[PATCH v2 10/32] drm/i915/xe3p_lpd: Wait for AUX channel power status

[Gustavo Sousa <gustavo.sousa@intel.com>]

The LT PHY in Xe3p_LPD allows polling for the AUX channel power status
to verify completion of power up and down. As such, let's use that field
to have a more precise waiting time instead of a fixed one.

Bspec: 68967
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
---
 .../drm/i915/display/intel_display_power_well.c    | 32 +++++++++++++++++-----
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_power_well.c b/drivers/gpu/drm/i915/display/intel_display_power_well.c
index 5e88b930f5aa..ba2552adb58b 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power_well.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power_well.c
@@ -1858,23 +1858,41 @@ static void xelpdp_aux_power_well_enable(struct intel_display *display,
 		     XELPDP_DP_AUX_CH_CTL_POWER_REQUEST,
 		     XELPDP_DP_AUX_CH_CTL_POWER_REQUEST);
 
-	/*
-	 * The power status flag cannot be used to determine whether aux
-	 * power wells have finished powering up.  Instead we're
-	 * expected to just wait a fixed 600us after raising the request
-	 * bit.
-	 */
-	usleep_range(600, 1200);
+	if (DISPLAY_VER(display) >= 35) {
+		if (intel_de_wait_for_set(display, XELPDP_DP_AUX_CH_CTL(display, aux_ch),
+					  XELPDP_DP_AUX_CH_CTL_POWER_STATUS, 1))
+			drm_warn(display->drm,
+				 "Timeout waiting for PHY %c AUX channel power to be up\n",
+				 phy_name(phy));
+	} else {
+		/*
+		 * The power status flag cannot be used to determine whether aux
+		 * power wells have finished powering up.  Instead we're
+		 * expected to just wait a fixed 600us after raising the request
+		 * bit.
+		 */
+		usleep_range(600, 1200);
+	}
 }
 
 static void xelpdp_aux_power_well_disable(struct intel_display *display,
 					  struct i915_power_well *power_well)
 {
 	enum aux_ch aux_ch = i915_power_well_instance(power_well)->xelpdp.aux_ch;
+	enum phy phy = icl_aux_pw_to_phy(display, power_well);
 
 	intel_de_rmw(display, XELPDP_DP_AUX_CH_CTL(display, aux_ch),
 		     XELPDP_DP_AUX_CH_CTL_POWER_REQUEST,
 		     0);
+
+	if (DISPLAY_VER(display) >= 35) {
+		if (intel_de_wait_for_clear(display, XELPDP_DP_AUX_CH_CTL(display, aux_ch),
+					    XELPDP_DP_AUX_CH_CTL_POWER_STATUS, 1))
+			drm_warn(display->drm,
+				 "Timeout waiting for PHY %c AUX channel power to be down\n",
+				 phy_name(phy));
+	}
+
 	usleep_range(10, 30);
 }
 

-- 
2.51.0