Merging upstream version 6.9.7.

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

3 files changed, 563 insertions, 1 deletions

diff --git a/Documentation/iio/adis16475.rst b/Documentation/iio/adis16475.rst
new file mode 100644
index 0000000000..130f9e97cc
--- /dev/null
+++ b/Documentation/iio/adis16475.rst
@@ -0,0 +1,403 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================
+ADIS16475 driver
+================
+
+This driver supports Analog Device's IMUs on SPI bus.
+
+1. Supported devices
+====================
+
+* `ADIS16465 <https://www.analog.com/ADIS16465>`_
+* `ADIS16467 <https://www.analog.com/ADIS16467>`_
+* `ADIS16470 <https://www.analog.com/ADIS16470>`_
+* `ADIS16475 <https://www.analog.com/ADIS16475>`_
+* `ADIS16477 <https://www.analog.com/ADIS16477>`_
+* `ADIS16500 <https://www.analog.com/ADIS16500>`_
+* `ADIS16505 <https://www.analog.com/ADIS16505>`_
+* `ADIS16507 <https://www.analog.com/ADIS16507>`_
+
+Each supported device is a precision, miniature microelectromechanical system
+(MEMS) inertial measurement unit (IMU) that includes a triaxial gyroscope and a
+triaxial accelerometer. Each inertial sensor in the IMU device combines with
+signal conditioning that optimizes dynamic performance. The factory calibration
+characterizes each sensor for sensitivity, bias, alignment, linear acceleration
+(gyroscope bias), and point of percussion (accelerometer location). As a result,
+each sensor has dynamic compensation formulas that provide accurate sensor
+measurements over a broad set of conditions.
+
+2. Device attributes
+====================
+
+Accelerometer, gyroscope measurements are always provided. Furthermore, the
+driver offers the capability to retrieve the delta angle and the delta velocity
+measurements computed by the device.
+
+The delta angle measurements represent a calculation of angular displacement
+between each sample update, while the delta velocity measurements represent a
+calculation of linear velocity change between each sample update.
+
+Finally, temperature data are provided which show a coarse measurement of
+the temperature inside of the IMU device. This data is most useful for
+monitoring relative changes in the thermal environment.
+
+The signal chain of each inertial sensor (accelerometers and gyroscopes)
+includes the application of unique correction formulas, which are derived from
+extensive characterization of bias, sensitivity, alignment, response to linear
+acceleration (gyroscopes), and point of percussion (accelerometer location)
+over a temperature range of −40°C to +85°C, for each ADIS device. These
+correction formulas are not accessible, but users do have the opportunity to
+adjust the bias for each sensor individually through the calibbias attribute.
+
+Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``,
+where X is the IIO index of the device. Under these folders reside a set of
+device files, depending on the characteristics and features of the hardware
+device in questions. These files are consistently generalized and documented in
+the IIO ABI documentation.
+
+The following tables show the adis16475 related device files, found in the
+specific device folder path ``/sys/bus/iio/devices/iio:deviceX``.
