On Mon, Apr 05, 2021 at 10:48:10PM +0200, Thomas Weißschuh wrote:
> Changes since v1:
> * Incorporate feedback from Barnabás Pőcze
> * Use a WMI driver instead of a platform driver
> * Let the kernel manage the driver lifecycle
> * Fix errno/ACPI error confusion
> * Fix resource cleanup
> * Document reason for integer casting
>
> Thank you Barnabás for your review, it is much appreciated.
>
> -- >8 --
>
> Tested with a X570 I Aorus Pro Wifi.
> The mainboard contains an ITE IT8688E chip for management.
> This chips is also handled by drivers/hwmon/i87.c but as it is also used
> by the firmware itself it needs an ACPI driver.
>
> Unfortunately not all sensor registers are handled by the firmware and even
> less are exposed via WMI.
>
> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> ---
> drivers/platform/x86/Kconfig | 11 +++
> drivers/platform/x86/Makefile | 1 +
> drivers/platform/x86/gigabyte-wmi.c | 138 ++++++++++++++++++++++++++++
Originally drivers/platform was supposed to be used for platform specific
code. Not that I have control over it, but I really dislike that more and
more hwmon drivers end up there.
At least hwmon is in good company - I see drivers for various other subsystems
there as well. I just wonder if that is such a good idea. That entire directory
is bypassing subsystem maintainer reviews.
Guenter
> 3 files changed, 150 insertions(+)
> create mode 100644 drivers/platform/x86/gigabyte-wmi.c
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index ad4e630e73e2..96622a2106f7 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -123,6 +123,17 @@ config XIAOMI_WMI
> To compile this driver as a module, choose M here: the module will
> be called xiaomi-wmi.
>
> +config GIGABYTE_WMI
> + tristate "Gigabyte WMI temperature driver"
> + depends on ACPI_WMI
> + depends on HWMON
> + help
> + Say Y here if you want to support WMI-based temperature reporting on
> + Gigabyte mainboards.
> +
> + To compile this driver as a module, choose M here: the module will
> + be called gigabyte-wmi.
> +
> config ACERHDF
> tristate "Acer Aspire One temperature and fan driver"
> depends on ACPI && THERMAL
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 60d554073749..1621ebfd04fd 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_INTEL_WMI_THUNDERBOLT) += intel-wmi-thunderbolt.o
> obj-$(CONFIG_MXM_WMI) += mxm-wmi.o
> obj-$(CONFIG_PEAQ_WMI) += peaq-wmi.o
> obj-$(CONFIG_XIAOMI_WMI) += xiaomi-wmi.o
> +obj-$(CONFIG_GIGABYTE_WMI) += gigabyte-wmi.o
>
> # Acer
> obj-$(CONFIG_ACERHDF) += acerhdf.o
> diff --git a/drivers/platform/x86/gigabyte-wmi.c b/drivers/platform/x86/gigabyte-wmi.c
> new file mode 100644
> index 000000000000..8618363e3ccf
> --- /dev/null
> +++ b/drivers/platform/x86/gigabyte-wmi.c
> @@ -0,0 +1,138 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2021 Thomas Weißschuh <thomas@xxxxxxxxxxxxxx>
> + */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/acpi.h>
> +#include <linux/hwmon.h>
> +#include <linux/module.h>
> +#include <linux/wmi.h>
> +
> +#define GIGABYTE_WMI_GUID "DEADBEEF-2001-0000-00A0-C90629100000"
> +
> +enum gigabyte_wmi_commandtype {
> + GIGABYTE_WMI_BUILD_DATE_QUERY = 0x1,
> + GIGABYTE_WMI_MAINBOARD_TYPE_QUERY = 0x2,
