hwmon: Add tachometer pulses per fan revolution to sysfs ABI

Some fan control chips support a configuration register to set the number of
tachometer pulses per fan revolution. Add an ABI attribute to support this
configuration register.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>

diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
index c6559f15358933cb2ab74a49d70a34ce90e34e91..83a698773ade1cffd9cf4c343a20d56adf7ee5f3 100644 (file)
--- a/Documentation/hwmon/sysfs-interface
+++ b/Documentation/hwmon/sysfs-interface
@@ -187,6 +187,17 @@ fan[1-*]_div       Fan divisor.
                Note that this is actually an internal clock divisor, which
                affects the measurable speed range, not the read value.
 
                Note that this is actually an internal clock divisor, which
                affects the measurable speed range, not the read value.
 

+fan[1-*]_pulses        Number of tachometer pulses per fan revolution.
+               Integer value, typically between 1 and 4.
+               RW
+               This value is a characteristic of the fan connected to the
+               device's input, so it has to be set in accordance with the fan
+               model.
+               Should only be created if the chip has a register to configure
+               the number of pulses. In the absence of such a register (and
+               thus attribute) the value assumed by all devices is 2 pulses
+               per fan revolution.
+

 fan[1-*]_target
                Desired fan speed
                Unit: revolution/min (RPM)
 fan[1-*]_target
                Desired fan speed
                Unit: revolution/min (RPM)