diff options
Diffstat (limited to 'Documentation/iio')
| -rw-r--r-- | Documentation/iio/ad3552r.rst | 72 | ||||
| -rw-r--r-- | Documentation/iio/ad4000.rst | 91 | ||||
| -rw-r--r-- | Documentation/iio/ad7380.rst | 7 | ||||
| -rw-r--r-- | Documentation/iio/ad7606.rst | 45 | ||||
| -rw-r--r-- | Documentation/iio/index.rst | 1 |
5 files changed, 215 insertions, 1 deletions
diff --git a/Documentation/iio/ad3552r.rst b/Documentation/iio/ad3552r.rst new file mode 100644 index 000000000000..f5d59e4e86c7 --- /dev/null +++ b/Documentation/iio/ad3552r.rst @@ -0,0 +1,72 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============== +AD3552R driver +============== + +Device driver for Analog Devices Inc. AD35XXR series of DACs. The module name +is ``ad3552r``. +With the same module name, two different driver variants are available, the +``generic spi`` variant, to be used with any classic SPI controllers, and the +``hs`` (high speed) variant, for an ADI ``axi-dac`` (IP core) based controller +that allows to reach the maximum sample rate supported from the DACs, using the +DMA transfer and all the SPI lines available (D/QDSPI).. +The high speed driver variant is intended to be used with the ``adi-axi-dac`` +backend support enabled, that is enabled by default when the driver is selected. + +Supported devices +================= + +* `AD3541R <https://www.analog.com/en/products/ad3541r.html>`_ +* `AD3542R <https://www.analog.com/en/products/ad3542r.html>`_ +* `AD3551R <https://www.analog.com/en/products/ad3551r.html>`_ +* `AD3552R <https://www.analog.com/en/products/ad3552r.html>`_ + +Wiring connections +================== + +Generic SPI +----------- +Use the classic SPI S_CLK/CS/SDO/SDI connection. + +High speed (using axi-dac backend) +---------------------------------- + +:: + + .-----------------. .-------. + | |--- D/QSPI -----| | + | DAC IP CORE |--- SPI S_CLK --| DAC | + | |--- SPI CS -----| | + | |--- LDAC -------| | + | |--- RESET ------| | + |_________________| |_______| + + +High speed features +=================== + +Device attributes +----------------- + +The following table shows the ad35xxr related device debug files, found in the +specific debugfs path ``/sys/kernel/debug/iio/iio:deviceX``. + ++-----------------------+------------------------------------------------------+ +| Debugfs device files | Description | ++-----------------------+------------------------------------------------------+ +| data_source | The used data source, as | +| | ``normal``, ``ramp-16bit``, etc. | ++-----------------------+------------------------------------------------------+ +| data_source_available | The available data sources. | ++-----------------------+------------------------------------------------------+ + +Usage examples +-------------- + +. code-block:: bash + root:/sys/bus/iio/devices/iio:device0# cat data_source + normal + root:/sys/bus/iio/devices/iio:device0# echo -n ramp-16bit > data_source + root:/sys/bus/iio/devices/iio:device0# cat data_source + ramp-16bit diff --git a/Documentation/iio/ad4000.rst b/Documentation/iio/ad4000.rst index de8fd3ae6e62..c1d04d3436d2 100644 --- a/Documentation/iio/ad4000.rst +++ b/Documentation/iio/ad4000.rst @@ -4,7 +4,7 @@ AD4000 driver ============= -Device driver for Analog Devices Inc. AD4000 series of ADCs. +Device driver for Analog Devices Inc. AD4000 series of ADCs and similar devices. Supported devices ================= @@ -25,6 +25,21 @@ Supported devices * `AD4022 <https://www.analog.com/AD4022>`_ * `ADAQ4001 <https://www.analog.com/ADAQ4001>`_ * `ADAQ4003 <https://www.analog.com/ADAQ4003>`_ +* `AD7685 <https://www.analog.com/AD7685>`_ +* `AD7686 <https://www.analog.com/AD7686>`_ +* `AD7687 <https://www.analog.com/AD7687>`_ +* `AD7688 <https://www.analog.com/AD7688>`_ +* `AD7690 <https://www.analog.com/AD7690>`_ +* `AD7691 <https://www.analog.com/AD7691>`_ +* `AD7693 <https://www.analog.com/AD7693>`_ +* `AD7942 <https://www.analog.com/AD7942>`_ +* `AD7946 <https://www.analog.com/AD7946>`_ +* `AD7980 <https://www.analog.com/AD7980>`_ +* `AD7982 <https://www.analog.com/AD7982>`_ +* `AD7983 <https://www.analog.com/AD7983>`_ +* `AD7984 <https://www.analog.com/AD7984>`_ +* `AD7988-1 <https://www.analog.com/AD7988-1>`_ +* `AD7988-5 <https://www.analog.com/AD7988-5>`_ Wiring connections ------------------ @@ -129,3 +144,77 @@ Set ``adi,sdi-pin`` to ``"cs"`` to select this mode. ^ | | +--------------------| SCLK | +-------------+ + +IIO Device characteristics +========================== + +The AD4000 series driver supports differential and pseudo-differential ADCs. + +The span compression feature available in AD4000 series devices can be +enabled/disabled by changing the ``_scale_available`` attribute of the voltage +channel. Note that span compression configuration requires writing to AD4000 +configuration register, which is only possible when the ADC is wired in 3-wire +turbo mode, and the SPI controller is ``SPI_MOSI_IDLE_HIGH`` capable. If those +conditions are not met, no ``_scale_available`` attribute is provided. + +Besides that, differential and pseudo-differential voltage channels present +slightly different sysfs interfaces. + +Pseudo-differential ADCs +------------------------ + +Typical voltage channel attributes of a pseudo-differential AD4000 series device: + ++-------------------------------------------+------------------------------------------+ +| Voltage Channel Attributes | Description | ++===========================================+==========================================+ +| ``in_voltage0_raw`` | Raw ADC output code. