iio: imu: inv_mpu6050: add new interrupt handler for WoM events

Add new interrupt handler for generating WoM event from int status register
bits. Launch from interrupt the trigger poll function for data buffer.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://lore.kernel.org/r/20240311160557.437337-4-inv.git-commit@tdk.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h

@@ -185,6 +185,7 @@ struct inv_mpu6050_hw {
  *  @magn_orient:       magnetometer sensor chip orientation if available.
  *  @suspended_sensors:	sensors mask of sensors turned off for suspend
  *  @data:		read buffer used for bulk reads.
+ *  @it_timestamp:	interrupt timestamp.
  */
 struct inv_mpu6050_state {
 	struct mutex lock;
@@ -210,6 +211,7 @@ struct inv_mpu6050_state {
 	unsigned int suspended_sensors;
 	bool level_shifter;
 	u8 *data;
+	s64 it_timestamp;
 };
 
 /*register and associated bit definition*/

drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c

@@ -51,21 +51,10 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
 	u32 fifo_period;
 	s64 timestamp;
 	u8 data[INV_MPU6050_OUTPUT_DATA_SIZE];
-	int int_status;
 	size_t i, nb;
 
 	mutex_lock(&st->lock);
 
-	/* ack interrupt and check status */
-	result = regmap_read(st->map, st->reg->int_status, &int_status);
-	if (result) {
-		dev_err(regmap_get_device(st->map),
-			"failed to ack interrupt\n");
-		goto flush_fifo;
-	}
-	if (!(int_status & INV_MPU6050_BIT_RAW_DATA_RDY_INT))
-		goto end_session;
-
 	if (!(st->chip_config.accl_fifo_enable |
 		st->chip_config.gyro_fifo_enable |
 		st->chip_config.magn_fifo_enable))

drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c

@@ -6,6 +6,7 @@
 #include <linux/pm_runtime.h>
 
 #include <linux/iio/common/inv_sensors_timestamp.h>
+#include <linux/iio/events.h>
 
 #include "inv_mpu_iio.h"
 
@@ -228,6 +229,65 @@ static const struct iio_trigger_ops inv_mpu_trigger_ops = {
 	.set_trigger_state = &inv_mpu_data_rdy_trigger_set_state,
 };
 
+static irqreturn_t inv_mpu6050_interrupt_timestamp(int irq, void *p)
+{
+	struct iio_dev *indio_dev = p;
+	struct inv_mpu6050_state *st = iio_priv(indio_dev);
+
+	st->it_timestamp = iio_get_time_ns(indio_dev);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t inv_mpu6050_interrupt_handle(int irq, void *p)
+{
+	struct iio_dev *indio_dev = p;
+	struct inv_mpu6050_state *st = iio_priv(indio_dev);
+	unsigned int int_status, wom_bits;
+	u64 ev_code;
+	int result;
+
+	switch (st->chip_type) {
+	case INV_MPU6050:
+	case INV_MPU6500:
+	case INV_MPU6515:
+	case INV_MPU6880:
+	case INV_MPU6000:
+	case INV_MPU9150:
+	case INV_MPU9250:
+	case INV_MPU9255:
+		wom_bits = INV_MPU6500_BIT_WOM_INT;
+		break;
+	default:
+		wom_bits = INV_ICM20608_BIT_WOM_INT;
+		break;
+	}
+
+	scoped_guard(mutex, &st->lock) {
+		/* ack interrupt and check status */
+		result = regmap_read(st->map, st->reg->int_status, &int_status);
+		if (result) {
+			dev_err(regmap_get_device(st->map), "failed to ack interrupt\n");
+			return IRQ_HANDLED;
+		}
+
+		/* handle WoM event */
+		if (st->chip_config.wom_en && (int_status & wom_bits)) {
+			ev_code = IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_X_OR_Y_OR_Z,
+						     IIO_EV_TYPE_ROC, IIO_EV_DIR_RISING);
+			iio_push_event(indio_dev, ev_code, st->it_timestamp);
+		}
+	}
+
+	/* handle raw data interrupt */
+	if (int_status & INV_MPU6050_BIT_RAW_DATA_RDY_INT) {
+		indio_dev->pollfunc->timestamp = st->it_timestamp;
+		iio_trigger_poll_nested(st->trig);
+	}
+
+	return IRQ_HANDLED;
+}
+
 int inv_mpu6050_probe_trigger(struct iio_dev *indio_dev, int irq_type)
 {
 	int ret;
@@ -240,11 +300,10 @@ int inv_mpu6050_probe_trigger(struct iio_dev *indio_dev, int irq_type)
 	if (!st->trig)
 		return -ENOMEM;
 
-	ret = devm_request_irq(&indio_dev->dev, st->irq,
-			       &iio_trigger_generic_data_rdy_poll,
-			       irq_type,
-			       "inv_mpu",
-			       st->trig);
+	ret = devm_request_threaded_irq(&indio_dev->dev, st->irq,
+					&inv_mpu6050_interrupt_timestamp,
+					&inv_mpu6050_interrupt_handle,
+					irq_type, "inv_mpu", indio_dev);
 	if (ret)
 		return ret;