Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v3] platform/x86: add Gigabyte WMI temperature driver
To:     Guenter Roeck <linux@roeck-us.net>,
        =?UTF-8?Q?Thomas_Wei=c3=9fschuh?= <linux@weissschuh.net>,
        platform-driver-x86@vger.kernel.org,
        Mark Gross <mgross@linux.intel.com>,
        linux-kernel@vger.kernel.org,
        =?UTF-8?Q?Barnab=c3=a1s_P=c5=91cze?= <pobrn@protonmail.com>,
        Jean Delvare <jdelvare@suse.com>, linux-hwmon@vger.kernel.org
Cc:     Matthew Garrett <mjg59@srcf.ucam.org>
References: <117cadef-c1cb-d66a-15f8-ce50d596be4b@redhat.com>
 <20210410144021.138035-1-linux@weissschuh.net>
 <3d974a64-14a6-2347-ac1a-666d1b8d6eef@roeck-us.net>
From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <6a096978-67ad-6def-6ed0-9ad38a460e95@redhat.com>
Date:   Sat, 10 Apr 2021 17:23:54 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.7.0
MIME-Version: 1.0
In-Reply-To: <3d974a64-14a6-2347-ac1a-666d1b8d6eef@roeck-us.net>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi,

On 4/10/21 5:15 PM, Guenter Roeck wrote:
> On 4/10/21 7:40 AM, 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
>>
>> Changes since v2:
>> * Style cleanups
>> * Test for usability during probing
>> * DMI-based whitelist
>> * CC hwmon maintainers
>>
>> -- >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@weissschuh.net>
>> ---
>>  MAINTAINERS                         |   6 +
>>  drivers/platform/x86/Kconfig        |  11 ++
>>  drivers/platform/x86/Makefile       |   1 +
>>  drivers/platform/x86/gigabyte-wmi.c | 194 ++++++++++++++++++++++++++++
>>  4 files changed, 212 insertions(+)
>>  create mode 100644 drivers/platform/x86/gigabyte-wmi.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index d92f85ca831d..9c10cfc00fe8 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -7543,6 +7543,12 @@ F:	Documentation/filesystems/gfs2*
>>  F:	fs/gfs2/
>>  F:	include/uapi/linux/gfs2_ondisk.h
>>  
>> +GIGABYTE WMI DRIVER
>> +M:	Thomas Weißschuh <linux@weissschuh.net>
>> +L:	platform-driver-x86@vger.kernel.org
>> +S:	Maintained
>> +F:	drivers/platform/x86/gigabyte-wmi.c
>> +
>>  GNSS SUBSYSTEM
>>  M:	Johan Hovold <johan@kernel.org>
>>  S:	Maintained
>> 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..fb4e6d4c1823
>> --- /dev/null
>> +++ b/drivers/platform/x86/gigabyte-wmi.c
>> @@ -0,0 +1,194 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + *  Copyright (C) 2021 Thomas Weißschuh <thomas@weissschuh.net>
>> + */
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/dmi.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/module.h>
>> +#include <linux/wmi.h>
>> +
>> +#define GIGABYTE_WMI_GUID "DEADBEEF-2001-0000-00A0-C90629100000"
>> +#define NUM_TEMPERATURE_SENSORS 6
> 
> Style: #define<space>name<tab>value
> 
> but of course that is Hans' call.

I agree that aligning the 2 define values with tabs would be better.

> 
>> +
>> +static bool force_load;
>> +module_param(force_load, bool, 0);
>> +MODULE_PARM_DESC(force_load, "Force loading on non-whitelisted platform");
>> +
>> +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(struct wmi_device *wdev,
>> +				      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 = wmidev_evaluate_method(wdev, 0x0, command, &in, out);
>> +
>> +	if ACPI_FAILURE(ret)
>> +		return -EIO;
>> +
>> +	return 0;
>> +}
>> +
>> +static int gigabyte_wmi_query_integer(struct wmi_device *wdev,
>> +				      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(wdev, command, args, &result);
>> +	if (ret)
>> +		return ret;
>> +	obj = result.pointer;
>> +	if (obj && obj->type == ACPI_TYPE_INTEGER)
>> +		*res = obj->integer.value;
>> +	else
>> +		ret = -EIO;
>> +	kfree(result.pointer);
>> +	return ret;
>> +}
>> +
>> +static int gigabyte_wmi_temperature(struct wmi_device *wdev, u8 sensor, long *res)
>> +{
>> +	struct gigabyte_wmi_args args = {
>> +		.arg1 = sensor,
>> +	};
>> +	u64 temp;
>> +	acpi_status ret;
>> +
>> +	ret = gigabyte_wmi_query_integer(wdev, GIGABYTE_WMI_TEMPERATURE_QUERY, &args, &temp);
>> +	if (ret == 0) {
>> +		if (temp == 0)
>> +			return -ENODEV;
> 
> That should be checked in gigabyte_wmi_hwmon_is_visible(); that is what that
> function is for.

