Hi Hauke, many thanks for your comprehensive and clearifying answers. Most of them met my thoughts about driver design.
>> - Should a driver support at least data-ready interrupts (if possible at >> all) to realize event-driven data retrieval? > If the driver comes with a 'full/extra' configuration, this is part of > it anyway, right? In the simples 'basic' configuration I don't think > this needs to be part of I would say. Agreed. >> - Should a driver always return normalized/converted data, or rather >> return the raw data and the application needs to convert them? The >> conversion is sometimes quite complex. I saw both approaches of them for >> similar sensors. > My opinion is quite clear: I am always in favor of returning > normalized/converted data. In 90% of the cases the conversion is not > expensive, so just do it. In those rare cases, where the conversions is > actually relatively expensive, we can always fall back by providing > additional `xx_read_raw()` or similar functions, that allow to access > the data before conversion. Agreed. All the drivers I wrote til now, either return normalized/converted and raw data with same read function or offer an additional read_raw function. >> The design rules that are clear to me are: >> >> - Drivers have to provide an interface for polling with init and read >> that is compatible with SAUL. > that is a nice to have, but not a MUST. Ok. >> - Output are always 16 bit integers. > Not quite true. The SAUL interface is build around 16-bit integers, and > at least when reading/writing data via SAUL the data needs to be > converted. But the driver specific interface can always use other data > types/lengths. If it is however easily possible to use int16, one should > use it. Ok. >> What else? > All this information should go into the 'device driver guide' > (https://github.com/RIOT-OS/RIOT/wiki/Guide:-Writing-a-device-driver-in-RIOT). > This guide needs however still work - and I will not have the time to do > it. So it would be nice if other people can help here :-) Agreed. Regards Gunar -- Wenn du laufen willst, lauf eine Meile. Wenn du ein neues Leben kennenlernen willst, dann lauf Marathon. (Emil Zatopek)
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