Hi Laurent,
> On Tuesday 11 Apr 2017 09:57:45 Ramesh Shanmugasundaram wrote:
> > > On Tuesday 07 Feb 2017 15:02:32 Ramesh Shanmugasundaram wrote:
> > >> Add device tree binding documentation for MAX2175 Rf to bits tuner
> > >> device.
> > >>
> > >> Signed-off-by: Ramesh Shanmugasundaram
> > >> <ramesh.shanmugasunda...@bp.renesas.com> ---
> > >>
> > >> .../devicetree/bindings/media/i2c/max2175.txt | 61
> +++++++++++++++
> > >> .../devicetree/bindings/property-units.txt | 1 +
> > >> 2 files changed, 62 insertions(+)
> > >> create mode 100644
> > >>
> > >> Documentation/devicetree/bindings/media/i2c/max2175.txt
> > >>
> > >> diff --git
> > >> a/Documentation/devicetree/bindings/media/i2c/max2175.txt
> > >> b/Documentation/devicetree/bindings/media/i2c/max2175.txt new file
> > >> mode 100644 index 0000000..f591ab4
> > >> --- /dev/null
> > >> +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
>
> [snip]
>
> > >> +- maxim,am-hiz : empty property indicates AM Hi-Z filter
> path
> > >> is
> > >> + selected for AM antenna input. By default this
> > >> + filter path is not used.
> > >
> > > Isn't this something that should be selected at runtime through a
> > > control ? Or does the hardware design dictate whether the filter has
> > > to be used or must not be used ?
> >
> > This is dictated by the h/w design and not selectable at run-time.
> > I will update these changes in the next patchset.
>
> In that case I'm fine with a property, but could we name it in such a way
> that it describes the hardware instead of instructing the software on how
> to configure the device ? For instance (and this is a made-up example as I
> don't know exactly how this works), if the AM Hi-Z filter is required when
> dealing with AM frequencies and forbidden when dealing with other
> frequency bands, and
> *if* boards have to be designed specifically for one frequency band (AM,
> FM, VHF, L, ...) without any way to accept different bands, then you could
> instead use
>
> maxim,frequency-band = "AM";
>
> and enable the filter accordingly in the driver. This would be in my
> opinion a better system hardware description.
I am not sure. The AM antenna input path has a default filter and AM Hi-Z
filter. H/W dictates the path to be used for AM input only and this is fixed.
The device can be configured to use different bands at runtime & not AM only. I
could edit the description as below:
- maxim,am-hiz : empty property indicates AM Hi-Z filter path usage for
AM antenna
input as dictated by hardware design. By default this
filter path is not used.
Is it any better? Do you still think the property name should be changed please?
Thanks,
Ramesh
