| Message ID | 20220115092705.491-1-nuno.sa@analog.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Add support for LTC2688 | expand |
> * 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. Ah, that's unfortunate given the clk is only needed in certain modes... Andy/Rafael/Rob, any thoughts on how we should handle this? Obviously ACPI and clocks is generally a no go, but in this particular case we aren't looking at a power management related use of clocks, but rather using the clk framework to provide a way to control one of our inputs used to generate the output dithered signal... If the device just its own clock then we'd just control it directly with no problems, but it uses and external source. We don't know of anyone actually looking at this device in conjunction with ACPI so maybe just using dt specific calls for now rather than generic firmware properties is the best we can do. Thanks, Jonathan > > 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'. > > [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 | 80 ++ > .../bindings/iio/dac/adi,ltc2688.yaml | 147 +++ > MAINTAINERS | 9 + > drivers/iio/dac/Kconfig | 11 + > drivers/iio/dac/Makefile | 1 + > drivers/iio/dac/ltc2688.c | 1070 +++++++++++++++++ > 6 files changed, 1318 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 >
On Sun, Jan 16, 2022 at 7:28 PM Jonathan Cameron <jic23@kernel.org> wrote: > > > > > * 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. > > Ah, that's unfortunate given the clk is only needed in certain modes... > > Andy/Rafael/Rob, any thoughts on how we should handle this? Obviously > ACPI and clocks is generally a no go, but in this particular case we > aren't looking at a power management related use of clocks, but rather > using the clk framework to provide a way to control one of our inputs > used to generate the output dithered signal... If the device just its > own clock then we'd just control it directly with no problems, but it uses > and external source. > > We don't know of anyone actually looking at this device in conjunction with > ACPI so maybe just using dt specific calls for now rather than generic > firmware properties is the best we can do. The problem is the CCF is so OF-centric and maintainer(s) seems skeptical about switching it to use fwnode APIs (they wanted, last time I tried, to show how exactly it will be used, so here is your chance!), but OTOH switching to fwnode API is a half made road, because for ACPI we might need a glue layer which may be way too tricky to be considered as a part of this series.
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'. [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 | 80 ++ .../bindings/iio/dac/adi,ltc2688.yaml | 147 +++ MAINTAINERS | 9 + drivers/iio/dac/Kconfig | 11 + drivers/iio/dac/Makefile | 1 + drivers/iio/dac/ltc2688.c | 1070 +++++++++++++++++ 6 files changed, 1318 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