docs/library/zephyr: Add libraries specific to the Zephyr port.

Includes documentation for Zephyr specific modules (zephyr and zsensor),
classes (DiskAccess and FlashArea), and functions.

Signed-off-by: Julia Hathaway <julia.hathaway@nxp.com>

docs/library/index.rst

@@ -176,3 +176,13 @@ The following libraries are specific to the RP2040, as used in the Raspberry Pi
   :maxdepth: 2
 
   rp2.rst
+
+Libraries specific to Zephyr
+----------------------------
+
+The following libraries are specific to the Zephyr port.
+
+.. toctree::
+  :maxdepth: 2
+
+  zephyr.rst

docs/library/zephyr.DiskAccess.rst

@@ -0,0 +1,38 @@
+.. currentmodule:: zephyr
+.. _zephyr.DiskAccess:
+
+class DiskAccess -- access to disk storage
+==========================================
+
+Uses `Zephyr Disk Access API <https://docs.zephyrproject.org/latest/reference/storage/disk/access.html>`_.
+
+This class allows access to storage devices on the board, such as support for SD card controllers and
+interfacing with SD cards via SPI. Disk devices are automatically detected and initialized on boot using
+Zephyr devicetree data.
+
+The Zephyr disk access class enables the transfer of data between a disk device and an accessible memory buffer given a disk name,
+buffer, starting disk block, and number of sectors to read. MicroPython reads as many blocks as necessary to fill the buffer, so
+the number of sectors to read is found by dividing the buffer length by block size of the disk.
+
+Constructors
+------------
+
+.. class:: DiskAccess(disk_name)
+
+   Gets an object for accessing disk memory of the specific disk.
+   For accessing an SD card on the mimxrt1050_evk, ``disk_name`` would be ``SDHC``. See board documentation and
+   devicetree for usable disk names for your board (ex. RT boards use style USDHC#).
+
+Methods
+-------
+
+.. method:: DiskAccess.readblocks(block_num, buf)
+            DiskAccess.readblocks(block_num, buf, offset)
+.. method:: DiskAccess.writeblocks(block_num, buf)
+            DiskAccess.writeblocks(block_num, buf, offset)
+.. method:: DiskAccess.ioctl(cmd, arg)
+
+    These methods implement the simple and extended
+    :ref:`block protocol <block-device-interface>` defined by
+    :class:`uos.AbstractBlockDev`.
+

docs/library/zephyr.FlashArea.rst

@@ -0,0 +1,40 @@
+.. currentmodule:: zephyr
+.. _zephyr.FlashArea:
+
+class FlashArea -- access to built-in flash storage
+===================================================
+
+Uses `Zephyr flash map API <https://docs.zephyrproject.org/latest/reference/storage/flash_map/flash_map.html#flash-map>`_.
+
+This class allows access to device flash partition data.
+Flash area structs consist of a globally unique ID number, the name of the flash device the partition is in,
+the start offset (expressed in relation to the flash memory beginning address per partition),
+and the size of the partition that the device represents. For fixed flash partitions, data from the device
+tree is used; however, fixed flash partitioning is not enforced in MicroPython because MCUBoot is not enabled.
+
+Constructors
+------------
+
+.. class:: FlashArea(id, block_size)
+
+   Gets an object for accessing flash memory at partition specified by ``id`` and with block size of ``block_size``.
+
+   ``id`` values are integers correlating to fixed flash partitions defined in the devicetree.
+   A commonly used partition is the designated flash storage area defined as ``FlashArea.STORAGE`` if
+   ``FLASH_AREA_LABEL_EXISTS(storage)`` returns true at boot.
+   Zephyr devicetree fixed flash partitions are ``boot_partition``, ``slot0_partition``, ``slot1_partition``, and
+   ``scratch_partition``. Because MCUBoot is not enabled by default for MicroPython, these fixed partitions can be accessed by
+   ID integer values 1, 2, 3, and 4, respectively.
+
+Methods
+-------
+
+.. method:: FlashArea.readblocks(block_num, buf)
+            FlashArea.readblocks(block_num, buf, offset)
+.. method:: FlashArea.writeblocks(block_num, buf)
+            FlashArea.writeblocks(block_num, buf, offset)
+.. method:: FlashArea.ioctl(cmd, arg)
+
+    These methods implement the simple and extended
+    :ref:`block protocol <block-device-interface>` defined by
+    :class:`uos.AbstractBlockDev`.

