drm/i915: Set invert bit for hpd based on VBT

This patch sets the invert bit for hpd detection for each port
based on VBT configuration. Since each AOB can be designed to
depend on invert bit or not, it is expected if an AOB requires
invert bit, the user will set respective bit in VBT.

v2: Separated VBT parsing from the rest of the logic. (Jani)

v3: Moved setting invert bit logic to bxt_hpd_irq_setup()
    and changed its logic to avoid looping twice. (Ville)

v4: Changed the logic to mask out the bits first and then
    set them to remove need of temporary variable. (Ville)

v5: Moved defines to existing set of defines for the register
    and added required breaks. (Ville)

Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[Jani: fixed some checkpatch noise, added kernel-doc.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459420907-11383-2-git-send-email-shubhangi.shrivastava@intel.com

1 files changed, 44 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 4222f52d95f8..eb756c41d9e1 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1598,3 +1598,47 @@ bool intel_bios_is_dsi_present(struct drm_i915_private *dev_priv,
 
 	return false;
 }
+
+/**
+ * intel_bios_is_port_hpd_inverted - is HPD inverted for %port
+ * @dev_priv:	i915 device instance
+ * @port:	port to check
+ *
+ * Return true if HPD should be inverted for %port.
+ */
+bool
+intel_bios_is_port_hpd_inverted(struct drm_i915_private *dev_priv,
+				enum port port)
+{
+	int i;
+
+	if (WARN_ON_ONCE(!IS_BROXTON(dev_priv)))
+		return false;
+
+	for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
+		if (!dev_priv->vbt.child_dev[i].common.hpd_invert)
+			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;
+		default:
+			break;
+		}
+	}
+
+	return false;
+}