[PATCH 12/18] drm/i915/dp: use generic read_poll_timeout() instead of wait_for() in link training

[Jani Nikula]

Prefer generic poll helpers over i915 custom helpers.

The functional change is losing the exponentially growing sleep of
wait_for(), which used to be 10, 20, 40, ..., 640, and 1280 us.

Use an arbitrary constant 500 us sleep instead. The timeout remains at
500 ms.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 .../drm/i915/display/intel_dp_link_training.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index a479b63112ea..d1d11de366b0 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -22,6 +22,7 @@
  */
 
 #include <linux/debugfs.h>
+#include <linux/iopoll.h>
 
 #include <drm/display/drm_dp_helper.h>
 #include <drm/drm_print.h>
@@ -1127,6 +1128,7 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp,
 {
 	struct intel_display *display = to_intel_display(intel_dp);
 	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
+	int ret;
 
 	intel_dp->link.active = true;
 
@@ -1134,9 +1136,13 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp,
 	intel_dp_program_link_training_pattern(intel_dp, crtc_state, DP_PHY_DPRX,
 					       DP_TRAINING_PATTERN_DISABLE);
 
-	if (intel_dp_is_uhbr(crtc_state) &&
-	    wait_for(intel_dp_128b132b_intra_hop(intel_dp, crtc_state) == 0, 500)) {
-		lt_dbg(intel_dp, DP_PHY_DPRX, "128b/132b intra-hop not clearing\n");
+	if (intel_dp_is_uhbr(crtc_state)) {
+		ret = read_poll_timeout(intel_dp_128b132b_intra_hop, ret,
+					ret == 0,
+					500, 500 * 1000, false,
+					intel_dp, crtc_state);
+		if (ret)
+			lt_dbg(intel_dp, DP_PHY_DPRX, "128b/132b intra-hop not clearing\n");
 	}
 
 	intel_hpd_unblock(encoder);
@@ -1574,8 +1580,13 @@ intel_dp_128b132b_link_train(struct intel_dp *intel_dp,
 			     int lttpr_count)
 {
 	bool passed = false;
+	int ret;
 
-	if (wait_for(intel_dp_128b132b_intra_hop(intel_dp, crtc_state) == 0, 500)) {
+	ret = read_poll_timeout(intel_dp_128b132b_intra_hop, ret,
+				ret == 0,
+				500, 500 * 1000, false,
+				intel_dp, crtc_state);
+	if (ret) {
 		lt_err(intel_dp, DP_PHY_DPRX, "128b/132b intra-hop not clear\n");
 		goto out;
 	}
-- 
2.39.5