[PATCH v5 4/4] powerpc/85xx: add sysfs for pw20 state and altivec idle

[Bharat Bhushan]

> > Those codes just for discuss with Bharat. He want to make one flow at
> > "show_pw20_wait_time"/" show_altivec_idle_wait_time" function. If we
> > do that, we need to initialize pw20_wt/altivec_idle_wt.
> >
> I will keep this stuff at "show_pw20_wait_time"/"show_altivec_idle_wait_time"
> and add a comment before our discussion.
> 
> /*
>  * If the "value" less than 10, this will overflow.
>  * From benchmark test, the default wait bit will not be set less than 10bit.
>  * Because 10 bit corresponds to the wait entry time is 439375573401999609(ns),
>  * for wait-entry-idle time this value looks too long, and we cannot use those
>  * "long" time as a default wait-entry time. So overflow could not have happened
>  * and we use this calculation method to get wait-entry-idle time.
>  */

I think now we will use same calculation code for default value and user set value, so adding the comment is not sufficient, we should error out from the code if value is less than 10. As default value is not less than 10 so this will always work with default value but if user tries to set less than 10 then error out and ask user to try more than 9.

-Bharat