diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 4511f01..9245572 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1799,6 +1799,11 @@
 #define CLKGATE_DIS_PSL_EXT(pipe) \
 	_MMIO_PIPE(pipe, _CLKGATE_DIS_PSL_EXT_A, _CLKGATE_DIS_PSL_EXT_B)
 
+/* DDI Buffer Control */
+#define _DDI_CLK_VALFREQ_A		0x64030
+#define _DDI_CLK_VALFREQ_B		0x64130
+#define DDI_CLK_VALFREQ(port)		_MMIO_PORT(port, _DDI_CLK_VALFREQ_A, _DDI_CLK_VALFREQ_B)
+
 /*
  * Display engine regs
  */