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[v3,0/3] Add support for LTC2688

Message ID 20220121142501.151-1-nuno.sa@analog.com (mailing list archive)
Headers show
Series Add support for LTC2688 | expand

Message

Nuno Sa Jan. 21, 2022, 2:24 p.m. UTC 
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

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

Comments

Jonathan Cameron Jan. 22, 2022, 5:27 p.m. UTC | #1 
On Fri, 21 Jan 2022 15:24:58 +0100
Nuno Sá <nuno.sa@analog.com> 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
>
Andy Shevchenko Feb. 5, 2022, 4:24 p.m. UTC | #2 
On Sat, Jan 22, 2022 at 05:27:06PM +0000, Jonathan Cameron wrote:
> On Fri, 21 Jan 2022 15:24:58 +0100
> Nuno Sá <nuno.sa@analog.com> wrote:

...

> Series looks good to me, but will have to wait a little longer for DT and
> any other review before I apply it.

Thanks! I have comments.