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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.4 */5 6#include <linux/acpi.h>7#include <linux/backlight.h>8#include <linux/mod_devicetable.h>9#include <linux/module.h>10#include <linux/platform_data/x86/nvidia-wmi-ec-backlight.h>11#include <linux/types.h>12#include <linux/wmi.h>13#include <acpi/video.h>14 15static bool force;16module_param(force, bool, 0444);17MODULE_PARM_DESC(force, "Force loading (disable acpi_backlight=xxx checks");18 19/**20 * wmi_brightness_notify() - helper function for calling WMI-wrapped ACPI method21 * @w: Pointer to the struct wmi_device identified by %WMI_BRIGHTNESS_GUID22 * @id: The WMI method ID to call (e.g. %WMI_BRIGHTNESS_METHOD_LEVEL or23 * %WMI_BRIGHTNESS_METHOD_SOURCE)24 * @mode: The operation to perform on the method (e.g. %WMI_BRIGHTNESS_MODE_SET25 * or %WMI_BRIGHTNESS_MODE_GET)26 * @val: Pointer to a value passed in by the caller when @mode is27 * %WMI_BRIGHTNESS_MODE_SET, or a value passed out to caller when @mode28 * is %WMI_BRIGHTNESS_MODE_GET or %WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL.29 *30 * Returns 0 on success, or a negative error number on failure.31 */32static int wmi_brightness_notify(struct wmi_device *w, enum wmi_brightness_method id, enum wmi_brightness_mode mode, u32 *val)33{34 struct wmi_brightness_args args = {35 .mode = mode,36 .val = 0,37 .ret = 0,38 };39 struct acpi_buffer buf = { (acpi_size)sizeof(args), &args };40 acpi_status status;41 42 if (id < WMI_BRIGHTNESS_METHOD_LEVEL ||43 id >= WMI_BRIGHTNESS_METHOD_MAX ||44 mode < WMI_BRIGHTNESS_MODE_GET || mode >= WMI_BRIGHTNESS_MODE_MAX)45 return -EINVAL;46 47 if (mode == WMI_BRIGHTNESS_MODE_SET)48 args.val = *val;49 50 status = wmidev_evaluate_method(w, 0, id, &buf, &buf);51 if (ACPI_FAILURE(status)) {52 dev_err(&w->dev, "EC backlight control failed: %s\n",53 acpi_format_exception(status));54 return -EIO;55 }56 57 if (mode != WMI_BRIGHTNESS_MODE_SET)58 *val = args.ret;59 60 return 0;61}62 63static int nvidia_wmi_ec_backlight_update_status(struct backlight_device *bd)64{65 struct wmi_device *wdev = bl_get_data(bd);66 67 return wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,68 WMI_BRIGHTNESS_MODE_SET,69 &bd->props.brightness);70}71 72static int nvidia_wmi_ec_backlight_get_brightness(struct backlight_device *bd)73{74 struct wmi_device *wdev = bl_get_data(bd);75 u32 level;76 int ret;77 78 ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,79 WMI_BRIGHTNESS_MODE_GET, &level);80 if (ret < 0)81 return ret;82 83 return level;84}85 86static const struct backlight_ops nvidia_wmi_ec_backlight_ops = {87 .update_status = nvidia_wmi_ec_backlight_update_status,88 .get_brightness = nvidia_wmi_ec_backlight_get_brightness,89};90 91static int nvidia_wmi_ec_backlight_probe(struct wmi_device *wdev, const void *ctx)92{93 struct backlight_properties props = {};94 struct backlight_device *bdev;95 int ret;96 97 /* drivers/acpi/video_detect.c also checks that SOURCE == EC */98 if (!force && acpi_video_get_backlight_type() != acpi_backlight_nvidia_wmi_ec)99 return -ENODEV;100 101 /*102 * Identify this backlight device as a firmware device so that it can103 * be prioritized over any exposed GPU-driven raw device(s).104 */105 props.type = BACKLIGHT_FIRMWARE;106 107 ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,108 WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL,109 &props.max_brightness);110 if (ret)111 return ret;112 113 ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,114 WMI_BRIGHTNESS_MODE_GET, &props.brightness);115 if (ret)116 return ret;117 118 bdev = devm_backlight_device_register(&wdev->dev,119 "nvidia_wmi_ec_backlight",120 &wdev->dev, wdev,121 &nvidia_wmi_ec_backlight_ops,122 &props);123 return PTR_ERR_OR_ZERO(bdev);124}125 126static const struct wmi_device_id nvidia_wmi_ec_backlight_id_table[] = {127 { .guid_string = WMI_BRIGHTNESS_GUID },128 { }129};130MODULE_DEVICE_TABLE(wmi, nvidia_wmi_ec_backlight_id_table);131 132static struct wmi_driver nvidia_wmi_ec_backlight_driver = {133 .driver = {134 .name = "nvidia-wmi-ec-backlight",135 },136 .probe = nvidia_wmi_ec_backlight_probe,137 .id_table = nvidia_wmi_ec_backlight_id_table,138};139module_wmi_driver(nvidia_wmi_ec_backlight_driver);140 141MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>");142MODULE_DESCRIPTION("NVIDIA WMI EC Backlight driver");143MODULE_LICENSE("GPL");144