forked from Minki/linux
platform/x86: Add driver for ACPI WMAA EC-based backlight control
A number of upcoming notebook computer designs drive the internal display panel's backlight PWM through the Embedded Controller (EC). This EC-based backlight control can be plumbed through to an ACPI "WMAA" method interface, which in turn can be wrapped by WMI with the GUID handle 603E9613-EF25-4338-A3D0-C46177516DB7. Add a new driver, aliased to the WMAA WMI GUID, to expose a sysfs backlight class driver to control backlight levels on systems with EC-driven backlights. Signed-off-by: Daniel Dadap <ddadap@nvidia.com> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20210903003838.15797-1-ddadap@nvidia.com Reviewed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Daniel Dadap
Hans de Goede
parent
4c51ba9af4
commit
ad62cd9319
@ -20246,6 +20246,12 @@ L: linux-wireless@vger.kernel.org
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S: Odd fixes
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F: drivers/net/wireless/wl3501*
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WMAA BACKLIGHT DRIVER
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M: Daniel Dadap <ddadap@nvidia.com>
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L: platform-driver-x86@vger.kernel.org
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S: Supported
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F: drivers/platform/x86/wmaa-backlight-wmi.c
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WOLFSON MICROELECTRONICS DRIVERS
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L: patches@opensource.cirrus.com
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S: Supported
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@ -91,6 +91,22 @@ config PEAQ_WMI
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help
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Say Y here if you want to support WMI-based hotkeys on PEAQ 2-in-1s.
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config WMAA_BACKLIGHT_WMI
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tristate "ACPI WMAA Backlight Driver"
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depends on ACPI_WMI
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depends on BACKLIGHT_CLASS_DEVICE
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help
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This driver provides a sysfs backlight interface for notebook
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systems which expose the WMAA ACPI method and an associated WMI
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wrapper to drive LCD backlight levels through the Embedded Controller
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(EC).
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Say Y or M here if you want to control the backlight on a notebook
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system with an EC-driven backlight using the ACPI WMAA method.
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If you choose to compile this driver as a module the module will be
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called wmaa-backlight-wmi.
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config XIAOMI_WMI
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tristate "Xiaomi WMI key driver"
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depends on ACPI_WMI
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@ -12,6 +12,7 @@ obj-$(CONFIG_WMI_BMOF) += wmi-bmof.o
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obj-$(CONFIG_HUAWEI_WMI) += huawei-wmi.o
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obj-$(CONFIG_MXM_WMI) += mxm-wmi.o
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obj-$(CONFIG_PEAQ_WMI) += peaq-wmi.o
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obj-$(CONFIG_WMAA_BACKLIGHT_WMI) += wmaa-backlight-wmi.o
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obj-$(CONFIG_XIAOMI_WMI) += xiaomi-wmi.o
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obj-$(CONFIG_GIGABYTE_WMI) += gigabyte-wmi.o
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205
drivers/platform/x86/wmaa-backlight-wmi.c
Normal file
205
drivers/platform/x86/wmaa-backlight-wmi.c
Normal file
@ -0,0 +1,205 @@
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// 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/types.h>
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#include <linux/wmi.h>
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/**
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* enum wmaa_method - WMI method IDs for ACPI WMAA
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* @WMAA_METHOD_LEVEL: Get or set the brightness level,
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* or get the maximum brightness level.
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* @WMAA_METHOD_SOURCE: Get the source for backlight control.
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*/
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enum wmaa_method {
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WMAA_METHOD_LEVEL = 1,
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WMAA_METHOD_SOURCE = 2,
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WMAA_METHOD_MAX
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};
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/**
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* enum wmaa_mode - Operation mode for ACPI WMAA method
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* @WMAA_MODE_GET: Get the current brightness level or source.
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* @WMAA_MODE_SET: Set the brightness level.
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* @WMAA_MODE_GET_MAX_LEVEL: Get the maximum brightness level. This is only
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* valid when the WMI method is %WMAA_METHOD_LEVEL.
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*/
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enum wmaa_mode {
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WMAA_MODE_GET = 0,
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WMAA_MODE_SET = 1,
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WMAA_MODE_GET_MAX_LEVEL = 2,
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WMAA_MODE_MAX
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};
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/**
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* enum wmaa_source - Backlight brightness control source identification
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* @WMAA_SOURCE_GPU: Backlight brightness is controlled by the GPU.
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* @WMAA_SOURCE_EC: Backlight brightness is controlled by the system's
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* Embedded Controller (EC).
