Input: tsc2007 - make interrupt optional

In case tsc2007 is used as an ADC sensor there will be no interrupt
provided at all, so set up an interrupt only if one is present.

Signed-off-by: Svyatoslav Ryhel <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/tsc2007_core.c

···
 	mb();
 	wake_up(&ts->wait);
 
-	disable_irq(ts->irq);
+	if (ts->irq)
+		disable_irq(ts->irq);
 }
 
 static int tsc2007_open(struct input_dev *input_dev)
···
 	ts->stopped = false;
 	mb();
 
-	enable_irq(ts->irq);
+	if (ts->irq)
+		enable_irq(ts->irq);
 
 	/* Prepare for touch readings - power down ADC and enable PENIRQ */
 	err = tsc2007_xfer(ts, PWRDOWN);
···
 			pdata->init_platform_hw();
 	}
 
-	err = devm_request_threaded_irq(&client->dev, ts->irq,
-					NULL, tsc2007_soft_irq,
-					IRQF_ONESHOT,
-					client->dev.driver->name, ts);
-	if (err) {
-		dev_err(&client->dev, "Failed to request irq %d: %d\n",
-			ts->irq, err);
-		return err;
-	}
+	if (ts->irq) {
+		err = devm_request_threaded_irq(&client->dev, ts->irq,
+						NULL, tsc2007_soft_irq,
+						IRQF_ONESHOT,
+						client->dev.driver->name, ts);
+		if (err) {
+			dev_err(&client->dev, "Failed to request irq %d: %d\n",
+				ts->irq, err);
+			return err;
+		}
 
-	tsc2007_stop(ts);
+		tsc2007_stop(ts);
+	}
 
 	/* power down the chip (TSC2007_SETUP does not ACK on I2C) */
 	err = tsc2007_xfer(ts, PWRDOWN);