On Mon, 2014-11-17 at 23:12 +0100, Hartmut Knaack wrote: > Ivan T. Ivanov schrieb am 12.11.2014 09:55: > > On Tue, 2014-11-11 at 23:39 +0100, Hartmut Knaack wrote: > > > Ivan T. Ivanov schrieb am 11.11.2014 09:21: > > > > Hi Hartmut, > > > > > > > > On Mon, 2014-11-10 at 22:11 +0100, Hartmut Knaack wrote: > > > > > Ivan T. Ivanov schrieb am 03.11.2014 16:24: > > > > > > From: Stanimir Varbanov <svarbanov@xxxxxxxxxx> > > > > > > > > > > > > The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has > > > > > > 15 bits resolution and register space inside PMIC accessible across > > > > > > SPMI bus. > > > > > > > > > > > > The vadc driver registers itself through IIO interface. > > > > > Reviewing again, I got the feeling that due to the complexity of adc reads (writing to > > > > > register > > > > > to start conversion, waiting a decent time for the conversion to complete, reading the > > > > > result), > > > > > it would be beneficial to use a mutex in vadc_read_raw or its depending functions. > > > > > > > > Hm, yes, but there is such a nice info_exist_lock :-) in core functions, > > > > which in practice serve the same purpose. > > > I seem to miss that. Please point me in the right direction. > > > > I am referring to info_exist_lock mutex part of struct iio_dev. > > It protects all operations inkern.c, no? > > > Good point, thanks for helping me there. I was wondering, is there a plan to improve this part of the code? I mean to remove per device lock and use something like try_module_get(), when clients are acquiring reference to iio channel? > > > > > > + > > > > > > + ret = of_property_read_u32(node, "reg", &res); > > > > > For u16, there would be of_property_read_u16(). > > > > > > + if (ret < 0) > > > > > > + return -ENODEV; > > > > > Just return ret here? > > > > > > > > I am usually trying to follow these recommendations[1]. In practice driver > > > > core cares only for EPROBE_DEFER, ENODEV and ENXIO, while of_property_read_u32() > > > > can return ENODATA and EOVERFLOW, which did't not make sense for the core. > > > Please point me in the right direction on this one, too. It is pretty common to pass error > > > codes > > > up, as it is also mentioned in [1]. > > > > Yes, I know that is common to just pass error codes up, but in this case it did't > > make too much sense, I think. Also take a look at realy_probe() and line 343. > This doesn't convince me. Actually, within the probe_failed part, it just doesn't care about > ENODEV and ENXIO as long as debug messages are disabled (which apart from some developers, is > default for the vast majority of devices). For all other error codes, it will at least print an > info or warning about what's going wrong (and that can be a lot of help for debugging). Well, if you insist... will change it. Thanks, Ivan -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
