mx6: clock: Introduce disable_ipu_clock()

Introduce disable_ipu_clock(). This is done in preparation for
configuring the NoC registers on i.MX6QP in SPL.

Afer the NoC registers are set the IPU clocks can be disabled.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/mx6/clock.c b/arch/arm/mach-imx/mx6/clock.c
index 9d432b4..6a9e673 100644
--- a/arch/arm/mach-imx/mx6/clock.c
+++ b/arch/arm/mach-imx/mx6/clock.c
@@ -1287,6 +1287,18 @@
 		setbits_le32(&mxc_ccm->CCGR3, MXC_CCM_CCGR3_IPU2_IPU_MASK);
 	}
 }
+
+void disable_ipu_clock(void)
+{
+	struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	clrbits_le32(&mxc_ccm->CCGR3, MXC_CCM_CCGR3_IPU1_IPU_MASK);
+
+	if (is_mx6dqp()) {
+		clrbits_le32(&mxc_ccm->CCGR6, MXC_CCM_CCGR6_PRG_CLK0_MASK);
+		clrbits_le32(&mxc_ccm->CCGR3, MXC_CCM_CCGR3_IPU2_IPU_MASK);
+	}
+}
 #endif
 
 #ifndef CONFIG_SPL_BUILD