| Message ID | 20200731202154.11382-1-ddadap@nvidia.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | [v2,1/2] platform/x86: Add driver for ACPI WMAA EC-based backlight control | expand |
Hi Dan, > Signed-off-by: Aaron Plattner <aplattner@nvidia.com> > Signed-off-by: Daniel Dadap <ddadap@nvidia.com> > --- > MAINTAINERS | 6 + > drivers/platform/x86/Kconfig | 11 ++ > drivers/platform/x86/Makefile | 2 + > drivers/platform/x86/wmaa-backlight-wmi.c | 188 ++++++++++++++++++++++ > 4 files changed, 207 insertions(+) > create mode 100644 drivers/platform/x86/wmaa-backlight-wmi.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index eeff55560759..e5ce6544a3c8 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -18249,6 +18249,12 @@ L: linux-wireless@vger.kernel.org > S: Odd fixes > F: drivers/net/wireless/wl3501* > > +WMAA BACKLIGHT DRIVER > +M: Daniel Dadap <ddadap@nvidia.com> > +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 > T: git https://github.com/CirrusLogic/linux-drivers.git > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig > index 0ad7ad8cf8e1..db342e480aa9 100644 > --- a/drivers/platform/x86/Kconfig > +++ b/drivers/platform/x86/Kconfig > @@ -1368,6 +1368,17 @@ config INTEL_TELEMETRY > directly via debugfs files. Various tools may use > this interface for SoC state monitoring. > > +config WMAA_BACKLIGHT_WMI > + tristate "ACPI WMAA Backlight Driver" > + depends on ACPI_WMI > + depends on ACPI > + 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 system's > + Embedded Controller. > + > endif # X86_PLATFORM_DEVICES > > config PMC_ATOM > diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile > index 53408d965874..fb6e16d62031 100644 > --- a/drivers/platform/x86/Makefile > +++ b/drivers/platform/x86/Makefile > @@ -146,3 +146,5 @@ obj-$(CONFIG_INTEL_TELEMETRY) += > intel_telemetry_core.o \ > intel_telemetry_pltdrv.o \ > intel_telemetry_debugfs.o > obj-$(CONFIG_PMC_ATOM) += pmc_atom.o > + > +obj-$(CONFIG_WMAA_BACKLIGHT_WMI) += wmaa-backlight-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..65117082787d > --- /dev/null > +++ b/drivers/platform/x86/wmaa-backlight-wmi.c > @@ -0,0 +1,188 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * WMAA Backlight WMI driver > + * > + * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <linux/module.h> > +#include <linux/acpi.h> > +#include <linux/backlight.h> > +#include <linux/wmi.h> > + > +MODULE_AUTHOR("Aaron Plattner <aplattner@nvidia.com>"); > +MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>"); > +MODULE_DESCRIPTION("WMAA Backlight WMI driver"); > +MODULE_LICENSE("GPL v2"); > + > +#define WMAA_WMI_GUID "603E9613-EF25-4338-A3D0-C46177516DB7" > + > +MODULE_ALIAS("wmi:"WMAA_WMI_GUID); With switching to wmidev is MODULE_ALIAS actually still needed? > + > +struct wmi_wmaa_priv { > + struct backlight_device *backlight; > +}; > + > +enum wmaa_method { > + WMAA_BRIGHTNESS_LEVEL = 1, > + WMAA_BRIGHTNESS_SOURCE = 2, > +}; > + > +enum wmaa_get_or_set { > + WMAA_GET = 0, > + WMAA_SET = 1, > + WMAA_GET_MAX = 2, // for WMAA_BRIGHTNESS_LEVEL only > +}; > + > +enum wmaa_source { > + WMAA_SOURCE_CLEAR = 0, > + WMAA_SOURCE_GPU = 1, > + WMAA_SOURCE_EC = 2, > + WMAA_SOURCE_AUX = 3, > + WMAA_SOURCE_COUNT > +}; > + > +struct