144 lines
4.4 KiB
C
144 lines
4.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
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*/
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#include <linux/acpi.h>
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#include <linux/backlight.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_data/x86/nvidia-wmi-ec-backlight.h>
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#include <linux/types.h>
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#include <linux/wmi.h>
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#include <acpi/video.h>
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static bool force;
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module_param(force, bool, 0444);
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MODULE_PARM_DESC(force, "Force loading (disable acpi_backlight=xxx checks");
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/**
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* wmi_brightness_notify() - helper function for calling WMI-wrapped ACPI method
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* @w: Pointer to the struct wmi_device identified by %WMI_BRIGHTNESS_GUID
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* @id: The WMI method ID to call (e.g. %WMI_BRIGHTNESS_METHOD_LEVEL or
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* %WMI_BRIGHTNESS_METHOD_SOURCE)
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* @mode: The operation to perform on the method (e.g. %WMI_BRIGHTNESS_MODE_SET
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* or %WMI_BRIGHTNESS_MODE_GET)
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* @val: Pointer to a value passed in by the caller when @mode is
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* %WMI_BRIGHTNESS_MODE_SET, or a value passed out to caller when @mode
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* is %WMI_BRIGHTNESS_MODE_GET or %WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL.
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*
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* Returns 0 on success, or a negative error number on failure.
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*/
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static int wmi_brightness_notify(struct wmi_device *w, enum wmi_brightness_method id, enum wmi_brightness_mode mode, u32 *val)
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{
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struct wmi_brightness_args args = {
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.mode = mode,
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.val = 0,
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.ret = 0,
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};
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struct acpi_buffer buf = { (acpi_size)sizeof(args), &args };
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acpi_status status;
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if (id < WMI_BRIGHTNESS_METHOD_LEVEL ||
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id >= WMI_BRIGHTNESS_METHOD_MAX ||
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mode < WMI_BRIGHTNESS_MODE_GET || mode >= WMI_BRIGHTNESS_MODE_MAX)
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return -EINVAL;
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if (mode == WMI_BRIGHTNESS_MODE_SET)
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args.val = *val;
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status = wmidev_evaluate_method(w, 0, id, &buf, &buf);
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if (ACPI_FAILURE(status)) {
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dev_err(&w->dev, "EC backlight control failed: %s\n",
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acpi_format_exception(status));
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return -EIO;
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}
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if (mode != WMI_BRIGHTNESS_MODE_SET)
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*val = args.ret;
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return 0;
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}
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static int nvidia_wmi_ec_backlight_update_status(struct backlight_device *bd)
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{
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struct wmi_device *wdev = bl_get_data(bd);
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return wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
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WMI_BRIGHTNESS_MODE_SET,
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&bd->props.brightness);
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}
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static int nvidia_wmi_ec_backlight_get_brightness(struct backlight_device *bd)
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{
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struct wmi_device *wdev = bl_get_data(bd);
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u32 level;
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int ret;
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ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
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WMI_BRIGHTNESS_MODE_GET, &level);
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if (ret < 0)
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return ret;
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return level;
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}
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static const struct backlight_ops nvidia_wmi_ec_backlight_ops = {
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.update_status = nvidia_wmi_ec_backlight_update_status,
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.get_brightness = nvidia_wmi_ec_backlight_get_brightness,
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};
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static int nvidia_wmi_ec_backlight_probe(struct wmi_device *wdev, const void *ctx)
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{
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struct backlight_properties props = {};
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struct backlight_device *bdev;
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int ret;
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/* drivers/acpi/video_detect.c also checks that SOURCE == EC */
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if (!force && acpi_video_get_backlight_type() != acpi_backlight_nvidia_wmi_ec)
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return -ENODEV;
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/*
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* Identify this backlight device as a firmware device so that it can
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* be prioritized over any exposed GPU-driven raw device(s).
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*/
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props.type = BACKLIGHT_FIRMWARE;
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ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
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WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL,
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&props.max_brightness);
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if (ret)
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return ret;
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ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
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WMI_BRIGHTNESS_MODE_GET, &props.brightness);
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if (ret)
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return ret;
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bdev = devm_backlight_device_register(&wdev->dev,
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"nvidia_wmi_ec_backlight",
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&wdev->dev, wdev,
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&nvidia_wmi_ec_backlight_ops,
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&props);
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return PTR_ERR_OR_ZERO(bdev);
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}
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static const struct wmi_device_id nvidia_wmi_ec_backlight_id_table[] = {
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{ .guid_string = WMI_BRIGHTNESS_GUID },
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{ }
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};
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MODULE_DEVICE_TABLE(wmi, nvidia_wmi_ec_backlight_id_table);
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static struct wmi_driver nvidia_wmi_ec_backlight_driver = {
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.driver = {
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.name = "nvidia-wmi-ec-backlight",
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},
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.probe = nvidia_wmi_ec_backlight_probe,
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.id_table = nvidia_wmi_ec_backlight_id_table,
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};
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module_wmi_driver(nvidia_wmi_ec_backlight_driver);
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MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>");
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MODULE_DESCRIPTION("NVIDIA WMI EC Backlight driver");
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MODULE_LICENSE("GPL");
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