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[PATCH v5 7/7] docs: iio: Add documentation for AD4000

Marcelo Schmitt posted 7 patches 1 year, 5 months ago
There is a newer version of this series
[PATCH v5 7/7] docs: iio: Add documentation for AD4000
Posted by Marcelo Schmitt 1 year, 5 months ago 
Document wiring configurations for the AD4000 series of ADCs.

Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
---
 Documentation/iio/ad4000.rst | 131 +++++++++++++++++++++++++++++++++++
 Documentation/iio/index.rst  |   1 +
 MAINTAINERS                  |   1 +
 3 files changed, 133 insertions(+)
 create mode 100644 Documentation/iio/ad4000.rst

diff --git a/Documentation/iio/ad4000.rst b/Documentation/iio/ad4000.rst
new file mode 100644
index 000000000000..de8fd3ae6e62
--- /dev/null
+++ b/Documentation/iio/ad4000.rst
@@ -0,0 +1,131 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+=============
+AD4000 driver
+=============
+
+Device driver for Analog Devices Inc. AD4000 series of ADCs.
+
+Supported devices
+=================
+
+* `AD4000 <https://www.analog.com/AD4000>`_
+* `AD4001 <https://www.analog.com/AD4001>`_
+* `AD4002 <https://www.analog.com/AD4002>`_
+* `AD4003 <https://www.analog.com/AD4003>`_
+* `AD4004 <https://www.analog.com/AD4004>`_
+* `AD4005 <https://www.analog.com/AD4005>`_
+* `AD4006 <https://www.analog.com/AD4006>`_
+* `AD4007 <https://www.analog.com/AD4007>`_
+* `AD4008 <https://www.analog.com/AD4008>`_
+* `AD4010 <https://www.analog.com/AD4010>`_
+* `AD4011 <https://www.analog.com/AD4011>`_
+* `AD4020 <https://www.analog.com/AD4020>`_
+* `AD4021 <https://www.analog.com/AD4021>`_
+* `AD4022 <https://www.analog.com/AD4022>`_
+* `ADAQ4001 <https://www.analog.com/ADAQ4001>`_
+* `ADAQ4003 <https://www.analog.com/ADAQ4003>`_
+
+Wiring connections
+------------------
+
+Devices of the AD4000 series can be connected to the SPI host controller in a
+few different modes.
+
+CS mode, 3-wire turbo mode
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Datasheet "3-wire" mode is what most resembles standard SPI connection which,
+for these devices, comprises of connecting the controller CS line to device CNV
+pin and other SPI lines as usual. This configuration is (misleadingly) called
+"CS Mode, 3-Wire Turbo Mode" connection in datasheets.
+NOTE: The datasheet definition of 3-wire mode for the AD4000 series is NOT the
+same of standard spi-3wire mode.
+This is the only connection mode that allows configuration register access but
+it requires the SPI controller to support the ``SPI_MOSI_IDLE_HIGH`` feature.
+
+Omit the ``adi,sdi-pin`` property in device tree to select this mode.
+
+::
+
+                                         +-------------+
+     + ----------------------------------| SDO         |
+     |                                   |             |
+     |               +-------------------| CS          |
+     |               v                   |             |
+     |    +--------------------+         |     HOST    |
+     |    |        CNV         |         |             |
+     +--->| SDI   AD4000   SDO |-------->| SDI         |
+          |        SCK         |         |             |
+          +--------------------+         |             |
+                    ^                    |             |
+                    +--------------------| SCLK        |
+                                         +-------------+
+
+CS mode, 3-wire, without busy indicator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Another wiring configuration supported as "3-wire" mode has the SDI pin
+hard-wired to digital input/output interface supply (VIO). In this setup, the
+controller is not required to support ``SPI_MOSI_IDLE_HIGH`` but register access
+is not possible. This connection mode saves one wire and works with any SPI
+controller.
+
+Set the ``adi,sdi-pin`` device tree property to ``"high"`` to select this mode.
+
+::
+
+                                         +-------------+
+                    +--------------------| CS          |
+                    v                    |             |
+    VIO   +--------------------+         |     HOST    |
+     |    |        CNV         |         |             |
+     +--->| SDI   AD4000   SDO |-------->| SDI         |
+          |        SCK         |         |             |
+          +--------------------+         |             |
+                    ^                    |             |
+                    +--------------------| SCLK        |
+                                         +-------------+
+
+Alternatively, a GPIO may be connected to the device CNV pin. This is similar to
+the previous wiring configuration but saves the use of a CS line.
+
+::
+
+                                         +-------------+
+                    +--------------------| GPIO        |
+                    v                    |             |
+    VIO   +--------------------+         |     HOST    |
+     |    |        CNV         |         |             |
+     +--->| SDI   AD4000   SDO |-------->| SDI         |
+          |        SCK         |         |             |
+          +--------------------+         |             |
+                    ^                    |             |
+                    +--------------------| SCLK        |
+                                         +-------------+
+
+CS mode, 4-wire without busy indicator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In datasheet "4-wire" mode, the controller CS line is connected to the ADC SDI
+pin and a GPIO is connected to the ADC CNV pin. This connection mode may better
+suit scenarios where multiple ADCs can share one CNV trigger.
+
+Set ``adi,sdi-pin`` to ``"cs"`` to select this mode.
+
+
+::
+
+                                         +-------------+
+     + ----------------------------------| CS          |
+     |                                   |             |
+     |               +-------------------| GPIO        |
+     |               v                   |             |
+     |    +--------------------+         |     HOST    |
+     |    |        CNV         |         |             |
+     +--->| SDI   AD4000   SDO |-------->| SDI         |
+          |        SCK         |         |             |
+          +--------------------+         |             |
+                    ^                    |             |
+                    +--------------------| SCLK        |
+                                         +-------------+
diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
index 4c13bfa2865c..5df157a44923 100644
--- a/Documentation/iio/index.rst
+++ b/Documentation/iio/index.rst
@@ -17,6 +17,7 @@ Industrial I/O Kernel Drivers
 .. toctree::
    :maxdepth: 1
 
