platform/x86: Rename wmaa-backlight-wmi to nvidia-wmi-ec-backlight

Rename the wmaa-backlight-wmi driver and associated KConfig option to
remove the remaining references to the "WMAA" ACPI handle which was
used in the previous name. The driver has already been updated to
remove internal references to "WMAA". As part of the renaming, the
components in the name have been rearranged to reflect the standard
vendor_wmi_feature pattern.

Signed-off-by: Daniel Dadap <ddadap@nvidia.com>
Link: https://lore.kernel.org/r/20210927202359.13684-2-ddadap@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 213 insertions, 0 deletions

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 <ddadap@nvidia.com>");
+MODULE_DESCRIPTION("NVIDIA WMI EC Backlight driver");
+MODULE_LICENSE("GPL");