/etc/portage/patches/sys-kernel/gentoo-sources/0006-add-nvidia-wmi-ec-backlight.patch

etcportagepatchessys-kernelgentoo-sources0006-add-nvidia-wmi-ec-backlight.patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 3b79fd441dde..c7f17525b340 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13400,6 +13400,12 @@ S:	Maintained
 F:	drivers/video/fbdev/nvidia/
 F:	drivers/video/fbdev/riva/
 
+NVIDIA WMI EC BACKLIGHT DRIVER
+M:	Daniel Dadap <[email protected]>
+L:	[email protected]
+S:	Supported
+F:	drivers/platform/x86/nvidia-wmi-ec-backlight.c
+
 NVM EXPRESS DRIVER
 M:	Keith Busch <[email protected]>
 M:	Jens Axboe <[email protected]>
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index e21ea3d23e6f..fddee2e60348 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -91,6 +91,21 @@ config PEAQ_WMI
 	help
 	 Say Y here if you want to support WMI-based hotkeys on PEAQ 2-in-1s.
 
+config NVIDIA_WMI_EC_BACKLIGHT
+	tristate "EC Backlight Driver for Hybrid Graphics Notebook Systems"
+	depends on ACPI_WMI
+	depends on BACKLIGHT_CLASS_DEVICE
+	help
+	  This driver provides a sysfs backlight interface for notebook systems
+	  which are equipped with NVIDIA hybrid graphics and drive LCD backlight
+	  levels through the Embedded Controller (EC).
+
+	  Say Y or M here if you want to control the backlight on a notebook
+	  system with an EC-driven backlight.
+
+	  If you choose to compile this driver as a module the module will be
+	  called nvidia-wmi-ec-backlight.
+
 config XIAOMI_WMI
 	tristate "Xiaomi WMI key driver"
 	depends on ACPI_WMI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 69690e26bb6d..0d046ed70da1 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_WMI_BMOF)		+= wmi-bmof.o
 # WMI drivers
 obj-$(CONFIG_HUAWEI_WMI)		+= huawei-wmi.o
 obj-$(CONFIG_MXM_WMI)			+= mxm-wmi.o
+obj-$(CONFIG_NVIDIA_WMI_EC_BACKLIGHT)	+= nvidia-wmi-ec-backlight.o
 obj-$(CONFIG_PEAQ_WMI)			+= peaq-wmi.o
 obj-$(CONFIG_XIAOMI_WMI)		+= xiaomi-wmi.o
 obj-$(CONFIG_GIGABYTE_WMI)		+= gigabyte-wmi.o
diff --git a/drivers/platform/x86/nvidia-wmi-ec-backlight.c b/drivers/platform/x86/nvidia-wmi-ec-backlight.c
new file mode 100644
index 000000000000..61e37194df70
--- /dev/null
+++ b/drivers/platform/x86/nvidia-wmi-ec-backlight.c
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/acpi.h>
+#include <linux/backlight.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/wmi.h>
+
+/**
+ * enum wmi_brightness_method - WMI method IDs
+ * @WMI_BRIGHTNESS_METHOD_LEVEL:  Get/Set EC brightness level status
+ * @WMI_BRIGHTNESS_METHOD_SOURCE: Get/Set EC Brightness Source
+ */
+enum wmi_brightness_method {
+	WMI_BRIGHTNESS_METHOD_LEVEL = 1,
+	WMI_BRIGHTNESS_METHOD_SOURCE = 2,
+	WMI_BRIGHTNESS_METHOD_MAX
+};
+
+/**
+ * enum wmi_brightness_mode - Operation mode for WMI-wrapped method
+ * @WMI_BRIGHTNESS_MODE_GET:            Get the current brightness level/source.
+ * @WMI_BRIGHTNESS_MODE_SET:            Set the brightness level.
+ * @WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL:  Get the maximum brightness level. This
+ *                                      is only valid when the WMI method is
+ *                                      %WMI_BRIGHTNESS_METHOD_LEVEL.
