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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-06-19 21:00:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-06-19 21:00:30 +0000
commite54def4ad8144ab15f826416e2e0f290ef1901b4 (patch)
tree583f8d4bd95cd67c44ff37b878a7eddfca9ab97a /Documentation/hwmon
parentAdding upstream version 6.8.12. (diff)
downloadlinux-upstream.tar.xz
linux-upstream.zip
Adding upstream version 6.9.2.upstream/6.9.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/hwmon')
-rw-r--r--Documentation/hwmon/aspeed-g6-pwm-tach.rst26
-rw-r--r--Documentation/hwmon/asus_rog_ryujin.rst47
-rw-r--r--Documentation/hwmon/chipcap2.rst73
-rw-r--r--Documentation/hwmon/emc2305.rst1
-rw-r--r--Documentation/hwmon/index.rst8
-rw-r--r--Documentation/hwmon/ltc4282.rst133
-rw-r--r--Documentation/hwmon/max6620.rst2
-rw-r--r--Documentation/hwmon/mpq8785.rst94
-rw-r--r--Documentation/hwmon/nct6683.rst1
-rw-r--r--Documentation/hwmon/nzxt-kraken3.rst74
-rw-r--r--Documentation/hwmon/oxp-sensors.rst1
-rw-r--r--Documentation/hwmon/pt5161l.rst42
-rw-r--r--Documentation/hwmon/sht3x.rst11
-rw-r--r--Documentation/hwmon/surface_fan.rst25
14 files changed, 536 insertions, 2 deletions
diff --git a/Documentation/hwmon/aspeed-g6-pwm-tach.rst b/Documentation/hwmon/aspeed-g6-pwm-tach.rst
new file mode 100644
index 000000000..17398fe39
--- /dev/null
+++ b/Documentation/hwmon/aspeed-g6-pwm-tach.rst
@@ -0,0 +1,26 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver aspeed-g6-pwm-tach
+=================================
+
+Supported chips:
+ ASPEED AST2600
+
+Authors:
+ <billy_tsai@aspeedtech.com>
+
+Description:
+------------
+This driver implements support for ASPEED AST2600 Fan Tacho controller.
+The controller supports up to 16 tachometer inputs.
+
+The driver provides the following sensor accesses in sysfs:
+
+=============== ======= ======================================================
+fanX_input ro provide current fan rotation value in RPM as reported
+ by the fan to the device.
+fanX_div rw Fan divisor: Supported value are power of 4 (1, 4, 16
+ 64, ... 4194304)
+ The larger divisor, the less rpm accuracy and the less
+ affected by fan signal glitch.
+=============== ======= ======================================================
diff --git a/Documentation/hwmon/asus_rog_ryujin.rst b/Documentation/hwmon/asus_rog_ryujin.rst
new file mode 100644
index 000000000..9f77da070
--- /dev/null
+++ b/Documentation/hwmon/asus_rog_ryujin.rst
@@ -0,0 +1,47 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver asus_rog_ryujin
+=============================
+
+Supported devices:
+
+* ASUS ROG RYUJIN II 360
+
+Author: Aleksa Savic
+
+Description
+-----------
+
+This driver enables hardware monitoring support for the listed ASUS ROG RYUJIN
+all-in-one CPU liquid coolers. Available sensors are pump, internal and external
+(controller) fan speed in RPM, their duties in PWM, as well as coolant temperature.
+
+Attaching external fans to the controller is optional and allows them to be
+controlled from the device. If not connected, the fan-related sensors will
+report zeroes. The controller is a separate hardware unit that comes bundled
+with the AIO and connects to it to allow fan control.
+
+The addressable LCD screen is not supported in this driver and should
+be controlled through userspace tools.
+
+Usage notes
+-----------
+
+As these are USB HIDs, the driver can be loaded automatically by the kernel and
+supports hot swapping.
