drm/i915/icl: Configure lane sequencing of combo phy transmitter

This patch set the loadgen select and latency optimization for
aux and transmit lanes of combo phy transmitters. It will be
used for MIPI DSI HS operations.

v2: Rebase
v3: Add empty line to make code more legible (Ville).
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1537095223-5184-2-git-send-email-madhav.chauhan@intel.com

drivers/gpu/drm/i915/icl_dsi.c

@@ -105,10 +105,49 @@ static void gen11_dsi_power_up_lanes(struct intel_encoder *encoder)
 	}
 }
 
+static void gen11_dsi_config_phy_lanes_sequence(struct intel_encoder *encoder)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+	enum port port;
+	u32 tmp;
+	int lane;
+
+	/* Step 4b(i) set loadgen select for transmit and aux lanes */
+	for_each_dsi_port(port, intel_dsi->ports) {
+		tmp = I915_READ(ICL_PORT_TX_DW4_AUX(port));
+		tmp &= ~LOADGEN_SELECT;
+		I915_WRITE(ICL_PORT_TX_DW4_AUX(port), tmp);
+		for (lane = 0; lane <= 3; lane++) {
+			tmp = I915_READ(ICL_PORT_TX_DW4_LN(port, lane));
+			tmp &= ~LOADGEN_SELECT;
+			if (lane != 2)
+				tmp |= LOADGEN_SELECT;
+			I915_WRITE(ICL_PORT_TX_DW4_LN(port, lane), tmp);
+		}
+	}
+
+	/* Step 4b(ii) set latency optimization for transmit and aux lanes */
+	for_each_dsi_port(port, intel_dsi->ports) {
+		tmp = I915_READ(ICL_PORT_TX_DW2_AUX(port));
+		tmp &= ~FRC_LATENCY_OPTIM_MASK;
+		tmp |= FRC_LATENCY_OPTIM_VAL(0x5);
+		I915_WRITE(ICL_PORT_TX_DW2_AUX(port), tmp);
+		tmp = I915_READ(ICL_PORT_TX_DW2_LN0(port));
+		tmp &= ~FRC_LATENCY_OPTIM_MASK;
+		tmp |= FRC_LATENCY_OPTIM_VAL(0x5);
+		I915_WRITE(ICL_PORT_TX_DW2_GRP(port), tmp);
+	}
+
+}
+
 static void gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder)
 {
 	/* step 4a: power up all lanes of the DDI used by DSI */
 	gen11_dsi_power_up_lanes(encoder);
+
+	/* step 4b: configure lane sequencing of the Combo-PHY transmitters */
+	gen11_dsi_config_phy_lanes_sequence(encoder);
 }
 
 static void __attribute__((unused))