Re: [PATCH v7 2/3] cpufreq: mediatek: Add MT8173 cpufreq driver

From: Viresh Kumar
Date: Wed Aug 19 2015 - 01:42:59 EST


On 19-08-15, 10:05, Pi-Cheng Chen wrote:
> Mediatek MT8173 is an ARMv8 based quad-core (2*Cortex-A53 and
> 2*Cortex-A72) SoC with duall clusters. For each cluster, two voltage
> inputs, Vproc and Vsram are supplied by two regulators. For the big
> cluster, two regulators come from different PMICs. In this case, when
> scaling voltage inputs of the cluster, the voltages of two regulator
> inputs need to be controlled by software explicitly under the SoC
> specific limitation:
>
> 100mV < Vsram - Vproc < 200mV
>
> which is called 'voltage tracking' mechanism. And when scaling the
> frequency of cluster clock input, the input MUX need to be parented to
> another "intermediate" stable PLL first and reparented to the original
> PLL once the original PLL is stable at the target frequency. This patch
> implements those mechanisms to enable CPU DVFS support for Mediatek
> MT8173 SoC.
>
> Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@xxxxxxxxxx>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
>
> Changes in v7:
> - add of_machine_is_compatible() check to be multiplatform friendly

Looks fine, thanks.

--
viresh
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