[Intel-gfx] [PATCH 1/2] drm/i915/skl: Support for edp low_vswing param in vbt

[Sonika Jindal]

v2: Adding VBT version check for low_vswing field, and correcting parsing

v3: (Damien)
 - Restrain the scope of the 'vswing' variable
 - Use the more idiomatic "ev_priv->vbt.edp_low_vswing = vswing == 0;"
  instead of if (foo) var = true; else var = false;
 - Shorten edp_vswing_premph_setting to edp_vswing_premph to fit in 80 chars
 - Add the version from which the edp_vswing_premph field is valid in the
  struct definition

Reviewed-by: Satheeshakrishna M <satheeshakrishna.m at intel.com> (v2)
Signed-off-by: Sonika Jindal <sonika.jindal at intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h   |    1 +
 drivers/gpu/drm/i915/intel_bios.c |    7 +++++++
 drivers/gpu/drm/i915/intel_bios.h |    1 +
 3 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c9d2b00..cbe668a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1466,6 +1466,7 @@ struct intel_vbt_data {
 	bool edp_initialized;
 	bool edp_support;
 	int edp_bpp;
+	bool edp_low_vswing;
 	struct edp_power_seq edp_pps;
 
 	struct {
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 3f17825..c684085 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -662,6 +662,13 @@ parse_edp(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
 			      edp_link_params->vswing);
 		break;
 	}
+
+	if (bdb->version >= 173) {
+		uint8_t vswing;
+
+		vswing = (edp->edp_vswing_preemph >> (panel_type * 4)) & 0xF;
+		dev_priv->vbt.edp_low_vswing = vswing == 0;
+	}
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index a6a8710..6afd5be 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -554,6 +554,7 @@ struct bdb_edp {
 	/* ith bit indicates enabled/disabled for (i+1)th panel */
 	u16 edp_s3d_feature;
 	u16 edp_t3_optimization;
+	u64 edp_vswing_preemph;		/* v173 */
 } __packed;
 
 struct psr_table {
-- 
1.7.10.4