RFC PATCH 2.6 sysfs names: fscher: change div to ripple

Grant Coady grant_lkml at dodo.com.au
Wed Apr 27 23:04:20 CEST 2005


Hi Philip,
On Wed, 27 Apr 2005 09:18:09 -0700, Philip Pokorny <ppokorny at penguincomputing.com> wrote:
>
>This ripple counter sounds like the same thing, but working on the fan 
>pulses directly rather than on the 22.5kHz clock.  So the fan tach 
>signal is slower with a higher divisor.

The main difference is that changing ripple will change fan speed 
reading, that aspect is different from other chips, thus the variable 
needs a different name.

The fan speed reading in fscher is defined as 0..255 U/sec.  What is 
a 'U'?   Code comments suggest revs / sec?  

>So the fan_ripple is the *inverse* of the fan_div value, but they have 
>the same net effect, and you can account for the reciprical in the 
>driver.  ie  fan_div = 8/fan_ripple  (if the max "ripple" value is 8)

Yes, you may do that, but without the chip to test I'd rather just 
put fsc* fan_div/fan_ripple into a different common name so user land 
sees it has a different meaning.

Sysfs names project is cleaning up and documenting sysfs naming.

I'm working up to fan speed control :)

Cheers,
--Grant.



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