On 03/09/2015 02:15 PM, Jonathan Cameron wrote:
On 09/03/15 05:28, abhijit wrote:
Hi All,
We are using AD7923 driver as reference for one of our customer's ADC IP
The ADC that we are using, has sequencer functionality. In current state of AD7923 driver, there is no support for sequencer functionality.
Can you please let me know whether the IIO driver team is coming up with design for sequencer functionality of the device.
Cc'd Lars, Michael and Patrick. Looks like a fairly standard sequencer.
Just a question of whether anyone has already looked at it.
I've been tormenting my head now for a while how to properly model
sequencers in IIO, but haven't come to a conclusion yet.
The problem is you have one physical channel but a configurable amount of
logical channels. The ADC will cycle through the selected channels one after
another.
IIO on the other hand expects that all channels that are selected are
actually converted at the same time. E.g. you have to supply all the
selected channels at the same time to iio_buffer_push_data() and also
metadata, like the timestamps, is expected to be supplied only once for
every set of samples and not for every individual logical channel.
Furthermore things like the output data rate of each channel depend on the
number of selected channels. So if you configure the sample rate and then
change the number of selected channels you potentially end up with a
different sample rate than initially selected.
- Lars
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