sensor: RTIO API support for FIFO streaming

Provides the necessary APIs to stream a sensors FIFO using RTIO

Adds an API call to enable explicitly reading the fifo from the sensor
at any time. The thinking is that while the sensors gpio trigger might
be one source of triggering a fifo read, external sources should be
possible.

Signed-off-by: Tom Burdick <[email protected]>

Author: teburd

include/zephyr/drivers/sensor.h

@@ -21,6 +21,7 @@
 
 #include <zephyr/types.h>
 #include <zephyr/device.h>
+#include <zephyr/rtio/rtio.h>
 #include <errno.h>
 
 #ifdef __cplusplus
@@ -318,6 +319,10 @@ enum sensor_attribute {
 	 *  to the new sampling frequency.
 	 */
 	SENSOR_ATTR_FF_DUR,
+	/** FIFO watermark attribute */
+	SENSOR_ATTR_FIFO_WATERMARK,
+	/** FIFO enable/disable fifo related interrupts */
+	SENSOR_ATTR_FIFO_INTERRUPT,
 	/**
 	 * Number of all common sensor attributes.
 	 */
@@ -394,12 +399,48 @@ typedef int (*sensor_channel_get_t)(const struct device *dev,
 				    enum sensor_channel chan,
 				    struct sensor_value *val);
 
+#ifdef CONFIG_RTIO
+
+/**
+ * @type sensor_fifo_iodev_t
+ * @brief Callback API for obtaining a reference to a sensors FIFO iodev.
+ */
+typedef int (*sensor_fifo_iodev_t)(const struct device *dev, struct rtio_iodev **iodev_sqe);
+
+/**
+ * @type sensor_fifo_read_t
+ * @brief Callback API for immediately triggering a FIFO read.
+ */
+typedef int (*sensor_fifo_read_t)(const struct device *dev);
+
+/**
+ * @type sensor_fifo_start_t
+ * @brief Callback API to start FIFO streaming.
+ */
+typedef int (*sensor_fifo_start_t)(const struct device *dev);
+
+/**
+ * @type sensor_fifo_stop_t
+ * @brief Callback API to stop FIFO streaming.
+ */
+typedef int (*sensor_fifo_stop_t)(const struct device *dev);
+
+
+#endif /* CONFIG_RTIO */
+
 __subsystem struct sensor_driver_api {
 	sensor_attr_set_t attr_set;
 	sensor_attr_get_t attr_get;
 	sensor_trigger_set_t trigger_set;
 	sensor_sample_fetch_t sample_fetch;
 	sensor_channel_get_t channel_get;
+
+#ifdef CONFIG_RTIO
+	sensor_fifo_iodev_t fifo_iodev;
+	sensor_fifo_read_t fifo_read;
+	sensor_fifo_start_t fifo_start;
+	sensor_fifo_stop_t fifo_stop;
+#endif /* CONFIG_RTIO */
 };
 
 /**
@@ -593,6 +634,70 @@ static inline int z_impl_sensor_channel_get(const struct device *dev,
 	return api->channel_get(dev, chan, val);
 }
 
+/**
+ * @brief Submit a request for the fifo stream (iodev) for this sensor.
+ */
+static inline int sensor_fifo_iodev(const struct device *dev, struct rtio_iodev **iodev)
+{
+#ifdef CONFIG_RTIO
+
+	const struct sensor_driver_api *api =
+		(const struct sensor_driver_api *)dev->api;
+
+	return api->fifo_iodev(dev, iodev);
+#else
+	return -ENOSYS;
+#endif
+}
+
+/**
+ * @brief Checkin a rtio_iodev pointer for this sensor, only one per device.
+ */
+static inline int sensor_fifo_read(const struct device *dev)
+{
+#ifdef CONFIG_RTIO
+
+	const struct sensor_driver_api *api =
+		(const struct sensor_driver_api *)dev->api;
+
+	return api->fifo_read(dev);
+#else
+	return -ENOSYS;
+#endif
+}
+
+/**
+ * @brief Start streaming the fifo for this sensor.
+ */
+static inline int sensor_fifo_start(const struct device *dev)
+{
+#ifdef CONFIG_RTIO
+
+	const struct sensor_driver_api *api =
+		(const struct sensor_driver_api *)dev->api;
+
+	return api->fifo_start(dev);
+#else
+	return -ENOSYS;
+#endif
+}
+
+/**
+ * @brief Stop streaming the fifo for this sensor.
+ */
+static inline int sensor_fifo_stop(const struct device *dev)
+{
+#ifdef CONFIG_RTIO
+
+	const struct sensor_driver_api *api =
+		(const struct sensor_driver_api *)dev->api;
+
+	return api->fifo_stop(dev);
+#else
+	return -ENOSYS;
+#endif
+}
+
 /**
  * @brief The value of gravitational constant in micro m/s^2.
  */