[PATCH v3 01/11] clk: davinci - add main PLL clock driver

Sekhar Nori nsekhar at ti.com
Thu Nov 1 07:01:32 EDT 2012


On 10/31/2012 7:16 PM, Murali Karicheri wrote:
> On 10/31/2012 08:29 AM, Sekhar Nori wrote:

>>> +    /*
>>> +     * if fixed_multiplier is non zero, multiply pllm value by this
>>> +     * value.
>>> +     */
>>> +    if (pll_data->fixed_multiplier)
>>> +        mult =  pll_data->fixed_multiplier *
>>> +                (mult & pll_data->pllm_mask);
>>> +    else
>>> +        mult = (mult & pll_data->pllm_mask) + 1;
>> Hmm, this is interpreting the 'mult' register field differently in both
>> cases. In one case it is 'actual multiplier - 1' and in other case it is
>> the 'actual multiplier' itself. Can we be sure that the mult register
>> definition will change whenever there is a fixed multiplier in the PLL
>> block? I don't think any of the existing DaVinci devices have a fixed
>> multiplier. Is this on keystone?
> Read section 6.4.3 (PLL Mode) in DM365 documentation (SPRUFG5a.pdf) that
> states PLL multiplies the clock by 2x the value in the PLLM. In the old
> code this is handled by a if cpu_is_* macro that we can't use in the
> driver. So this is represented by a fixed_multiplier that can be set to
> 2 for DM365 and zero on other SoCs.

Thanks for the clarification.

Regards,
Sekhar



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