[SCSI] libsas: Add a sysfs knob to enable/disable a phy

This patch lets a user arbitrarily enable or disable a phy via sysfs.
Potential applications include shutting down a phy to replace one
lane of wide port, and (more importantly) providing a method for the
libata SATL to control the phy.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index da96bcf..0689d66 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -614,6 +614,9 @@
 extern int sas_register_ha(struct sas_ha_struct *);
 extern int sas_unregister_ha(struct sas_ha_struct *);
 
+int sas_set_phy_speed(struct sas_phy *phy,
+		      struct sas_phy_linkrates *rates);
+int sas_phy_enable(struct sas_phy *phy, int enabled);
 int sas_phy_reset(struct sas_phy *phy, int hard_reset);
 extern int sas_queuecommand(struct scsi_cmnd *,
 		     void (*scsi_done)(struct scsi_cmnd *));