Although this callback is optional and documented as such, it requires
a platform_suspend_ops::begin callback to be implemented in order to
provide an accurate suspend/resume state within the driver that
implements this platform_suspend_ops.

An enumeration: platform_target_state is defined which currently defines
the standard ACPI_S[1-4] states and can be extended with platform
specific suspend states.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 include/linux/suspend.h | 25 +++++++++++++++++++++++++
 kernel/power/suspend.c  | 15 +++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 0b1cf32edfd7..6e6cc0778816 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h

@@ -50,6 +50,16 @@ enum suspend_stat_step {
 	SUSPEND_RESUME
 };
 
+enum platform_target_state {
+	PLATFORM_STATE_UNKNOWN = -1,
+	PLATFORM_STATE_WORKING = 0,
+	PLATFORM_STATE_ACPI_S1,
+	PLATFORM_STATE_ACPI_S2,
+	PLATFORM_STATE_ACPI_S3,
+	PLATFORM_STATE_ACPI_S4,
+	/* Add platform specific states here */
+};
+