linux-imx

spi: omap2-mcspi: Idle hardware during suspend and resume

We currently are calling mcspi suspend and resume without considering
that mcspi might provide resources for other device driver such as
regulators. This means resume can fail and will produce -EACCES if
errors if anything calls mcspi functions between device_prepare()
and device_complete().

To fix the issue, let's do the following changes:

1. Let's add checking for return values for pm_runtime_get calls,
   and call pm_runtime_put_noidle() on errors. Things still fail
   after this change, but at least we see something is wrong as
   we now see -EACCES errors on resume.

2. Let's use noirq level for suspend and resume as other drivers
   can still call SPI related functions on suspend and resume. This
   still won't fix the -EACCES issue, but gets us to something a bit
   saner.

3. Finally, let's modify suspend and resume to call to make sure
   the device is idled properly on suspend. We have device_prepare()
   call pm_runtime_get_noresume() that won't get released until in
   device_complete() when it calls pm_runtime_put(). So if SPI is
   still active on entering suspend, it will never get idled unless
   we add calls to pm_runtime_force_suspend() and resume. This also
   fixes the -EACCES errors on resume together with changes 1 and 2
   above.

And since we're already rewriting suspend resume functions, let's
arrange the order of suspend and resume functions to be like they
usually are with suspend first.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>