wmaa_args { > + u32 set; > + u32 val; > + u32 ret; > + u32 ignored[3]; > +}; > + > +static const struct wmi_device_id wmaa_backlight_wmi_id_table[] = { > + { .guid_string = WMAA_WMI_GUID }, > + { }, > +}; > + > +static struct wmi_device *wdev; > + > +static int wmi_call_wmaa(enum wmaa_method method, enum wmaa_get_or_set set, > + u32 *val) > +{ > + struct wmaa_args args = { > + .set = set, > + .val = 0, > + .ret = 0, > + }; > + struct acpi_buffer buf = { (acpi_size)sizeof(args), &args }; > + acpi_status status; > + > + if (set == WMAA_SET) > + args.val = *val; > + > + status = wmidev_evaluate_method(wdev, 0, method, &buf, &buf); > + if (ACPI_FAILURE(status)) { > + pr_err("ACPI WMAA failed with %s\n", > + acpi_format_exception(status)); > + return -EIO; > + } > + > + if (set != WMAA_SET) > + *val = args.ret; > + > + return 0; > +} > + > +static int wmaa_get_brightness(u32 *level) > +{ > + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_GET, level); > +} > + > +static int wmaa_set_brightness(u32 level) > +{ > + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_SET, &level); > +} > + > +static int wmaa_backlight_update_status(struct backlight_device *bd) > +{ > + return wmaa_set_brightness(bd->props.brightness); > +} > + > +static int wmaa_backlight_get_brightness(struct backlight_device *bd) > +{ > + u32 level; > + int ret = wmaa_get_brightness(&level); > + > + WARN_ON(ret != 0); > + return ret == 0 ? level : 0; > +} > + > +static const struct backlight_ops wmaa_backlight_ops = { > + .update_status = wmaa_backlight_update_status, > + .get_brightness = wmaa_backlight_get_brightness, > +}; > + > +static int wmaa_get_max_brightness(u32 *level) > +{ > + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_GET_MAX, level); > +} > + > +static int wmaa_get_brightness_source(u32 *source) > +{ > + return wmi_call_wmaa(WMAA_BRIGHTNESS_SOURCE, WMAA_GET, source); > +} > + > +static int wmaa_backlight_wmi_probe(struct wmi_device *w, const void *ctx) > +{ > + struct wmi_wmaa_priv *priv; > + struct backlight_properties props = {0}; > + u32 source; > + > + priv = devm_kmalloc(&w->dev, sizeof(*priv), GFP_KERNEL); > + if(!priv) > + return -ENOMEM; > + > + wdev = w; > + > + if (wmaa_get_brightness_source(&source)) > + return -EINVAL; > + if (source != WMAA_SOURCE_EC) > + return -ENODEV; > + > + // Register a backlight handler > + props.type = BACKLIGHT_PLATFORM; > + if (wmaa_get_max_brightness(&props.max_brightness) || > + wmaa_get_brightness(&props.brightness)) > + return -EINVAL; > + > + priv->backlight = backlight_device_register("wmaa_backlight", > + NULL, NULL, &wmaa_backlight_ops, &props); > + if (IS_ERR(priv->backlight)) > + return PTR_ERR(priv->backlight); > + > + dev_set_drvdata(&w->dev, priv); > + > + return 0; > +} > + > +static int wmaa_backlight_wmi_remove(struct wmi_device *wdev) > +{ > + struct wmi_wmaa_priv *priv = dev_get_drvdata(&wdev->dev); > + > + backlight_device_unregister(priv->backlight); > + > + return 0; > +} > + > +static struct wmi_driver wmaa_backlight_wmi_driver = { > + .driver = { > + .name = "wmaa-backlight", > + }, > + .probe = wmaa_backlight_wmi_probe, > + .remove = wmaa_backlight_wmi_remove, > + .id_table = wmaa_backlight_wmi_id_table, > +}; > + > +module_wmi_driver(wmaa_backlight_wmi_driver); > -- > 2.18.4
