// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved. */ #include #include #include #include #include #include /** * enum wmaa_method - WMI method IDs for ACPI WMAA * @WMAA_METHOD_LEVEL: Get or set the brightness level, * or get the maximum brightness level. * @WMAA_METHOD_SOURCE: Get the source for backlight control. */ enum wmaa_method { WMAA_METHOD_LEVEL = 1, WMAA_METHOD_SOURCE = 2, WMAA_METHOD_MAX }; /** * enum wmaa_mode - Operation mode for ACPI WMAA method * @WMAA_MODE_GET: Get the current brightness level or source. * @WMAA_MODE_SET: Set the brightness level. * @WMAA_MODE_GET_MAX_LEVEL: Get the maximum brightness level. This is only * valid when the WMI method is %WMAA_METHOD_LEVEL. */ enum wmaa_mode { WMAA_MODE_GET = 0, WMAA_MODE_SET = 1, WMAA_MODE_GET_MAX_LEVEL = 2, WMAA_MODE_MAX }; /** * enum wmaa_source - Backlight brightness control source identification * @WMAA_SOURCE_GPU: Backlight brightness is controlled by the GPU. * @WMAA_SOURCE_EC: Backlight brightness is controlled by the system's * Embedded Controller (EC). * @WMAA_SOURCE_AUX: Backlight brightness is controlled over the DisplayPort * AUX channel. */ enum wmaa_source { WMAA_SOURCE_GPU = 1, WMAA_SOURCE_EC = 2, WMAA_SOURCE_AUX = 3, WMAA_SOURCE_MAX }; /** * struct wmaa_args - arguments for the ACPI WMAA method * @mode: Pass in an &enum wmaa_mode value to select between getting or * setting a value. * @val: In parameter for value to set when operating in %WMAA_MODE_SET * mode. Not used in %WMAA_MODE_GET or %WMAA_MODE_GET_MAX_LEVEL mode. * @ret: Out parameter returning retrieved value when operating in * %WMAA_MODE_GET or %WMAA_MODE_GET_MAX_LEVEL mode. Not used in * %WMAA_MODE_SET mode. * @ignored: Padding; not used. The ACPI method expects a 24 byte params struct. * * This is the parameters structure for the ACPI WMAA 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 %WMAA_METHOD_LEVEL, or an &enum wmaa_source value * when the WMI method ID is %WMAA_METHOD_SOURCE. */ struct wmaa_args { u32 mode; u32 val; u32 ret; u32 ignored[3]; }; /** * wmi_call_wmaa() - helper function for calling ACPI WMAA via its WMI wrapper * @w: Pointer to the struct wmi_device identified by %WMAA_WMI_GUID * @id: The method ID for the ACPI WMAA method (e.g. %WMAA_METHOD_LEVEL or * %WMAA_METHOD_SOURCE) * @mode: The operation to perform on the ACPI WMAA method (e.g. %WMAA_MODE_SET * or %WMAA_MODE_GET) * @val: Pointer to a value passed in by the caller when @mode is * %WMAA_MODE_SET, or a value passed out to the caller when @mode is * %WMAA_MODE_GET or %WMAA_MODE_GET_MAX_LEVEL. * * Returns 0 on success, or a negative error number on failure. */ static int wmi_call_wmaa(struct wmi_device *w, enum wmaa_method id, enum wmaa_mode mode, u32 *val) { struct wmaa_args args = { .mode = mode, .val = 0, .ret = 0, }; struct acpi_buffer buf = { (acpi_size)sizeof(args), &args }; acpi_status status; if (id < WMAA_METHOD_LEVEL || id >= WMAA_METHOD_MAX || mode < WMAA_MODE_GET || mode >= WMAA_MODE_MAX) return -EINVAL; if (mode == WMAA_MODE_SET) args.val = *val; status = wmidev_evaluate_method(w, 0, id, &buf, &buf); if (ACPI_FAILURE(status)) { dev_err(&w->dev, "ACPI WMAA failed: %s\n", acpi_format_exception(status)); return -EIO; } if (mode != WMAA_MODE_SET) *val = args.ret; return 0; } static int wmaa_backlight_update_status(struct backlight_device *bd) { struct wmi_device *wdev = bl_get_data(bd); return wmi_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_MODE_SET, &bd->props.brightness); } static int wmaa_backlight_get_brightness(struct backlight_device *bd) { struct wmi_device *wdev = bl_get_data(bd); u32 level; int ret; ret = wmi_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_MODE_GET, &level); if (ret < 0) return ret; return level; } static const struct backlight_ops wmaa_backlight_ops = { .update_status = wmaa_backlight_update_status, .get_brightness = wmaa_backlight_get_brightness, }; static int wmaa_backlight_wmi_probe(struct wmi_device *wdev, const void *ctx) { struct backlight_properties props = {}; struct backlight_device *bdev; u32 source; int ret; ret = wmi_call_wmaa(wdev, WMAA_METHOD_SOURCE, WMAA_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 != WMAA_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_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_MODE_GET_MAX_LEVEL, &props.max_brightness); if (ret) return ret; ret = wmi_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_MODE_GET, &props.brightness); if (ret) return ret; bdev = devm_backlight_device_register(&wdev->dev, "wmaa_backlight", &wdev->dev, wdev, &wmaa_backlight_ops, &props); return PTR_ERR_OR_ZERO(bdev); } #define WMAA_WMI_GUID "603E9613-EF25-4338-A3D0-C46177516DB7" static const struct wmi_device_id wmaa_backlight_wmi_id_table[] = { { .guid_string = WMAA_WMI_GUID }, { } }; MODULE_DEVICE_TABLE(wmi, wmaa_backlight_wmi_id_table); static struct wmi_driver wmaa_backlight_wmi_driver = { .driver = { .name = "wmaa-backlight", }, .probe = wmaa_backlight_wmi_probe, .id_table = wmaa_backlight_wmi_id_table, }; module_wmi_driver(wmaa_backlight_wmi_driver); MODULE_AUTHOR("Daniel Dadap "); MODULE_DESCRIPTION("WMAA Backlight WMI driver"); MODULE_LICENSE("GPL");