+   ad4000
    ad7944
    adis16475
    adis16480
diff --git a/MAINTAINERS b/MAINTAINERS
index f4ffedada8ea..a03b3db9157c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1205,6 +1205,7 @@ L:	linux-iio@vger.kernel.org
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
+F:	Documentation/iio/ad4000.rst
 F:	drivers/iio/adc/ad4000.c
 
 ANALOG DEVICES INC AD4130 DRIVER
-- 
2.43.0
Re: [PATCH v5 7/7] docs: iio: Add documentation for AD4000
Posted by David Lechner 1 year, 5 months ago 
On 6/25/24 4:55 PM, Marcelo Schmitt wrote:
> Document wiring configurations for the AD4000 series of ADCs.
> 
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
> ---
>  Documentation/iio/ad4000.rst | 131 +++++++++++++++++++++++++++++++++++
>  Documentation/iio/index.rst  |   1 +
>  MAINTAINERS                  |   1 +
>  3 files changed, 133 insertions(+)
>  create mode 100644 Documentation/iio/ad4000.rst
> 
> diff --git a/Documentation/iio/ad4000.rst b/Documentation/iio/ad4000.rst
> new file mode 100644
> index 000000000000..de8fd3ae6e62
> --- /dev/null
> +++ b/Documentation/iio/ad4000.rst
> @@ -0,0 +1,131 @@
> +.. SPDX-License-Identifier: GPL-2.0-only
> +
> +=============
> +AD4000 driver
> +=============
> +
> +Device driver for Analog Devices Inc. AD4000 series of ADCs.
> +
> +Supported devices
> +=================
> +
> +* `AD4000 <https://www.analog.com/AD4000>`_
> +* `AD4001 <https://www.analog.com/AD4001>`_
> +* `AD4002 <https://www.analog.com/AD4002>`_
> +* `AD4003 <https://www.analog.com/AD4003>`_
> +* `AD4004 <https://www.analog.com/AD4004>`_
> +* `AD4005 <https://www.analog.com/AD4005>`_
> +* `AD4006 <https://www.analog.com/AD4006>`_
> +* `AD4007 <https://www.analog.com/AD4007>`_
> +* `AD4008 <https://www.analog.com/AD4008>`_
> +* `AD4010 <https://www.analog.com/AD4010>`_
> +* `AD4011 <https://www.analog.com/AD4011>`_
> +* `AD4020 <https://www.analog.com/AD4020>`_
> +* `AD4021 <https://www.analog.com/AD4021>`_
> +* `AD4022 <https://www.analog.com/AD4022>`_
> +* `ADAQ4001 <https://www.analog.com/ADAQ4001>`_
> +* `ADAQ4003 <https://www.analog.com/ADAQ4003>`_
> +
> +Wiring connections
> +------------------
> +
> +Devices of the AD4000 series can be connected to the SPI host controller in a
> +few different modes.
> +
> +CS mode, 3-wire turbo mode
> +^^^^^^^^^^^^^^^^^^^^^^^^^^

The datasheet also has the same diagram in _Figure 55. CS Mode, 4-Wire Turbo Mode
Connection Diagram_. So maybe we should call this "register support mode" or
something like that instead of mentioning 3 or 4-wire?

