libata: identify and init ZPODD devices

The ODD can be enabled for ZPODD if the following three conditions are
satisfied:
1 The ODD supports device attention;
2 The platform can runtime power off the ODD through ACPI;
3 The ODD is either slot type or drawer type.
For such ODDs, zpodd_init is called and a new structure is allocated for
it to store ZPODD related stuffs.

And the zpodd_dev_enabled function is used to test if ZPODD is currently
enabled for this ODD.

A new config CONFIG_SATA_ZPODD is added to selectively build ZPODD code.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index e08d322..996d16c 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -58,6 +58,19 @@ config ATA_ACPI
 	  You can disable this at kernel boot time by using the
 	  option libata.noacpi=1
 
+config SATA_ZPODD
+	bool "SATA Zero Power ODD Support"
+	depends on ATA_ACPI
+	default n
+	help
+	  This option adds support for SATA ZPODD. It requires both
+	  ODD and the platform support, and if enabled, will automatically
+	  power on/off the ODD when certain condition is satisfied. This
+	  does not impact user's experience of the ODD, only power is saved
+	  when ODD is not in use(i.e. no disc inside).
+
+	  If unsure, say N.
+
 config SATA_PMP
 	bool "SATA Port Multiplier support"
 	default y