iio: accel: adxl345: introduce interrupt handling

Add the possibility to claim an interrupt. Init the state structure
with an interrupt line obtained from the DT. The adxl345 can use
two different interrupt lines for event handling. Only one is used.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Link: https://patch.msgid.link/20241228232949.72487-2-l.rubusch@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: Rubusch

drivers/iio/accel/adxl345_core.c

@@ -7,6 +7,7 @@
  * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
  */
 
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
@@ -17,9 +18,15 @@
 
 #include "adxl345.h"
 
+#define ADXL345_INT_NONE		0xff
+#define ADXL345_INT1			0
+#define ADXL345_INT2			1
+
 struct adxl345_state {
 	const struct adxl345_chip_info *info;
 	struct regmap *regmap;
+	int irq;
+	u8 intio;
 };
 
 #define ADXL345_CHANNEL(index, axis) {					\
@@ -262,6 +269,15 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 	if (ret < 0)
 		return ret;
 
+	st->intio = ADXL345_INT1;
+	st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "INT1");
+	if (st->irq < 0) {
+		st->intio = ADXL345_INT2;
+		st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "INT2");
+		if (st->irq < 0)
+			st->intio = ADXL345_INT_NONE;
+	}
+
 	return devm_iio_device_register(dev, indio_dev);
 }
 EXPORT_SYMBOL_NS_GPL(adxl345_core_probe, "IIO_ADXL345");