Hi Ramesh, 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.shanmugasundaram@xxxxxxxxxxxxxx> --- > >> > >> .../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. -- Regards, Laurent Pinchart
