Re: [PATCH v1 3/5] spi: Added way to check for pm support for flash devices

[Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Mon, Feb 06, 2017 at 11:44:09AM +0100, Cyrille Pitchen wrote:
> Le 04/02/2017 à 21:47, Kamal Dasu a écrit :

> >> What is "flash pm" and how would a client use it given that no API for
> >> actually managing power is being added here?  Someone looking at the API
> >> needs to be able to figure these things out and right now I can't see
> >> how they'd do that...o

> > The flash_pm function just indicates if  m25p80 resume op that does a
> > spi_nor_pm_rescan() is needed, and by default will do nothing for
> > other platforms. So the basic idea of the patches was to execute the
> > only necessary spi_nor_pm_rescan() on resume when flash parts are
> > reset on suspend. So from controller perspective there is no

I can't tell what this means, sorry, and writing this e-mail does not
address the incomprehensibility of the API.  Why would the controller
driver have anything to do with whatever this spi_nor_pm_rescan()
operation does?

> I don't understand why we extend in the SPI framework API to add power
> management features but only for SPI flashes. I guess concerning the power
> management, there is nothing special about SPI flashes: they are just SPI
> devices like others. So why not extend the SPI framework, if needed, with
> something working for all SPI devices, not just for SPI flashes.

It's already possible for SPI devices to do runtime PM.

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