On Thu, Nov 07, 2019 at 03:54:03AM +0300, Dmitry Osipenko wrote: > 07.11.2019 02:10, Stephen Boyd пишет: > > Quoting Sowjanya Komatineni (2019-08-16 12:41:52) > >> This patch adds an API clk_hw_get_parent_index to get index of the > >> clock parent to use during the clock restore operations on system > >> resume. > > > > Is there a reason we can't save the clk hw index at suspend time by > > reading the hardware to understand the current parent? The parent index > > typically doesn't matter unless we're trying to communicate something > > from the framework to the provider driver. Put another way, I would > > think the provider driver can figure out the index itself without having > > to go through the framework to do so. > > Isn't it a bit wasteful to duplicate information about the parent within > a provider if framework already has that info? The whole point of this > new API is to allow providers to avoid that unnecessary duplication. > > Please note that clk_hw_get_parent_index is getting used only at the > resume time and not at suspend. I agree with this. All of the information that we need is already cached in the framework. Doing this in the driver would mean essentially adding a "saved parent" field along with code to read the value at suspend time to the three types of clocks that currently use this core helper. That's certainly something that we *can* do, but it doesn't sound like a better option than simply querying the framework for the value that we need. Thierry
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