Re: [PATCH] regmap: mmio: prepare/unprepare clk only when read/write

[Mark Brown <broonie@kernel.org>]

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On Thu, Apr 23, 2020 at 10:51:36AM +0000, Peng Fan wrote:

> > This will mean that we're doing clk_prepare() during I/O which isn't good
> > since for MMIO regmaps we support I/O operations in atomic contexts.

> Ah, yes. Do you have any suggestions? If we use clk_prepare at the very
> beginning, the power that binded to the clk device will be always on,
> and cause power consumption high.

Not really in regmap itself - I think your best bet here is to move the
clock handling out of regmap and up into the driver.  regmap won't do
any I/O unless your driver calls it so this will work fine, this support
is only there in regmap as a convenience but if it's getting in the way
then you're probably going to be able to do a better job pushing this
into rutime PM in the driver or just having direct clock calls.

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