Input: ili210x - add support for polling mode

There are designs incorporating Ilitek ILI2xxx touch controller that
do not connect interrupt pin, for example Waveshare 13.3" DSI display.
To support such systems use polling mode for the input device when I2C
client does not have interrupt assigned to it.

Factor out ili210x_firmware_update_noirq() to allow conditional scoped
guard around this code. The scoped guard has to be applied only in case
the IRQ line is connected, and not applied otherwise.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Link: https://patch.msgid.link/20260121230736.114623-2-marek.vasut+renesas@mailbox.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: Marek Vasut

drivers/input/touchscreen/ili210x.c

@@ -327,9 +327,8 @@ static bool ili210x_report_events(struct ili210x *priv, u8 *touchdata)
 	return contact;
 }
 
-static irqreturn_t ili210x_irq(int irq, void *irq_data)
+static void ili210x_process_events(struct ili210x *priv)
 {
-	struct ili210x *priv = irq_data;
 	struct i2c_client *client = priv->client;
 	const struct ili2xxx_chip *chip = priv->chip;
 	u8 touchdata[ILI210X_DATA_SIZE] = { 0 };
@@ -356,8 +355,22 @@ static irqreturn_t ili210x_irq(int irq, void *irq_data)
 				usleep_range(time_delta, time_delta + 1000);
 		}
 	} while (!priv->stop && keep_polling);
+}
+
+static irqreturn_t ili210x_irq(int irq, void *irq_data)
+{
+	struct ili210x *priv = irq_data;
+
+	ili210x_process_events(priv);
 
 	return IRQ_HANDLED;
+};
+
+static void ili210x_work_i2c_poll(struct input_dev *input)
+{
+	struct ili210x *priv = input_get_drvdata(input);
+
+	ili210x_process_events(priv);
 }
 
 static int ili251x_firmware_update_resolution(struct device *dev)
@@ -829,12 +842,32 @@ static int ili210x_do_firmware_update(struct ili210x *priv,
 	return 0;
 }
 
+static ssize_t ili210x_firmware_update(struct device *dev, const u8 *fwbuf,
+				       u16 ac_end, u16 df_end)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	const char *fwname = ILI251X_FW_FILENAME;
+	int error;
+
+	dev_dbg(dev, "Firmware update started, firmware=%s\n", fwname);
+
+	ili210x_hardware_reset(priv->reset_gpio);
+
+	error = ili210x_do_firmware_update(priv, fwbuf, ac_end, df_end);
+
+	ili210x_hardware_reset(priv->reset_gpio);
+
+	dev_dbg(dev, "Firmware update ended, error=%i\n", error);
+
+	return error;
+}
+
 static ssize_t ili210x_firmware_update_store(struct device *dev,
 					     struct device_attribute *attr,
 					     const char *buf, size_t count)
 {
 	struct i2c_client *client = to_i2c_client(dev);
-	struct ili210x *priv = i2c_get_clientdata(client);
 	const char *fwname = ILI251X_FW_FILENAME;
 	u16 ac_end, df_end;
 	int error;
@@ -860,16 +893,11 @@ static ssize_t ili210x_firmware_update_store(struct device *dev,
 	 * the touch controller to disable the IRQs during update, so we have
 	 * to do it this way here.
 	 */
-	scoped_guard(disable_irq, &client->irq) {
-		dev_dbg(dev, "Firmware update started, firmware=%s\n", fwname);
-
-		ili210x_hardware_reset(priv->reset_gpio);
-
-		error = ili210x_do_firmware_update(priv, fwbuf, ac_end, df_end);
-
-		ili210x_hardware_reset(priv->reset_gpio);
-
-		dev_dbg(dev, "Firmware update ended, error=%i\n", error);
+	if (client->irq > 0) {
+		guard(disable_irq)(&client->irq);
+		error = ili210x_firmware_update(dev, fwbuf, ac_end, df_end);
+	} else {
+		error = ili210x_firmware_update(dev, fwbuf, ac_end, df_end);
 	}
 
 	return error ?: count;
@@ -945,9 +973,6 @@ static int ili210x_i2c_probe(struct i2c_client *client)
 	if (!chip)
 		return dev_err_probe(&client->dev, -ENODEV, "unknown device model\n");
 
-	if (client->irq <= 0)
-		return dev_err_probe(dev, -EINVAL, "No IRQ!\n");
-
 	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(reset_gpio))
 		return PTR_ERR(reset_gpio);
@@ -997,10 +1022,20 @@ static int ili210x_i2c_probe(struct i2c_client *client)
 	if (error)
 		return dev_err_probe(dev, error, "Unable to set up slots\n");
 
-	error = devm_request_threaded_irq(dev, client->irq, NULL, ili210x_irq,
-					  IRQF_ONESHOT, client->name, priv);
-	if (error)
-		return dev_err_probe(dev, error, "Unable to request touchscreen IRQ\n");
+	input_set_drvdata(input, priv);
+
+	if (client->irq > 0) {
+		error = devm_request_threaded_irq(dev, client->irq, NULL, ili210x_irq,
+						  IRQF_ONESHOT, client->name, priv);
+		if (error)
+			return dev_err_probe(dev, error, "Unable to request touchscreen IRQ\n");
+	} else {
+		error = input_setup_polling(input, ili210x_work_i2c_poll);
+		if (error)
+			return dev_err_probe(dev, error, "Could not set up polling mode\n");
+
+		input_set_poll_interval(input, ILI2XXX_POLL_PERIOD);
+	}
 
 	error = devm_add_action_or_reset(dev, ili210x_stop, priv);
 	if (error)