diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index a6a2e00cc075..981e24120a87 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -2795,7 +2795,10 @@ tgl_dkl_phy_ddi_vswing_sequence(struct intel_encoder *encoder, int link_clock,
 	 * All registers programmed here use HIP_INDEX_REG 0 or 1
 	 */
 	for (ln = 0; ln < 2; ln++) {
-		I915_WRITE(HIP_INDEX_REG(tc_port), ln);
+		val = I915_READ(HIP_INDEX_REG(tc_port));
+		val &= ~HIP_INDEX_MASK(tc_port);
+		val |= HIP_INDEX_INDEX_VAL(tc_port, ln);
+		I915_WRITE(HIP_INDEX_REG(tc_port), val);
 
 		/* All the registers are RMW */
 		val = I915_READ(DKL_TX_DPCNTL0(tc_port));
@@ -3134,7 +3137,10 @@ tgl_phy_clock_gating(struct intel_digital_port *dig_port, bool enable)
 	       DKL_DP_MODE_CFG_GAONPWR_GATING;
 
 	for (ln = 0; ln < 2; ln++) {
-		I915_WRITE(HIP_INDEX_REG(tc_port), ln);
+		val = I915_READ(HIP_INDEX_REG(tc_port));
+		val &= ~HIP_INDEX_MASK(tc_port);
+		val |= HIP_INDEX_INDEX_VAL(tc_port, ln);
+		I915_WRITE(HIP_INDEX_REG(tc_port), val);
 
 		val = I915_READ(DKL_DP_MODE(tc_port));
 		if (enable)
@@ -3249,16 +3255,23 @@ static void tgl_program_dkl_dp_mode(struct intel_digital_port *intel_dig_port)
 	struct drm_i915_private *dev_priv = to_i915(intel_dig_port->base.base.dev);
 	enum port port = intel_dig_port->base.port;
 	enum tc_port tc_port = intel_port_to_tc(dev_priv, port);
-	u32 ln0, ln1, lane_mask, pin_mask;
+	u32 ln0, ln1, lane_mask, pin_mask, val;
 	int num_lanes;
 
 	if (tc_port == PORT_TC_NONE ||
 	    intel_dig_port->tc_mode == TC_PORT_TBT_ALT)
 		return;
 
-	I915_WRITE(HIP_INDEX_REG(tc_port), 0x0);
+	val = I915_READ(HIP_INDEX_REG(tc_port));
+	val &= ~HIP_INDEX_MASK(tc_port);
+	val |= HIP_INDEX_INDEX_VAL(tc_port, 0x0);
+	I915_WRITE(HIP_INDEX_REG(tc_port), val);
 	ln0 = I915_READ(DKL_DP_MODE(tc_port));
-	I915_WRITE(HIP_INDEX_REG(tc_port), 0x1);
+
+	val = I915_READ(HIP_INDEX_REG(tc_port));
+	val &= ~HIP_INDEX_MASK(tc_port);
+	val |= HIP_INDEX_INDEX_VAL(tc_port, 0x1);
+	I915_WRITE(HIP_INDEX_REG(tc_port), val);
 	ln1 = I915_READ(DKL_DP_MODE(tc_port));
 
 	num_lanes = intel_dig_port->dp.lane_count;
@@ -3327,9 +3340,16 @@ static void tgl_program_dkl_dp_mode(struct intel_digital_port *intel_dig_port)
 		return;
 	}
 
-	I915_WRITE(HIP_INDEX_REG(tc_port), 0x0);
+	val = I915_READ(HIP_INDEX_REG(tc_port));
+	val &= ~HIP_INDEX_MASK(tc_port);
+	val |= HIP_INDEX_INDEX_VAL(tc_port, 0x0);
+	I915_WRITE(HIP_INDEX_REG(tc_port), val);
 	I915_WRITE(DKL_DP_MODE(tc_port), ln0);
-	I915_WRITE(HIP_INDEX_REG(tc_port), 0x1);
+
+	val = I915_READ(HIP_INDEX_REG(tc_port));
+	val &= ~HIP_INDEX_MASK(tc_port);
+	val |= HIP_INDEX_INDEX_VAL(tc_port, 0x1);
+	I915_WRITE(HIP_INDEX_REG(tc_port), val);
 	I915_WRITE(DKL_DP_MODE(tc_port), ln1);
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
index afc9b609b63d..9304606c1c0a 100644
--- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
@@ -3109,7 +3109,10 @@ static bool dkl_pll_get_hw_state(struct drm_i915_private *dev_priv,
 	 * All registers read here have the same HIP_INDEX_REG even though
 	 * they are on different building blocks
 	 */
-	I915_WRITE(HIP_INDEX_REG(tc_port), 0x2);
+	val = I915_READ(HIP_INDEX_REG(tc_port));
+	val &= ~HIP_INDEX_MASK(tc_port);
+	val |= HIP_INDEX_INDEX_VAL(tc_port, 0x2);
+	I915_WRITE(HIP_INDEX_REG(tc_port), val);
 
 	hw_state->mg_refclkin_ctl = I915_READ(DKL_REFCLKIN_CTL(tc_port));
 	hw_state->mg_refclkin_ctl &= MG_REFCLKIN_CTL_OD_2_MUX_MASK;
@@ -3301,7 +3304,10 @@ static void dkl_pll_write(struct drm_i915_private *dev_priv,
 	 * All registers programmed here have the same HIP_INDEX_REG even
 	 * though on different building block
 	 */
-	I915_WRITE(HIP_INDEX_REG(tc_port), 0x2);
+	val = I915_READ(HIP_INDEX_REG(tc_port));
+	val &= ~HIP_INDEX_MASK(tc_port);
+	val |= HIP_INDEX_INDEX_VAL(tc_port, 0x2);
+	I915_WRITE(HIP_INDEX_REG(tc_port), val);
 
 	/* All the registers are RMW */
 	val = I915_READ(DKL_REFCLKIN_CTL(tc_port));
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 95a4232c8e0a..625f458e9b1c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -10265,6 +10265,9 @@ enum skl_power_gate {
 #define HIP_INDEX_REG(tc_port)	_MMIO((tc_port) < 4 \
 				      ? _HIP_INDEX_REG0 \
 				      : _HIP_INDEX_REG1)
+#define _HIP_INDEX_SHIFT(tc_port) (8 * ((tc_port) % 4))
+#define HIP_INDEX_MASK(tc_port) (0xff << _HIP_INDEX_SHIFT(tc_port))
+#define HIP_INDEX_INDEX_VAL(tc_port, index) ((index) << _HIP_INDEX_SHIFT(tc_port))
 
 /* BXT display engine PLL */
 #define BXT_DE_PLL_CTL			_MMIO(0x6d000)