docs/library/zephyr.rst

@@ -0,0 +1,60 @@
+.. currentmodule:: zephyr
+
+:mod:`zephyr` --- functionality specific to the Zephyr port
+===========================================================
+
+.. module:: zephyr
+    :synopsis: functionality specific to Zephyr
+
+The ``zephyr`` module contains functions and classes specific to the Zephyr port.
+
+Functions
+---------
+
+.. function:: is_preempt_thread()
+
+   Returns true if the current thread is a preemptible thread.
+
+   Zephyr preemptible threads are those with non-negative priority values (low priority levels), which therefore,
+   can be supplanted as soon as a higher or equal priority thread becomes ready.
+
+.. function:: current_tid()
+
+   Returns the thread id of the current thread, which is used to reference the thread.
+
+.. function:: thread_analyze()
+
+   Runs the Zephyr debug thread analyzer on the current thread and prints stack size statistics in the format:
+
+    "``thread_name``-20s: STACK: unused ``available_stack_space`` usage ``stack_space_used``
+    / ``stack_size`` (``percent_stack_space_used`` %); CPU: ``cpu_utilization`` %"
+
+    * *CPU utilization is only printed if runtime statistics are configured via the ``CONFIG_THREAD_RUNTIME_STATS`` kconfig*
+
+   This function can only be accessed if ``CONFIG_THREAD_ANALYZER`` is configured for the port in ``zephyr/prj.conf``.
+   For more infomation, see documentation for Zephyr `thread analyzer
+   <https://docs.zephyrproject.org/latest/guides/debug_tools/thread-analyzer.html#thread-analyzer>`_.
+
+.. function:: shell_exec(cmd_in)
+
+   Executes the given command on an UART backend. This function can only be accessed if ``CONFIG_SHELL_BACKEND_SERIAL``
+   is configured for the port in ``zephyr/prj.conf``.
+
+   A list of possible commands can be found in the documentation for Zephyr `shell commands <https://docs.zephyrproject.org/latest/reference/shell/index.html?highlight=shell_execute_cmd#commands>`_.
+
+Classes
+-------
+
+.. toctree::
+    :maxdepth: 1
+
+    zephyr.DiskAccess.rst
+    zephyr.FlashArea.rst
+
+Additional Modules
+------------------
+
+.. toctree::
+    :maxdepth: 1
+
+    zephyr.zsensor.rst

docs/library/zephyr.zsensor.rst

@@ -0,0 +1,123 @@
+.. currentmodule:: zsensor
+
+:mod:`zsensor` --- Zephyr sensor bindings
+=========================================
+
+.. module:: zsensor
+    :synopsis: zephyr sensor bindings
+
+The ``zsensor`` module contains a class for using sensors with Zephyr.
+
+.. _zsensor.Sensor:
+
+class Sensor --- sensor control for the Zephyr port
+---------------------------------------------------
+
+Use this class to access data from sensors on your board.
+See Zephyr documentation for sensor usage here: `Sensors
+<https://docs.zephyrproject.org/latest/reference/peripherals/sensor.html?highlight=sensor#sensors>`_.
+
+Sensors are defined in the Zephyr devicetree for each board. The quantities that a given sensor can
+measure are called a sensor channels. Sensors can have multiple channels to represent different axes
+of one property or different properties a sensor can measure. See `Channels`_ below for defined sensor
+channels.
+
+Constructor
+~~~~~~~~~~~
+
+.. class:: Sensor(device_name)
+
+    Device names are defined in the devicetree for your board.
+    For example, the device name for the accelerometer in the FRDM-k64f board is "FXOS8700".
+
+Methods
+~~~~~~~
+
+.. method:: Sensor.measure()
+
+    Obtains a measurement sample from the sensor device using Zephyr sensor_sample_fetch and
+    stores it in an internal driver buffer as a useful value, a pair of (integer part of value,
+    fractional part of value in 1-millionths).
+    Returns none if successful or OSError value if failure.
+
+.. method:: Sensor.get_float(sensor_channel)
+
+    Returns the value of the sensor measurement sample as a float.
+
+.. method:: Sensor.get_micros(sensor_channel)
+
+    Returns the value of the sensor measurement sample in millionths.
+    (Ex. value of ``(1, 500000)`` returns as ``1500000``)
+
+.. method:: Sensor.get_millis(sensor_channel)
+
+    Returns the value of sensor measurement sample in thousandths.
+    (Ex. value of ``(1, 500000)`` returns as ``1500``)
+
+.. method:: Sensor.get_int(sensor_channel)
+
+    Returns only the integer value of the measurement sample.
+    (Ex. value of ``(1, 500000)`` returns as ``1``)
+
+Channels
+~~~~~~~~
+
+.. data:: ACCEL_X
+
+    Acceleration on the X axis, in m/s^2.
+
+.. data:: ACCEL_Y
+
+    Acceleration on the Y axis, in m/s^2.
+
+.. data:: ACCEL_Z
+
+    Acceleration on the Z axis, in m/s^2.
+
+.. data:: GYRO_X
+
+    Angular velocity around the X axis, in radians/s.
+
+.. data:: GYRO_Y
+
+    Angular velocity around the Y axis, in radians/s.
+
+.. data:: GYRO_Z
+
+    Angular velocity around the Z axis, in radians/s.
+
+.. data:: MAGN_X
+
+    Magnetic field on the X axis, in Gauss.
+
+.. data:: MAGN_Y
+
+    Magnetic field on the Y axis, in Gauss.
+
+.. data:: MAGN_Z
+
+    Magnetic field on the Z axis, in Gauss.
+
+.. data:: DIE_TEMP
+
+    Device die temperature in degrees Celsius.
+
+.. data:: PRESS
+
+    Pressure in kilopascal.
+
+.. data:: PROX
+
+    Proximity. Dimensionless. A value of 1 indicates that an object is close.
+
+.. data:: HUMIDITY
+
+    Humidity, in percent.
+
+.. data:: LIGHT
+
+    Illuminance in visible spectrum, in lux.
+
+.. data:: ALTITUDE
+
+    Altitude, in meters.