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. 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 > > > > -- heikki
