	input_set_capability(input, EV_KEY, KEY_POWER);
+	input_set_capability(input, EV_KEY, KEY_LEFTMETA);
+	input_set_capability(input, EV_KEY, KEY_VOLUMEUP);
+	input_set_capability(input, EV_KEY, KEY_VOLUMEDOWN);
+
+	error = input_register_device(input);
+	if (error)
+		goto err_free_input;
+
+	device_init_wakeup(&device->dev, true);
+	dev_info(&device->dev,
+			"%s [%s]\n", name, acpi_device_bid(device));
+	return 0;
+
+ err_free_input:
+	input_free_device(input);
+ err_free_button:
+	kfree(button);
+	return error;
+}
+
+static int surface_button_remove(struct acpi_device *device)
+{
+	struct surface_button *button = acpi_driver_data(device);
+
+	input_unregister_device(button->input);
+	kfree(button);
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(surface_button_pm,
+		surface_button_suspend, surface_button_resume);
+
+static struct acpi_driver surface_button_driver = {
+	.name = "surface_pro3_button",
+	.class = "SurfacePro3",
+	.ids = surface_button_device_ids,
+	.ops = {
+		.add = surface_button_add,
+		.remove = surface_button_remove,
+		.notify = surface_button_notify,
+	},
+	.drv.pm = &surface_button_pm,
+};
+
+module_acpi_driver(surface_button_driver);