+
++-------------------------------------------+----------------------------------------------------------+
+| 3-Axis Accelerometer related device files | Description                                              |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_scale                            | Scale for the accelerometer channels.                    |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_x_calibbias                      | Calibration offset for the X-axis accelerometer channel. |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_x_raw                            | Raw X-axis accelerometer channel value.                  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_y_calibbias                      | Calibration offset for the Y-axis accelerometer channel. |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_y_raw                            | Raw Y-axis accelerometer channel value.                  |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_z_calibbias                      | Calibration offset for the Z-axis accelerometer channel. |
++-------------------------------------------+----------------------------------------------------------+
+| in_accel_z_raw                            | Raw Z-axis accelerometer channel value.                  |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_scale                    | Scale for delta velocity channels.                       |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_x_raw                    | Raw X-axis delta velocity channel value.                 |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_y_raw                    | Raw Y-axis delta velocity channel value.                 |
++-------------------------------------------+----------------------------------------------------------+
+| in_deltavelocity_z_raw                    | Raw Z-axis delta velocity channel value.                 |
++-------------------------------------------+----------------------------------------------------------+
+
++---------------------------------------+------------------------------------------------------+
+| 3-Axis Gyroscope related device files | Description                                          |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_scale                      | Scale for the gyroscope channels.                    |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_x_calibbias                | Calibration offset for the X-axis gyroscope channel. |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_x_raw                      | Raw X-axis gyroscope channel value.                  |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_y_calibbias                | Calibration offset for the Y-axis gyroscope channel. |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_y_raw                      | Raw Y-axis gyroscope channel value.                  |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_z_calibbias                | Calibration offset for the Z-axis gyroscope channel. |
++---------------------------------------+------------------------------------------------------+
+| in_anglvel_z_raw                      | Raw Z-axis gyroscope channel value.                  |
++---------------------------------------+------------------------------------------------------+
+| in_deltaangl_scale                    | Scale for delta angle channels.                      |
++---------------------------------------+------------------------------------------------------+
+| in_deltaangl_x_raw                    | Raw X-axis delta angle channel value.                |
++---------------------------------------+------------------------------------------------------+
+| in_deltaangl_y_raw                    | Raw Y-axis delta angle channel value.                |
++---------------------------------------+------------------------------------------------------+
+| in_deltaangl_z_raw                    | Raw Z-axis delta angle channel value.                |
++---------------------------------------+------------------------------------------------------+
+
++----------------------------------+-------------------------------------------+
+| Temperature sensor related files | Description                               |
++----------------------------------+-------------------------------------------+
+| in_temp0_raw                     | Raw temperature channel value.            |
++----------------------------------+-------------------------------------------+
+| in_temp0_scale                   | Scale for the temperature sensor channel. |
++----------------------------------+-------------------------------------------+
+
++-------------------------------+---------------------------------------------------------+
+| Miscellaneous device files    | Description                                             |
++-------------------------------+---------------------------------------------------------+
+| name                          | Name of the IIO device.                                 |
++-------------------------------+---------------------------------------------------------+
+| sampling_frequency            | Currently selected sample rate.                         |
++-------------------------------+---------------------------------------------------------+
+| filter_low_pass_3db_frequency | Bandwidth for the accelerometer and gyroscope channels. |
++-------------------------------+---------------------------------------------------------+
+
+The following table shows the adis16475 related device debug files, found in the
+specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``.
+
++----------------------+-------------------------------------------------------------------------+
+| Debugfs device files | Description                                                             |
++----------------------+-------------------------------------------------------------------------+
+| serial_number        | The serial number of the chip in hexadecimal format.                    |
++----------------------+-------------------------------------------------------------------------+
+| product_id           | Chip specific product id (e.g. 16475, 16500, 16505, etc.).              |
++----------------------+-------------------------------------------------------------------------+
+| flash_count          | The number of flash writes performed on the device.                     |
++----------------------+-------------------------------------------------------------------------+
+| firmware_revision    | String containing the firmware revision in the following format ##.##.  |
++----------------------+-------------------------------------------------------------------------+
+| firmware_date        | String containing the firmware date in the following format mm-dd-yyyy. |
++----------------------+-------------------------------------------------------------------------+
+
+Channels processed values
+-------------------------
+
+A channel value can be read from its _raw attribute. The value returned is the
+raw value as reported by the devices. To get the processed value of the channel,
+apply the following formula:
+
+.. code-block:: bash
+
+        processed value = (_raw + _offset) * _scale
+
+Where _offset and _scale are device attributes. If no _offset attribute is
+present, simply assume its value is 0.
