From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH v5 04/11] dt-bindings: iio: adc: add AXP803 ADC bindings Date: Sun, 11 Nov 2018 15:30:09 +0000 Message-ID: <20181111152952.0375b969@archlinux> References: <20181023185330.10472-1-oskari@lemmela.net> <20181023185330.10472-5-oskari@lemmela.net> <20181024135633.GA342@bogus> <20181028154011.04efdecf@archlinux> <20181029130757.m5okrfvusjl5fu5m@qschulz> <20181103102153.4f0481ad@archlinux> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Chen-Yu Tsai Cc: Rob Herring , Lars-Peter Clausen , "open list:THERMAL" , linux-iio@vger.kernel.org, Linus Walleij , Sebastian Reichel , linux-kernel , Vasily Khoruzhick , Quentin Schulz , devicetree , oskari@lemmela.net, linux-gpio@vger.kernel.org, Hartmut Knaack , Lee Jones , linux-arm-kernel , Quentin Schulz List-Id: linux-gpio@vger.kernel.org On Mon, 5 Nov 2018 13:47:50 +0800 Chen-Yu Tsai wrote: > On Sat, Nov 3, 2018 at 6:22 PM Jonathan Cameron > wrote: > > > > On Wed, 31 Oct 2018 10:29:59 +0800 > > Chen-Yu Tsai wrote: > > > > > On Mon, Oct 29, 2018 at 9:10 PM Quentin Schulz > > > 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 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 > > > > > > > --- > > > > > > > Documentation/devicetree/bindings/iio/adc/axp20x_adc.txt | 2 ++ > > > > > > > 1 file changed, 2 insertions(+) > > > > > > > > > > > > > > > > > > > Reviewed-by: Rob Herring > > > > > > > > > > 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