On 7/31/20 3:51 PM, Limonciello, Mario wrote: > External email: Use caution opening links or attachments > > > Hi Dan, > >> Signed-off-by: Aaron Plattner <aplattner@nvidia.com> >> Signed-off-by: Daniel Dadap <ddadap@nvidia.com> >> --- >> MAINTAINERS | 6 + >> drivers/platform/x86/Kconfig | 11 ++ >> drivers/platform/x86/Makefile | 2 + >> drivers/platform/x86/wmaa-backlight-wmi.c | 188 ++++++++++++++++++++++ >> 4 files changed, 207 insertions(+) >> create mode 100644 drivers/platform/x86/wmaa-backlight-wmi.c >> >> diff --git a/MAINTAINERS b/MAINTAINERS >> index eeff55560759..e5ce6544a3c8 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -18249,6 +18249,12 @@ L: linux-wireless@vger.kernel.org >> S: Odd fixes >> F: drivers/net/wireless/wl3501* >> >> +WMAA BACKLIGHT DRIVER >> +M: Daniel Dadap <ddadap@nvidia.com> >> +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 >> T: git https://github.com/CirrusLogic/linux-drivers.git >> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig >> index 0ad7ad8cf8e1..db342e480aa9 100644 >> --- a/drivers/platform/x86/Kconfig >> +++ b/drivers/platform/x86/Kconfig >> @@ -1368,6 +1368,17 @@ config INTEL_TELEMETRY >> directly via debugfs files. Various tools may use >> this interface for SoC state monitoring. >> >> +config WMAA_BACKLIGHT_WMI >> + tristate "ACPI WMAA Backlight Driver" >> + depends on ACPI_WMI >> + depends on ACPI >> + 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 system's >> + Embedded Controller. >> + >> endif # X86_PLATFORM_DEVICES >> >> config PMC_ATOM >> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile >> index 53408d965874..fb6e16d62031 100644 >> --- a/drivers/platform/x86/Makefile >> +++ b/drivers/platform/x86/Makefile >> @@ -146,3 +146,5 @@ obj-$(CONFIG_INTEL_TELEMETRY) += >> intel_telemetry_core.o \ >> intel_telemetry_pltdrv.o \ >> intel_telemetry_debugfs.o >> obj-$(CONFIG_PMC_ATOM) += pmc_atom.o >> + >> +obj-$(CONFIG_WMAA_BACKLIGHT_WMI) += wmaa-backlight-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..65117082787d >> --- /dev/null >> +++ b/drivers/platform/x86/wmaa-backlight-wmi.c >> @@ -0,0 +1,188 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * WMAA Backlight WMI driver >> + * >> + * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved. >> + * >> + * This program is free software; you can redistribute it and/or modify it >> + * under the terms and conditions of the GNU General Public License, >> + * version 2, as published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope it will be useful, but WITHOUT >> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or >> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for >> + * more details. >> + * >> + */ >> + >> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt >> + >> +#include <linux/module.h> >> +#include <linux/acpi.h> >> +#include <linux/backlight.h> >> +#include <linux/wmi.h> >> + >> +MODULE_AUTHOR("Aaron Plattner <aplattner@nvidia.com>"); >> +MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>"); >> +MODULE_DESCRIPTION("WMAA Backlight WMI driver"); >> +MODULE_LICENSE("GPL v2"); >> + >> +#define WMAA_WMI_GUID "603E9613-EF25-4338-A3D0-C46177516DB7" >> + >> +MODULE_ALIAS("wmi:"WMAA_WMI_GUID); > With