The adt7310/adt7320 is the SPI version of the adt7410/adt7420. The register map
layout is a bit different, i.e. the register addresses differ between the two
variants, but the bit layouts of the individual registers are identical. So both
chip variants can easily be supported by the same driver. The issue of non
matching register address layouts is solved by a simple look-up table which
translates the I2C addresses to the SPI addresses.

The patch moves the bulk of the adt7410 driver to a common module that will be
shared by the adt7410 and adt7310 drivers. This common module implements the
driver logic and uses a set of virtual functions to perform IO access. The
adt7410 and adt7310 driver modules provide proper implementations of these IO
accessor functions for I2C respective SPI.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

The adt7410 driver supports the ADT7420, but its documentation file
makes no mention of that. Add this refrence, and a brief a description
of the differences between the ADT7410 and the ADT7420.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

This patch brings basic support for the Analog Devices ADT7410 temperature
sensor. The following functionality has been implemented:

  * get current temperature
  * get/set minimum, maximum and critical temperature
  * get/set hysteresis
  * get alarm events for minimum, maximum and critical temperature

All implemented sysfs attributes have been sucessfully tested at temperatures
of 15°C to 40°C.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>