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// 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/platform_data/x86/nvidia-wmi-ec-backlight.h>
#include <linux/types.h>
#include <linux/wmi.h>
#include <acpi/video.h>
static bool force;
module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "Force loading (disable acpi_backlight=xxx checks");
/**
* 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;
int ret;
/* drivers/acpi/video_detect.c also checks that SOURCE == EC */
if (!force && acpi_video_get_backlight_type() != acpi_backlight_nvidia_wmi_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);
}
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");
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