hwmon: Driver for Maxim MAX31790

The driver supports the Maxim MAX31790.
Signed-off-by: Il Han <corone.il.han@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/max31790

+Kernel driver max31790
+======================
+
+Supported chips:
+  * Maxim MAX31790
+    Prefix: 'max31790'
+    Addresses scanned: -
+    Datasheet: http://pdfserv.maximintegrated.com/en/ds/MAX31790.pdf
+
+Author: Il Han <corone.il.han@gmail.com>
+
+
+Description
+-----------
+
+This driver implements support for the Maxim MAX31790 chip.
+
+The MAX31790 controls the speeds of up to six fans using six independent
+PWM outputs. The desired fan speeds (or PWM duty cycles) are written
+through the I2C interface. The outputs drive "4-wire" fans directly,
+or can be used to modulate the fan's power terminals using an external
+pass transistor.
+
+Tachometer inputs monitor fan tachometer logic outputs for precise (+/-1%)
+monitoring and control of fan RPM as well as detection of fan failure.
+Six pins are dedicated tachometer inputs. Any of the six PWM outputs can
+also be configured to serve as tachometer inputs.
+
+
+Sysfs entries
+-------------
+
+fan[1-12]_input    RO  fan tachometer speed in RPM
+fan[1-12]_fault    RO  fan experienced fault
+fan[1-6]_target    RW  desired fan speed in RPM
+pwm[1-6]_enable    RW  regulator mode, 0=disabled, 1=manual mode, 2=rpm mode
+pwm[1-6]           RW  fan target duty cycle (0-255)

drivers/hwmon/Kconfig

@@ -840,6 +840,16 @@ config SENSORS_MAX6697
 	  This driver can also be built as a module.  If so, the module
 	  will be called max6697.
 
+config SENSORS_MAX31790
+	tristate "Maxim MAX31790 sensor chip"
+	depends on I2C
+	help
+	  If you say yes here you get support for 6-Channel PWM-Output
+	  Fan RPM Controller.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called max31790.
+
 config SENSORS_HTU21
 	tristate "Measurement Specialties HTU21D humidity/temperature sensors"
 	depends on I2C

drivers/hwmon/Makefile

@@ -115,6 +115,7 @@ obj-$(CONFIG_SENSORS_MAX6639)	+= max6639.o
 obj-$(CONFIG_SENSORS_MAX6642)	+= max6642.o
 obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_MAX6697)	+= max6697.o
+obj-$(CONFIG_SENSORS_MAX31790)	+= max31790.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
 obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
 obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o