hwmon/f71805f: Add support for the Fintek F71872F/FG chip

Add support for the Fintek F71872F/FG Super-I/O chip. It is basically the
same as the Fintek F71805F/FG as far as hardware monitoring is concerned,
with two additional internal voltages monitored (VSB and battery), and 6
VID inputs (not yet supported.)

To make things a bit more confusing, two of the voltage input pins (in4
and in8) can be used for other functions. The driver reads the pin
configuration from the Super-I/O configuration space to decide whether
it must create interface files for these inputs or not.

Many thanks to Nikolay Derkach for testing the early iterations of this
code and reporting bugs.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Documentation/hwmon/f71805f

@@ -6,6 +6,10 @@ Supported chips:
     Prefix: 'f71805f'
     Addresses scanned: none, address read from Super I/O config space
     Datasheet: Provided by Fintek on request
+  * Fintek F71872F/FG
+    Prefix: 'f71872f'
+    Addresses scanned: none, address read from Super I/O config space
+    Datasheet: Provided by Fintek on request
 
 Author: Jean Delvare <khali@linux-fr.org>
 
@@ -30,6 +34,10 @@ source), 3 fans and 3 temperature sensors.
 This chip also has fan controlling features, using either DC or PWM, in
 three different modes (one manual, two automatic).
 
+The Fintek F71872F/FG Super I/O chip is almost the same, with two
+additional internal voltages monitored (VSB and battery). It also features
+6 VID inputs. The VID inputs are not yet supported by this driver.
+
 The driver assumes that no more than one chip is present, which seems
 reasonable.
 
@@ -41,7 +49,8 @@ Voltages are sampled by an 8-bit ADC with a LSB of 8 mV. The supported
 range is thus from 0 to 2.040 V. Voltage values outside of this range
 need external resistors. An exception is in0, which is used to monitor
 the chip's own power source (+3.3V), and is divided internally by a
-factor 2.
+factor 2. For the F71872F/FG, in9 (VSB) and in10 (battery) are also
+divided internally by a factor 2.
 
 The two LSB of the voltage limit registers are not used (always 0), so
 you can only set the limits in steps of 32 mV (before scaling).
@@ -60,9 +69,12 @@ in5     VIN5    +12V        200K     20K       11.00    1.05 V
 in6     VIN6    VCC1.5V      10K       -        1.00    1.50 V
 in7     VIN7    VCORE        10K       -        1.00   ~1.40 V (1)
 in8     VIN8    VSB5V       200K     47K        1.00    0.95 V
+in10    VSB     VSB3.3V     int.    int.        2.00    1.65 V (3)
+in9     VBAT    VBATTERY    int.    int.        2.00    1.50 V (3)
 
 (1) Depends on your hardware setup.
 (2) Obviously not correct, swapping R1 and R2 would make more sense.
+(3) F71872F/FG only.
 
 These values can be used as hints at best, as motherboard manufacturers
 are free to use a completely different setup. As a matter of fact, the

drivers/hwmon/Kconfig

@@ -142,11 +142,12 @@ config SENSORS_DS1621
 	  will be called ds1621.
 
 config SENSORS_F71805F
-	tristate "Fintek F71805F/FG"
+	tristate "Fintek F71805F/FG and F71872F/FG"
 	depends on HWMON && EXPERIMENTAL
 	help
 	  If you say yes here you get support for hardware monitoring
-	  features of the Fintek F71805F/FG chips.
+	  features of the Fintek F71805F/FG and F71872F/FG Super-I/O
+	  chips.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called f71805f.