Hi, Bo-Chen:

On Wed, 2022-07-27 at 12:50 +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 [off-list ref]

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Guillaume Ranquet <redacted>
Signed-off-by: Bo-Chen Chen <redacted>
---

[snip]

+
+static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
+{
+	struct mtk_dp *mtk_dp = dev;
+
+	if (mtk_dp->train_info.hpd_inerrupt) {

When the thread is running, mtk_dp->train_info.hpd_inerrupt would be
true. So this checking is redundant.

+		dev_dbg(mtk_dp->dev, "MTK_DP_HPD_INTERRUPT\n");
+		mtk_dp->train_info.hpd_inerrupt = false;
+		mtk_dp_hpd_sink_event(mtk_dp);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mtk_dp_hpd_event(int hpd, void *dev)
+{
+	struct mtk_dp *mtk_dp = dev;
+	struct mtk_dp_train_info *train_info = &mtk_dp->train_info;
+	u32 irq_status;
+
+	irq_status = mtk_dp_read(mtk_dp, MTK_DP_TOP_IRQ_STATUS);
+
+	if (!irq_status)
+		return IRQ_HANDLED;
+
+	if (irq_status & RGS_IRQ_STATUS_TRANSMITTER) {

Combine this if-checking with previous if-checking, it would be:

if (!(irq_status & RGS_IRQ_STATUS_TRANSMITTER))
	return IRQ_HANDLED;

+		irq_status = mtk_dp_swirq_get_clear(mtk_dp) |
+			     mtk_dp_hwirq_get_clear(mtk_dp);
+
+		if (!irq_status)
+			return IRQ_HANDLED;
+
+		if (irq_status & MTK_DP_HPD_INTERRUPT)

Does this interrupt MTK_DP_HPD_INTERRUPT have any relation with
MTK_DP_HPD_CONNECT and MTK_DP_HPD_CONNECT? From the naming, I guess
that when MTK_DP_HPD_CONNECT happen, MTK_DP_HPD_INTERRUPT would also
happen. Either for MTK_DP_HPD_DISCONNECT. When would
MTK_DP_HPD_INTERRUPT happen but MTK_DP_HPD_CONNECT or
MTK_DP_HPD_DISCONNECT does not happen.

Regards,
CK

+			train_info->hpd_inerrupt = true;
+
+		if (!(irq_status & MTK_DP_HPD_CONNECT ||
+		      irq_status & MTK_DP_HPD_DISCONNECT))
+			return IRQ_WAKE_THREAD;
+
+		if (!!(mtk_dp_read(mtk_dp, MTK_DP_TRANS_P0_3414) &
+		       HPD_DB_DP_TRANS_P0_MASK))
+			train_info->cable_plugged_in = true;
+		else
+			train_info->cable_plugged_in = false;
+
+		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
+				   DP_PWR_STATE_BANDGAP_TPLL_LANE,
+				   DP_PWR_STATE_MASK);
+	}
+
+	return IRQ_HANDLED;
+}
+