hwmon: (asus-ec-sensors) add driver for ASUS EC

This driver provides the same data as the asus_wmi_ec_sensors driver
(and gets it from the same source) but does not use WMI, polling
the ACPI EC directly.

That provides two enhancements: sensor reading became quicker (on some
systems or kernel configuration it took almost a full second to read
all the sensors, that transfers less than 15 bytes of data), the driver
became more flexible. The driver now relies on ACPI mutex to lock access
to the EC in the same way as the WMI code does.

Signed-off-by: Eugene Shalygin <eugene.shalygin@gmail.com>

MAINTAINERS

@@ -3012,6 +3012,12 @@ L:	linux-hwmon@vger.kernel.org
 S:	Maintained
 F:	drivers/hwmon/asus_wmi_ec_sensors.c
 
+ASUS EC HARDWARE MONITOR DRIVER
+M:	Eugene Shalygin <eugene.shalygin@gmail.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	drivers/hwmon/asus-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

@@ -2253,6 +2253,17 @@ config SENSORS_ASUS_WMI_EC
 	  This driver can also be built as a module. If so, the module
 	  will be called asus_wmi_sensors_ec.
 
+config SENSORS_ASUS_EC
+	tristate "ASUS EC Sensors"
+	help
+	  If you say yes here you get support for the ACPI embedded controller
+	  hardware monitoring interface found in ASUS motherboards. The driver
+	  currently supports B550/X570 boards, although other ASUS boards might
+	  provide this monitoring interface as well.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called asus_ec_sensors.
+
 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_EC)	+= asus-ec-sensors.o
 obj-$(CONFIG_SENSORS_ASUS_WMI)	+= asus_wmi_sensors.o
 obj-$(CONFIG_SENSORS_ASUS_WMI_EC)	+= asus_wmi_ec_sensors.o