hwmon: Add Texas Instruments TMP108 temperature sensor driver.

Add support for the TI TMP108 temperature sensor with some device
configuration parameters.

Signed-off-by: John Muir <john@jmuir.com>
[groeck: Initialize of_match_table]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/tmp108

@@ -0,0 +1,36 @@
+Kernel driver tmp108
+====================
+
+Supported chips:
+  * Texas Instruments TMP108
+    Prefix: 'tmp108'
+    Addresses scanned: none
+    Datasheet: http://www.ti.com/product/tmp108
+
+Author:
+	John Muir <john@jmuir.com>
+
+Description
+-----------
+
+The Texas Instruments TMP108 implements one temperature sensor. An alert pin
+can be set when temperatures exceed minimum or maximum values plus or minus a
+hysteresis value. (This driver does not support interrupts for the alert pin,
+and the device runs in comparator mode.)
+
+The sensor is accurate to 0.75C over the range of -25 to +85 C, and to 1.0
+degree from -40 to +125 C. Resolution of the sensor is 0.0625 degree. The
+operating temperature has a minimum of -55 C and a maximum of +150 C.
+Hysteresis values can be set to 0, 1, 2, or 4C.
+
+The TMP108 has a programmable update rate that can select between 8, 4, 1, and
+0.5 Hz.
+
+By default the TMP108 reads the temperature continuously. To conserve power,
+the TMP108 has a one-shot mode where the device is normally shut-down. When a
+one shot is requested the temperature is read, the result can be retrieved,
+and then the device is shut down automatically. (This driver only supports
+continuous mode.)
+
+The driver provides the common sysfs-interface for temperatures (see
+Documentation/hwmon/sysfs-interface under Temperatures).