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Thu, 13 Aug 2026 20:39:24 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:da43:aeff:fecc:bfd5]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d3aeb29f45sm3765685ad.43.2026.08.13.20.39.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Aug 2026 20:39:23 -0700 (PDT) Sender: Guenter Roeck Date: Thu, 13 Aug 2026 20:39:23 -0700 From: Guenter Roeck To: Nikita Dubrovskih Cc: linux-hwmon@vger.kernel.org, Hans de Goede , Ilpo =?iso-8859-1?Q?J=E4rvinen?= , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2] hwmon: Add fan monitoring support for HONOR FMI-XX Message-ID: References: <20260812192242.859307-1-testname142@gmail.com> <20260813091411.1186193-1-testname142@gmail.com> Precedence: bulk X-Mailing-List: linux-hwmon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260813091411.1186193-1-testname142@gmail.com> On Thu, Aug 13, 2026 at 12:14:11PM +0300, Nikita Dubrovskih wrote: > The HONOR FMI-XX firmware exposes a serialized \\GFNS ACPI method. > It returns a status byte and a 16-bit fan speed in RPM for either of two > firmware channels. > > Add a DMI-restricted, read-only hwmon driver using that firmware > interface. The driver deliberately exposes no fan control or direct > Embedded Controller access. > > The interface was validated on firmware 1.09 with fan channel 0 > reporting approximately 2500-2800 RPM. Channel 1 is readable and > remained at 0 RPM during idle and a short CPU load. > > Signed-off-by: Nikita Dubrovskih > --- Looks ok. I do not have any further comments. This is an RFC, so I won't apply it. Thanks, Guenter > Changes in v2: > - Drop the redundant mutex and callback argument validation. > - Remove unused platform drvdata and simplify the init error path. > - Align the macro definition and order the MAINTAINERS entry. > > Documentation/hwmon/honor-fmi.rst | 32 ++++++ > Documentation/hwmon/index.rst | 1 + > MAINTAINERS | 7 ++ > drivers/hwmon/Kconfig | 10 ++ > drivers/hwmon/Makefile | 1 + > drivers/hwmon/honor-fmi.c | 178 ++++++++++++++++++++++++++++++ > 6 files changed, 229 insertions(+) > create mode 100644 Documentation/hwmon/honor-fmi.rst > create mode 100644 drivers/hwmon/honor-fmi.c > > diff --git a/Documentation/hwmon/honor-fmi.rst b/Documentation/hwmon/honor-fmi.rst > new file mode 100644 > index 0000000..a42a1dd > --- /dev/null > +++ b/Documentation/hwmon/honor-fmi.rst > @@ -0,0 +1,32 @@ > +.. SPDX-License-Identifier: GPL-2.0-only > + > +Kernel driver honor-fmi > +======================= > + > +Supported systems: > + > + * HONOR FMI-XX > + > +Author: Nikita Dubrovskih > + > +Description > +----------- > + > +The driver provides read-only monitoring of the fan speed on the HONOR FMI-XX. > +The system firmware implements a ``GFNS`` ACPI method which returns the speed > +of one of two firmware fan channels in RPM. Embedded Controller access and > +serialization are handled by the firmware method. > + > +The driver does not expose fan control or direct Embedded Controller access. > + > +Sysfs entries > +------------- > + > +The following attributes are supported: > + > +======================= ======= ============================================= > +Name Perm Description > +======================= ======= ============================================= > +``fan1_input`` RO Fan channel 0 speed in RPM > +``fan2_input`` RO Fan channel 1 speed in RPM > +======================= ======= ============================================= > diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst > index 29130df..91052fa 100644 > --- a/Documentation/hwmon/index.rst > +++ b/Documentation/hwmon/index.rst > @@ -90,6 +90,7 @@ Hardware Monitoring Kernel Drivers > gxp-fan-ctrl > hac300s > hih6130 > + honor-fmi > hp-wmi-sensors > hs3001 > htu31 > diff --git a/MAINTAINERS b/MAINTAINERS > index 8014b9f..7f2e3f8 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -11876,6 +11876,13 @@ S: Maintained > F: Documentation/devicetree/bindings/iio/pressure/honeywell,mprls0025pa.yaml > F: drivers/iio/pressure/mprls0025pa* > > +HONOR FMI-XX HARDWARE MONITOR DRIVER > +M: Nikita Dubrovskih > +L: linux-hwmon@vger.kernel.org > +S: Maintained > +F: Documentation/hwmon/honor-fmi.rst > +F: drivers/hwmon/honor-fmi.c > + > HP BIOSCFG DRIVER > M: Jorge Lopez > L: platform-driver-x86@vger.kernel.org > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 2bfbcc0..8a11a30 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -2785,6 +2785,16 @@ config SENSORS_ASUS_EC > This driver can also be built as a module. If so, the module > will be called asus_ec_sensors. > > +config SENSORS_HONOR_FMI > + tristate "HONOR FMI-XX fan monitor" > + depends on X86 > + help > + If you say yes here, you get support for fan speed monitoring on > + the HONOR FMI-XX laptop through its firmware ACPI method. > + > + This driver can also be built as a module. If so, the module > + will be called honor-fmi. > + > config SENSORS_HP_WMI > tristate "HP WMI Sensors" > depends on ACPI_WMI > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index 