+
+Sysfs entries
+-------------
+
+=========== =============================================
+fan1_input Pump speed (in rpm)
+fan2_input Internal fan speed (in rpm)
+fan3_input External (controller) fan 1 speed (in rpm)
+fan4_input External (controller) fan 2 speed (in rpm)
+fan5_input External (controller) fan 3 speed (in rpm)
+fan6_input External (controller) fan 4 speed (in rpm)
+temp1_input Coolant temperature (in millidegrees Celsius)
+pwm1 Pump duty
+pwm2 Internal fan duty
+pwm3 External (controller) fan duty
+=========== =============================================
diff --git a/Documentation/hwmon/chipcap2.rst b/Documentation/hwmon/chipcap2.rst
new file mode 100644
index 000000000..dc165becc
--- /dev/null
+++ b/Documentation/hwmon/chipcap2.rst
@@ -0,0 +1,73 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver ChipCap2
+======================
+
+Supported chips:
+
+ * Amphenol CC2D23, CC2D23S, CC2D25, CC2D25S, CC2D33, CC2D33S, CC2D35, CC2D35S
+
+ Prefix: 'chipcap2'
+
+ Addresses scanned: -
+
+ Datasheet: https://www.amphenol-sensors.com/en/telaire/humidity/527-humidity-sensors/3095-chipcap-2
+
+Author:
+
+ - Javier Carrasco <javier.carrasco.cruz@gmail.com>
+
+Description
+-----------
+
+This driver implements support for the Amphenol ChipCap 2, a humidity and
+temperature chip family. Temperature is measured in milli degrees celsius,
+relative humidity is expressed as a per cent mille. The measurement ranges
+are the following:
+
+ - Relative humidity: 0 to 100000 pcm (14-bit resolution)
+ - Temperature: -40000 to +125000 m°C (14-bit resolution)
+
+The device communicates with the I2C protocol and uses the I2C address 0x28
+by default.
+
+Depending on the hardware configuration, up to two humidity alarms to control
+minimum and maximum values are provided. Their thresholds and hystersis can be
+configured via sysfs.
+
+Thresholds and hysteris must be provided as a per cent mille. These values
+might be truncated to match the 14-bit device resolution (6.1 pcm/LSB)
+
+Known Issues
+------------
+
+The driver does not support I2C address and command window length modification.
+
+sysfs-Interface
+---------------
+
+The following list includes the sysfs attributes that the driver always provides,
+their permissions and a short description:
+
+=============================== ======= ========================================
+Name Perm Description
+=============================== ======= ========================================
+temp1_input: RO temperature input
+humidity1_input: RO humidity input
+=============================== ======= ========================================
+
+The following list includes the sysfs attributes that the driver may provide
+depending on the hardware configuration:
+
+=============================== ======= ========================================
+Name Perm Description
+=============================== ======= ========================================
+humidity1_min: RW humidity low limit. Measurements under
+ this limit trigger a humidity low alarm
+humidity1_max: RW humidity high limit. Measurements above
+ this limit trigger a humidity high alarm
+humidity1_min_hyst: RW humidity low hystersis
+humidity1_max_hyst: RW humidity high hystersis
+humidity1_min_alarm: RO humidity low alarm indicator
+humidity1_max_alarm: RO humidity high alarm indicator
+=============================== ======= ========================================
diff --git a/Documentation/hwmon/emc2305.rst b/Documentation/hwmon/emc2305.rst
index 2403dbaf2..d0bfffe46 100644
--- a/Documentation/hwmon/emc2305.rst
+++ b/Documentation/hwmon/emc2305.rst
@@ -6,7 +6,6 @@ Kernel driver emc2305
Supported chips:
Microchip EMC2305, EMC2303, EMC2302, EMC2301
- Addresses scanned: I2C 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d