Good point, actually the way I think this should be done is cache the result of
the initial probe done in gigabyte_wmi_validate_sensor_presence() and use that in
is_visible to return either 0 (not visible) or 0444, this way you can also
hide sensors when there is a whole in the range of sensors somehow.

So I guess we do need a v4 of this patch after all.

> 
>> +		*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)
>> +{
>> +	struct wmi_device *wdev = dev_get_drvdata(dev);
>> +
>> +	return gigabyte_wmi_temperature(wdev, 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_validate_sensor_presence(struct wmi_device *wdev)
>> +{
>> +	int working_sensors = 0, i;
>> +	long temp;
>> +
>> +	for (i = 0; i < NUM_TEMPERATURE_SENSORS; i++) {
>> +		if (!gigabyte_wmi_temperature(wdev, i, &temp))
>> +			working_sensors++;
>> +	}
>> +	return working_sensors ? 0 : -ENODEV;
>> +}
>> +
>> +static const struct dmi_system_id gigabyte_wmi_known_working_platforms[] = {
>> +	{ .matches = {
>> +		DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."),
>> +		DMI_EXACT_MATCH(DMI_BOARD_NAME, "B550 GAMING X V2"),
>> +	}},
>> +	{ .matches = {
>> +		DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."),
>> +		DMI_EXACT_MATCH(DMI_BOARD_NAME, "B550M DS3H"),
>> +	}},
>> +	{ .matches = {
>> +		DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."),
>> +		DMI_EXACT_MATCH(DMI_BOARD_NAME, "Z390 I AORUS PRO WIFI-CF"),
>> +	}},
>> +	{ .matches = {
>> +		DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."),
>> +		DMI_EXACT_MATCH(DMI_BOARD_NAME, "X570 I AORUS PRO WIFI"),
>> +	}},
>> +	{ }
>> +};
>> +
>> +static int gigabyte_wmi_probe(struct wmi_device *wdev, const void *context)
>> +{
>> +	struct device *hwmon_dev;
>> +	int ret;
>> +
>> +	if (!dmi_check_system(gigabyte_wmi_known_working_platforms)) {
>> +		if (force_load)
>> +			dev_warn(&wdev->dev, "Forcing loading on non-whitelisted platform");
>> +		else
>> +			return -ENODEV;
> 
> Style:
> 		if (!force_load)
> 			return -ENODEV;
> 		dev_warn(&wdev->dev, "Forcing loading on non-whitelisted platform");

Ack, that would be better.

> 
>> +	}
>> +
>> +	ret = gigabyte_wmi_validate_sensor_presence(wdev);
>> +	if (ret) {
>> +		dev_info(&wdev->dev, "No temperature sensors usable");
> 
> Normally one does not display a message if a probe function returns -ENODEV,
> unless it is an error, to avoid polluting the kernel log.

This will normally only be shown when the force_load module parameter is used,
at which point I think it makes sense to explain why the driver is still not
loading.

Regards,

Hans


> 
>> +		return ret;
>> +	}
>> +
>> +	hwmon_dev = devm_hwmon_device_register_with_info(&wdev->dev, "gigabyte_wmi", wdev,
>> +							 &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@weissschuh.net>");
>> +MODULE_DESCRIPTION("Gigabyte WMI temperature Driver");
>> +MODULE_LICENSE("GPL");
>>
>> base-commit: 144c79ef33536b4ecb4951e07dbc1f2b7fa99d32
>>
>