Input: adp5588-keys - add support for pure gpio

Keypad specific setup is relaxed if no keypad rows/columns are specified,
enabling a purely gpio operation.
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Utsav Agarwal <utsav.agarwal@analog.com>
Link: https://lore.kernel.org/r/20240826-adp5588_gpio_support-v11-2-3e5ac2bd31b7@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/adp5588-keys.c

@@ -188,6 +188,7 @@ struct adp5588_kpad {
 	u32 cols;
 	u32 unlock_keys[2];
 	int nkeys_unlock;
+	bool gpio_only;
 	unsigned short keycode[ADP5588_KEYMAPSIZE];
 	unsigned char gpiomap[ADP5588_MAXGPIO];
 	struct gpio_chip gc;
@@ -431,10 +432,17 @@ static int adp5588_gpio_add(struct adp5588_kpad *kpad)
 	kpad->gc.label = kpad->client->name;
 	kpad->gc.owner = THIS_MODULE;
 
-	girq = &kpad->gc.irq;
-	gpio_irq_chip_set_chip(girq, &adp5588_irq_chip);
-	girq->handler = handle_bad_irq;
-	girq->threaded = true;
+	if (device_property_present(dev, "interrupt-controller")) {
+		if (!kpad->client->irq) {
+			dev_err(dev, "Unable to serve as interrupt controller without interrupt");
+			return -EINVAL;
+		}
+
+		girq = &kpad->gc.irq;
+		gpio_irq_chip_set_chip(girq, &adp5588_irq_chip);
+		girq->handler = handle_bad_irq;
+		girq->threaded = true;
+	}
 
 	mutex_init(&kpad->gpio_lock);
 
@@ -632,6 +640,18 @@ static int adp5588_fw_parse(struct adp5588_kpad *kpad)
 	struct i2c_client *client = kpad->client;
 	int ret, i;
 
+	/*
+	 * Check if the device is to be operated purely in GPIO mode. To do
+	 * so, check that no keypad rows or columns have been specified,
+	 * since all GPINS should be configured as GPIO.
+	 */
+	if (!device_property_present(&client->dev, "keypad,num-rows") &&
+	    !device_property_present(&client->dev, "keypad,num-columns")) {
+		/* If purely GPIO, skip keypad setup */
+		kpad->gpio_only = true;
+		return 0;
+	}
+
 	ret = matrix_keypad_parse_properties(&client->dev, &kpad->rows,
 					     &kpad->cols);
 	if (ret)
@@ -775,17 +795,19 @@ static int adp5588_probe(struct i2c_client *client)
 	if (error)
 		return error;
 
-	error = devm_request_threaded_irq(&client->dev, client->irq,
-					  adp5588_hard_irq, adp5588_thread_irq,
-					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
-					  client->dev.driver->name, kpad);
-	if (error) {
-		dev_err(&client->dev, "failed to request irq %d: %d\n",
-			client->irq, error);
-		return error;
+	if (client->irq) {
+		error = devm_request_threaded_irq(&client->dev, client->irq,
+						  adp5588_hard_irq, adp5588_thread_irq,
+						  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+						  client->dev.driver->name, kpad);
+		if (error) {
+			dev_err(&client->dev, "failed to request irq %d: %d\n",
+				client->irq, error);
+			return error;
+		}
 	}
 
-	dev_info(&client->dev, "Rev.%d keypad, irq %d\n", revid, client->irq);
+	dev_info(&client->dev, "Rev.%d controller\n", revid);
 	return 0;
 }