> +
> +Datasheet "3-wire" mode is what most resembles standard SPI connection which,
> +for these devices, comprises of connecting the controller CS line to device CNV
> +pin and other SPI lines as usual. This configuration is (misleadingly) called
> +"CS Mode, 3-Wire Turbo Mode" connection in datasheets.
> +NOTE: The datasheet definition of 3-wire mode for the AD4000 series is NOT the
> +same of standard spi-3wire mode.
> +This is the only connection mode that allows configuration register access but
> +it requires the SPI controller to support the ``SPI_MOSI_IDLE_HIGH`` feature.
> +
> +Omit the ``adi,sdi-pin`` property in device tree to select this mode.
> +
> +::
> +
> +                                         +-------------+
> +     + ----------------------------------| SDO         |
> +     |                                   |             |
> +     |               +-------------------| CS          |
> +     |               v                   |             |
> +     |    +--------------------+         |     HOST    |
> +     |    |        CNV         |         |             |
> +     +--->| SDI   AD4000   SDO |-------->| SDI         |
> +          |        SCK         |         |             |
> +          +--------------------+         |             |
> +                    ^                    |             |
> +                    +--------------------| SCLK        |
> +                                         +-------------+
> +

I think the rest of the explanations are good.
Re: [PATCH v5 7/7] docs: iio: Add documentation for AD4000
Posted by Marcelo Schmitt 1 year, 5 months ago 
On 06/26, David Lechner wrote:
> On 6/25/24 4:55 PM, Marcelo Schmitt wrote:
> > Document wiring configurations for the AD4000 series of ADCs.
> > 
> > Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
> > ---
> >  Documentation/iio/ad4000.rst | 131 +++++++++++++++++++++++++++++++++++
> >  Documentation/iio/index.rst  |   1 +
> >  MAINTAINERS                  |   1 +
...
> > +Wiring connections
> > +------------------
> > +
> > +Devices of the AD4000 series can be connected to the SPI host controller in a
> > +few different modes.
> > +
> > +CS mode, 3-wire turbo mode
> > +^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> The datasheet also has the same diagram in _Figure 55. CS Mode, 4-Wire Turbo Mode
> Connection Diagram_. So maybe we should call this "register support mode" or
> something like that instead of mentioning 3 or 4-wire?
> 
Humm, ADAQ4003 datasheet has the same figure for CS Mode, 4-wire turbo mode
and CS mode, 4-wire with busy indicator although other datasheets have MOSI
to SDI in 4-wire turbo as you said. The register read/write functionality
sections say CNV must be brought low to access the configuration register.
I'll leave it as it is for now as I have not tested reg access with CNV high.
We can update this in the future if find out reg access to work in 4-wire mode.

> > +
> > +Datasheet "3-wire" mode is what most resembles standard SPI connection which,
> > +for these devices, comprises of connecting the controller CS line to device CNV
> > +pin and other SPI lines as usual. This configuration is (misleadingly) called
> > +"CS Mode, 3-Wire Turbo Mode" connection in datasheets.
> > +NOTE: The datasheet definition of 3-wire mode for the AD4000 series is NOT the
> > +same of standard spi-3wire mode.
> > +This is the only connection mode that allows configuration register access but
> > +it requires the SPI controller to support the ``SPI_MOSI_IDLE_HIGH`` feature.
> > +
> > +Omit the ``adi,sdi-pin`` property in device tree to select this mode.
> > +
> > +::
> > +
> > +                                         +-------------+
> > +     + ----------------------------------| SDO         |
> > +     |                                   |             |
> > +     |               +-------------------| CS          |
> > +     |               v                   |             |
> > +     |    +--------------------+         |     HOST    |
> > +     |    |        CNV         |         |             |
> > +     +--->| SDI   AD4000   SDO |-------->| SDI         |
> > +          |        SCK         |         |             |
> > +          +--------------------+         |             |
> > +                    ^                    |             |
> > +                    +--------------------| SCLK        |
> > +                                         +-------------+
> > +
> 
> I think the rest of the explanations are good.
>

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