Prefixes: 'emc2305'
Datasheet: Publicly available at the Microchip website :
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index c7ed1f73a..1ca7a4fe1 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -44,13 +44,16 @@ Hardware Monitoring Kernel Drivers
aquacomputer_d5next
asb100
asc7621
+ aspeed-g6-pwm-tach
aspeed-pwm-tacho
asus_ec_sensors
+ asus_rog_ryujin
asus_wmi_sensors
bcm54140
bel-pfe
bpa-rs600
bt1-pvt
+ chipcap2
coretemp
corsair-cpro
corsair-psu
@@ -129,6 +132,7 @@ Hardware Monitoring Kernel Drivers
ltc4245
ltc4260
ltc4261
+ ltc4282
ltc4286
max127
max15301
@@ -163,6 +167,7 @@ Hardware Monitoring Kernel Drivers
mp2975
mp5023
mp5990
+ mpq8785
nct6683
nct6775
nct7802
@@ -171,6 +176,7 @@ Hardware Monitoring Kernel Drivers
nsa320
ntc_thermistor
nzxt-kraken2
+ nzxt-kraken3
nzxt-smart2
occ
oxp-sensors
@@ -185,6 +191,7 @@ Hardware Monitoring Kernel Drivers
pmbus
powerz
powr1220
+ pt5161l
pxe1610
pwm-fan
q54sj108a2
@@ -208,6 +215,7 @@ Hardware Monitoring Kernel Drivers
smsc47m1
sparx5-temp
stpddc60
+ surface_fan
sy7636a-hwmon
tc654
tc74
diff --git a/Documentation/hwmon/ltc4282.rst b/Documentation/hwmon/ltc4282.rst
new file mode 100644
index 000000000..a87ec3564
--- /dev/null
+++ b/Documentation/hwmon/ltc4282.rst
@@ -0,0 +1,133 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel drivers ltc4282
+==========================================
+
+Supported chips:
+
+ * Analog Devices LTC4282
+
+ Prefix: 'ltc4282'
+
+ Addresses scanned: - I2C 0x40 - 0x5A (7-bit)
+ Addresses scanned: - I2C 0x80 - 0xB4 with a step of 2 (8-bit)
+
+ Datasheet:
+
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4282.pdf
+
+Author: Nuno Sá <nuno.sa@analog.com>
+
+Description
+___________
+
+The LTC4282 hot swap controller allows a board to be safely inserted and removed
+from a live backplane. Using one or more external N-channel pass transistors,
+board supply voltage and inrush current are ramped up at an adjustable rate. An
+I2C interface and onboard ADC allows for monitoring of board current, voltage,
+power, energy and fault status. The device features analog foldback current
+limiting and supply monitoring for applications from 2.9V to 33V. Dual 12V gate
+drive allows high power applications to either share safe operating area across
+parallel MOSFETs or support a 2-stage start-up that first charges the load
+capacitance followed by enabling a low on-resistance path to the load. The
+LTC4282 is well suited to high power applications because the precise monitoring
+capability and accurate current limiting reduce the extremes in which both loads
+and power supplies must safely operate. Non-volatile configuration allows for
+flexibility in the autonomous generation of alerts and response to faults.
+
+Sysfs entries
+_____________
+
+The following attributes are supported. Limits are read-write and all the other
+attributes are read-only. Note that in0 and in1 are mutually exclusive. Enabling
+one disables the other and disabling one enables the other.
+
+======================= ==========================================
+in0_input Output voltage (mV).
+in0_min Undervoltage threshold
+in0_max Overvoltage threshold
+in0_lowest Lowest measured voltage
+in0_highest Highest measured voltage
+in0_reset_history Write 1 to reset in0 history.
+ Also clears fet bad and short fault logs.
+in0_min_alarm Undervoltage alarm
+in0_max_alarm Overvoltage alarm
+in0_enable Enable/Disable VSOURCE monitoring
+in0_fault Failure in the MOSFETs. Either bad or shorted FET.
+in0_label Channel label (VSOURCE)
+
+in1_input Input voltage (mV).
+in1_min Undervoltage threshold
+in1_max Overvoltage threshold
+in1_lowest Lowest measured voltage
+in1_highest Highest measured voltage
+in1_reset_history Write 1 to reset in1 history.
+ Also clears over/undervoltage fault logs.