> + GIGABYTE_WMI_FIRMWARE_VERSION_QUERY = 0x4,
> + GIGABYTE_WMI_MAINBOARD_NAME_QUERY = 0x5,
> + GIGABYTE_WMI_TEMPERATURE_QUERY = 0x125,
> +};
> +
> +struct gigabyte_wmi_args {
> + u32 arg1;
> +};
> +
> +static int gigabyte_wmi_perform_query(enum gigabyte_wmi_commandtype command,
> + struct gigabyte_wmi_args *args, struct acpi_buffer *out)
> +{
> + const struct acpi_buffer in = {
> + .length = sizeof(*args),
> + .pointer = args,
> + };
> +
> + acpi_status ret = wmi_evaluate_method(GIGABYTE_WMI_GUID, 0x0, command, &in, out);
> + if (ret == AE_OK) {
> + return 0;
> + } else {
> + return -EIO;
> + };
> +}
> +
> +static int gigabyte_wmi_query_integer(enum gigabyte_wmi_commandtype command,
> + struct gigabyte_wmi_args *args, u64 *res)
> +{
> + union acpi_object *obj;
> + struct acpi_buffer result = { ACPI_ALLOCATE_BUFFER, NULL };
> + int ret;
> +
> + ret = gigabyte_wmi_perform_query(command, args, &result);
> + if (ret) {
> + goto out;
> + }
> + obj = result.pointer;
> + if (obj && obj->type == ACPI_TYPE_INTEGER) {
> + *res = obj->integer.value;
> + ret = 0;
> + } else {
> + ret = -EIO;
> + }
> +out:
> + kfree(result.pointer);
> + return ret;
> +}
> +
> +static int gigabyte_wmi_temperature(u8 sensor, long *res)
> +{
> + struct gigabyte_wmi_args args = {
> + .arg1 = sensor,
> + };
> + u64 temp;
> + acpi_status ret;
> +
> + ret = gigabyte_wmi_query_integer(GIGABYTE_WMI_TEMPERATURE_QUERY, &args, &temp);
> + if (ret == 0)
> + *res = (s8) temp * 1000; // value is a signed 8-bit integer
> + return ret;
> +}
> +
> +static int gigabyte_wmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + return gigabyte_wmi_temperature(channel, val);
> +}
> +
> +static umode_t gigabyte_wmi_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + return 0444;
> +}
> +
> +static const struct hwmon_channel_info *gigabyte_wmi_hwmon_info[] = {
> + HWMON_CHANNEL_INFO(temp,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT),
> + NULL,
> +};
> +
> +static const struct hwmon_ops gigabyte_wmi_hwmon_ops = {
> + .read = gigabyte_wmi_hwmon_read,
> + .is_visible = gigabyte_wmi_hwmon_is_visible,
> +};
> +
> +static const struct hwmon_chip_info gigabyte_wmi_hwmon_chip_info = {
> + .ops = &gigabyte_wmi_hwmon_ops,
> + .info = gigabyte_wmi_hwmon_info,
> +};
> +
> +static int gigabyte_wmi_probe(struct wmi_device *wdev, const void *context)
> +{
> + struct device *hwmon_dev = devm_hwmon_device_register_with_info(&wdev->dev,
> + "gigabyte_wmi", NULL,
> + &gigabyte_wmi_hwmon_chip_info, NULL);
> +
> + return PTR_ERR_OR_ZERO(hwmon_dev);
> +}
> +
> +static const struct wmi_device_id gigabyte_wmi_id_table[] = {
> + { GIGABYTE_WMI_GUID, NULL },
> + { },
> +};
> +
> +static struct wmi_driver gigabyte_wmi_driver = {
> + .driver = {
> + .name = "gigabyte-wmi",
> + },
> + .id_table = gigabyte_wmi_id_table,
> + .probe = gigabyte_wmi_probe,
> +};
> +module_wmi_driver(gigabyte_wmi_driver);
> +
> +MODULE_DEVICE_TABLE(wmi, gigabyte_wmi_id_table);
> +MODULE_AUTHOR("Thomas Weißschuh <thomas@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Gigabyte Temperature WMI Driver");
> +MODULE_LICENSE("GPL");
>
> base-commit: 144c79ef33536b4ecb4951e07dbc1f2b7fa99d32
> --
> 2.31.1
>
