ACPI / platform / LPSS: Enable async suspend/resume of LPSS devices

To seed up suspend and resume of devices included into Intel SoCs
handled by the ACPI LPSS driver during system suspend, make
acpi_lpss_create_device() call device_enable_async_suspend() for
every device created by it.

This requires acpi_create_platform_device() to be modified to return
a pointer to struct platform_device instead of an int.  As a result,
acpi_create_platform_device() cannot be pointed to by the .attach
pointer in platform_handler directly any more, so a simple wrapper
around it is necessary for this purpose.  That, in turn, allows the
second unused argument of acpi_create_platform_device() to be
dropped, which is an improvement.

Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / LPSS: custom power domain for LPSS

A power domain where we save the context of the additional
LPSS registers. We need to do this or all LPSS devices are
left in reset state when resuming from D3 on some Baytrails.
The devices with the fractional clock divider also have
zeros for N and M values after resuming unless they are
reset.

Li Aubrey found the root cause for the issue. The idea of
using power domain for LPSS came from Mika Westerberg.

Reported-by: Jin Yao <yao.jin@linux.intel.com>
Suggested-by: Li Aubrey <aubrey.li@linux.intel.com>
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
[rjw: Added the .complete() callback to the PM domain, fixed build
 warning on 32-bit.]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-clk' into acpi-lpss
ACPI / LPSS: support for fractional divider clock

This creates fractional divider type clock for the ones that
have it. It is needed by the UART driver as the clock rate must
accommodate to the requested baud rate.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-platform' into acpi-lpss
Merge branch 'acpi-platform' into bleeding-edge

* acpi-platform:
  ACPI / platform / LPSS: Enable async suspend/resume of LPSS devices
Merge branch 'acpi-lpss' into bleeding-edge

* acpi-lpss:
  ACPI / LPSS: support for fractional divider clock
  ACPI / LPSS: custom power domain for LPSS
PM / sleep: Add state field to pm_states[] entries

To allow sleep states corresponding to the "mem", "standby" and
"freeze" lables to be different from the pm_states[] indexes of
those strings, introduce struct pm_sleep_state, consisting of
a string label and a state number, and turn pm_states[] into an
array of objects of that type.

This modification should not lead to any functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / sleep: Use valid_state() for platform-dependent sleep states only

Use the observation that, for platform-dependent sleep states
(PM_SUSPEND_STANDBY, PM_SUSPEND_MEM), a given state is either
always supported or always unsupported and store that information
in pm_states[] instead of calling valid_state() every time we
need to check it.

Also do not use valid_state() for PM_SUSPEND_FREEZE, which is always
valid, and move the pm_test_level validity check for PM_SUSPEND_FREEZE
directly into enter_state().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / sleep: Introduce command line argument for sleep state enumeration

On some systems the platform doesn't support neither
PM_SUSPEND_MEM nor PM_SUSPEND_STANDBY, so PM_SUSPEND_FREEZE is the
only available system sleep state.  However, some user space frameworks
only use the "mem" and (sometimes) "standby" sleep state labels, so
the users of those systems need to modify user space in order to be
able to use system suspend at all and that is not always possible.

For this reason, add a new kernel command line argument,
relative_sleep_states, allowing the users of those systems to change
the way in which the kernel assigns labels to system sleep states.
Namely, for relative_sleep_states=1, the "mem", "standby" and "freeze"
labels will enumerate the available system sleem states from the
deepest to the shallowest, respectively, so that "mem" is always
present in /sys/power/state and the other state strings may or may
not be presend depending on what is supported by the platform.

Update system sleep states documentation to reflect this change.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-sleep' into bleeding-edge

* pm-sleep:
  PM / sleep: Introduce command line argument for sleep state enumeration
  PM / sleep: Use valid_state() for platform-dependent sleep states only
  PM / sleep: Add state field to pm_states[] entries