Dear Jonathan Cameron,
I last reported that after creating device node and opening it, read() call was failing.
I got to fix this.
The reason was this:
4 functions are exported from ad7793 module to iio-ring module as ring setup ops:
namely:
.preenable = &ad7793_ring_preenable,
.postenable = &iio_triggered_ring_postenable,
.predisable = &iio_triggered_ring_predisable,
.postdisable = &ad7793_ring_postdisable,
In the iio-ring modules "iio_store_ring_enable" function is invoked from user app,which
inturn invokes the func "ad7793_ring_preenable" and subsequently driver's postenable
function.
The "iio_triggered_ring_postenable" function then attaches the poll function to the ring
trigger soft interrupt.
Since continuous mode was set and enabled the configured GPIO interrupt for capturing
data ready signal (in ad7793_ring_preenable) as interrupt, iio_trigger_poll() invoked on
interrupt (from drivers data rdy interrupt handler) failed to raise soft interrupt and
as a consequence driver's ad7793_trigger_handler() was not invoked when data ready.
I patched as follows in ad7793.c:
1. Moved irq enabling from ad7793_ring_preenable to ad7793_ring_postenable
2. Defined ad7793_ring_setup_ops ".postenable" as ad7793_ring_postenable
3. In ad7793_ring_postenable, invoked &iio_triggered_ring_postenable and then enabled
the data ready signalling GPIO interrupt.
Then, from user app after opening the device, Poll() for rcv data presence was
successful and read() call returned non-zero size . Could print the data from ring buffer.
Sincere thanks to you and Michael for guiding me through.
Take care.
regards
Mala
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