it87: Add support for the IT8718F

it87: Add support for the IT8718F

The IT8718F is a Super-I/O chip with integrated hardware monitoring
functions. It is very similar to the IT8716F, so adding support to the
it87 driver was pretty straightforward. The most significant difference
is that the IT8718F has up to 8 VID pins, instead of 6 for the older
chips.

For the IT8718F, the VID value can only be read from Super-I/O space.

Userspace support is already in lm_sensors SVN (to be soon released
as 2.10.1.)

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/hwmon/it87

@@ -18,6 +18,12 @@ Supported chips:
     Addresses scanned: from Super I/O config space (8 I/O ports)
     Datasheet: Publicly available at the ITE website
                http://www.ite.com.tw/product_info/file/pc/IT8716F_V0.3.ZIP
+  * IT8718F
+    Prefix: 'it8718'
+    Addresses scanned: from Super I/O config space (8 I/O ports)
+    Datasheet: Publicly available at the ITE website
+               http://www.ite.com.tw/product_info/file/pc/IT8718F_V0.2.zip
+               http://www.ite.com.tw/product_info/file/pc/IT8718F_V0%203_(for%20C%20version).zip
   * SiS950   [clone of IT8705F]
     Prefix: 'it87'
     Addresses scanned: from Super I/O config space (8 I/O ports)
@@ -48,8 +54,8 @@ Module Parameters
 Description
 -----------
 
-This driver implements support for the IT8705F, IT8712F, IT8716F and
-SiS950 chips.
+This driver implements support for the IT8705F, IT8712F, IT8716F,
+IT8718F and SiS950 chips.
 
 These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
 joysticks and other miscellaneous stuff. For hardware monitoring, they
@@ -62,14 +68,21 @@ the IT8716F and late IT8712F have 6. They are shared with other functions
 though, so the functionality may not be available on a given system.
 The driver dumbly assume it is there.
 
-The IT8716F and later IT8712F revisions have support for 2 additional
-fans. They are not yet supported by the driver.
+The IT8718F also features VID inputs (up to 8 pins) but the value is
+stored in the Super-I/O configuration space. Due to technical limitations,
+this value can currently only be read once at initialization time, so
+the driver won't notice and report changes in the VID value. The two
+upper VID bits share their pins with voltage inputs (in5 and in6) so you
+can't have both on a given board.
 
-The IT8716F and late IT8712F and IT8705F also have optional 16-bit
-tachometer counters for fans 1 to 3. This is better (no more fan
+The IT8716F, IT8718F and later IT8712F revisions have support for
+2 additional fans. They are not yet supported by the driver.
+
+The IT8716F and IT8718F, and late IT8712F and IT8705F also have optional
+16-bit tachometer counters for fans 1 to 3. This is better (no more fan
 clock divider mess) but not compatible with the older chips and
 revisions. For now, the driver only uses the 16-bit mode on the
-IT8716F.
+IT8716F and IT8718F.
 
 Temperatures are measured in degrees Celsius. An alarm is triggered once
 when the Overtemperature Shutdown limit is crossed.
@@ -89,9 +102,9 @@ zero'; this is important for negative voltage measurements. All voltage
 inputs can measure voltages between 0 and 4.08 volts, with a resolution of
 0.016 volt. The battery voltage in8 does not have limit registers.
 
-The VID lines (IT8712F/IT8716F) encode the core voltage value: the voltage
-level your processor should work with. This is hardcoded by the mainboard
-and/or processor itself. It is a value in volts.
+The VID lines (IT8712F/IT8716F/IT8718F) encode the core voltage value:
+the voltage level your processor should work with. This is hardcoded by
+the mainboard and/or processor itself. It is a value in volts.
 
 If an alarm triggers, it will remain triggered until the hardware register
 is read at least once. This means that the cause for the alarm may already