+in1_min_alarm Undervoltage alarm
+in1_max_alarm Overvoltage alarm
+in1_lcrit_alarm Critical Undervoltage alarm
+in1_crit_alarm Critical Overvoltage alarm
+in1_enable Enable/Disable VDD monitoring
+in1_label Channel label (VDD)
+
+in2_input GPIO voltage (mV)
+in2_min Undervoltage threshold
+in2_max Overvoltage threshold
+in2_lowest Lowest measured voltage
+in2_highest Highest measured voltage
+in2_reset_history Write 1 to reset in2 history
+in2_min_alarm Undervoltage alarm
+in2_max_alarm Overvoltage alarm
+in2_label Channel label (VGPIO)
+
+curr1_input Sense current (mA)
+curr1_min Undercurrent threshold
+curr1_max Overcurrent threshold
+curr1_lowest Lowest measured current
+curr1_highest Highest measured current
+curr1_reset_history Write 1 to reset curr1 history.
+ Also clears overcurrent fault logs.
+curr1_min_alarm Undercurrent alarm
+curr1_max_alarm Overcurrent alarm
+curr1_crit_alarm Critical Overcurrent alarm
+curr1_label Channel label (ISENSE)
+
+power1_input Power (in uW)
+power1_min Low power threshold
+power1_max High power threshold
+power1_input_lowest Historical minimum power use
+power1_input_highest Historical maximum power use
+power1_reset_history Write 1 to reset power1 history.
+ Also clears power bad fault logs.
+power1_min_alarm Low power alarm
+power1_max_alarm High power alarm
+power1_label Channel label (Power)
+
+energy1_input Measured energy over time (in microJoule)
+energy1_enable Enable/Disable Energy accumulation
+======================= ==========================================
+
+DebugFs entries
+_______________
+
+The chip also has a fault log register where failures can be logged. Hence,
+as these are logging events, we give access to them in debugfs. Note that
+even if some failure is detected in these logs, it does necessarily mean
+that the failure is still present. As mentioned in the proper Sysfs entries,
+these logs can be cleared by writing in the proper reset_history attribute.
+
+.. warning:: The debugfs interface is subject to change without notice
+ and is only available when the kernel is compiled with
+ ``CONFIG_DEBUG_FS`` defined.
+
+``/sys/kernel/debug/ltc4282-hwmon[X]/``
+contains the following attributes:
+
+======================= ==========================================
+power1_bad_fault_log Set to 1 by a power1 bad fault occurring.
+in0_fet_short_fault_log Set to 1 when the ADC detects a FET-short fault.
+in0_fet_bad_fault_log Set to 1 when a FET-BAD fault occurs.
+in1_crit_fault_log Set to 1 by a VDD overvoltage fault occurring.
+in1_lcrit_fault_log Set to 1 by a VDD undervoltage fault occurring.
+curr1_crit_fault_log Set to 1 by an overcurrent fault occurring.
+======================= ==========================================
diff --git a/Documentation/hwmon/max6620.rst b/Documentation/hwmon/max6620.rst
index 84c1c44d3..d70173bf0 100644
--- a/Documentation/hwmon/max6620.rst
+++ b/Documentation/hwmon/max6620.rst
@@ -11,7 +11,7 @@ Supported chips:
Addresses scanned: none
- Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
+ Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/max6620.pdf
Authors:
- L\. Grunenberg <contact@lgrunenberg.de>
diff --git a/Documentation/hwmon/mpq8785.rst b/Documentation/hwmon/mpq8785.rst
new file mode 100644
index 000000000..bf8176b87
--- /dev/null
+++ b/Documentation/hwmon/mpq8785.rst
@@ -0,0 +1,94 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver mpq8785
+=======================
+
+Supported chips:
+
+ * MPS MPQ8785
+
+ Prefix: 'mpq8785'
+
+Author: Charles Hsu <ythsu0511@gmail.com>
+
+Description
+-----------
+
+The MPQ8785 is a fully integrated, PMBus-compatible, high-frequency, synchronous
+buck converter. The MPQ8785 offers a very compact solution that achieves up to
+40A output current per phase, with excellent load and line regulation over a
+wide input supply range. The MPQ8785 operates at high efficiency over a wide
+output current load range.
+
+The PMBus interface provides converter configurations and key parameters
+monitoring.
+
+The MPQ8785 adopts MPS's proprietary multi-phase digital constant-on-time (MCOT)
+control, which provides fast transient response and eases loop stabilization.
+The MCOT scheme also allows multiple MPQ8785 devices to be connected in parallel
+with excellent current sharing and phase interleaving for high-current
+applications.
