On Mon, Feb 24, 2014 at 08:38:07AM -0600, Nishanth Menon wrote: > Intent here is to allow drivers such as cpufreq-cpu0 to be reused on > platforms such as TI's OMAP derivatives, and other SoCs which differ > only by the sequence involved in voltage scale operations. So, this > patch provides a framework for registering the underlying > implementation of the SoC specific voltage change methodology. That bit is clear, what's very opaque from the code is how this is going to be accomplished. > Overall the sequence takes place after this patch is as follows: > a) voltage domain drivers such as those of TI or others register with > voltage domain with devm_voltdm_register. > b) cpufreq-cpu0/devfreq drivers: > of_pm_voltdm_notifier_register(introduced as part of patch #1) to > register notifiers around clk of interest. This request is linked to > the specific voltage domain using phandle in device tree. > c) when cpufreq-cpu0/devfreq does a clk_set_rate, the common clock > framework triggers notifiers in voltage domain core which in turn, > invokes the corresponding handlers for the voltage domain driver > ensuring the right dvfs sequence specific to the SoC is triggered. So the first question I have here is what happens if multiple clocks need to be updated in lock step - if we're only triggering off clock notifiers that seems tricky. The other thing here is that the fact that your API is "of_" suggests that it is in fact linked very srongly to DT - it'd be good to split out the layers to make sure things make sense standalone, the DT helpers are obviously good but the API should be able to stand separately.
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