switching to wmidev is MODULE_ALIAS actually still needed? Yes, it appears to be necessary. After you pointed this out, I removed the MODULE_ALIAS line, rebuilt the kernel, and rebooted, and the driver is no longer automatically loaded. It seems other drivers that use the module_wmi_driver macro explicitly use MODULE_DEVICE_TABLE or MODULE_ALIAS as well. As a separate cleanup change, we can probably update the macro to also wrap MODULE_DEVICE_TABLE and remove the redundant MODULE_DEVICE_TABLE usage from users of the module_wmi_driver macro. >> +enum wmaa_method { >> + WMAA_BRIGHTNESS_LEVEL = 1, >> + WMAA_BRIGHTNESS_SOURCE = 2, >> +}; >> + >> +enum wmaa_get_or_set { >> + WMAA_GET = 0, >> + WMAA_SET = 1, >> + WMAA_GET_MAX = 2, // for WMAA_BRIGHTNESS_LEVEL only >> +}; >> + >> +enum wmaa_source { >> + WMAA_SOURCE_CLEAR = 0, >> + WMAA_SOURCE_GPU = 1, >> + WMAA_SOURCE_EC = 2, >> + WMAA_SOURCE_AUX = 3, >> + WMAA_SOURCE_COUNT >> +}; >> + >> +struct wmaa_args { >> + u32 set; >> + u32 val; >> + u32 ret; >> + u32 ignored[3]; >> +}; >> + >> +static const struct wmi_device_id wmaa_backlight_wmi_id_table[] = { >> + { .guid_string = WMAA_WMI_GUID }, >> + { }, >> +}; >> + >> +static struct wmi_device *wdev; >> + >> +static int wmi_call_wmaa(enum wmaa_method method, enum wmaa_get_or_set set, >> + u32 *val) >> +{ >> + struct wmaa_args args = { >> + .set = set, >> + .val = 0, >> + .ret = 0, >> + }; >> + struct acpi_buffer buf = { (acpi_size)sizeof(args), &args }; >> + acpi_status status; >> + >> + if (set == WMAA_SET) >> + args.val = *val; >> + >> + status = wmidev_evaluate_method(wdev, 0, method, &buf, &buf); >> + if (ACPI_FAILURE(status)) { >> + pr_err("ACPI WMAA failed with %s\n", >> + acpi_format_exception(status)); >> + return -EIO; >> + } >> + >> + if (set != WMAA_SET) >> + *val = args.ret; >> + >> + return 0; >> +} >> + >> +static int wmaa_get_brightness(u32 *level) >> +{ >> + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_GET, level); >> +} >> + >> +static int wmaa_set_brightness(u32 level) >> +{ >> + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_SET, &level); >> +} >> + >> +static int wmaa_backlight_update_status(struct backlight_device *bd) >> +{ >> + return wmaa_set_brightness(bd->props.brightness); >> +} >> + >> +static int wmaa_backlight_get_brightness(struct backlight_device *bd) >> +{ >> + u32 level; >> + int ret = wmaa_get_brightness(&level); >> + >> + WARN_ON(ret != 0); >> + return ret == 0 ? level : 0; >> +} >> + >> +static const struct backlight_ops wmaa_backlight_ops = { >> + .update_status = wmaa_backlight_update_status, >> + .get_brightness = wmaa_backlight_get_brightness, >> +}; >> + >> +static int wmaa_get_max_brightness(u32 *level) >> +{ >> + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_GET_MAX, level); >> +} >> + >> +static int wmaa_get_brightness_source(u32 *source) >> +{ >> + return wmi_call_wmaa(WMAA_BRIGHTNESS_SOURCE, WMAA_GET, source); >> +} >> + >> +static int wmaa_backlight_wmi_probe(struct wmi_device *w, const void *ctx) >> +{ >> + struct wmi_wmaa_priv *priv; >> + struct backlight_properties props = {0}; >> + u32 source; >> + >> + priv = devm_kmalloc(&w->dev, sizeof(*priv), GFP_KERNEL); >> + if(!priv) >> + return -ENOMEM; >> + >> + wdev = w; >> + >> + if (wmaa_get_brightness_source(&source)) >> + return -EINVAL; >> + if (source != WMAA_SOURCE_EC) >> + return -ENODEV; >> + >> + // Register a backlight handler >> + props.type = BACKLIGHT_PLATFORM; >> + if (wmaa_get_max_brightness(&props.max_brightness) || >> + wmaa_get_brightness(&props.brightness)) >> + return -EINVAL; >> + >> + priv->backlight = backlight_device_register("wmaa_backlight", >> + NULL, NULL, &wmaa_backlight_ops, &props); >> + if (IS_ERR(priv->backlight)) >> + return PTR_ERR(priv->backlight); >> + >> + dev_set_drvdata(&w->dev, priv); >> + >> + return 0; >> +} >> + >> +static int wmaa_backlight_wmi_remove(struct wmi_device *wdev) >> +{ >> + struct wmi_wmaa_priv *priv = dev_get_drvdata(&wdev->dev); >> + >> + backlight_device_unregister(priv->backlight); >> + >> + return 0; >> +} >> + >> +static struct wmi_driver wmaa_backlight_wmi_driver = { >> + .driver = { >> + .name = "wmaa-backlight", >> + }, >> + .probe = wmaa_backlight_wmi_probe, >> + .remove = wmaa_backlight_wmi_remove, >> + .id_table = wmaa_backlight_wmi_id_table, >> +}; >> + >> +module_wmi_driver(wmaa_backlight_wmi_driver); >> -- >> 2.18.4
diff --git a/MAINTAINERS b/MAINTAINERS index eeff55560759..e5ce6544a3c8 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18249,6 +18249,12 @@ L: linux-wireless@vger.kernel.org S: Odd fixes F: drivers/net/wireless/wl3501* +WMAA BACKLIGHT DRIVER +M: Daniel Dadap <ddadap@nvidia.com> +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 T: git https://github.com/CirrusLogic/linux-drivers.git diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index 0ad7ad8cf8e1..db342e480aa9 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -1368,6 +1368,17 @@ config INTEL_TELEMETRY directly via debugfs files. Various tools may use this interface for SoC state monitoring. +config WMAA_BACKLIGHT_WMI + tristate "ACPI WMAA Backlight Driver" + depends on ACPI_WMI + depends on ACPI + 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 system's + Embedded Controller. + endif # X86_PLATFORM_DEVICES config PMC_ATOM diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile index 53408d965874..fb6e16d62031 100644 --- a/drivers/platform/x86/Makefile +++ b/drivers/platform/x86/Makefile @@ -146,3 +146,5 @@ obj-$(CONFIG_INTEL_TELEMETRY) += intel_telemetry_core.o \ intel_telemetry_pltdrv.o \ intel_telemetry_debugfs.o obj-$(CONFIG_PMC_ATOM) += pmc_atom.o + +obj-$(CONFIG_WMAA_BACKLIGHT_WMI) += wmaa-backlight-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..65117082787d --- /dev/null +++ b/drivers/platform/x86/wmaa-backlight-wmi.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * WMAA Backlight WMI driver + * + * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/acpi.h> +#include <linux/backlight.h> +#include <linux/wmi.h> + +MODULE_AUTHOR("Aaron Plattner <aplattner@nvidia.com>"); +MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>"); +MODULE_DESCRIPTION("WMAA Backlight WMI driver"); +MODULE_LICENSE("GPL v2"); + +#define WMAA_WMI_GUID "603E9613-EF25-4338-A3D0-C46177516DB7" + +MODULE_ALIAS("wmi:"WMAA_WMI_GUID); + +struct wmi_wmaa_priv { + struct backlight_device *backlight; +}; + +enum wmaa_method { + WMAA_BRIGHTNESS_LEVEL = 1, + WMAA_BRIGHTNESS_SOURCE = 2, +}; + +enum wmaa_get_or_set { + WMAA_GET = 0, + WMAA_SET = 1, + WMAA_GET_MAX = 2, // for WMAA_BRIGHTNESS_LEVEL only +}; + +enum wmaa_source { + WMAA_SOURCE_CLEAR = 0, + WMAA_SOURCE_GPU = 1, + WMAA_SOURCE_EC = 2, + WMAA_SOURCE_AUX = 3, + WMAA_SOURCE_COUNT +}; + +struct wmaa_args { + u32 set; + u32 val; + u32 ret; + u32 ignored[3]; +}; + +static const struct wmi_device_id wmaa_backlight_wmi_id_table[] = { + { .guid_string = WMAA_WMI_GUID }, + { }, +}; + +static struct wmi_device *wdev; + +static int wmi_call_wmaa(enum wmaa_method method, enum wmaa_get_or_set set, + u32 *val) +{ + struct wmaa_args args = { + .set = set, + .val = 0, + .ret = 0, + }; + struct acpi_buffer buf = { (acpi_size)sizeof(args), &args }; + acpi_status status; + + if (set == WMAA_SET) + args.val = *val; + + status = wmidev_evaluate_method(wdev, 0, method, &buf, &buf); + if (ACPI_FAILURE(status)) { + pr_err("ACPI WMAA failed with %s\n", + acpi_format_exception(status)); + return -EIO; + } + + if (set != WMAA_SET) + *val = args.ret; + + return 0; +} + +static int wmaa_get_brightness(u32 *level) +{ + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_GET, level); +} + +static int wmaa_set_brightness(u32 level) +{ + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_SET, &level); +} + +static int wmaa_backlight_update_status(struct backlight_device *bd) +{ + return wmaa_set_brightness(bd->props.brightness); +} + +static int wmaa_backlight_get_brightness(struct backlight_device *bd) +{ + u32 level; + int ret = wmaa_get_brightness(&level); + + WARN_ON(ret != 0); + return ret == 0 ? level : 0; +} + +static const struct backlight_ops wmaa_backlight_ops = { + .update_status = wmaa_backlight_update_status, + .get_brightness = wmaa_backlight_get_brightness, +}; + +static int wmaa_get_max_brightness(u32 *level) +{ + return wmi_call_wmaa(WMAA_BRIGHTNESS_LEVEL, WMAA_GET_MAX, level); +} + +static int wmaa_get_brightness_source(u32 *source) +{ + return wmi_call_wmaa(WMAA_BRIGHTNESS_SOURCE, WMAA_GET, source); +} + +static int wmaa_backlight_wmi_probe(struct wmi_device *w, const void *ctx) +{ + struct wmi_wmaa_priv *priv; + struct backlight_properties props = {0}; + u32 source; + + priv = devm_kmalloc(&w->dev, sizeof(*priv), GFP_KERNEL); + if(!priv) + return -ENOMEM; + + wdev = w; + + if (wmaa_get_brightness_source(&source)) + return -EINVAL; + if (source != WMAA_SOURCE_EC) + return -ENODEV; + + // Register a backlight handler + props.type = BACKLIGHT_PLATFORM; + if (wmaa_get_max_brightness(&props.max_brightness) || + wmaa_get_brightness(&props.brightness)) + return -EINVAL; + + priv->backlight = backlight_device_register("wmaa_backlight", + NULL, NULL, &wmaa_backlight_ops, &props); + if (IS_ERR(priv->backlight)) + return PTR_ERR(priv->backlight); + + dev_set_drvdata(&w->dev, priv); + + return 0; +} + +static int wmaa_backlight_wmi_remove(struct wmi_device *wdev) +{ + struct wmi_wmaa_priv *priv = dev_get_drvdata(&wdev->dev); + + backlight_device_unregister(priv->backlight); + + return 0; +} + +static struct wmi_driver wmaa_backlight_wmi_driver = { + .driver = { + .name = "wmaa-backlight", + }, + .probe = wmaa_backlight_wmi_probe, + .remove = wmaa_backlight_wmi_remove, + .id_table = wmaa_backlight_wmi_id_table, +}; + +module_wmi_driver(wmaa_backlight_wmi_driver);