hwmon: add driver for Aquacomputer D5 Next

This driver exposes hardware sensors of the Aquacomputer D5 Next
watercooling pump, which communicates through a proprietary USB HID
protocol.

Available sensors are pump and fan speed, power, voltage and current, as
well as coolant temperature. Also available through debugfs are the serial
number, firmware version and power-on count.

Attaching a fan is optional and allows it to be controlled using
temperature curves directly from the pump. If it's not connected,
the fan-related sensors will report zeroes.

The pump can be configured either through software or via its physical
interface. Configuring the pump through this driver is not implemented,
as it seems to require sending it a complete configuration. That
includes addressable RGB LEDs, for which there is no standard sysfs
interface. Thus, that task is better suited for userspace tools.

This driver has been tested on x86_64, both in-kernel and as a module.

Signed-off-by: Aleksa Savic <savicaleksa83@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/aquacomputer_d5next.rst

@@ -0,0 +1,61 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver aquacomputer-d5next
+=================================
+
+Supported devices:
+
+* Aquacomputer D5 Next watercooling pump
+
+Author: Aleksa Savic
+
+Description
+-----------
+
+This driver exposes hardware sensors of the Aquacomputer D5 Next watercooling
+pump, which communicates through a proprietary USB HID protocol.
+
+Available sensors are pump and fan speed, power, voltage and current, as
+well as coolant temperature. Also available through debugfs are the serial
+number, firmware version and power-on count.
+
+Attaching a fan is optional and allows it to be controlled using temperature
+curves directly from the pump. If it's not connected, the fan-related sensors
+will report zeroes.
+
+The pump can be configured either through software or via its physical
+interface. Configuring the pump through this driver is not implemented, as it
+seems to require sending it a complete configuration. That includes addressable
+RGB LEDs, for which there is no standard sysfs interface. Thus, that task is
+better suited for userspace tools.
+
+Usage notes
+-----------
+
+The pump communicates via HID reports. The driver is loaded automatically by
+the kernel and supports hotswapping.
+
+Sysfs entries
+-------------
+
+============ =============================================
+temp1_input  Coolant temperature (in millidegrees Celsius)
+fan1_input   Pump speed (in RPM)
+fan2_input   Fan speed (in RPM)
+power1_input Pump power (in micro Watts)
+power2_input Fan power (in micro Watts)
+in0_input    Pump voltage (in milli Volts)
+in1_input    Fan voltage (in milli Volts)
+in2_input    +5V rail voltage (in milli Volts)
+curr1_input  Pump current (in milli Amperes)
+curr2_input  Fan current (in milli Amperes)
+============ =============================================
+
+Debugfs entries
+---------------
+
+================ ===============================================
+serial_number    Serial number of the pump
+firmware_version Version of installed firmware
+power_cycles     Count of how many times the pump was powered on
+================ ===============================================

Documentation/hwmon/index.rst

@@ -39,6 +39,7 @@ Hardware Monitoring Kernel Drivers
    adt7475
    aht10
    amc6821
+   aquacomputer_d5next
    asb100
    asc7621
    aspeed-pwm-tacho

MAINTAINERS

@@ -1316,6 +1316,13 @@ L:	linux-media@vger.kernel.org
 S:	Maintained
 F:	drivers/media/i2c/aptina-pll.*
 
+AQUACOMPUTER D5 NEXT PUMP SENSOR DRIVER
+M:	Aleksa Savic <savicaleksa83@gmail.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/aquacomputer_d5next.rst
+F:	drivers/hwmon/aquacomputer_d5next.c
+
 AQUANTIA ETHERNET DRIVER (atlantic)
 M:	Igor Russkikh <irusskikh@marvell.com>
 L:	netdev@vger.kernel.org

drivers/hwmon/Kconfig

@@ -254,6 +254,16 @@ config SENSORS_AHT10
 	  This driver can also be built as a module. If so, the module
 	  will be called aht10.
 
+config SENSORS_AQUACOMPUTER_D5NEXT
+	tristate "Aquacomputer D5 Next watercooling pump"
+	depends on USB_HID
+	help
+	  If you say yes here you get support for the Aquacomputer D5 Next
+	  watercooling pump sensors.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called aquacomputer_d5next.
+
 config SENSORS_AS370
 	tristate "Synaptics AS370 SoC hardware monitoring driver"
 	help

drivers/hwmon/Makefile

@@ -46,6 +46,7 @@ obj-$(CONFIG_SENSORS_ADT7470)	+= adt7470.o
 obj-$(CONFIG_SENSORS_ADT7475)	+= adt7475.o
 obj-$(CONFIG_SENSORS_AHT10)	+= aht10.o
 obj-$(CONFIG_SENSORS_APPLESMC)	+= applesmc.o
+obj-$(CONFIG_SENSORS_AQUACOMPUTER_D5NEXT) += aquacomputer_d5next.o
 obj-$(CONFIG_SENSORS_ARM_SCMI)	+= scmi-hwmon.o
 obj-$(CONFIG_SENSORS_ARM_SCPI)	+= scpi-hwmon.o
 obj-$(CONFIG_SENSORS_AS370)	+= as370-hwmon.o