1 files changed, 51 insertions, 5 deletions

diff --git a/Documentation/hwmon/f71805f b/Documentation/hwmon/f71805f
index 2ca69df669c3..bfd0f154959c 100644
--- a/Documentation/hwmon/f71805f
+++ b/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>
 
@@ -13,8 +17,8 @@ Thanks to Denis Kieft from Barracuda Networks for the donation of a
 test system (custom Jetway K8M8MS motherboard, with CPU and RAM) and
 for providing initial documentation.
 
-Thanks to Kris Chen from Fintek for answering technical questions and
-providing additional documentation.
+Thanks to Kris Chen and Aaron Huang from Fintek for answering technical
+questions and providing additional documentation.
 
 Thanks to Chris Lin from Jetway for providing wiring schematics and
 answering technical questions.
@@ -28,8 +32,11 @@ capabilities. It can monitor up to 9 voltages (counting its own power
 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 driver doesn't
-support these features yet.
+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.
@@ -42,7 +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).
@@ -61,9 +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
@@ -103,3 +114,38 @@ sensor. Each channel can be used for connecting either a thermal diode
 or a thermistor. The driver reports the currently selected mode, but
 doesn't allow changing it. In theory, the BIOS should have configured
 everything properly.
+
+
+Fan Control
+-----------
+
+Both PWM (pulse-width modulation) and DC fan speed control methods are
+supported. The right one to use depends on external circuitry on the
+motherboard, so the driver assumes that the BIOS set the method
+properly. The driver will report the method, but won't let you change
+it.
+
+When the PWM method is used, you can select the operating frequency,
+from 187.5 kHz (default) to 31 Hz. The best frequency depends on the
+fan model. As a rule of thumb, lower frequencies seem to give better
+control, but may generate annoying high-pitch noise. Fintek recommends
+not going below 1 kHz, as the fan tachometers get confused by lower
+frequencies as well.
+
+When the DC method is used, Fintek recommends not going below 5 V, which
+corresponds to a pwm value of 106 for the driver. The driver doesn't
+enforce this limit though.
+
+Three different fan control modes are supported:
+
+* Manual mode
+  You ask for a specific PWM duty cycle or DC voltage.
+
+* Fan speed mode
+  You ask for a specific fan speed. This mode assumes that pwm1
+  corresponds to fan1, pwm2 to fan2 and pwm3 to fan3.
+
+* Temperature mode
+  You define 3 temperature/fan speed trip points, and the fan speed is
+  adjusted depending on the measured temperature, using interpolation.
+  This mode is not yet supported by the driver.