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

[Kamal Dasu]

On Sat, Feb 4, 2017 at 6:25 AM, Mark Brown <broonie at kernel.org> wrote:
> On Fri, Feb 03, 2017 at 06:31:14PM -0500, Kamal Dasu wrote:
>
>> Device drivers can check if the master controller driver has to support
>> flash pm. The controller driver indicates this using flash_pm_supported()
>> spi master interface.
>
> 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
additional pm activity to be done. Patches 1/5-2/5 is what is needed
actually. And Patches 3/3 - 5/5 only add a check if m25p80 resume
should call spi_nor_pm_rescan(). And the controller driver shall
implement the flash_pm function and return true if it does need a
rescan to be done on resume.