On 14/06/15 16:45, Lars-Peter Clausen wrote: > On 06/14/2015 05:15 AM, Gergely Imreh wrote: >> On 14 June 2015 at 02:30, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >>> On 11/06/15 09:22, Gergely Imreh wrote: >>>> The Xilinx XADC driver has both a temperature channel and 8 voltage >>>> channels. The voltage channels have no offset, but actually were still >>>> set the same offset as the temperature channel. This did not cause >>>> problems in /sys/bus/iio/ but can cause problems with other drivers >>>> using iio data. For example iio-hwmon did return wrong voltage values >>>> because of the offset. >>>> >>>> Change tested with the Parallella board. >>>> >>>> Signed-off-by: Gergely Imreh <imrehg@xxxxxxxxx> >>> Well spotted on the bug, but I think we are better off fixing this at the >>> true source of the problem which is in drivers/iio/inkern.c >>> iio_convert_raw_to_processed_unlocked which does a call to >>> iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET) then uses >>> the error return to check if the offset parameter is available. It should >>> be checking that before making this call with a call to iio_channel_has_info. >>> >>> I don't suppose you could prepare a patch fixing that as you found the problem? >> >> I'll check it out, and send an updated patch! Thanks for the pointers >> to the core of the issue. > > The issue was already fixed a while ago, see this patch: > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=65de7654d39c70c2b942f801cea01590cf7e3458 > > Starting with that commit iio_channel_read() returns an error when > the attribute is not available, which causes > iio_convert_raw_to_processed_unlocked() to skip the offset if it is > not available. > oops. Good spot. I'd completely forgotten about that and failed to spot the check when looking at the code yesterday. Glad you were keeping an eagle eye on things ;) J > - Lars -- 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
