12.02.2020 11:41, Jiada Wang пишет:

From: Nick Dyer <redacted>

The workaround of reading all messages until an invalid is received is a
way of forcing the CHG line high, which means that when using
edge-triggered interrupts the interrupt can be acquired.

With level-triggered interrupts the workaround is unnecessary.

Also, most recent maXTouch chips have a feature called RETRIGEN which, when
enabled, reasserts the interrupt line every cycle if there are messages
waiting. This also makes the workaround unnecessary.

Note: the RETRIGEN feature is only in some firmware versions/chips, it's
not valid simply to enable the bit.

...

+static int mxt_check_retrigen(struct mxt_data *data)
+{
+	struct i2c_client *client = data->client;
+	int error;
+	int val;
+
+	data->use_retrigen_workaround = false;
+
+	if (irq_get_trigger_type(data->irq) & IRQF_TRIGGER_LOW)
+		return 0;
+
+	if (data->T18_address) {
+		error = __mxt_read_reg(client,
+				       data->T18_address + MXT_COMMS_CTRL,
+				       1, &val);
+		if (error)
+			return error;
+
+		if (val & MXT_COMMS_RETRIGEN)
+			return 0;
+	}
+
+	dev_warn(&client->dev, "Enabling RETRIGEN workaround\n");
+	data->use_retrigen_workaround = true;
+	return 0;
+}

Hello Jiada,

I'm seeing "Enabling RETRIGEN workaround" message with the following
device-tree entry:

touchscreen@4c {
	compatible = "atmel,maxtouch";
	reg = <0x4c>;

	interrupt-parent = <&gpio>;
	interrupts = <TEGRA_GPIO(V, 6) IRQ_TYPE_LEVEL_LOW>;

	reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_HIGH>;
};

This happens because data->irq is NULL. Please fix it, thanks in advance.