On Wed, 2022-06-15 at 13:50 +0800, CK Hu wrote:
Hi, Bo-Chen:
On Fri, 2022-06-10 at 18:55 +0800, Bo-Chen Chen wrote:
From: Markus Schneider-Pargmann msp@baylibre.com
This patch adds a embedded displayport driver for the MediaTek mt8195 SoC.
It supports the MT8195, the embedded DisplayPort units. It offers DisplayPort 1.4 with up to 4 lanes.
The driver creates a child device for the phy. The child device will never exist without the parent being active. As they are sharing a register range, the parent passes a regmap pointer to the child so that both can work with the same register range. The phy driver sets device data that is read by the parent to get the phy device that can be used to control the phy properties.
This driver is based on an initial version by Jitao shi jitao.shi@mediatek.com
Signed-off-by: Markus Schneider-Pargmann msp@baylibre.com Signed-off-by: Guillaume Ranquet granquet@baylibre.com [Bo-Chen: Cleanup the drivers and modify comments from reviewers] Signed-off-by: Bo-Chen Chen rex-bc.chen@mediatek.com
[snip]
+static int mtk_dp_train_flow(struct mtk_dp *mtk_dp, u8 target_link_rate,
u8 target_lane_count)+{
- u8 lane_adjust[2] = {};
- bool pass_tps1 = false;
- bool pass_tps2_3 = false;
- int train_retries;
- int status_control;
- int iteration_count;
- int ret;
- u8 prev_lane_adjust;
- drm_dp_dpcd_writeb(&mtk_dp->aux, DP_LINK_BW_SET,
target_link_rate);
- drm_dp_dpcd_writeb(&mtk_dp->aux, DP_LANE_COUNT_SET,
target_lane_count |DP_LANE_COUNT_ENHANCED_FRAME_EN);
- if (mtk_dp->train_info.sink_ssc)
drm_dp_dpcd_writeb(&mtk_dp->aux, DP_DOWNSPREAD_CTRL,DP_SPREAD_AMP_0_5);- train_retries = 0;
- status_control = 0;
- iteration_count = 1;
- prev_lane_adjust = 0xFF;
- mtk_dp_set_lanes(mtk_dp, target_lane_count / 2);
- ret = mtk_dp_phy_configure(mtk_dp, target_link_rate,
target_lane_count);
- if (ret)
return -EINVAL;- dev_dbg(mtk_dp->dev,
"Link train target_link_rate = 0x%x, target_lane_count= 0x%x\n",
target_link_rate, target_lane_count);- do {
train_retries++;if (!mtk_dp->train_info.cable_plugged_in ||mtk_dp->train_info.irq_sta.hpd_disconnect) {return -ENODEV;}if (mtk_dp->train_state < MTK_DP_TRAIN_STATE_TRAINING)This checking would never be true, so remove it.
Hello CK,
ok, I will do this.
return -EAGAIN;if (!pass_tps1) {ret = mtk_dp_train_tps_1(mtk_dp,target_lane_count,
&iteration_count,lane_adjust,
&status_control,&prev_lane_adjust);if (!ret) {pass_tps1 = true;train_retries = 0;} else if (ret == -EINVAL) {break;}} else {ret = mtk_dp_train_tps_2_3(mtk_dp,target_link_rate,
target_lane_count,&iteration_count,lane_adjust,&status_control,
&prev_lane_adjust);if (!ret) {pass_tps2_3 = true;break;} else if (ret == -EINVAL) {break;}}drm_dp_dpcd_read(&mtk_dp->aux,DP_ADJUST_REQUEST_LANE0_1,
lane_adjust, sizeof(lane_adjust));mtk_dp_train_update_swing_pre(mtk_dp,target_lane_count,
lane_adjust);- } while (train_retries < MTK_DP_TRAIN_RETRY_LIMIT &&
iteration_count < MTK_DP_TRAIN_MAX_ITERATIONS);mtk_dp_train_tps_1() & mtk_dp_train_tps_2_3() would only be called once and never be called twice, so remove this loop.
Regards, CK
- drm_dp_dpcd_writeb(&mtk_dp->aux, DP_TRAINING_PATTERN_SET,
DP_TRAINING_PATTERN_DISABLE);- ret = mtk_dp_train_set_pattern(mtk_dp, 0);
- if (ret)
return -EINVAL;- if (!pass_tps2_3)
return -ETIMEDOUT;- mtk_dp->train_info.link_rate = target_link_rate;
- mtk_dp->train_info.lane_count = target_lane_count;
- mtk_dp_training_set_scramble(mtk_dp, true);
- drm_dp_dpcd_writeb(&mtk_dp->aux, DP_LANE_COUNT_SET,
target_lane_count |DP_LANE_COUNT_ENHANCED_FRAME_EN);- mtk_dp_set_enhanced_frame_mode(mtk_dp, true);
- return ret;
+}