hwmon: Driver for MAX1668

This patch adds support for MAX1668 and compatible temperature sensors.
Signed-off-by: David George <david.george@ska.ac.za>
[guenter.roeck@ericsson.com: minor cleanup of probe error path]
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

Documentation/hwmon/max1668

+Kernel driver max1668
+=====================
+
+Supported chips:
+  * Maxim MAX1668, MAX1805 and MAX1989
+    Prefix: 'max1668'
+    Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e
+    Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX1668-MAX1989.pdf
+
+Author:
+    David George <david.george@ska.ac.za>
+
+Description
+-----------
+
+This driver implements support for the Maxim MAX1668, MAX1805 and MAX1989
+chips.
+
+The three devices are very similar, but the MAX1805 has a reduced feature
+set; only two remote temperature inputs vs the four avaible on the other
+two ICs.
+
+The driver is able to distinguish between the devices and creates sysfs
+entries as follows:
+
+MAX1805, MAX1668 and MAX1989:
+
+temp1_input     ro local (ambient) temperature
+temp1_max       rw local temperature maximum threshold for alarm
+temp1_max_alarm ro local temperature maximum threshold alarm
+temp1_min       rw local temperature minimum threshold for alarm
+temp1_min_alarm ro local temperature minimum threshold alarm
+temp2_input     ro remote temperature 1
+temp2_max       rw remote temperature 1 maximum threshold for alarm
+temp2_max_alarm ro remote temperature 1 maximum threshold alarm
+temp2_min       rw remote temperature 1 minimum threshold for alarm
+temp2_min_alarm ro remote temperature 1 minimum threshold alarm
+temp3_input     ro remote temperature 2
+temp3_max       rw remote temperature 2 maximum threshold for alarm
+temp3_max_alarm ro remote temperature 2 maximum threshold alarm
+temp3_min       rw remote temperature 2 minimum threshold for alarm
+temp3_min_alarm ro remote temperature 2 minimum threshold alarm
+
+MAX1668 and MAX1989 only:
+temp4_input     ro remote temperature 3
+temp4_max       rw remote temperature 3 maximum threshold for alarm
+temp4_max_alarm ro remote temperature 3 maximum threshold alarm
+temp4_min       rw remote temperature 3 minimum threshold for alarm
+temp4_min_alarm ro remote temperature 3 minimum threshold alarm
+temp5_input     ro remote temperature 4
+temp5_max       rw remote temperature 4 maximum threshold for alarm
+temp5_max_alarm ro remote temperature 4 maximum threshold alarm
+temp5_min       rw remote temperature 4 minimum threshold for alarm
+temp5_min_alarm ro remote temperature 4 minimum threshold alarm
+
+Module Parameters
+-----------------
+
+* read_only: int
+  Set to non-zero if you wish to prevent write access to alarm thresholds.

MAINTAINERS

@@ -4120,6 +4120,13 @@ S:	Orphan
 F:	drivers/video/matrox/matroxfb_*
 F:	include/linux/matroxfb.h
 
+MAX1668 TEMPERATURE SENSOR DRIVER
+M:	"David George" <david.george@ska.ac.za>
+L:	lm-sensors@lm-sensors.org
+S:	Maintained
+F:	Documentation/hwmon/max1668
+F:	drivers/hwmon/max1668.c
+
 MAX6650 HARDWARE MONITOR AND FAN CONTROLLER DRIVER
 M:	"Hans J. Koch" <hjk@hansjkoch.de>
 L:	lm-sensors@lm-sensors.org

drivers/hwmon/Kconfig

@@ -736,6 +736,16 @@ config SENSORS_MAX1619
 	  This driver can also be built as a module.  If so, the module
 	  will be called max1619.
 
+config SENSORS_MAX1668
+	tristate "Maxim MAX1668 and compatibles"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for MAX1668, MAX1989 and
+	  MAX1805 chips.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called max1668.
+
 config SENSORS_MAX6639
 	tristate "Maxim MAX6639 sensor chip"
 	depends on I2C && EXPERIMENTAL

drivers/hwmon/Makefile

@@ -87,6 +87,7 @@ obj-$(CONFIG_SENSORS_LTC4261)	+= ltc4261.o
 obj-$(CONFIG_SENSORS_MAX1111)	+= max1111.o
 obj-$(CONFIG_SENSORS_MAX16065)	+= max16065.o
 obj-$(CONFIG_SENSORS_MAX1619)	+= max1619.o
+obj-$(CONFIG_SENSORS_MAX1668)	+= max1668.o
 obj-$(CONFIG_SENSORS_MAX6639)	+= max6639.o
 obj-$(CONFIG_SENSORS_MAX6642)	+= max6642.o
 obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o