+
+The adis16475 driver offers data for 5 types of channels, the table below shows
+the measurement units for the processed value, which are defined by the IIO
+framework:
+
++-------------------------------------+---------------------------+
+| Channel type                        | Measurement unit          |
++-------------------------------------+---------------------------+
+| Acceleration on X, Y, and Z axis    | Meters per Second squared |
++-------------------------------------+---------------------------+
+| Angular velocity on X, Y and Z axis | Radians per second        |
++-------------------------------------+---------------------------+
+| Delta velocity on X. Y, and Z axis  | Meters per Second         |
++-------------------------------------+---------------------------+
+| Delta angle on X, Y, and Z axis     | Radians                   |
++-------------------------------------+---------------------------+
+| Temperature                         | Millidegrees Celsius      |
++-------------------------------------+---------------------------+
+
+Usage examples
+--------------
+
+Show device name:
+
+.. code-block:: bash
+
+	root:/sys/bus/iio/devices/iio:device0> cat name
+        adis16505-2
+
+Show accelerometer channels value:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw
+        -275924
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw
+        -30142222
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw
+        261265769
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale
+        0.000000037
+
+- X-axis acceleration = in_accel_x_raw * in_accel_scale = −0.010209188 m/s^2
+- Y-axis acceleration = in_accel_y_raw * in_accel_scale = −1.115262214 m/s^2
+- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.666833453 m/s^2
+
+Show gyroscope channels value:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw
+        -3324626
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw
+        1336980
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw
+        -602983
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale
+        0.000000006
+
+- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = −0.019947756 rad/s
+- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = 0.00802188 rad/s
+- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = −0.003617898 rad/s
+
+Set calibration offset for accelerometer channels:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias
+        0
+
+        root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias
+        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias
+        5000
+
+Set calibration offset for gyroscope channels:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias
+        0
+
+        root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias
+        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias
+        -5000
+
+Set sampling frequency:
+
+.. code-block:: bash
+
+	root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency
+        2000.000000
+
+        root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency
+        1000.000000
+
+Set bandwidth for accelerometer and gyroscope:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat filter_low_pass_3db_frequency
+        720
+
+        root:/sys/bus/iio/devices/iio:device0> echo 360 > filter_low_pass_3db_frequency
+        root:/sys/bus/iio/devices/iio:device0> cat filter_low_pass_3db_frequency
+        360
+
+Show serial number:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat serial_number
+        0x04f9
+
+Show product id:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat product_id
+        16505
+
+Show flash count:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat flash_count
+        150
+
+Show firmware revision:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision
+        1.6
+
+Show firmware date:
+
+.. code-block:: bash
+
+        root:/sys/kernel/debug/iio/iio:device0> cat firmware_date
+        06-27-2019
+
+3. Device buffers
+=================
+
+This driver supports IIO buffers.
+
+All devices support retrieving the raw acceleration, gyroscope and temperature
+measurements using buffers.
+
+The following device families also support retrieving the delta velocity, delta
+angle and temperature measurements using buffers:
+
+- ADIS16477
+- ADIS16500
+- ADIS16505
+- ADIS16507
+
+However, when retrieving acceleration or gyroscope data using buffers, delta
+readings will not be available and vice versa.
+
+Usage examples
+--------------
+
+Set device trigger in current_trigger, if not already set:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
+
+        root:/sys/bus/iio/devices/iio:device0> echo adis16505-2-dev0 > trigger/current_trigger
+        root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
+        adis16505-2-dev0
+
+Select channels for buffer read:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_en
+
+Set the number of samples to be stored in the buffer:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length
+
+Enable buffer readings:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable
+
+Obtain buffered data:
+
+.. code-block:: bash
+
+        root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0
+        ...
+        00001680  01 1f 00 00 ff ff fe ef  00 00 47 bf 00 03 35 55  |..........G...5U|
+        00001690  01 1f 00 00 ff ff ff d9  00 00 46 f1 00 03 35 35  |..........F...55|
+        000016a0  01 1f 00 00 ff ff fe fc  00 00 46 cb 00 03 35 7b  |..........F...5{|
+        000016b0  01 1f 00 00 ff ff fe 41  00 00 47 0d 00 03 35 8b  |.......A..G...5.|
+        000016c0  01 1f 00 00 ff ff fe 37  00 00 46 b4 00 03 35 90  |.......7..F...5.|
+        000016d0  01 1d 00 00 ff ff fe 5a  00 00 45 d7 00 03 36 08  |.......Z..E...6.|
+        000016e0  01 1b 00 00 ff ff fe fb  00 00 45 e7 00 03 36 60  |..........E...6`|
+        000016f0  01 1a 00 00 ff ff ff 17  00 00 46 bc 00 03 36 de  |..........F...6.|
+        00001700  01 1a 00 00 ff ff fe 59  00 00 46 d7 00 03 37 b8  |.......Y..F...7.|
+        00001710  01 1a 00 00 ff ff fe ae  00 00 46 95 00 03 37 ba  |..........F...7.|
+        00001720  01 1a 00 00 ff ff fe c5  00 00 46 63 00 03 37 9f  |..........Fc..7.|
+        00001730  01 1a 00 00 ff ff fe 55  00 00 46 89 00 03 37 c1  |.......U..F...7.|
+        00001740  01 1a 00 00 ff ff fe 31  00 00 46 aa 00 03 37 f7  |.......1..F...7.|
+        ...