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_offset`` | Offset to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_scale`` | Scale factor to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_scale_available`` | Toggles input span compression | ++-------------------------------------------+------------------------------------------+ + +Differential ADCs +----------------- + +Typical voltage channel attributes of a differential AD4000 series device: + ++-------------------------------------------+------------------------------------------+ +| Voltage Channel Attributes | Description | ++===========================================+==========================================+ +| ``in_voltage0-voltage1_raw`` | Raw ADC output code. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0-voltage1_scale`` | Scale factor to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0-voltage1_scale_available`` | Toggles input span compression | ++-------------------------------------------+------------------------------------------+ + +SPI offload support +------------------- + +To be able to achieve the maximum sample rate, the driver can be used with SPI +offload engines such as the one usually present in `AXI SPI Engine`_, to provide +SPI offload support. + +.. _AXI SPI Engine: http://analogdevicesinc.github.io/hdl/projects/pulsar_adc/index.html + +To keep up with SPI offloading transfer speeds, the ADC must be connected either +in 3-wire turbo mode or in 3-wire without busy indicator mode and have SPI +controller CS line connected to the CNV pin. + +When set for SPI offload support, the IIO device will provide different +interfaces. + +* Either ``in_voltage0_sampling_frequency`` or + ``in_voltage0-voltage1_sampling_frequency`` file is provided to allow setting + the sample rate. +* IIO trigger device is not provided (no ``trigger`` directory). +* ``timestamp`` channel is not provided. + +Also, because the ADC output has a one sample latency (delay) when the device is +wired in "3-wire" mode and only one transfer per sample is done when using SPI +offloading, the first data sample in the buffer is not valid because it contains +the output of an earlier conversion result. diff --git a/Documentation/iio/ad7380.rst b/Documentation/iio/ad7380.rst index 24a92a1c4371..d51f9ee3e939 100644 --- a/Documentation/iio/ad7380.rst +++ b/Documentation/iio/ad7380.rst @@ -27,6 +27,7 @@ The following chips are supported by this driver: * `AD7386-4 <https://www.analog.com/en/products/ad7386-4.html>`_ * `AD7387-4 <https://www.analog.com/en/products/ad7387-4.html>`_ * `AD7388-4 <https://www.analog.com/en/products/ad7388-4.html>`_ +* `AD7389-4 <https://www.analog.com/en/products/ad7389-4.html>`_ * `ADAQ4370-4 <https://www.analog.com/en/products/adaq4370-4.html>`_ * `ADAQ4380-4 <https://www.analog.com/en/products/adaq4380-4.html>`_ * `ADAQ4381-4 <https://www.analog.com/en/products/adaq4381-4.html>`_ @@ -50,6 +51,12 @@ ad7380-4 ad7380-4 supports only an external reference voltage (2.5V to 3.3V). It must be declared in the device tree as ``refin-supply``. +ad7389-4 +~~~~~~~~ + +ad7389-4 supports only an internal reference voltage. ``refin-supply`` and +``refio-supply`` properties are both omitted in this case. + ADAQ devices ~~~~~~~~~~~~ diff --git a/Documentation/iio/ad7606.rst b/Documentation/iio/ad7606.rst index 930199e03c67..5e02516bab40 100644 --- a/Documentation/iio/ad7606.rst +++ b/Documentation/iio/ad7606.rst @@ -26,6 +26,35 @@ SPI wiring modes These ADCs can output data on several SDO lines (1/2/4/8). The driver currently supports only 1 SDO line. +SPI offload wiring +------------------ +When used with a SPI offload, the supported wiring configuration is: + +.. code-block:: + + +-------------+ +-------------+ + | BUSY |-------->| TRIGGER | + | CS |<--------| CS | + | | | | + | ADC | | SPI | + | | | | + | SDI |<--------| SDO | + | DOUTA |-------->| SDI | + | SCLK |<--------| SCLK | + | | | | + | | +-------------+ + | CONVST |<--------| PWM | + +-------------+ +-------------+ + +In this case, the ``pwms`` property is required. +The ``#trigger-source-cells = <1>`` property is also required to connect back +to the SPI offload. The SPI offload will have ``trigger-sources`` property +with a cell to indicate the busy signal: +``<&ad7606 AD4695_TRIGGER_EVENT_BUSY>``. + +.. seealso:: `SPI offload support`_ + + Parallel wiring mode -------------------- @@ -123,6 +152,22 @@ Unimplemented features - CRC indication - Calibration +SPI offload support +=================== + +To be able to achieve the maximum sample rate, the driver can be used with the +`AXI SPI Engine`_ to provide SPI offload support. + +.. _AXI SPI Engine: https://analogdevicesinc.github.io/hdl/library/spi_engine/index.html + +When SPI offload is being used, some attributes will be different. + +* ``trigger`` directory is removed. +* ``sampling_frequency`` attribute is added for setting the sample rate. +* ``timestamp`` channel is removed. +* Buffer data format may be different compared to when offload is not used, + e.g. the ``in_voltage0_type`` attribute. + Device buffers ============== diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst index bbb2edce8272..2d6afc5a8ed5 100644 --- a/Documentation/iio/index.rst +++ b/Documentation/iio/index.rst @@ -19,6 +19,7 @@ Industrial I/O Kernel Drivers .. toctree:: :maxdepth: 1 + ad3552r ad4000 ad4030 ad4695 |