On Sat, 15 Jan 2022 10:27:04 +0100 Nuno Sá <nuno.sa@xxxxxxxxxx> wrote: > Define the sysfs interface for toggle or dither capable channels. Dither > capable channels will have the extended interface: > > * out_voltageY_dither_en > * out_voltageY_dither_raw > * out_voltageY_dither_offset > * out_voltageY_dither_raw_available > * out_voltageY_dither_frequency > * out_voltageY_dither_frequency_available > * out_voltageY_dither_phase > * out_voltageY_dither_phase_available > > Toggle enabled channels will have: > > * out_voltageY_toggle_en > * out_voltageY_raw0 > * out_voltageY_raw1 > * out_voltageY_symbol Maybe worth just stating the normal interface here as well because it's not clear from these examples if out_voltageY_raw still exists for toggle enabled channels (I'm assuming not?) > > Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx> ABI seems good to me, just a few comments on details of the documentation. Thanks, Jonathan > --- > .../ABI/testing/sysfs-bus-iio-dac-ltc2688 | 80 +++++++++++++++++++ > MAINTAINERS | 1 + > 2 files changed, 81 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688 > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688 b/Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688 > new file mode 100644 > index 000000000000..38d1df81c6dc > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688 > @@ -0,0 +1,80 @@ > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_en > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Dither enable. Write 1 to enable dither or 0 to disable it. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_raw > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + This raw, unscaled value refers to the dither signal amplitude. > + The same scale as in out_voltageY_raw applies. However, the > + offset might be different as it's always 0 for this attribute. We'll have to be careful if we ever generalize these docs but what you have here is fine whilst it applies to just this device. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_raw_available > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Available range for dither raw amplitude values. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_offset > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Offset applied to out_voltageY_dither_raw. Read only attribute > + always set to 0. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_frequency > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Sets the dither signal frequency. Units. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_frequency_available > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Returns the available values for the dither frequency. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_phase > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Sets the dither signal phase. Units. Radians, or refer to the main _phase docs and say it's the same. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_dither_phase_available > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Returns the available values for the dither phase. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_toggle_en > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Toggle enable. Write 1 to enable toggle or 0 to disable it. Say why this is useful (presumably toggle with a clock rather than via _symbol) > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_raw0 > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + It has the same meaning as out_voltageY_raw. This attribute is > + specific to toggle enabled channels and refers to the DAC output > + code in INPUT_A. The same scale, offset, etc applies. Same as what? > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_raw1 > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Same as out_voltageY_raw0 but referring to the DAC output code > + in INPUT_B. You could combine this with previous and have two what lines. Might allow a slightly more compact clear description. > + > +What: /sys/bus/iio/devices/iio:deviceX/out_voltageY_symbol Ah. That answers one of my binding related questions :) You have kept software control as an option for toggle. > +KernelVersion: 5.17 > +Contact: linux-iio@xxxxxxxxxxxxxxx > +Description: > + Performs a SW toggle. This attribute is specific to toggle > + enabled channels and allows to toggle between out_voltageY_raw _raw0 > + and out_voltageY_raw1 through software. Writing 0 will select > + out_voltageY_raw while 1 selects out_voltageY_raw1. _raw0 > diff --git a/MAINTAINERS b/MAINTAINERS > index 16e344d52b1e..16a7fd7f98ee 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -11187,6 +11187,7 @@ M: Nuno Sá <nuno.sa@xxxxxxxxxx> > L: linux-iio@xxxxxxxxxxxxxxx > S: Supported > W: http://ez.analog.com/community/linux-device-drivers > +F: Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688 > F: drivers/iio/dac/ltc2688.c > > LTC2947 HARDWARE MONITOR DRIVER
