diff --git a/drivers/scsi/isci/host.c b/drivers/scsi/isci/host.c
index 418391b1c3616b07f2976467720565d7e9ee4479..508aa8ce25b42b4012454fb30193e5a3f4f9fb79 100644
--- a/drivers/scsi/isci/host.c
+++ b/drivers/scsi/isci/host.c
@@ -1491,6 +1491,15 @@ sci_controller_set_interrupt_coalescence(struct isci_host *ihost,
 static void sci_controller_ready_state_enter(struct sci_base_state_machine *sm)
 {
 	struct isci_host *ihost = container_of(sm, typeof(*ihost), sm);
+	u32 val;
+
+	/* enable clock gating for power control of the scu unit */
+	val = readl(&ihost->smu_registers->clock_gating_control);
+	val &= ~(SMU_CGUCR_GEN_BIT(REGCLK_ENABLE) |
+		 SMU_CGUCR_GEN_BIT(TXCLK_ENABLE) |
+		 SMU_CGUCR_GEN_BIT(XCLK_ENABLE));
+	val |= SMU_CGUCR_GEN_BIT(IDLE_ENABLE);
+	writel(val, &ihost->smu_registers->clock_gating_control);
 
 	/* set the default interrupt coalescence number and timeout value. */
 	sci_controller_set_interrupt_coalescence(ihost, 0, 0);
diff --git a/drivers/scsi/isci/registers.h b/drivers/scsi/isci/registers.h
index eaa541afc7550a0b2c9d06a6ccae8fc61f1e3c30..7eb0ccd45fe679d8851539d10f28269667d0de1b 100644
--- a/drivers/scsi/isci/registers.h
+++ b/drivers/scsi/isci/registers.h
@@ -370,6 +370,27 @@ struct scu_iit_entry {
 		>> SMU_DEVICE_CONTEXT_CAPACITY_MAX_RNC_SHIFT \
 	)
 
+/* ***************************************************************************** */
+#define SMU_CLOCK_GATING_CONTROL_IDLE_ENABLE_SHIFT    (0)
+#define SMU_CLOCK_GATING_CONTROL_IDLE_ENABLE_MASK     (0x00000001)
+#define SMU_CLOCK_GATING_CONTROL_XCLK_ENABLE_SHIFT    (1)
+#define SMU_CLOCK_GATING_CONTROL_XCLK_ENABLE_MASK     (0x00000002)
+#define SMU_CLOCK_GATING_CONTROL_TXCLK_ENABLE_SHIFT   (2)
+#define SMU_CLOCK_GATING_CONTROL_TXCLK_ENABLE_MASK    (0x00000004)
+#define SMU_CLOCK_GATING_CONTROL_REGCLK_ENABLE_SHIFT  (3)
+#define SMU_CLOCK_GATING_CONTROL_REGCLK_ENABLE_MASK   (0x00000008)
+#define SMU_CLOCK_GATING_CONTROL_IDLE_TIMEOUT_SHIFT   (16)
+#define SMU_CLOCK_GATING_CONTROL_IDLE_TIMEOUT_MASK    (0x000F0000)
+#define SMU_CLOCK_GATING_CONTROL_FORCE_IDLE_SHIFT     (31)
+#define SMU_CLOCK_GATING_CONTROL_FORCE_IDLE_MASK      (0x80000000)
+#define SMU_CLOCK_GATING_CONTROL_RESERVED_MASK        (0x7FF0FFF0)
+
+#define SMU_CGUCR_GEN_VAL(name, value) \
+	SCU_GEN_VALUE(SMU_CLOCK_GATING_CONTROL_##name, value)
+
+#define SMU_CGUCR_GEN_BIT(name) \
+	SCU_GEN_BIT(SMU_CLOCK_GATING_CONTROL_##name)
+
 /* -------------------------------------------------------------------------- */
 
 #define SMU_CONTROL_STATUS_TASK_CONTEXT_RANGE_ENABLE_SHIFT      (0)
@@ -992,8 +1013,10 @@ struct smu_registers {
 	u32 mmr_address_window;
 /* 0x00A4 SMDW */
 	u32 mmr_data_window;
-	u32 reserved_A8;
-	u32 reserved_AC;
+/* 0x00A8 CGUCR */
+	u32 clock_gating_control;
+/* 0x00AC CGUPC */
+	u32 clock_gating_performance;
 /* A whole bunch of reserved space */
 	u32 reserved_Bx[4];
 	u32 reserved_Cx[4];