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? 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 > >
