Hi! Am 01.12.2014 um 11:49 schrieb Harald Geyer: > Hi Richard! > > Richard Weinberger writes: >> Staring with 3.12 gpiolib refuses to set an GPIO used as IRQ into output mode. >> see commit d468bf9e (gpio: add API to be strict about GPIO IRQ usage) >> The dht driver does this and is therefore not functional. >> As the dht11 driver got merged in 3.13 there is a high chance that it >> never worked. > > Well, I'm developing on mxs and there it works on 3.13 and 3.14 at least. > (I have it in production using 3.14.18 ATM.) > >> Harald, are you aware of this issue? > > I got one report about this issue, but couldn't reproduce it yet and > the reporter didn't agree to quoting his messages to kernel mailing lists, > so this has been rather low priority on my todo list. Next plan is to > see if I can reproduce the issue on sunxi (A10). Not all gpio drivers use the new IRQ lock stuff. > However anybody able to reproduce this and willing to test patches, would > of course push this up on my todo list. > > Any input from gpiolib people about what the proper fix would be in > their opinion, of course is appreciated. I don't think the dht11 driver > is doing anything unreasonable per se, so maybe they can clarify how > the API is intended to be used? Your driver sets up a GPIO as IRQ and then you switch the mode to output to enable the DHT sensor. This is not an API issue, it is an design issue. I'm not a hardware expert but AFAIK setting an IRQ pin into output mode can lead to undefined behavior. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
