drm/i915/dsi: Configure transcoder operation for command mode.

Configure the transcoder to operate in TE GATE command mode
and  take TE events from GPIO.
Also disable the periodic command mode, that GOP would have
programmed.

v2: Disable util pin (Jani)
v3: Use intel_de_write (Jani)
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@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/20200312053841.2794-2-vandita.kulkarni@intel.com

drivers/gpu/drm/i915/display/icl_dsi.c

@@ -744,6 +744,18 @@ gen11_dsi_configure_transcoder(struct intel_encoder *encoder,
 				tmp |= VIDEO_MODE_SYNC_PULSE;
 				break;
 			}
+		} else {
+			/*
+			 * FIXME: Retrieve this info from VBT.
+			 * As per the spec when dsi transcoder is operating
+			 * in TE GATE mode, TE comes from GPIO
+			 * which is UTIL PIN for DSI 0.
+			 * Also this GPIO would not be used for other
+			 * purposes is an assumption.
+			 */
+			tmp &= ~OP_MODE_MASK;
+			tmp |= CMD_MODE_TE_GATE;
+			tmp |= TE_SOURCE_GPIO;
 		}
 
 		intel_de_write(dev_priv, DSI_TRANS_FUNC_CONF(dsi_trans), tmp);
@@ -1016,6 +1028,32 @@ static void gen11_dsi_setup_timeouts(struct intel_encoder *encoder,
 	}
 }
 
+static void gen11_dsi_config_util_pin(struct intel_encoder *encoder,
+				      bool enable)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
+	u32 tmp;
+
+	/*
+	 * used as TE i/p for DSI0,
+	 * for dual link/DSI1 TE is from slave DSI1
+	 * through GPIO.
+	 */
+	if (is_vid_mode(intel_dsi) || (intel_dsi->ports & BIT(PORT_B)))
+		return;
+
+	tmp = intel_de_read(dev_priv, UTIL_PIN_CTL);
+
+	if (enable) {
+		tmp |= UTIL_PIN_DIRECTION_INPUT;
+		tmp |= UTIL_PIN_ENABLE;
+	} else {
+		tmp &= ~UTIL_PIN_ENABLE;
+	}
+	intel_de_write(dev_priv, UTIL_PIN_CTL, tmp);
+}
+
 static void
 gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder,
 			      const struct intel_crtc_state *crtc_state)
@@ -1037,6 +1075,9 @@ gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder,
 	/* setup D-PHY timings */
 	gen11_dsi_setup_dphy_timings(encoder, crtc_state);
 
+	/* Since transcoder is configured to take events from GPIO */
+	gen11_dsi_config_util_pin(encoder, true);
+
 	/* step 4h: setup DSI protocol timeouts */
 	gen11_dsi_setup_timeouts(encoder, crtc_state);
 
@@ -1180,6 +1221,15 @@ static void gen11_dsi_deconfigure_trancoder(struct intel_encoder *encoder)
 	enum transcoder dsi_trans;
 	u32 tmp;
 
+	/* disable periodic update mode */
+	if (is_cmd_mode(intel_dsi)) {
+		for_each_dsi_port(port, intel_dsi->ports) {
+			tmp = intel_de_read(dev_priv, DSI_CMD_FRMCTL(port));
+			tmp &= ~DSI_PERIODIC_FRAME_UPDATE_ENABLE;
+			intel_de_write(dev_priv, DSI_CMD_FRMCTL(port), tmp);
+		}
+	}
+
 	/* put dsi link in ULPS */
 	for_each_dsi_port(port, intel_dsi->ports) {
 		dsi_trans = dsi_port_to_transcoder(port);
@@ -1286,6 +1336,8 @@ static void gen11_dsi_disable(struct intel_encoder *encoder,
 	/* step3: disable port */
 	gen11_dsi_disable_port(encoder);
 
+	gen11_dsi_config_util_pin(encoder, false);
+
 	/* step4: disable IO power */
 	gen11_dsi_disable_io_power(encoder);
 }