From: Daniel Dadap Date: Fri, 3 Sep 2021 00:38:39 +0000 (-0500) Subject: platform/x86: Add driver for ACPI WMAA EC-based backlight control X-Git-Tag: v5.16-rc1~139^2~104 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ad62cd93198bde6644ecb5ff8f6f4c5394b5821a;p=linux-platform-drivers-x86.git 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 Reviewed-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20210903003838.15797-1-ddadap@nvidia.com Reviewed-by: Hans de Goede Signed-off-by: Hans de Goede --- diff --git a/MAINTAINERS b/MAINTAINERS index eeb4c70b3d5b..72837339b3ae 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20246,6 +20246,12 @@ L: linux-wireless@vger.kernel.org S: Odd fixes F: drivers/net/wireless/wl3501* +WMAA BACKLIGHT DRIVER +M: Daniel Dadap +L: platform-driver-x86@vger.kernel.org +S: Supported +F: drivers/platform/x86/wmaa-backlight-wmi.c + WOLFSON MICROELECTRONICS DRIVERS L: patches@opensource.cirrus.com S: Supported diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index 1ebce7b775f2..f3dbb0273884 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -91,6 +91,22 @@ config PEAQ_WMI help Say Y here if you want to support WMI-based hotkeys on PEAQ 2-in-1s. +config WMAA_BACKLIGHT_WMI + tristate "ACPI WMAA Backlight Driver" + depends on ACPI_WMI + depends on BACKLIGHT_CLASS_DEVICE + help + This driver provides a sysfs backlight interface for notebook + systems which expose the WMAA ACPI method and an associated WMI + wrapper to drive LCD backlight levels through the Embedded Controller + (EC). + + Say Y or M here if you want to control the backlight on a notebook + system with an EC-driven backlight using the ACPI WMAA method. + + If you choose to compile this driver as a module the module will be + called wmaa-backlight-wmi. + config XIAOMI_WMI tristate "Xiaomi WMI key driver" depends on ACPI_WMI diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile index 69690e26bb6d..edde481c14ad 100644 --- a/drivers/platform/x86/Makefile +++ b/drivers/platform/x86/Makefile @@ -12,6 +12,7 @@ obj-$(CONFIG_WMI_BMOF) += wmi-bmof.o obj-$(CONFIG_HUAWEI_WMI) += huawei-wmi.o obj-$(CONFIG_MXM_WMI) += mxm-wmi.o obj-$(CONFIG_PEAQ_WMI) += peaq-wmi.o +obj-$(CONFIG_WMAA_BACKLIGHT_WMI) += wmaa-backlight-wmi.o obj-$(CONFIG_XIAOMI_WMI) += xiaomi-wmi.o obj-$(CONFIG_GIGABYTE_WMI) += gigabyte-wmi.o diff --git a/drivers/platform/x86/wmaa-backlight-wmi.c b/drivers/platform/x86/wmaa-backlight-wmi.c new file mode 100644 index 000000000000..f5c4f8337c2c --- /dev/null +++ b/drivers/platform/x86/wmaa-backlight-wmi.c @@ -0,0 +1,205 @@ +// 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");