Hi, Guillaume:

On Mon, 2022-05-23 at 12:47 +0200, Guillaume Ranquet wrote:

From: Markus Schneider-Pargmann <msp@baylibre.com>

This patch adds a 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
Jason-JH.Lin [off-list ref].

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

[snip]

+
+static irqreturn_t mtk_dp_hpd_isr_handler(struct mtk_dp *mtk_dp)
+{
+	bool connected;
+	u16 swirq_status = mtk_dp_swirq_get_clear(mtk_dp);
+	u8 hwirq_status = mtk_dp_hwirq_get_clear(mtk_dp);
+	struct mtk_dp_train_info *train_info = &mtk_dp->train_info;
+
+	train_info->irq_status |= hwirq_status | swirq_status;

You mix software control variable and irq status here. Break each flag
in irq_status to variables in train_info to decouple software control
variable and irq status.

+
+	if (!train_info->irq_status)
+		return IRQ_HANDLED;
+
+	connected = mtk_dp_plug_state(mtk_dp);
+	if (connected || !train_info->cable_plugged_in)
+		train_info->irq_status &= ~MTK_DP_HPD_DISCONNECT;
+	else if (!connected || train_info->cable_plugged_in)
+		train_info->irq_status &= ~MTK_DP_HPD_CONNECT;
+
+	if (!(train_info->irq_status &
+	      (MTK_DP_HPD_CONNECT | MTK_DP_HPD_DISCONNECT)))
+		return IRQ_HANDLED;
+
+	if (train_info->irq_status & MTK_DP_HPD_CONNECT) {
+		train_info->irq_status &= ~MTK_DP_HPD_CONNECT;
+		train_info->cable_plugged_in = true;
+	} else {
+		train_info->irq_status &= ~MTK_DP_HPD_DISCONNECT;
+		train_info->cable_plugged_in = false;
+		mtk_dp->train_state = MTK_DP_TRAIN_STATE_STARTUP;
+	}
+	train_info->cable_state_change = true;
+
+	return IRQ_WAKE_THREAD;
+}
+