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. 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 >>> >>> >
