Adding upstream version 6.10.3.upstream/6.10.3

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 157 insertions, 0 deletions

diff --git a/Documentation/iio/ad7944.rst b/Documentation/iio/ad7944.rst
new file mode 100644
index 0000000000..0d26e56aba
--- /dev/null
+++ b/Documentation/iio/ad7944.rst
@@ -0,0 +1,156 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+=============
+AD7944 driver
+=============
+
+ADC driver for Analog Devices Inc. AD7944 and similar devices. The module name
+is ``ad7944``.
+
+
+Supported devices
+=================
+
+The following chips are supported by this driver:
+
+* `AD7944 <https://www.analog.com/AD7944>`_
+* `AD7985 <https://www.analog.com/AD7985>`_
+* `AD7986 <https://www.analog.com/AD7986>`_
+
+
+Supported features
+==================
+
+SPI wiring modes
+----------------
+
+The driver currently supports three of the many possible SPI wiring configurations.
+
+CS mode, 3-wire, without busy indicator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block::
+
+                                         +-------------+
+                    +--------------------| CS          |
+                    v                    |             |
+    VIO   +--------------------+         |     HOST    |
+     |    |        CNV         |         |             |
+     +--->| SDI   AD7944   SDO |-------->| SDI         |
+          |        SCK         |         |             |
+          +--------------------+         |             |
+                    ^                    |             |
+                    +--------------------| SCLK        |
+                                         +-------------+
+
+To select this mode in the device tree, set the ``adi,spi-mode`` property to
+``"single"`` and omit the ``cnv-gpios`` property.
+
+CS mode, 4-wire, without busy indicator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block::
+
+                                         +-------------+
+     +-----------------------------------| CS          |
+     |                                   |             |
+     |              +--------------------| GPIO        |
+     |              v                    |             |
+     |    +--------------------+         |     HOST    |
+     |    |        CNV         |         |             |
+     +--->| SDI   AD7944   SDO |-------->| SDI         |
+          |        SCK         |         |             |
+          +--------------------+         |             |
+                    ^                    |             |
+                    +--------------------| SCLK        |
+                                         +-------------+
+
+To select this mode in the device tree, omit the ``adi,spi-mode`` property and
+provide the ``cnv-gpios`` property.
+
+Chain mode, without busy indicator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block::
+
+                                                                 +-------------+
+                  +-------------------------+--------------------| CS          |
+                  v                         v                    |             |
+        +--------------------+    +--------------------+         |     HOST    |
+        |        CNV         |    |        CNV         |         |             |
+   +--->| SDI   AD7944   SDO |--->| SDI   AD7944   SDO |-------->| SDI         |
+   |    |        SCK         |    |        SCK         |         |             |
+  GND   +--------------------+    +--------------------+         |             |
+                  ^                         ^                    |             |
+                  +-------------------------+--------------------| SCLK        |
+                                                                 +-------------+
+
+To select this mode in the device tree, set the ``adi,spi-mode`` property to
+``"chain"``, add the ``spi-cs-high`` flag, add the ``#daisy-chained-devices``
+property, and omit the ``cnv-gpios`` property.
+
+Reference voltage
+-----------------
+
+All 3 possible reference voltage sources are supported:
+
+- Internal reference
+- External 1.2V reference and internal buffer
+- External reference
+
+The source is determined by the device tree. If ``ref-supply`` is present, then
+the external reference is used. If ``refin-supply`` is present, then the internal
+buffer is used. If neither is present, then the internal reference is used.
+
+Unimplemented features
+----------------------
+
+- ``BUSY`` indication
+- ``TURBO`` mode
+
+
+Device attributes
+=================
+
+There are two types of ADCs in this family, pseudo-differential and fully
+differential. The channel name is different depending on the type of ADC.
+
+Pseudo-differential ADCs
+------------------------
+
+AD7944 and AD7985 are pseudo-differential ADCs and have the following attributes:
+
++---------------------------------------+--------------------------------------------------------------+
+| Attribute                             | Description                                                  |
++=======================================+==============================================================+
+| ``in_voltage0_raw``                   | Raw ADC voltage value (*IN+* referenced to ground sense).    |
++---------------------------------------+--------------------------------------------------------------+
+| ``in_voltage0_scale``                 | Scale factor to convert raw value to mV.                     |
++---------------------------------------+--------------------------------------------------------------+
+
+In "chain" mode, additional chips will appear as additional voltage input
+channels, e.g. ``in_voltage1_raw``.
+
+Fully-differential ADCs
+-----------------------
+
+AD7986 is a fully-differential ADC and has the following attributes:
+
++---------------------------------------+--------------------------------------------------------------+
+| Attribute                             | Description                                                  |
++=======================================+==============================================================+
+| ``in_voltage0-voltage1_raw``          | Raw ADC voltage value (*IN+* - *IN-*).                       |
++---------------------------------------+--------------------------------------------------------------+
+| ``in_voltage0-voltage1_scale``        | Scale factor to convert raw value to mV.                     |
++---------------------------------------+--------------------------------------------------------------+
+
+In "chain" mode, additional chips will appear as additional voltage input
+channels, e.g. ``in_voltage2-voltage3_raw``.
+
+
+Device buffers
+==============
+
+This driver supports IIO triggered buffers.
+
+See :doc:`iio_devbuf` for more information.
diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
index 30b09eefe7..fb6f9d7432 100644
--- a/Documentation/iio/index.rst
+++ b/Documentation/iio/index.rst
@@ -16,6 +16,7 @@ Industrial I/O Kernel Drivers
 .. toctree::
    :maxdepth: 1
 
+   ad7944
    adis16475
    bno055
    ep93xx_adc