hwmon: (nct6775) Add support for weighted fan control

The NCT677X series support weighted fan control. In this mode, a secondary
temperature source is used in addition to the primary temperature source to
control fan speed. Add support for this feature.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/Documentation/hwmon/nct6775 b/Documentation/hwmon/nct6775
index b4fe6bc4d371..3f5587e39093 100644
--- a/Documentation/hwmon/nct6775
+++ b/Documentation/hwmon/nct6775
@@ -92,6 +92,25 @@ Common fan control attributes
 
 pwm[1-5]_temp_sel       Temperature source. Value is temperature sensor index.
                         For example, select '1' for temp1_input.
+pwm[1-5]_weight_temp_sel
+                        Secondary temperature source. Value is temperature
+                        sensor index. For example, select '1' for temp1_input.
+                        Set to 0 to disable secondary temperature control.
+
+If secondary temperature functionality is enabled, it is controlled with the
+following attributes.
+
+pwm[1-5]_weight_duty_step
+                        Duty step size.
+pwm[1-5]_weight_temp_step
+                        Temperature step size. With each step over
+                        temp_step_base, the value of weight_duty_step is added
+                        to the current pwm value.
+pwm[1-5]_weight_temp_step_base
+                        Temperature at which secondary temperature control kicks
+                        in.
+pwm[1-5]_weight_temp_step_tol
+                        Temperature step tolerance.
 
 Thermal Cruise mode (2)
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