drm/i915/crt: Populate connector->ddc

Populate connector->ddc, and thus create the "ddc" symlink
in sysfs for analog VGA connectors.

As a bonus we can replace a bunch of intel_gmbus_get_adapter()
lookups with just the connector->ddc pointer. Sadly one extra
lookup still remains due to the g4x DVI-I shenanigans. We could
perhaps consider borrowing the ddc proxy idea from SDVO to deal
with that in a perhaps nicer way, but can't really be bothered
right now at least. Also not sure exposing such a dual ddc bus
to userspace would be quite wise.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829113920.13713-6-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -652,11 +652,9 @@ static bool intel_crt_detect_ddc(struct drm_connector *connector)
 	struct intel_crt *crt = intel_attached_crt(to_intel_connector(connector));
 	struct drm_i915_private *dev_priv = to_i915(crt->base.base.dev);
 	const struct drm_edid *drm_edid;
-	struct i2c_adapter *ddc;
 	bool ret = false;
 
-	ddc = intel_gmbus_get_adapter(dev_priv, dev_priv->display.vbt.crt_ddc_pin);
-	drm_edid = intel_crt_get_edid(connector, ddc);
+	drm_edid = intel_crt_get_edid(connector, connector->ddc);
 
 	if (drm_edid) {
 		/*
@@ -922,8 +920,7 @@ static int intel_crt_get_modes(struct drm_connector *connector)
 	wakeref = intel_display_power_get(dev_priv,
 					  intel_encoder->power_domain);
 
-	ddc = intel_gmbus_get_adapter(dev_priv, dev_priv->display.vbt.crt_ddc_pin);
-	ret = intel_crt_ddc_get_modes(connector, ddc);
+	ret = intel_crt_ddc_get_modes(connector, connector->ddc);
 	if (ret || !IS_G4X(dev_priv))
 		goto out;
 
@@ -987,6 +984,7 @@ void intel_crt_init(struct drm_i915_private *dev_priv)
 	struct intel_crt *crt;
 	struct intel_connector *intel_connector;
 	i915_reg_t adpa_reg;
+	u8 ddc_pin;
 	u32 adpa;
 
 	if (HAS_PCH_SPLIT(dev_priv))
@@ -1023,10 +1021,14 @@ void intel_crt_init(struct drm_i915_private *dev_priv)
 		return;
 	}
 
+	ddc_pin = dev_priv->display.vbt.crt_ddc_pin;
+
 	connector = &intel_connector->base;
 	crt->connector = intel_connector;
-	drm_connector_init(&dev_priv->drm, &intel_connector->base,
-			   &intel_crt_connector_funcs, DRM_MODE_CONNECTOR_VGA);
+	drm_connector_init_with_ddc(&dev_priv->drm, connector,
+				    &intel_crt_connector_funcs,
+				    DRM_MODE_CONNECTOR_VGA,
+				    intel_gmbus_get_adapter(dev_priv, ddc_pin));
 
 	drm_encoder_init(&dev_priv->drm, &crt->base.base, &intel_crt_enc_funcs,
 			 DRM_MODE_ENCODER_DAC, "CRT");