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* @WMAA_SOURCE_AUX: Backlight brightness is controlled over the DisplayPort
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* AUX channel.
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*/
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enum wmaa_source {
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WMAA_SOURCE_GPU = 1,
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WMAA_SOURCE_EC = 2,
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WMAA_SOURCE_AUX = 3,
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WMAA_SOURCE_MAX
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};
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/**
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* struct wmaa_args - arguments for the ACPI WMAA method
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* @mode: Pass in an &enum wmaa_mode value to select between getting or
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* setting a value.
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* @val: In parameter for value to set when operating in %WMAA_MODE_SET
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* mode. Not used in %WMAA_MODE_GET or %WMAA_MODE_GET_MAX_LEVEL mode.
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* @ret: Out parameter returning retrieved value when operating in
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* %WMAA_MODE_GET or %WMAA_MODE_GET_MAX_LEVEL mode. Not used in
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* %WMAA_MODE_SET mode.
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* @ignored: Padding; not used. The ACPI method expects a 24 byte params struct.
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*
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* This is the parameters structure for the ACPI WMAA method as wrapped by WMI.
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* The value passed in to @val or returned by @ret will be a brightness value
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* when the WMI method ID is %WMAA_METHOD_LEVEL, or an &enum wmaa_source value
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* when the WMI method ID is %WMAA_METHOD_SOURCE.
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*/
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struct wmaa_args {
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u32 mode;
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u32 val;
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u32 ret;
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u32 ignored[3];
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};
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/**
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* wmi_call_wmaa() - helper function for calling ACPI WMAA via its WMI wrapper
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* @w: Pointer to the struct wmi_device identified by %WMAA_WMI_GUID
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* @id: The method ID for the ACPI WMAA method (e.g. %WMAA_METHOD_LEVEL or
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* %WMAA_METHOD_SOURCE)
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* @mode: The operation to perform on the ACPI WMAA method (e.g. %WMAA_MODE_SET
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* or %WMAA_MODE_GET)
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* @val: Pointer to a value passed in by the caller when @mode is
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* %WMAA_MODE_SET, or a value passed out to the caller when @mode is
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* %WMAA_MODE_GET or %WMAA_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_call_wmaa(struct wmi_device *w, enum wmaa_method id, enum wmaa_mode mode, u32 *val)
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{
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struct wmaa_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 < WMAA_METHOD_LEVEL || id >= WMAA_METHOD_MAX ||
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mode < WMAA_MODE_GET || mode >= WMAA_MODE_MAX)
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return -EINVAL;
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if (mode == WMAA_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, "ACPI WMAA 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 != WMAA_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 wmaa_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_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_MODE_SET,
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&bd->props.brightness);
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}
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static int wmaa_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_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_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 wmaa_backlight_ops = {
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.update_status = wmaa_backlight_update_status,
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.get_brightness = wmaa_backlight_get_brightness,
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};
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static int wmaa_backlight_wmi_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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u32 source;
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int ret;
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ret = wmi_call_wmaa(wdev, WMAA_METHOD_SOURCE, WMAA_MODE_GET, &source);
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if (ret)
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return ret;
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/*
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* This driver is only to be used when brightness control is handled
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* by the EC; otherwise, the GPU driver(s) should control brightness.
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*/
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if (source != WMAA_SOURCE_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_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_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_call_wmaa(wdev, WMAA_METHOD_LEVEL, WMAA_MODE_GET,
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&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, "wmaa_backlight",
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&wdev->dev, wdev,
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&wmaa_backlight_ops, &props);
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return PTR_ERR_OR_ZERO(bdev);
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}
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#define WMAA_WMI_GUID "603E9613-EF25-4338-A3D0-C46177516DB7"
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static const struct wmi_device_id wmaa_backlight_wmi_id_table[] = {
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{ .guid_string = WMAA_WMI_GUID },
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{ }
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};
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MODULE_DEVICE_TABLE(wmi, wmaa_backlight_wmi_id_table);
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static struct wmi_driver wmaa_backlight_wmi_driver = {
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.driver = {
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.name = "wmaa-backlight",
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},
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.probe = wmaa_backlight_wmi_probe,
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.id_table = wmaa_backlight_wmi_id_table,
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};
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module_wmi_driver(wmaa_backlight_wmi_driver);
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MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>");
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MODULE_DESCRIPTION("WMAA Backlight WMI driver");
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MODULE_LICENSE("GPL");
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Block a user