+
+Fully integrated protection features include over-current protection (OCP),
+over-voltage protection (OVP), under-voltage protection (UVP), and
+over-temperature protection (OTP).
+
+The MPQ8785 requires a minimal number of readily available, standard external
+components, and is available in a TLGA (5mmx6mm) package.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_max**
+
+**in1_max_alarm**
+
+**in1_min**
+
+**in1_min_alarm**
+
+**in1_crit**
+
+**in1_crit_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+**curr1_crit**
+
+**curr1_crit_alarm**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_max**
+
+**temp1_max_alarm**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
diff --git a/Documentation/hwmon/nct6683.rst b/Documentation/hwmon/nct6683.rst
index 3e7f6ee77..2a7a78eb1 100644
--- a/Documentation/hwmon/nct6683.rst
+++ b/Documentation/hwmon/nct6683.rst
@@ -64,4 +64,5 @@ Intel DB85FL NCT6683D EC firmware version 1.0 build 04/03/13
ASRock X570 NCT6683D EC firmware version 1.0 build 06/28/19
ASRock X670E NCT6686D EC firmware version 1.0 build 05/19/22
MSI B550 NCT6687D EC firmware version 1.0 build 05/07/20
+MSI X670-P NCT6687D EC firmware version 0.0 build 09/27/22
=============== ===============================================
diff --git a/Documentation/hwmon/nzxt-kraken3.rst b/Documentation/hwmon/nzxt-kraken3.rst
new file mode 100644
index 000000000..90fd9dec1
--- /dev/null
+++ b/Documentation/hwmon/nzxt-kraken3.rst
@@ -0,0 +1,74 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver nzxt-kraken3
+==========================
+
+Supported devices:
+
+* NZXT Kraken X53
+* NZXT Kraken X63
+* NZXT Kraken X73
+* NZXT Kraken Z53
+* NZXT Kraken Z63
+* NZXT Kraken Z73
+
+Author: Jonas Malaco, Aleksa Savic
+
+Description
+-----------
+
+This driver enables hardware monitoring support for NZXT Kraken X53/X63/X73 and
+Z53/Z63/Z73 all-in-one CPU liquid coolers. All models expose liquid temperature
+and pump speed (in RPM), as well as PWM control (either as a fixed value
+or through a temp-PWM curve). The Z-series models additionally expose the speed
+and duty of an optionally connected fan, with the same PWM control capabilities.
+
+Pump and fan duty control mode can be set through pwm[1-2]_enable, where 1 is
+for the manual control mode and 2 is for the liquid temp to PWM curve mode.
+Writing a 0 disables control of the channel through the driver after setting its
+duty to 100%.
+
+The temperature of the curves relates to the fixed [20-59] range, correlating to
+the detected liquid temperature. Only PWM values (ranging from 0-255) can be set.
+If in curve mode, setting point values should be done in moderation - the devices
+require complete curves to be sent for each change; they can lock up or discard
+the changes if they are too numerous at once. Suggestion is to set them while
+in an another mode, and then apply them by switching to curve.
+
+The devices can report if they are faulty. The driver supports that situation
+and will issue a warning. This can also happen when the USB cable is connected,
+but SATA power is not.
+
+The addressable RGB LEDs and LCD screen (only on Z-series models) are not
+supported in this driver, but can be controlled through existing userspace tools,
+such as `liquidctl`_.
+
+.. _liquidctl: https://github.com/liquidctl/liquidctl
+
+Usage Notes
+-----------
+
+As these are USB HIDs, the driver can be loaded automatically by the kernel and
+supports hot swapping.
