[PATCH 13/20] drm/i915/dp: use generic poll_timeout_us() 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.nik...@intel.com>
---
 .../drm/i915/display/intel_dp_link_training.c   | 17 +++++++++++++----
 1 file changed, 13 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 9d14b4e59545..27f3716bdc1f 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>
@@ -1135,15 +1136,19 @@ 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;
 
        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 = poll_timeout_us(ret = 
intel_dp_128b132b_intra_hop(intel_dp, crtc_state),
+                                     ret == 0,
+                                     500, 500 * 1000, false);
+               if (ret)
+                       lt_dbg(intel_dp, DP_PHY_DPRX, "128b/132b intra-hop not 
clearing\n");
        }
 
        intel_hpd_unblock(encoder);
@@ -1581,8 +1586,12 @@ 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 = poll_timeout_us(ret = intel_dp_128b132b_intra_hop(intel_dp, 
crtc_state),
+                             ret == 0,
+                             500, 500 * 1000, false);
+       if (ret) {
                lt_err(intel_dp, DP_PHY_DPRX, "128b/132b intra-hop not 
clear\n");
                goto out;
        }
-- 
2.47.2