Re: omap3 pm: dependency between opp layer and cpufreq

[Kevin Hilman <khilman@deeprootsystems.com>]

Nishanth Menon <menon.nishanth@gmail.com> writes:

> On 05/30/2010 01:50 PM, Premi, Sanjeev wrote:
>>
[...]

>> [sp] There is no mention of cpufreq not working; but specifically the support of bootarg "mpurate" which is independent of cpufreq.
>>
>> The bootarg mpurate has been existing since quite sometime. I am neither creating a new layer / replacement
>> for cpufreq not trying to duplicate the code. The intent is simply
>> as 
> stated below:
>>
>> 1) Expose OPP layer - don't hinde it under CONFIG_CPU_FREQ.
> ok with this
>>
>> 2) Use OPP layer to:
>>      - Validate that the requested mpurate is defined in the OPP table for the device
>>      - And get the voltage corresponding to the OPP.
> sounds good too
>>
>> 3) Ensure that right freq and voltage is set - at init time - based on the mpurate.
> ok
>
>>
>> 4) And at some poit later break the linkage between op player amd PMIC.
>>
> aah you mean a simple patch as follows?
> diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile
> index 2b9ebf0..bfb3d0e 100644
> --- a/arch/arm/plat-omap/Makefile
> +++ b/arch/arm/plat-omap/Makefile
> @@ -16,7 +16,8 @@ obj-$(CONFIG_ARCH_OMAP16XX) += ocpi.o
>  # XXX The OPP TWL/TPS code should only be included when a TWL/TPS
>  # PMIC is selected.
>  ifdef CONFIG_CPU_FREQ
> -obj-$(CONFIG_ARCH_OMAP3) += opp.o opp_twl_tps.o
> +obj-$(CONFIG_ARCH_OMAP3) += opp.o
> +obj-$(CONFIG_TWL4030_CORE) += opp_twl_tps.o
>  endif
>
>  # omap_device support (OMAP2+ only at the moment)
> --
> note - opp layer was never tied to pmic -> there is pmic voltage
> conversion apis in opp_twl_tps.c
>
> or is there more in your view?
>
>>>
>>>>
>>>> anyways for cpufreq to work at 720Mhz, you need to add that frequency
>>>> and corresponding voltage to the opptable, neither exists, further
>>>> mpurate should work with opp table as well, else
>>>> clockframework has no
>>>> direct mechanism to verify the valid OPPs on a runtime
>>>> system. that was
>>>> the intent of opp layer - to provide the rest of the users with a
>>>> mechanism to verify, query and use opps without functional
>>>> knowledge of
>>>> the silicon it works on..
>
> ofcourse, please feel free to post a patch for the missing frequencies.
>


OK, I must admit to not reading this whole thread since I've just
restructured OPP and CPUfreq support in the PM branch.

OPP support is now in the pm-opp branch (based on mainline) and
CPUfreq support is now in the pm-cpufreq branch (based on mainline.)

Please update this patch/series against one (or both) of those
branches for more discussion.

FWIW, I like the name change from cpufreq34xx --> opp34xx_data, and
the Makefile change above makes sense.  Both of these changes should
be re-submitted against my pm-opp branch.

Kevin