hwmon: (asus_wmi_ec_sensors) Support B550 Asus WMI.

Linux HWMON sensors driver for ASUS motherboards to read
sensors from the embedded controller.

Many ASUS motherboards do not publish all the available
sensors via the Super I/O chip but the missing ones are
available through the embedded controller (EC) registers.

This driver implements reading those sensor data via the
WMI method BREC, which is known to be present in all ASUS
motherboards based on the AMD 500 series chipsets (and
probably is available in other models too). The driver
needs to know exact register addresses for the sensors and
thus support for each motherboard has to be added explicitly.

The EC registers do not provide critical values for the
sensors and as such they are not published to the HWMON.

Supported motherboards:
* PRIME X570-PRO
* Pro WS X570-ACE
* ROG CROSSHAIR VIII HERO
* ROG CROSSHAIR VIII DARK HERO
* ROG CROSSHAIR VIII FORMULA
* ROG STRIX X570-E GAMING
* ROG STRIX B550-I GAMING
* ROG STRIX B550-E GAMING
Co-developed-by: Eugene Shalygin <eugene.shalygin@gmail.com>
Signed-off-by: Eugene Shalygin <eugene.shalygin@gmail.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Denis Pauk <pauk.denis@gmail.com>
Tested-by: Tor Vic <torvic9@mailbox.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/asus_wmi_ec_sensors.rst

+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver asus_wmi_ec_sensors
+=================================
+
+Supported boards:
+ * PRIME X570-PRO,
+ * Pro WS X570-ACE,
+ * ROG CROSSHAIR VIII DARK HERO,
+ * ROG CROSSHAIR VIII FORMULA,
+ * ROG CROSSHAIR VIII HERO,
+ * ROG STRIX B550-E GAMING,
+ * ROG STRIX B550-I GAMING,
+ * ROG STRIX X570-E GAMING.
+
+Authors:
+    - Eugene Shalygin <eugene.shalygin@gmail.com>
+
+Description:
+------------
+ASUS mainboards publish hardware monitoring information via Super I/O
+chip and the ACPI embedded controller (EC) registers. Some of the sensors
+are only available via the EC.
+
+ASUS WMI interface provides a method (BREC) to read data from EC registers,
+which is utilized by this driver to publish those sensor readings to the
+HWMON system. The driver is aware of and reads the following sensors:
+
+1. Chipset (PCH) temperature
+2. CPU package temperature
+3. Motherboard temperature
+4. Readings from the T_Sensor header
+5. VRM temperature
+6. CPU_Opt fan RPM
+7. Chipset fan RPM
+8. Readings from the "Water flow meter" header (RPM)
+9. Readings from the "Water In" and "Water Out" temperature headers
+10. CPU current

Documentation/hwmon/index.rst

@@ -43,6 +43,7 @@ Hardware Monitoring Kernel Drivers
    asb100
    asc7621
    aspeed-pwm-tacho
+   asus_wmi_ec_sensors
    bcm54140
    bel-pfe
    bpa-rs600

MAINTAINERS

@@ -2998,6 +2998,13 @@ W:	http://acpi4asus.sf.net
 F:	drivers/platform/x86/asus*.c
 F:	drivers/platform/x86/eeepc*.c
 
+ASUS WMI EC HARDWARE MONITOR DRIVER
+M:	Eugene Shalygin <eugene.shalygin@gmail.com>
+M:	Denis Pauk <pauk.denis@gmail.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	drivers/hwmon/asus_wmi_ec_sensors.c
+
 ASUS WIRELESS RADIO CONTROL DRIVER
 M:	João Paulo Rechi Vita <jprvita@gmail.com>
 L:	platform-driver-x86@vger.kernel.org

drivers/hwmon/Kconfig

@@ -2228,6 +2228,18 @@ config SENSORS_ATK0110
 	  This driver can also be built as a module. If so, the module
 	  will be called asus_atk0110.
 
+config SENSORS_ASUS_WMI_EC
+	tristate "ASUS WMI B550/X570"
+	depends on ACPI_WMI
+	help
+	  If you say yes here you get support for the ACPI embedded controller
+	  hardware monitoring interface found in B550/X570 ASUS motherboards.
+	  This driver will provide readings of fans, voltages and temperatures
+	  through the system firmware.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called asus_wmi_sensors_ec.
+
 endif # ACPI
 
 endif # HWMON

drivers/hwmon/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_HWMON_VID)		+= hwmon-vid.o
 # APCI drivers
 obj-$(CONFIG_SENSORS_ACPI_POWER) += acpi_power_meter.o
 obj-$(CONFIG_SENSORS_ATK0110)	+= asus_atk0110.o
+obj-$(CONFIG_SENSORS_ASUS_WMI_EC)	+= asus_wmi_ec_sensors.o
 
 # Native drivers
 # asb100, then w83781d go first, as they can override other drivers' addresses.