drm: extract helpers to compute new training values from sink request

Safe for the minor difference that the intel versions get an offset
into the link_status as an argument, both are the same again.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 1378b789bd10..9461e2f27316 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -255,3 +255,30 @@ bool drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE],
         return true;
 }
 EXPORT_SYMBOL(drm_dp_clock_recovery_ok);
+
+u8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE],
+                                     int lane)
+{
+        int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
+        int s = ((lane & 1) ?
+                 DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
+                 DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
+        u8 l = dp_link_status(link_status, i);
+
+        return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
+}
+EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage);
+
+u8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE],
+                                          int lane)
+{
+        int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
+        int s = ((lane & 1) ?
+                 DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
+                 DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
+        u8 l = dp_link_status(link_status, i);
+
+        return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
+}
+EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis);
+