On Wed, Dec 25, 2024 at 02:01:50PM +0100, Lothar Rubusch wrote: > On Thu, Dec 19, 2024 at 7:21 PM Conor Dooley <conor@xxxxxxxxxx> wrote: > > > > On Thu, Dec 19, 2024 at 05:58:15PM +0000, Jonathan Cameron wrote: > > > On Sun, 15 Dec 2024 14:56:58 +0000 > > > Conor Dooley <conor@xxxxxxxxxx> wrote: > > > > > > > On Sat, Dec 14, 2024 at 12:10:57PM +0000, Jonathan Cameron wrote: > > > > > On Fri, 13 Dec 2024 21:19:05 +0000 > > > > > Lothar Rubusch <l.rubusch@xxxxxxxxx> wrote: > > > > > > > > > > > Add interrupt-names INT1 and INT2 for the two interrupt lines of the > > > > > > sensor. > > > > > > > > > > > > When one of the two interrupt lines is connected, the interrupt as its > > > > > > interrupt-name, need to be declared in the devicetree. The driver then > > > > > > configures the sensor to indicate its events on either INT1 or INT2. > > > > > > > > > > > > If no interrupt is configured, then no interrupt-name should be > > > > > > configured, and vice versa. In this case the sensor runs in FIFO BYPASS > > > > > > mode. This allows sensor measurements, but none of the sensor events. > > > > > > > > > > > > Signed-off-by: Lothar Rubusch <l.rubusch@xxxxxxxxx> > > > > > > > > > > Just to repeat what I sent in reply to v6 (well after you'd posted this). > > > > > Maybe we can maintain compatibility with the binding before this by adding > > > > > a default of INT1. > > > > > > > > But can you make that assumption? If we did, and it's not universally > > > > true, we break systems that had INT2 connected that previously worked. > > > > > > I guess there is a possibility of a driver in some other OS assuming INT2, but > > > seems an odd 'default' choice. > > > > Ye, I think that it is unlikely a driver author would think that way. > > > > > Also odd for a writer of DT for a platform > > > to assume it. > > > > I agree, I think it is unlikely that someone would assume it'd work like > > this. I think a lack of attention paid to the schematic of the board is > > a more likely culprit. > > > > > There is a thing that comes up in spec orgs when discussing whether to > > > rush out an errata. "Is this bug something people would get wrong > > > thinking the answer was clear, or something where the would ask a question?" > > > Anyone who thinks INT2 is the obvious choice for me falls into the would > > > ask category. > > > > > > However, in the linux driver we would would go from assuming no interrupts > > > to assuming the wrong one. That's indeed bad. So I guess this doesn't work. > > > Oh well no default it is. > > > > I don't think you really lose anything from having no default. The > > driver works just fine without the interrupt, so the albeit small risk > > just doesn't seem worth it. > > Agree. To be honest, I'm not sure if I catch the point here. IMHO, > falling back to FIFO bypass should match with backward compatibility. > Please let me know what I'm missing here. Ye, falling back to the current behaviour is fine. The only problematic thing is not checking "for a specified INT name" but assuming the provided interrupt is either INT1 or INT2 when interrupt-names is not provided. > > I would prefer just to check for a specified INT name. Then configure > the specified interrupt line in the probe. In this sense, the > interrupt line is only useful also if the INT name is defined in the > DT. If no INT name is specified, the iio driver will setup FIFO_BYPASS > which is the legacy behavior (according to the datasheet: if none of > the FIFO mode bits are set, defaults to bypass mode). This is the new > behavior. > > The old iio driver did not use interrupts at all. It stayed in > FIFO_BYPASS mode (or did not change it, after power on, it assumes > FIFO_BYPASS to my interpretation). Thus declaring the IRQ line yes or > no, with or without INT names - for the iio driver implementation > before this patch series, should not make any difference. It uses > FIFO_BYPASS in all cases. > > The input driver (AFAIR we already agreed on ignoring this driver) > needed interrupts. Defining INT names here does not change anything, > either. The input driver configures by default INT1 and simply ignores > what was specified as INT names in the DT. > > I cannot really think of any third case here. Please, let me know if > I'm wrong. If not I will keep the above explained behavior, since to > my understanding it should match the desired compatibility > requirements. Am I wrong here? > > Sorry for the late answer. Best, > L
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