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The delay of frequency/voltage scaling

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Dear all, 

I'm reading the MPSS3.3 source codes.

In \drivers\micpm\mic_cpufreq.c, there are some definitions as following:

#define K1OM_FREQ_DELAY    10    /* delay this many usecs, for each loop of the freq set routine */
#define K1OM_VID_DELAY    50    /* delay this many usecs for each loop of the vid set routine   */
#define K1OM_FREQ_LOOPS    50    /*  # of times to loop before we bail                           */
#define K1OM_VID_LOOPS    2

By checking the routines of set_cur_freq_k1om() and set_vid_k1om(), where the above definitions are used to control the frequency/voltage scaling, I guess that maximal delay of frequency scaling is 10x50=500 usecs, while it's 50x2x2=200 usecs for voltage scaling.

Am I right?

And my question is why the voltage scaling takes shorter than frequency scaling. Usually, the voltage scaling takes much longer.

Is there some documents where I can find some information about the delay of frequency/voltage scaling?

Thanks a lot.

 

 

AllegatoDimensione
Scaricamic_cpufreq.c46.71 KB

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