On 31/08/15 17:52, Michael Welling wrote: > On Mon, Aug 31, 2015 at 05:24:21PM +0100, Jonathan Cameron wrote: >> On 31/08/15 17:01, Greg Wilson-Lindberg wrote: >>> >>> >>>> -----Original Message----- >>>> From: Michael Welling [mailto:mwelling79@xxxxxxxxx] On Behalf >>>> Of Michael Welling >>>> Sent: Friday, August 28, 2015 5:32 PM >>>> To: Greg Wilson-Lindberg >>>> Cc: linux-iio@xxxxxxxxxxxxxxx >>>> Subject: Re: Adding MAX1363 to BBB >>>> >>>> On Fri, Aug 28, 2015 at 04:56:20PM -0700, Greg Wilson-Lindberg wrote: >>>>> >>>>> I've got the system running, but I get an invalid argument >>>> error on the call to iio_buffer_refill(). I'm basically >>>> using the same code as for the tsadc, just added in a fourth >>>> channel, and none of the setup calls are returning errors, >>>> but the first iio_buffer_refill() call returns an error. >>>> I've dumped out the parameter that is being passed to the >>>> iio_buffer_refill() call and it is the same as the value that >>>> was returned from the iio_device_create_buffer() call. >>>>> >>>>> I've looked at the libiio source and I don't see anything >>>> obvious that should return invalid argument for the >>>> iio_buffer_refill() call. >>>>> >>>> >>>> I believe that you need to register an interrupt for buffered >>>> access to work. >>>> >>>> Do you have an interrupt connected and registered? >>>> >>> >>> Nope, no interrupt. So I guess I would need to ask, how would I register the interrupt in the Device Tree? >> The max1363 (and similar) don't have a dataready interrupt as they >> are clocked of the actual clock cycles of the i2c transfers. So >> they only read on demand. >> > > Ah, yes. Looking at the datasheet the interrupt is triggered by a window > comparator not end of sample. That takes me back. It was one of my first drivers ;) They monitor stuff is real pain as it does output normal readings when monitor is running but only after a whole load of other stuff. I think I got lazy and decided not to unwind that but just to make the driver not read the channels when monitor was enabled. > >>> >>> Or, alternatively, can I just get individual readings through IIO? >> Either via sysfs, or by adding a sysfs trigger and poking that. >> To add a sysfs trigger you'll need to probe the module, then poke >> a number into the add_trigger attribute to create a trigger which can >> then be associated with the max1363 (as normal). >> >> Then to 'fire' the trigger write to the trigger_now attribute of the >> relevant trigger. >> >> Ideally Daniel will be back soonish with a final version of the >> high resolution timer trigger that would also work well here. >> (it's rather tied up with some configfs support which wis >> trickier!). > > It is probably easiest to sample using sysfs directly. > > This would be same as the last method we tried while trying to > access to TI ADC and touchscreen simultaneously. > > http://www.spinics.net/lists/linux-iio/msg20577.html That should work fine. Jonathan > >> >> Jonathan >>> -- >>> 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 >>> >> > -- > 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 > -- 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
