drm/msm/dp: allow voltage swing / pre emphasis of 3

Both dp_link_adjust_levels() and dp_ctrl_update_vx_px() limit swing and
pre-emphasis to 2, while the real maximum value for the sum of the
voltage swing and pre-emphasis is 3. Fix the DP code to remove this
limitation.

Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Tested-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/577006/
Link: https://lore.kernel.org/r/20240203-dp-swing-3-v1-1-6545e1706196@linaro.org

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index c4dda1faef677071acd254dcb8942924c1d94060..112c7e54fc7a6c57fdf6869b3c5c27bbdec63e2b 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1052,14 +1052,14 @@ static int dp_ctrl_update_vx_px(struct dp_ctrl_private *ctrl)
        if (ret)
                return ret;
 
-       if (voltage_swing_level >= DP_TRAIN_VOLTAGE_SWING_MAX) {
+       if (voltage_swing_level >= DP_TRAIN_LEVEL_MAX) {
                drm_dbg_dp(ctrl->drm_dev,
                                "max. voltage swing level reached %d\n",
                                voltage_swing_level);
                max_level_reached |= DP_TRAIN_MAX_SWING_REACHED;
        }
 
-       if (pre_emphasis_level >= DP_TRAIN_PRE_EMPHASIS_MAX) {
+       if (pre_emphasis_level >= DP_TRAIN_LEVEL_MAX) {
                drm_dbg_dp(ctrl->drm_dev,
                                "max. pre-emphasis level reached %d\n",
                                pre_emphasis_level);
@@ -1150,7 +1150,7 @@ static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl,
                }
 
                if (ctrl->link->phy_params.v_level >=
-                       DP_TRAIN_VOLTAGE_SWING_MAX) {
+                       DP_TRAIN_LEVEL_MAX) {
                        DRM_ERROR_RATELIMITED("max v_level reached\n");
                        return -EAGAIN;
                }

diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
index 49dfac1fd1ef2158626f4a417b22e810414b76f9..ea911d9244be7e5850861cefeabd61304e0419cd 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_link.c
+++ b/drivers/gpu/drm/msm/dp/dp_link.c
@@ -1109,6 +1109,7 @@ int dp_link_get_colorimetry_config(struct dp_link *dp_link)
 int dp_link_adjust_levels(struct dp_link *dp_link, u8 *link_status)
 {
        int i;
+       u8 max_p_level;
        int v_max = 0, p_max = 0;
        struct dp_link_private *link;
 
@@ -1140,30 +1141,29 @@ int dp_link_adjust_levels(struct dp_link *dp_link, u8 *link_status)
         * Adjust the voltage swing and pre-emphasis level combination to within
         * the allowable range.
         */
-       if (dp_link->phy_params.v_level > DP_TRAIN_VOLTAGE_SWING_MAX) {
+       if (dp_link->phy_params.v_level > DP_TRAIN_LEVEL_MAX) {
                drm_dbg_dp(link->drm_dev,
                        "Requested vSwingLevel=%d, change to %d\n",
                        dp_link->phy_params.v_level,
-                       DP_TRAIN_VOLTAGE_SWING_MAX);
-               dp_link->phy_params.v_level = DP_TRAIN_VOLTAGE_SWING_MAX;
+                       DP_TRAIN_LEVEL_MAX);
+               dp_link->phy_params.v_level = DP_TRAIN_LEVEL_MAX;
        }
 
-       if (dp_link->phy_params.p_level > DP_TRAIN_PRE_EMPHASIS_MAX) {
+       if (dp_link->phy_params.p_level > DP_TRAIN_LEVEL_MAX) {
                drm_dbg_dp(link->drm_dev,
                        "Requested preEmphasisLevel=%d, change to %d\n",
                        dp_link->phy_params.p_level,
-                       DP_TRAIN_PRE_EMPHASIS_MAX);
-               dp_link->phy_params.p_level = DP_TRAIN_PRE_EMPHASIS_MAX;
+                       DP_TRAIN_LEVEL_MAX);
+               dp_link->phy_params.p_level = DP_TRAIN_LEVEL_MAX;
        }
 
-       if ((dp_link->phy_params.p_level > DP_TRAIN_PRE_EMPHASIS_LVL_1)
-               && (dp_link->phy_params.v_level ==
-                       DP_TRAIN_VOLTAGE_SWING_LVL_2)) {
+       max_p_level = DP_TRAIN_LEVEL_MAX - dp_link->phy_params.v_level;
+       if (dp_link->phy_params.p_level > max_p_level) {
                drm_dbg_dp(link->drm_dev,
                        "Requested preEmphasisLevel=%d, change to %d\n",
                        dp_link->phy_params.p_level,
-                       DP_TRAIN_PRE_EMPHASIS_LVL_1);
-               dp_link->phy_params.p_level = DP_TRAIN_PRE_EMPHASIS_LVL_1;
+                       max_p_level);
+               dp_link->phy_params.p_level = max_p_level;
        }
 
        drm_dbg_dp(link->drm_dev, "adjusted: v_level=%d, p_level=%d\n",

diff --git a/drivers/gpu/drm/msm/dp/dp_link.h b/drivers/gpu/drm/msm/dp/dp_link.h
index 83da170bc56bfe3516b23c90b7db9d75813fcf95..42aed9c90b7320ebe2f2ff49f1b78cc0fd220d38 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_link.h
+++ b/drivers/gpu/drm/msm/dp/dp_link.h
@@ -19,19 +19,7 @@ struct dp_link_info {
        unsigned long capabilities;
 };
 
-enum dp_link_voltage_level {
-       DP_TRAIN_VOLTAGE_SWING_LVL_0    = 0,
-       DP_TRAIN_VOLTAGE_SWING_LVL_1    = 1,
-       DP_TRAIN_VOLTAGE_SWING_LVL_2    = 2,
-       DP_TRAIN_VOLTAGE_SWING_MAX      = DP_TRAIN_VOLTAGE_SWING_LVL_2,
-};
-
-enum dp_link_preemaphasis_level {
-       DP_TRAIN_PRE_EMPHASIS_LVL_0     = 0,
-       DP_TRAIN_PRE_EMPHASIS_LVL_1     = 1,
-       DP_TRAIN_PRE_EMPHASIS_LVL_2     = 2,
-       DP_TRAIN_PRE_EMPHASIS_MAX       = DP_TRAIN_PRE_EMPHASIS_LVL_2,
-};
+#define DP_TRAIN_LEVEL_MAX     3
 
 struct dp_link_test_video {
        u32 test_video_pattern;