[PATCH] drm/i915/pps: Disable DPLS_GATING around pps sequence

[Suraj Kandpal <suraj.kandpal@intel.com>]

Disable bit 29 of SCLKGATE_DIS register around pps sequence
when we turn panel power on.

--v2
-Squash two commit together [Jani]
-Use IS_DISPLAY_VER [Jani]
-Fix multiline comment [Jani]

Bspec: 49304
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_pps.c | 12 ++++++++++++
 drivers/gpu/drm/i915/i915_reg.h          |  4 ++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
index 3078dfac7817..2b2cead22a7d 100644
--- a/drivers/gpu/drm/i915/display/intel_pps.c
+++ b/drivers/gpu/drm/i915/display/intel_pps.c
@@ -948,6 +948,14 @@ void intel_pps_on_unlocked(struct intel_dp *intel_dp)
 		intel_de_posting_read(dev_priv, pp_ctrl_reg);
 	}
 
+	/*
+	 * WA: 16023567976
+	 * Disable DPLS gating around power sequence.
+	 */
+	if (IS_DISPLAY_VER(dev_priv, 12, 14))
+		intel_de_rmw(dev_priv, SCLKGATE_DIS,
+			     DPLS_GATING_DISABLE, 1);
+
 	pp |= PANEL_POWER_ON;
 	if (!IS_IRONLAKE(dev_priv))
 		pp |= PANEL_POWER_RESET;
@@ -958,6 +966,10 @@ void intel_pps_on_unlocked(struct intel_dp *intel_dp)
 	wait_panel_on(intel_dp);
 	intel_dp->pps.last_power_on = jiffies;
 
+	if (IS_DISPLAY_VER(dev_priv, 12, 14))
+		intel_de_rmw(dev_priv, SCLKGATE_DIS,
+			     DPLS_GATING_DISABLE, 0);
+
 	if (IS_IRONLAKE(dev_priv)) {
 		pp |= PANEL_POWER_RESET; /* restore panel reset bit */
 		intel_de_write(dev_priv, pp_ctrl_reg, pp);
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3f34efcd7d6c..1c2cd6cc254f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6250,6 +6250,10 @@ enum skl_power_gate {
 #define  SFUSE_STRAP_DDIC_DETECTED	(1 << 1)
 #define  SFUSE_STRAP_DDID_DETECTED	(1 << 0)
 
+/* SCLKGATE_DIS */
+#define SCLKGATE_DIS			_MMIO(0xc2020)
+#define  DPLS_GATING_DISABLE		REG_BIT(29)
+
 #define WM_MISC				_MMIO(0x45260)
 #define  WM_MISC_DATA_PARTITION_5_6	(1 << 0)
 
-- 
2.43.2