+ */
+enum wmi_brightness_mode {
+	WMI_BRIGHTNESS_MODE_GET = 0,
+	WMI_BRIGHTNESS_MODE_SET = 1,
+	WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL = 2,
+	WMI_BRIGHTNESS_MODE_MAX
+};
+
+/**
+ * enum wmi_brightness_source - Backlight brightness control source selection
+ * @WMI_BRIGHTNESS_SOURCE_GPU: Backlight brightness is controlled by the GPU.
+ * @WMI_BRIGHTNESS_SOURCE_EC:  Backlight brightness is controlled by the
+ *                             system's Embedded Controller (EC).
+ * @WMI_BRIGHTNESS_SOURCE_AUX: Backlight brightness is controlled over the
+ *                             DisplayPort AUX channel.
+ */
+enum wmi_brightness_source {
+	WMI_BRIGHTNESS_SOURCE_GPU = 1,
+	WMI_BRIGHTNESS_SOURCE_EC = 2,
+	WMI_BRIGHTNESS_SOURCE_AUX = 3,
+	WMI_BRIGHTNESS_SOURCE_MAX
+};
+
+/**
+ * struct wmi_brightness_args - arguments for the WMI-wrapped ACPI method
+ * @mode:    Pass in an &enum wmi_brightness_mode value to select between
+ *           getting or setting a value.
+ * @val:     In parameter for value to set when using %WMI_BRIGHTNESS_MODE_SET
+ *           mode. Not used in conjunction with %WMI_BRIGHTNESS_MODE_GET or
+ *           %WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL mode.
+ * @ret:     Out parameter returning retrieved value when operating in
+ *           %WMI_BRIGHTNESS_MODE_GET or %WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL
+ *           mode. Not used in %WMI_BRIGHTNESS_MODE_SET mode.
+ * @ignored: Padding; not used. The ACPI method expects a 24 byte params struct.
+ *
+ * This is the parameters structure for the WmiBrightnessNotify ACPI method as
+ * wrapped by WMI. The value passed in to @val or returned by @ret will be a
+ * brightness value when the WMI method ID is %WMI_BRIGHTNESS_METHOD_LEVEL, or
+ * an &enum wmi_brightness_source value with %WMI_BRIGHTNESS_METHOD_SOURCE.
+ */
+struct wmi_brightness_args {
+	u32 mode;
+	u32 val;
+	u32 ret;
+	u32 ignored[3];
+};
+
+/**
+ * wmi_brightness_notify() - helper function for calling WMI-wrapped ACPI method
+ * @w:    Pointer to the struct wmi_device identified by %WMI_BRIGHTNESS_GUID
+ * @id:   The WMI method ID to call (e.g. %WMI_BRIGHTNESS_METHOD_LEVEL or
+ *        %WMI_BRIGHTNESS_METHOD_SOURCE)
+ * @mode: The operation to perform on the method (e.g. %WMI_BRIGHTNESS_MODE_SET
+ *        or %WMI_BRIGHTNESS_MODE_GET)
+ * @val:  Pointer to a value passed in by the caller when @mode is
+ *        %WMI_BRIGHTNESS_MODE_SET, or a value passed out to caller when @mode
+ *        is %WMI_BRIGHTNESS_MODE_GET or %WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL.
+ *
+ * Returns 0 on success, or a negative error number on failure.
