Hi Rob, On 02/05/22 11:00, Aswath Govindraju wrote: > Hi Rob, > > On 26/04/22 12:27, Heikki Krogerus wrote: >> On Tue, Apr 26, 2022 at 09:42:31AM +0300, Roger Quadros wrote: >>> Hi, >>> >>> On 22/04/2022 08:07, Aswath Govindraju wrote: >>>> Hi Roger, >>>> >>>> On 21/04/22 00:46, Roger Quadros wrote: >>>>> Hi, >>>>> >>>>> On 18/04/2022 08:19, Aswath Govindraju wrote: >>>>>> Hi Roger, >>>>>> >>>>>> On 14/04/22 23:40, Roger Quadros wrote: >>>>>>> Hi, >>>>>>> >>>>>>> On 14/04/2022 11:31, Aswath Govindraju wrote: >>>>>>>> Support for polling has been added in the driver, which will be used by >>>>>>>> default if interrupts property is not populated. Therefore, remove >>>>>>>> interrupts and interrupt-names from the required properties and add a note >>>>>>>> under interrupts property describing the above support in driver. >>>>>>>> >>>>>>>> Suggested-by: Roger Quadros <rogerq@xxxxxxxxxx> >>>>>>> >>>>>>> I did not suggest to make interrupts optional by default. >>>>>>> >>>>>>> What I suggested was that if a DT property exists to explicitly >>>>>>> indicate polling mode then interrupts are not required. >>>>>>> >>>>>> >>>>>> ohh okay, got it. However, may I know if adding a dt property to >>>>>> indicate polling for aiding the driver, is the correct approach to model it? >>>>>> >>>>>> In terms of modelling hardware, as interrupts are not connected we are >>>>>> not populating the interrupts property. Shouldn't that be all. If we are >>>>>> adding a property explicitly to indicate polling that can be used by >>>>>> driver, wouldn't that be a software aid being added in the device tree? >>>>> >>>>> The hardware (tps6598x chip) has an interrupt pin and is expected to be used >>>>> in normal case. >>>>> >>>>> Some buggy boards might have forgot to connect it. We are adding polling mode only for these buggy boards. ;) >>>>> So polling mode is an exception. >>>>> >>>> >>>> Yes as you mentioned the interrupt line is expected to connected but >>>> there could be cases where there are not enough pins on the SoC and >>>> polling is used intentionally. In these cases this would be a feature >>>> rather than a bug. >>> >>> I do not agree that this is a feature but a board defect. You can always use >>> a GPIO expander to add more GPIOs than the SoC can provide. >>> >>> Type-C events are asynchronous and polling is a waste of CPU time. >>> What will you do if system suspends and you need to wake up on Type-C >>> status change? >>> So polling mode is just an exception for the defective boards or could >>> be used for debugging. >>> >>>> >>>> Also, I feel like not adding interrupts property in the dt nodes will >>>> indicate polling. My question is why are we adding an extra property >>>> (which is being used only as an aid in the driver) when this feature can >>>> be modeled by making interrupts property optional. >>> >>> Because interrupt property was not originally optional for this driver. >>> >>> I would like to hear what Heikki has to say about this. >>> >>> Any thoughts Heikki? >> >> I think the question is generic. How should DT describe the >> connection/lack of connection? Rob should comment on this. >> > > A gentle ping regarding this. > A gentle ping regarding the above question. Thanks, Aswath > Thanks, > Aswath > >> thanks, >> >> >>> cheers, >>> -roger >>> >>>> >>>> Thanks, >>>> Aswath >>>> >>>>> cheers, >>>>> -roger >>>>> >>>>>> >>>>>> Thanks, >>>>>> Aswath >>>>>> >>>>>>>> Signed-off-by: Aswath Govindraju <a-govindraju@xxxxxx> >>>>>>>> --- >>>>>>>> Documentation/devicetree/bindings/usb/ti,tps6598x.yaml | 4 ++-- >>>>>>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>>>>>> >>>>>>>> diff --git a/Documentation/devicetree/bindings/usb/ti,tps6598x.yaml b/Documentation/devicetree/bindings/usb/ti,tps6598x.yaml >>>>>>>> index a4c53b1f1af3..1c4b8c6233e5 100644 >>>>>>>> --- a/Documentation/devicetree/bindings/usb/ti,tps6598x.yaml >>>>>>>> +++ b/Documentation/devicetree/bindings/usb/ti,tps6598x.yaml >>>>>>>> @@ -25,6 +25,8 @@ properties: >>>>>>>> >>>>>>>> interrupts: >>>>>>>> maxItems: 1 >>>>>>>> + description: >>>>>>>> + If interrupts are not populated then by default polling will be used. >>>>>>>> >>>>>>>> interrupt-names: >>>>>>>> items: >>>>>>>> @@ -33,8 +35,6 @@ properties: >>>>>>>> required: >>>>>>>> - compatible >>>>>>>> - reg >>>>>>>> - - interrupts >>>>>>>> - - interrupt-names >>>>>>>> >>>>>>>> additionalProperties: true >>>>>>>> >>>>>>> >>>>>>> cheers, >>>>>>> -roger >>>> >>>> >> -- Thanks, Aswath