63effc0..e098793 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -11,6 +11,7 @@ obj-$(CONFIG_SENSORS_ACPI_POWER) += acpi_power_meter.o > obj-$(CONFIG_SENSORS_ATK0110) += asus_atk0110.o > obj-$(CONFIG_SENSORS_ASUS_EC) += asus-ec-sensors.o > obj-$(CONFIG_SENSORS_ASUS_WMI) += asus_wmi_sensors.o > +obj-$(CONFIG_SENSORS_HONOR_FMI) += honor-fmi.o > obj-$(CONFIG_SENSORS_HP_WMI) += hp-wmi-sensors.o > > # Native drivers > diff --git a/drivers/hwmon/honor-fmi.c b/drivers/hwmon/honor-fmi.c > new file mode 100644 > index 0000000..3421e40 > --- /dev/null > +++ b/drivers/hwmon/honor-fmi.c > @@ -0,0 +1,178 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Read-only fan monitoring for the HONOR FMI-XX. > + * > + * The firmware-provided \GFNS ACPI method accepts a three-byte buffer. > + * Byte 2 selects fan 0 or 1. It returns a status byte followed by a > + * little-endian 16-bit fan speed in RPM. The method owns all Embedded > + * Controller access and serialization; this driver deliberately exposes no > + * fan control interface. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define HONOR_FMI_GFNS_RESULT_SIZE 3 > + > +struct honor_fmi_data { > + acpi_handle gfns; > +}; > + > +static const struct dmi_system_id honor_fmi_dmi_table[] = { > + { > + .matches = { > + DMI_MATCH(DMI_SYS_VENDOR, "HONOR"), > + DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "FMI-XX"), > + }, > + }, > + {} > +}; > +MODULE_DEVICE_TABLE(dmi, honor_fmi_dmi_table); > + > +static int honor_fmi_read_rpm(struct honor_fmi_data *data, int channel, > + long *rpm) > +{ > + union acpi_object input = { > + .buffer = { > + .type = ACPI_TYPE_BUFFER, > + .length = 3, > + }, > + }; > + struct acpi_object_list arguments = { > + .count = 1, > + .pointer = &input, > + }; > + struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; > + union acpi_object *result; > + u8 input_bytes[3] = { 0, 0, channel }; > + acpi_status status; > + int ret = 0; > + > + input.buffer.pointer = input_bytes; > + > + status = acpi_evaluate_object(data->gfns, NULL, &arguments, &output); > + if (ACPI_FAILURE(status)) > + return -EIO; > + > + result = output.pointer; > + if (!result || result->type != ACPI_TYPE_BUFFER || > + result->buffer.length < HONOR_FMI_GFNS_RESULT_SIZE) { > + ret = -EPROTO; > + goto out_free; > + } > + > + if (result->buffer.pointer[0]) { > + ret = -EIO; > + goto out_free; > + } > + > + *rpm = result->buffer.pointer[1] | > + (result->buffer.pointer[2] << 8); > + > +out_free: > + kfree(output.pointer); > + return ret; > +} > + > +static umode_t honor_fmi_is_visible(const void *data, > + enum hwmon_sensor_types type, u32 attr, > + int channel) > +{ > + return 0444; > +} > + > +static int honor_fmi_read(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, long *value) > +{ > + struct honor_fmi_data *data = dev_get_drvdata(dev); > + > + return honor_fmi_read_rpm(data, channel, value); > +} > + > +static const struct hwmon_ops honor_fmi_hwmon_ops = { > + .is_visible = honor_fmi_is_visible, > + .read = honor_fmi_read, > +}; > + > +static const struct hwmon_channel_info * const honor_fmi_hwmon_info[] = { > + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT, HWMON_F_INPUT), > + NULL > +}; > + > +static const struct hwmon_chip_info honor_fmi_chip_info = { > + .ops = &honor_fmi_hwmon_ops, > + .info = honor_fmi_hwmon_info, > +}; > + > +static int honor_fmi_probe(struct platform_device *pdev) > +{ > + struct honor_fmi_data *data; > + struct device *hwmon_dev; > + acpi_status status; > + > + if (!dmi_check_system(honor_fmi_dmi_table)) > + return -ENODEV; > + > + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + status = acpi_get_handle(NULL, "\\GFNS", &data->gfns); > + if (ACPI_FAILURE(status)) > + return dev_err_probe(&pdev->dev, -ENODEV, > + "firmware does not provide \\GFNS\n"); > + > + hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, "honor_fmi", > + data, > + &honor_fmi_chip_info, > + NULL); > + return PTR_ERR_OR_ZERO(hwmon_dev); > +} > + > +static struct platform_driver honor_fmi_driver = { > + .probe = honor_fmi_probe, > + .driver = { > + .name = "honor-fmi-hwmon", > + }, > +}; > + > +static struct platform_device *honor_fmi_device; > + > +static int __init honor_fmi_init(void) > +{ > + int ret; > + > + if (!dmi_check_system(honor_fmi_dmi_table)) > + return -ENODEV; > + > + ret = platform_driver_register(&honor_fmi_driver); > + if (ret) > + return ret; > + > + honor_fmi_device = platform_device_register_simple("honor-fmi-hwmon", > + PLATFORM_DEVID_NONE, > + NULL, 0); > + if (IS_ERR(honor_fmi_device)) { > + platform_driver_unregister(&honor_fmi_driver); > + return PTR_ERR(honor_fmi_device); > + } > + > + return 0; > +} > + > +static void __exit honor_fmi_exit(void) > +{ > + platform_device_unregister(honor_fmi_device); > + platform_driver_unregister(&honor_fmi_driver); > +} > + > +module_init(honor_fmi_init); > +module_exit(honor_fmi_exit); > + > +MODULE_AUTHOR("Nikita Dubrovskih "); > +MODULE_DESCRIPTION("HONOR FMI-XX fan speed monitor"); > +MODULE_LICENSE("GPL");