+ */
+static int wmi_brightness_notify(struct wmi_device *w, enum wmi_brightness_method id, enum wmi_brightness_mode mode, u32 *val)
+{
+	struct wmi_brightness_args args = {
+		.mode = mode,
+		.val = 0,
+		.ret = 0,
+	};
+	struct acpi_buffer buf = { (acpi_size)sizeof(args), &args };
+	acpi_status status;
+
+	if (id < WMI_BRIGHTNESS_METHOD_LEVEL ||
+	    id >= WMI_BRIGHTNESS_METHOD_MAX ||
+	    mode < WMI_BRIGHTNESS_MODE_GET || mode >= WMI_BRIGHTNESS_MODE_MAX)
+		return -EINVAL;
+
+	if (mode == WMI_BRIGHTNESS_MODE_SET)
+		args.val = *val;
+
+	status = wmidev_evaluate_method(w, 0, id, &buf, &buf);
+	if (ACPI_FAILURE(status)) {
+		dev_err(&w->dev, "EC backlight control failed: %s\n",
+			acpi_format_exception(status));
+		return -EIO;
+	}
+
+	if (mode != WMI_BRIGHTNESS_MODE_SET)
+		*val = args.ret;
+
+	return 0;
+}
+
+static int nvidia_wmi_ec_backlight_update_status(struct backlight_device *bd)
+{
+	struct wmi_device *wdev = bl_get_data(bd);
+
+	return wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+	                             WMI_BRIGHTNESS_MODE_SET,
+			             &bd->props.brightness);
+}
+
+static int nvidia_wmi_ec_backlight_get_brightness(struct backlight_device *bd)
+{
+	struct wmi_device *wdev = bl_get_data(bd);
+	u32 level;
+	int ret;
+
+	ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+	                            WMI_BRIGHTNESS_MODE_GET, &level);
+	if (ret < 0)
+		return ret;
+
+	return level;
+}
+
+static const struct backlight_ops nvidia_wmi_ec_backlight_ops = {
+	.update_status = nvidia_wmi_ec_backlight_update_status,
+	.get_brightness = nvidia_wmi_ec_backlight_get_brightness,
+};
+
+static int nvidia_wmi_ec_backlight_probe(struct wmi_device *wdev, const void *ctx)
+{
+	struct backlight_properties props = {};
+	struct backlight_device *bdev;
+	u32 source;
+	int ret;
+
+	ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_SOURCE,
+	                           WMI_BRIGHTNESS_MODE_GET, &source);
+	if (ret)
+		return ret;
+
+	/*
+	 * This driver is only to be used when brightness control is handled
+	 * by the EC; otherwise, the GPU driver(s) should control brightness.
+	 */
+	if (source != WMI_BRIGHTNESS_SOURCE_EC)
+		return -ENODEV;
+
+	/*
+	 * Identify this backlight device as a firmware device so that it can
+	 * be prioritized over any exposed GPU-driven raw device(s).
+	 */
+	props.type = BACKLIGHT_FIRMWARE;
+
+	ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+	                           WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL,
+	                           &props.max_brightness);
+	if (ret)
+		return ret;
+
+	ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+	                           WMI_BRIGHTNESS_MODE_GET, &props.brightness);
+	if (ret)
+		return ret;
+
+	bdev = devm_backlight_device_register(&wdev->dev,
+	                                      "nvidia_wmi_ec_backlight",
+					      &wdev->dev, wdev,
+					      &nvidia_wmi_ec_backlight_ops,
+					      &props);
+	return PTR_ERR_OR_ZERO(bdev);
+}
+
+#define WMI_BRIGHTNESS_GUID "603E9613-EF25-4338-A3D0-C46177516DB7"
+
+static const struct wmi_device_id nvidia_wmi_ec_backlight_id_table[] = {
+	{ .guid_string = WMI_BRIGHTNESS_GUID },
+	{ }
+};
+MODULE_DEVICE_TABLE(wmi, nvidia_wmi_ec_backlight_id_table);
+
+static struct wmi_driver nvidia_wmi_ec_backlight_driver = {
+	.driver = {
+		.name = "nvidia-wmi-ec-backlight",
+	},
+	.probe = nvidia_wmi_ec_backlight_probe,
+	.id_table = nvidia_wmi_ec_backlight_id_table,
+};
+module_wmi_driver(nvidia_wmi_ec_backlight_driver);
+
+MODULE_AUTHOR("Daniel Dadap <[email protected]>");
+MODULE_DESCRIPTION("NVIDIA WMI EC Backlight driver");
+MODULE_LICENSE("GPL");