drm/i915: Parse VBT data for lspcon

Many GEN9 boards come with on-board lspcon cards.
Fot these boards, VBT configuration should properly point out
if a particular port contains lspcon device, so that driver can
initialize it properly.

This patch adds a utility function, which checks the VBT flag
for lspcon bit, and tells us if a port is configured to have a
lspcon device or not.

V2: Fixed review comments from Ville
- Do not forget PORT_D while checking lspcon for GEN9

V3: Addressed review comments from Rodrigo
- Create a HAS_LSPCON() macro for better use case handling.
- Do not dump warnings for non-gen-9 platforms, it will be noise.

V4: Rebase
V5: Rebase
V6: Pass dev_priv to HAS_LSPCON() macro

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1476455212-27893-4-git-send-email-shashank.sharma@intel.com

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 83667e8cdd6b..32e1def6a9ef 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1763,3 +1763,52 @@ intel_bios_is_port_hpd_inverted(struct drm_i915_private *dev_priv,
 
         return false;
 }
+
+/**
+ * intel_bios_is_lspcon_present - if LSPCON is attached on %port
+ * @dev_priv:   i915 device instance
+ * @port:       port to check
+ *
+ * Return true if LSPCON is present on this port
+ */
+bool
+intel_bios_is_lspcon_present(struct drm_i915_private *dev_priv,
+                                enum port port)
+{
+        int i;
+
+        if (!HAS_LSPCON(dev_priv))
+                return false;
+
+        for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
+                if (!dev_priv->vbt.child_dev[i].common.lspcon)
+                        continue;
+
+                switch (dev_priv->vbt.child_dev[i].common.dvo_port) {
+                case DVO_PORT_DPA:
+                case DVO_PORT_HDMIA:
+                        if (port == PORT_A)
+                                return true;
+                        break;
+                case DVO_PORT_DPB:
+                case DVO_PORT_HDMIB:
+                        if (port == PORT_B)
+                                return true;
+                        break;
+                case DVO_PORT_DPC:
+                case DVO_PORT_HDMIC:
+                        if (port == PORT_C)
+                                return true;
+                        break;
+                case DVO_PORT_DPD:
+                case DVO_PORT_HDMID:
+                        if (port == PORT_D)
+                                return true;
+                        break;
+                default:
+                        break;
+                }
+        }
+
+        return false;
+}