On Fri, 21 Jan 2022 15:24:58 +0100
Nuno Sá <nuno.sa@xxxxxxxxxx> wrote:
> The ABI defined for this driver has some subtleties that were previously
> discussed in this RFC [1]. This might not be the final state but,
> hopefully, we are close to it:
>
> toggle mode channels:
>
> * out_voltageY_toggle_en
> * out_voltageY_raw0
> * out_voltageY_raw1
> * out_voltageY_symbol
>
> dither mode channels:
>
> * out_voltageY_dither_en
> * out_voltageY_dither_raw
> * out_voltageY_dither_raw_available
> * out_voltageY_dither_offset
> * out_voltageY_dither_frequency
> * out_voltageY_dither_frequency_available
> * out_voltageY_dither_phase
> * out_voltageY_dither_phase_available
>
> Default channels won't have any of the above ABIs. A channel is toggle
> capable if the devicetree 'adi,toggle-mode' flag is set. For dither, the
> assumption is more silent. If 'adi,toggle-mode' is not given and a
> channel is associated with a TGPx pin through 'adi,toggle-dither-input',
> then the channel is assumed to be dither capable (there's no point in
> having a dither capable channel without an input clock).
>
> changes in v2:
>
> ltc2688:
> * Use local buffer for regmap read. Do not assume that reg is part of
> larger buffer;
> * Renamed GPIO to "clr" so that is consistent with the datasheet;
> * Renamed 'mask' and 'm' to info. 'mask' is a thing from the past;
> * Removed 'LTC2688_CHAN_TOGGLE()' and defined to static ext_info arrays;
> * Use 'regmap_set_bits' to set external ref;
> * Use FIELD_{PREP|GET} for dither amplitude and channel calibbias where
> only 13bits are used;
> * Use 'regmap_write()' instead of update_bits for channels settings;
> * Init 'val' at the beginning of the channel configuration loop
> (and drop mask);
> * Comment 'ltc2688_reg_writable()' to account for the special condition;
> * Kmemdup default channels so that it can be safely changed per probed
> device;
> * Replace extended info multiplexer functions by individual functions;
> * Use raw0 ABI for toggle channels;
> * Use dedicated offset ABI for dither channels;
> * Misc changes (spell fixes, blank lines...);
> * Have a clock property per channel. Note that we this I moved to OF
> since we now have to use 'devm_get_clk_from_child()' which is using
> device_node. Note that I could use 'to_of_node()' but mixing of.h and
> property.h does not feel like a good idea.
>
> ABI:
> * Added out_voltageY_raw0 ABI for toggle mode;
> * Added out_voltageY_dither_offset.
>
> Bindings:
> * Use standard microvolt unit;
> * Added constrains for adi,output-range-microvolt and removed negative
> values from the dts example;
> * Moved clocks to the channel object;
> * Dropped clock-names;
> * Add a dependency between 'adi,toggle-dither-input' and 'clocks'.
>
> Changes in v3:
>
> ltc2688:
> * Fix mismatch between functions and function pointers detected by kernel
> test bot;
> * Always use if (ret) when ret > 0 has no meaning;
> * Rename ltc2688_bulk_disable -> ltc2688_disable_regulators;
> * Report dither phase in radians rather than degrees.
>
> ABI:
> * Specify units for dither_phase and dither_freqency;
> * Say why its useful to have dither_en and toggle_en;
> * Combine out_voltageY_raw0 and out_voltageY_raw1;
> * Fix some description issues in out_voltageY_raw{0|1} and
> out_voltageY_symbol.
>
> Bindings:
> * Remove mentions to ABI (linux specifix);
> * Slightly rephrased VREF and adi,toggle-dither-input properties and
> suggested.
>
> [1]: https://marc.info/?l=linux-iio&m=163662843603265&w=2
Series looks good to me, but will have to wait a little longer for DT and
any other review before I apply it.
Thanks,
Jonathan
>
> Nuno Sá (3):
> iio: dac: add support for ltc2688
> iio: ABI: add ABI file for the LTC2688 DAC
> dt-bindings: iio: Add ltc2688 documentation
>
> .../ABI/testing/sysfs-bus-iio-dac-ltc2688 | 86 ++
> .../bindings/iio/dac/adi,ltc2688.yaml | 146 +++
> MAINTAINERS | 9 +
> drivers/iio/dac/Kconfig | 11 +
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/ltc2688.c | 1070 +++++++++++++++++
> 6 files changed, 1323 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688
> create mode 100644 Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> create mode 100644 drivers/iio/dac/ltc2688.c
>