+
+See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered
+data is structured.
+
+4. IIO Interfacing Tools
+========================
+
+Linux Kernel Tools
+------------------
+
+Linux Kernel provides some userspace tools that can be used to retrieve data
+from IIO sysfs:
+
+* lsiio: example application that provides a list of IIO devices and triggers
+* iio_event_monitor: example application that reads events from an IIO device
+  and prints them
+* iio_generic_buffer: example application that reads data from buffer
+* iio_utils: set of APIs, typically used to access sysfs files.
+
+LibIIO
+------
+
+LibIIO is a C/C++ library that provides generic access to IIO devices. The
+library abstracts the low-level details of the hardware, and provides a simple
+yet complete programming interface that can be used for advanced projects.
+
+For more information about LibIIO, please see:
+https://github.com/analogdevicesinc/libiio
diff --git a/Documentation/iio/iio_devbuf.rst b/Documentation/iio/iio_devbuf.rst
new file mode 100644
index 0000000000..9919e4792d
--- /dev/null
+++ b/Documentation/iio/iio_devbuf.rst
@@ -0,0 +1,152 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============================
+Industrial IIO device buffers
+=============================
+
+1. Overview
+===========
+
+The Industrial I/O core offers a way for continuous data capture based on a
+trigger source. Multiple data channels can be read at once from
+``/dev/iio:deviceX`` character device node, thus reducing the CPU load.
+
+Devices with buffer support feature an additional sub-directory in the
+``/sys/bus/iio/devices/iio:deviceX/`` directory hierarchy, called bufferY, where
+Y defaults to 0, for devices with a single buffer.
+
+2. Buffer attributes
+====================
+
+An IIO buffer has an associated attributes directory under
+``/sys/bus/iio/iio:deviceX/bufferY/``. The attributes are described below.
+
+``length``
+----------
+
+Read / Write attribute which states the total number of data samples (capacity)
+that can be stored by the buffer.
+
+``enable``
+----------
+
+Read / Write attribute which starts / stops the buffer capture. This file should
+be written last, after length and selection of scan elements. Writing a non-zero
+value may result in an error, such as EINVAL, if, for example, an unsupported
+combination of channels is given.
+
+``watermark``
+-------------
+
+Read / Write positive integer attribute specifying the maximum number of scan
+elements to wait for.
+
+Poll will block until the watermark is reached.
+
+Blocking read will wait until the minimum between the requested read amount or
+the low watermark is available.
+
+Non-blocking read will retrieve the available samples from the buffer even if
+there are less samples than the watermark level. This allows the application to
+block on poll with a timeout and read the available samples after the timeout
+expires and thus have a maximum delay guarantee.
+
+Data available
+--------------
+
+Read-only attribute indicating the bytes of data available in the buffer. In the
+case of an output buffer, this indicates the amount of empty space available to
+write data to. In the case of an input buffer, this indicates the amount of data
+available for reading.
+
+Scan elements
+-------------
+
+The meta information associated with a channel data placed in a buffer is called
+a scan element. The scan elements attributes are presented below.
+
+**_en**
+
+Read / Write attribute used for enabling a channel. If and only if its value
+is non-zero, then a triggered capture will contain data samples for this
+channel.
