On Fri, Aug 22, 2014 at 01:50:23PM +0200, Johannes Pointner wrote: > Hello Guenter, > > thank you for your quick answer. > > 2014-08-21 15:25 GMT+02:00 Guenter Roeck <linux@xxxxxxxxxxxx>: > > On Thu, Aug 21, 2014 at 09:29:56AM +0200, Johannes Pointner wrote: > >> Hello, > >> > >> I found out that since this patch https://lkml.org/lkml/2014/6/11/201, > >> which fixes the return values in this function, the ntc_thermistor > >> driver isn't working anymore for me. > >> The problem is that before the driver asked for probe deferral because > >> the adc driver isn't loaded at this point and now the probe fails in > >> the function iio_channel_get_sys and returns -ENODEV. > >> My question is: Who is in this case responsible to request a deferral? > >> The driver or the subsystem? > >> > > Unless I am missing something, iio_get_channel() should request probe deferral. > > There is no other way for the driver to know that the adc driver is not loaded > > yet. > > Yes, I missed that. In the function __of_iio_channel_get the subsystem > returns a -EPROBE_DEFER. > > > > > The problem here may be that the devicetree entry for the ntc_thermistor driver > > may not be correct. The above referenced patch fixes a bug in that area, and > > devicetree data is now better validated. > > > But the problem is, that this statement: > if (np && !of_get_property(np, "io-channel-ranges", NULL)) > return NULL; > overrides the -EPROBE_DEFER. Before the fix there was a break > statement and the -EPROBE_DEFER was returned. > I think the code further up should be if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER) break; > Do I have made a mistake in the devicetree if I put the ntc > declaration directly under the root node? > No, I don't think so. I would suggest to submit a patch to fix the above. Guenter -- 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
