On 16.3.2017 22:20, Lars-Peter Clausen wrote: > On 03/16/2017 07:06 PM, Michal Simek wrote: >> On 16.3.2017 17:51, Lars-Peter Clausen wrote: >>> On 03/16/2017 05:45 PM, Michal Simek wrote: >>>> On 16.3.2017 17:39, Moritz Fischer wrote: >>>>> On Thu, Mar 16, 2017 at 9:16 AM, Michal Simek <michal.simek@xxxxxxxxxx> wrote: >>>>>> Hi, >>>>>> >>>>>> On 8.3.2017 21:11, Moritz Fischer wrote: >>>>>>> Fix >>>>>>> >>>>>>> OF: /iio_hwmon: could not get #io-channel-cells for >>>>>>> /amba/adc@f8007100 >>>>>>> OF: /iio_hwmon: could not get #io-channel-cells for >>>>>>> /amba/adc@f8007100 >>>>>>> OF: /iio_hwmon: could not get #io-channel-cells for >>>>>>> /amba/adc@f8007100 >>>>>>> >>>>>>> by adding the #io-channel-cells property. >>>>>>> >>>>>>> Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx> >>>>>>> Cc: Michal Simek <michal.simek@xxxxxxxxxx> >>>>>>> Cc: Sören Brinkmann <soren.brinkmann@xxxxxxxxxx> >>>>>>> Cc: Julia Cartwright <julia@xxxxxx> >>>>>>> Cc: linux-kernel@xxxxxxxxxxxxxxx >>>>>>> Cc: devicetree@xxxxxxxxxxxxxxx >>>>>>> --- >>>>>>> >>>>>>> Changes from v1: >>>>>>> - fix messed up commit message >>>>>>> --- >>>>>>> arch/arm/boot/dts/zynq-7000.dtsi | 1 + >>>>>>> 1 file changed, 1 insertion(+) >>>>>>> >>>>>>> diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi >>>>>>> index f3ac9bf..98233a8 100644 >>>>>>> --- a/arch/arm/boot/dts/zynq-7000.dtsi >>>>>>> +++ b/arch/arm/boot/dts/zynq-7000.dtsi >>>>>>> @@ -72,6 +72,7 @@ >>>>>>> interrupts = <0 7 4>; >>>>>>> interrupt-parent = <&intc>; >>>>>>> clocks = <&clkc 12>; >>>>>>> + #io-channel-cells = <1>; >>>>>>> }; >>>>>>> >>>>>>> can0: can@e0008000 { >>>>>>> >>>>>> >>>>>> I think it will be good to the next step too. >>>>>> It means also add iio-hwmon node too. >>>>>> >>>>>> What do you think? >>>>> >>>>> I hadn't put it in there since dts is supposed to describe hw, >>>>> but obviously putting the actual hwmon in there makes it more useful. >>>> >>>> I had one discussion about this with Grant in past and it is common >>>> mistake. It is simplification of purpose of dts. >>>> >>> >>> If the iio-hwmon binding had gone through review it would have been rejected. >> >> Isn't it a time to deprecate it? > > Well, it's ABI now and has to stay forever. Deprecating it makes only sense > if there is a replacement, which there is not. The iio-hwmon bridge has its > usecases it's just instantiating it via devicetree which is not so nice. > >> >>> >>>>> >>>>> I can resubmit with the hwmon node in there. >>>> >>>> If you grep kernel tree you will see that others are using it too. >>>> Also there is accepted binding for that that's why I can't see big >>>> problem with it. >>> >>> Since this is an application specific binding I wouldn't put it in the >>> generic DT include file. It's a bit like adding a gpio-key binding for each >>> of the GPIOs just in case somebody wants to use it. >> >> psci is system specific too. >> >> IIRC this driver for zynq was written by ADI or with ADI help that's why >> you know much better than I what's the correct configuration. >> >> This targets PS IP which should be present in the hw all the time. >> Not sure if for all configuration but I expect at least the part of it >> is there all them time. >> >> If binding is incorrect then please remove it with removing from all >> dts/dtsi files which have this. The same is for of probe function in the >> driver itself. >> If this is not done then this is just +1 case. >> >> If you still insist that we shouldn't do it then please at least extend >> commit message and put there example how to wire it on zynq. > > There is a IIO driver for the XADC, this driver has a userspace interface > that exposes the measurements provided by the hardware. Using the hwmon > bridge will expose the same information just through a hwmon interface. > > One reason for using the iio-hwmon bridge is because you have a legacy > application that expects the a hwmon interface. But new applications that > want to access the XADC should really use the IIO interface if possible. > > In my opinion instantiating the hwmon bridge by default will only cause > confusion. There are now redundant interfaces and users will wonder what is > the difference between the two. Is it the same data, is it different data? > Which is the preferred interface? Which one is 'better'? IMHO this should be covered by documentation. One paragraph in iio-hwmon binding can have answers for this and it will be very clear what people should use. Thanks, Michal -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html