New interface is proposed for dither functionality. This future allows
composing an external signals to the selected output channel.
The dither signal can be turned on/off, scaled, inverted, or it can be
selected from different sources.
Signed-off-by: Cristian Pop <[email protected]>
---
Changelog v4:
- Change to "in_voltageY_dither_enable"
- Change scale to numbers + 100% for no scaling
- Possible dither source values: 0 - N0, 1 - N1
.../ABI/testing/sysfs-bus-iio-dac-ad5766 | 36 +++++++++++++++++++
1 file changed, 36 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766 b/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
new file mode 100644
index 000000000000..72100edb88bb
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
@@ -0,0 +1,36 @@
+What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_pwr
+KernelVersion:
+Contact: [email protected]
+Description:
+ Dither enable. Write 1 to enable dither or 0 to disable it.
+
+What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_invert
+KernelVersion:
+Contact: [email protected]
+Description:
+ Inverts the dither applied to the selected DAC channel. Dither is not
+ inverted by default. Write "1" to invert dither.
+
+What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_scale_available
+KernelVersion:
+Contact: [email protected]
+Description:
+ Returns possible scalings available for the current channel:
+ "100 75 50 25" scaling.
+
+What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_scale
+KernelVersion:
+Contact: [email protected]
+Description:
+ Scales the dither before it is applied to the selected channel:
+ 100 - No scaling
+ 75 - 75% scaling
+ 50 - 50% scaling
+ 25 - 25% scaling
+
+What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_source
+KernelVersion:
+Contact: [email protected]
+Description:
+ Selects dither source applied to the selected channel. Write "0" to
+ select N0 source, write "1" to select N1 source.
--
2.17.1
On Fri, 18 Dec 2020 19:12:30 +0200
Cristian Pop <[email protected]> wrote:
> New interface is proposed for dither functionality. This future allows
> composing an external signals to the selected output channel.
> The dither signal can be turned on/off, scaled, inverted, or it can be
> selected from different sources.
>
> Signed-off-by: Cristian Pop <[email protected]>
Coming together nicely though a few more thoughts came to mind when reading
this. Only significant one is whether we are better with decimal scaling
than percentage scaling for consistency with channel scales etc?
Jonathan
> ---
> Changelog v4:
> - Change to "in_voltageY_dither_enable"
> - Change scale to numbers + 100% for no scaling
> - Possible dither source values: 0 - N0, 1 - N1
> .../ABI/testing/sysfs-bus-iio-dac-ad5766 | 36 +++++++++++++++++++
> 1 file changed, 36 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766 b/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
> new file mode 100644
> index 000000000000..72100edb88bb
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
> @@ -0,0 +1,36 @@
> +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_pwr
in_voltageY_dither_en would be more consistent with existing ABI naming.
> +KernelVersion:
> +Contact: [email protected]
> +Description:
> + Dither enable. Write 1 to enable dither or 0 to disable it.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_invert
> +KernelVersion:
> +Contact: [email protected]
> +Description:
> + Inverts the dither applied to the selected DAC channel. Dither is not
> + inverted by default. Write "1" to invert dither.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_scale_available
> +KernelVersion:
> +Contact: [email protected]
> +Description:
> + Returns possible scalings available for the current channel:
Given this one is self defining and may well get generalized to other devices I'd
got with a description that doesn't provide values.
Returns possible scalings as percentages.
However, thinking more on this it's a bit inconsistent with other scale values we have
which are given in decimal. Would "1 0.75 0.5 0.25" work as well here?
> + "100 75 50 25" scaling.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_scale
> +KernelVersion:
> +Contact: [email protected]
> +Description:
> + Scales the dither before it is applied to the selected channel:
> + 100 - No scaling
> + 75 - 75% scaling
> + 50 - 50% scaling
> + 25 - 25% scaling
As above, I'm don't really see an advantage in providing the values. Any userspace
ought to cope with any (finding out what is there via _available).
"Scales the dither before it is applied to the selected channel. 1 corresponds
to no scaling".
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_source
> +KernelVersion:
Please fill in the expected kernel version. I'll fix it if this happens to merge near
the change over in a cycle, but it's easier to fix something that is there
than to add it from scratch :)
> +Contact: [email protected]
> +Description:
> + Selects dither source applied to the selected channel. Write "0" to
> + select N0 source, write "1" to select N1 source.
On Tue, 29 Dec 2020 16:27:58 +0000
Jonathan Cameron <[email protected]> wrote:
> On Fri, 18 Dec 2020 19:12:30 +0200
> Cristian Pop <[email protected]> wrote:
>
> > New interface is proposed for dither functionality. This future allows
> > composing an external signals to the selected output channel.
> > The dither signal can be turned on/off, scaled, inverted, or it can be
> > selected from different sources.
> >
> > Signed-off-by: Cristian Pop <[email protected]>
> Coming together nicely though a few more thoughts came to mind when reading
> this. Only significant one is whether we are better with decimal scaling
> than percentage scaling for consistency with channel scales etc?
>
> Jonathan
>
> > ---
> > Changelog v4:
> > - Change to "in_voltageY_dither_enable"
> > - Change scale to numbers + 100% for no scaling
> > - Possible dither source values: 0 - N0, 1 - N1
> > .../ABI/testing/sysfs-bus-iio-dac-ad5766 | 36 +++++++++++++++++++
> > 1 file changed, 36 insertions(+)
> > create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766 b/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
> > new file mode 100644
> > index 000000000000..72100edb88bb
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-ad5766
> > @@ -0,0 +1,36 @@
> > +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_pwr
>
> in_voltageY_dither_en would be more consistent with existing ABI naming.
Seems to be different in the code (dither_enable I think) so please sanity
check this file carefully against the driver.
Thanks,
Jonathan
>
> > +KernelVersion:
> > +Contact: [email protected]
> > +Description:
> > + Dither enable. Write 1 to enable dither or 0 to disable it.
> > +
> > +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_invert
> > +KernelVersion:
> > +Contact: [email protected]
> > +Description:
> > + Inverts the dither applied to the selected DAC channel. Dither is not
> > + inverted by default. Write "1" to invert dither.
> > +
> > +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_scale_available
> > +KernelVersion:
> > +Contact: [email protected]
> > +Description:
> > + Returns possible scalings available for the current channel:
>
> Given this one is self defining and may well get generalized to other devices I'd
> got with a description that doesn't provide values.
>
> Returns possible scalings as percentages.
>
> However, thinking more on this it's a bit inconsistent with other scale values we have
> which are given in decimal. Would "1 0.75 0.5 0.25" work as well here?
>
> > + "100 75 50 25" scaling.
> > +
> > +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_scale
> > +KernelVersion:
> > +Contact: [email protected]
> > +Description:
> > + Scales the dither before it is applied to the selected channel:
> > + 100 - No scaling
> > + 75 - 75% scaling
> > + 50 - 50% scaling
> > + 25 - 25% scaling
>
> As above, I'm don't really see an advantage in providing the values. Any userspace
> ought to cope with any (finding out what is there via _available).
> "Scales the dither before it is applied to the selected channel. 1 corresponds
> to no scaling".
>
> > +
> > +What: /sys/bus/iio/devices/iio:deviceX/in_voltageY_dither_source
> > +KernelVersion:
>
> Please fill in the expected kernel version. I'll fix it if this happens to merge near
> the change over in a cycle, but it's easier to fix something that is there
> than to add it from scratch :)
>
> > +Contact: [email protected]
> > +Description:
> > + Selects dither source applied to the selected channel. Write "0" to
> > + select N0 source, write "1" to select N1 source.
>