+
+Possible pwm_enable values are:
+
+====== ==========================================================================
+0 Set fan to 100%
+1 Direct PWM mode (applies value in corresponding PWM entry)
+2 Curve control mode (applies the temp-PWM duty curve based on coolant temp)
+====== ==========================================================================
+
+Sysfs entries
+-------------
+
+============================== ================================================================
+fan1_input Pump speed (in rpm)
+fan2_input Fan speed (in rpm)
+temp1_input Coolant temperature (in millidegrees Celsius)
+pwm1 Pump duty (value between 0-255)
+pwm1_enable Pump duty control mode (0: disabled, 1: manual, 2: curve)
+pwm2 Fan duty (value between 0-255)
+pwm2_enable Fan duty control mode (0: disabled, 1: manual, 2: curve)
+temp[1-2]_auto_point[1-40]_pwm Temp-PWM duty curves (for pump and fan), related to coolant temp
+============================== ================================================================
diff --git a/Documentation/hwmon/oxp-sensors.rst b/Documentation/hwmon/oxp-sensors.rst
index 3adeb7406..55b1ef616 100644
--- a/Documentation/hwmon/oxp-sensors.rst
+++ b/Documentation/hwmon/oxp-sensors.rst
@@ -33,6 +33,7 @@ Currently the driver supports the following handhelds:
- AOK ZOE A1 PRO
- Aya Neo 2
- Aya Neo AIR
+ - Aya Neo AIR Plus (Mendocino)
- Aya Neo AIR Pro
- Aya Neo Geek
- OneXPlayer AMD
diff --git a/Documentation/hwmon/pt5161l.rst b/Documentation/hwmon/pt5161l.rst
new file mode 100644
index 000000000..1b9733699
--- /dev/null
+++ b/Documentation/hwmon/pt5161l.rst
@@ -0,0 +1,42 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver pt5161l
+=====================
+
+Supported chips:
+
+ * Astera Labs PT5161L
+
+ Prefix: 'pt5161l'
+
+ Addresses scanned: I2C 0x20 - 0x27
+
+ Datasheet: Not publicly available.
+
+Authors: Cosmo Chou <cosmo.chou@quantatw.com>
+
+Description
+-----------
+
+This driver implements support for temperature monitoring of Astera Labs
+PT5161L series PCIe retimer chips.
+
+This driver implementation originates from the CSDK available at
+https://github.com/facebook/openbmc/tree/helium/common/recipes-lib/retimer-v2.14
+The communication protocol utilized is based on the I2C/SMBus standard.
+
+Sysfs entries
+----------------
+
+================ ==============================================
+temp1_input Measured temperature (in millidegrees Celsius)
+================ ==============================================
+
+Debugfs entries
+----------------
+
+================ ===============================
+fw_load_status Firmware load status
+fw_ver Firmware version of the retimer
+heartbeat_status Heartbeat status
+================ ===============================
diff --git a/Documentation/hwmon/sht3x.rst b/Documentation/hwmon/sht3x.rst
index 957c854f5..9585fa7c5 100644
--- a/Documentation/hwmon/sht3x.rst
+++ b/Documentation/hwmon/sht3x.rst
@@ -65,6 +65,10 @@ When the temperature and humidity readings move back between the hysteresis
values, the alert bit is set to 0 and the alert pin on the sensor is set to
low.
+The serial number exposed to debugfs allows for unique identification of the
+sensors. For sts32, sts33 and sht33, the manufacturer provides calibration
+certificates through an API.
+
sysfs-Interface
---------------
@@ -99,3 +103,10 @@ repeatability: write or read repeatability, higher repeatability means
- 1: medium repeatability
- 2: high repeatability
=================== ============================================================
+
+debugfs-Interface
+-----------------
+
+=================== ============================================================
+serial_number: unique serial number of the sensor in decimal
+=================== ============================================================
diff --git a/Documentation/hwmon/surface_fan.rst b/Documentation/hwmon/surface_fan.rst
new file mode 100644
index 000000000..07942574c
--- /dev/null
+++ b/Documentation/hwmon/surface_fan.rst
@@ -0,0 +1,25 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver surface_fan
+=========================
+
+Supported Devices:
+
+ * Microsoft Surface Pro 9
+
+Author: Ivor Wanders <ivor@iwanders.net>
+
+Description
+-----------
+
+This provides monitoring of the fan found in some Microsoft Surface Pro devices,
+like the Surface Pro 9. The fan is always controlled by the onboard controller.
+
+Sysfs interface
+---------------
+
+======================= ======= =========================================
+Name Perm Description
+======================= ======= =========================================
+``fan1_input`` RO Current fan speed in RPM.
+======================= ======= =========================================