On Mon, 5 Nov 2018 13:47:50 +0800 Chen-Yu Tsai <wens@xxxxxxxx> wrote: > On Sat, Nov 3, 2018 at 6:22 PM Jonathan Cameron > <jic23@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > > On Wed, 31 Oct 2018 10:29:59 +0800 > > Chen-Yu Tsai <wens@xxxxxxxx> wrote: > > > > > On Mon, Oct 29, 2018 at 9:10 PM Quentin Schulz > > > <quentin.schulz@xxxxxxxxxxx> wrote: > > > > > > > > Hi Jonathan, > > > > > > > > On Sun, Oct 28, 2018 at 03:40:11PM +0000, Jonathan Cameron wrote: > > > > > On Wed, 24 Oct 2018 08:56:33 -0500 > > > > > Rob Herring <robh@xxxxxxxxxx> wrote: > > > > > > > > > > > On Tue, 23 Oct 2018 21:53:23 +0300, Oskari Lemmela wrote: > > > > > > > The AXP803 ADC is compatible with AXP813 ADC, but add > > > > > > > specific compatible for it. > > > > > > > > > > > > > > Signed-off-by: Oskari Lemmela <oskari@xxxxxxxxxxx> > > > > > > > --- > > > > > > > Documentation/devicetree/bindings/iio/adc/axp20x_adc.txt | 2 ++ > > > > > > > 1 file changed, 2 insertions(+) > > > > > > > > > > > > > > > > > > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> > > > > > > > > > > This doesn't seem to have any dependencies with the other patches > > > > > so applied to the togreg branch of iio.git and pushed out as testing > > > > > for the autobuilders to ignore. However I am a little curious to know > > > > > why we would add the ID and then not use it (that I can see)? > > > > > > > > > > > > > Sometimes with Allwinner (and X-Powers), two IPs seem identical until we > > > > discover something that is slightly different. When this happens, we > > > > have to add a compatible to differentiate both. However, we would also > > > > need to change the Device Tree to change the compatible. We would need > > > > to handle the driver behaviour for both Device Trees. > > > > > > > > So better anticipate a possible difference so that we don't have to do > > > > some hacks in the driver to handle the device correctly. > > > > > > > > As always, Chen-Yu or Maxime may know better so I'm just stating what I > > > > seem to recall. > > > > > > With Allwinner stuff (X-Powers included), sometimes the documents are > > > incomplete or have errors. We tend to add a model-specific compatible > > > just in case things turn out not to be so compatible, unless someone > > > has triple-checked everything, documents and actual hardware included. > > > > > > However we don't actually document these, so this patch isn't strictly > > > needed. (I suppose this might annoy the device tree binding maintainers.) > > > > > > ChenYu > > I don't think it does any harm so I'll leave it in place. Thanks for > > the explanations. > > It might cause a bit of confusion though. We are not targetting these > compatibles in terms of driver support, and they should not be used > individually. IMO dropping this patch altogether is better. In the > device tree we would use the tuplet axp803 + axp813. > OK. Dropped. Thanks, Jonathan > ChenYu