+
+**_index**
+
+Read-only unsigned integer attribute specifying the position of the channel in
+the buffer. Note these are not dependent on what is enabled and may not be
+contiguous. Thus for userspace to establish the full layout these must be used
+in conjunction with all _en attributes to establish which channels are present,
+and the relevant _type attributes to establish the data storage format.
+
+**_type**
+
+Read-only attribute containing the description of the scan element data storage
+within the buffer and hence the form in which it is read from userspace. Format
+is [be|le]:[s|u]bits/storagebits[Xrepeat][>>shift], where:
+
+- **be** or **le** specifies big or little-endian.
+- **s** or **u** specifies if signed (2's complement) or unsigned.
+- **bits** is the number of valid data bits.
+- **storagebits** is the number of bits (after padding) that it occupies in the
+  buffer.
+- **repeat** specifies the number of bits/storagebits repetitions. When the
+  repeat element is 0 or 1, then the repeat value is omitted.
+- **shift** if specified, is the shift that needs to be applied prior to
+  masking out unused bits.
+
+For example, a driver for a 3-axis accelerometer with 12-bit resolution where
+data is stored in two 8-bit registers is as follows::
+
+          7   6   5   4   3   2   1   0
+        +---+---+---+---+---+---+---+---+
+        |D3 |D2 |D1 |D0 | X | X | X | X | (LOW byte, address 0x06)
+        +---+---+---+---+---+---+---+---+
+
+          7   6   5   4   3   2   1   0
+        +---+---+---+---+---+---+---+---+
+        |D11|D10|D9 |D8 |D7 |D6 |D5 |D4 | (HIGH byte, address 0x07)
+        +---+---+---+---+---+---+---+---+
+
+will have the following scan element type for each axis:
+
+.. code-block:: bash
+
+        $ cat /sys/bus/iio/devices/iio:device0/buffer0/in_accel_y_type
+        le:s12/16>>4
+
+A userspace application will interpret data samples read from the buffer as
+two-byte little-endian signed data, that needs a 4 bits right shift before
+masking out the 12 valid bits of data.
+
+It is also worth mentioning that the data in the buffer will be naturally
+aligned, so the userspace application has to handle the buffers accordingly.
+
+Take for example, a driver with four channels with the following description:
+- channel0: index: 0, type: be:u16/16>>0
+- channel1: index: 1, type: be:u32/32>>0
+- channel2: index: 2, type: be:u32/32>>0
+- channel3: index: 3, type: be:u64/64>>0
+
+If all channels are enabled, the data will be aligned in the buffer as follows::
+
+          0-1   2   3   4-7  8-11  12  13  14  15  16-23   -> buffer byte number
+        +-----+---+---+-----+-----+---+---+---+---+-----+
+        |CHN_0|PAD|PAD|CHN_1|CHN_2|PAD|PAD|PAD|PAD|CHN_3|  -> buffer content
+        +-----+---+---+-----+-----+---+---+---+---+-----+
+
+If only channel0 and channel3 are enabled, the data will be aligned in the
+buffer as follows::
+
+          0-1   2   3   4   5   6   7  8-15    -> buffer byte number
+        +-----+---+---+---+---+---+---+-----+
+        |CHN_0|PAD|PAD|PAD|PAD|PAD|PAD|CHN_3|  -> buffer content
+        +-----+---+---+---+---+---+---+-----+
+
+Typically the buffered data is found in raw format (unscaled with no offset
+applied), however there are corner cases in which the buffered data may be found
+in a processed form. Please note that these corner cases are not addressed by
+this documentation.
+
+Please see ``Documentation/ABI/testing/sysfs-bus-iio`` for a complete
+description of the attributes.
diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
index 1b7292c58c..30b09eefe7 100644
--- a/Documentation/iio/index.rst
+++ b/Documentation/iio/index.rst
@@ -8,7 +8,14 @@ Industrial I/O
    :maxdepth: 1
 
    iio_configfs
+   iio_devbuf
 
-   ep93xx_adc
+Industrial I/O Kernel Drivers
+=============================
 
+.. toctree::
+   :maxdepth: 1
+
+   adis16475
    bno055
+   ep93xx_adc