it87: Add support for the IT8716F

it87: Add support for the IT8716F

The IT8716F is a Super-I/O chip with integrated hardware monitoring
functions. It is very similar to the IT8712F, so adding support to the
it87 driver was pretty straightforward. The most significant change here
is that the IT8716F has 16-bit fan speed counters, so the user no more
needs to tweak the fan clock dividers to get the best readings.

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

Thanks to Stian Oksavik, Olivier Nicolas, Prakash Punnoor and
Juergen Kilb for testing the early versions of this patch.

Thanks also to ITE for providing datasheets and answering my questions.

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

Documentation/hwmon/it87

@@ -13,6 +13,11 @@ Supported chips:
                        from Super I/O config space (8 I/O ports)
     Datasheet: Publicly available at the ITE website
                http://www.ite.com.tw/
+  * IT8716F
+    Prefix: 'it8716'
+    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
   * SiS950   [clone of IT8705F]
     Prefix: 'it87'
     Addresses scanned: from Super I/O config space (8 I/O ports)
@@ -43,26 +48,39 @@ Module Parameters
 Description
 -----------
 
-This driver implements support for the IT8705F, IT8712F and SiS950 chips.
-
-This driver also supports IT8712F, which adds SMBus access, and a VID
-input, used to report the Vcore voltage of the Pentium processor.
-The IT8712F additionally features VID inputs.
+This driver implements support for the IT8705F, IT8712F, IT8716F and
+SiS950 chips.
 
 These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
 joysticks and other miscellaneous stuff. For hardware monitoring, they
 include an 'environment controller' with 3 temperature sensors, 3 fan
 rotation speed sensors, 8 voltage sensors, and associated alarms.
 
+The IT8712F and IT8716F additionally feature VID inputs, used to report
+the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
+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 IT8716F 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.
+
 Temperatures are measured in degrees Celsius. An alarm is triggered once
 when the Overtemperature Shutdown limit is crossed.
 
 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
-triggered if the rotation speed has dropped below a programmable limit. Fan
-readings can be divided by a programmable divider (1, 2, 4 or 8) to give the
-readings more range or accuracy. Not all RPM values can accurately be
-represented, so some rounding is done. With a divider of 2, the lowest
-representable value is around 2600 RPM.
+triggered if the rotation speed has dropped below a programmable limit. When
+16-bit tachometer counters aren't used, fan readings can be divided by
+a programmable divider (1, 2, 4 or 8) to give the readings more range or
+accuracy. With a divider of 2, the lowest representable value is around
+2600 RPM. Not all RPM values can accurately be represented, so some rounding
+is done.
 
 Voltage sensors (also known as IN sensors) report their values in volts. An
 alarm is triggered if the voltage has crossed a programmable minimum or
@@ -71,7 +89,7 @@ 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 only) encode the core voltage value: the voltage
+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.