linux/drivers/staging/comedi
Ian Abbott 1e3de428d1 staging: comedi: mf6x4: Fix AI end-of-conversion detection
commit 56c90457ebfe9422496aac6ef3d3f0f0ea8b2ec2 upstream.

I have had reports from two different people that attempts to read the
analog input channels of the MF624 board fail with an `ETIMEDOUT` error.

After triggering the conversion, the code calls `comedi_timeout()` with
`mf6x4_ai_eoc()` as the callback function to check if the conversion is
complete.  The callback returns 0 if complete or `-EBUSY` if not yet
complete.  `comedi_timeout()` returns `-ETIMEDOUT` if it has not
completed within a timeout period which is propagated as an error to the
user application.

The existing code considers the conversion to be complete when the EOLC
bit is high.  However, according to the user manuals for the MF624 and
MF634 boards, this test is incorrect because EOLC is an active low
signal that goes high when the conversion is triggered, and goes low
when the conversion is complete.  Fix the problem by inverting the test
of the EOLC bit state.

Fixes: 04b565021a ("comedi: Humusoft MF634 and MF624 DAQ cards driver")
Cc: <stable@vger.kernel.org> # v4.4+
Cc: Rostislav Lisovy <lisovy@gmail.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20201207145806.4046-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-30 11:51:35 +01:00
..
drivers staging: comedi: mf6x4: Fix AI end-of-conversion detection 2020-12-30 11:51:35 +01:00
kcomedilib
Kconfig
Makefile
TODO
comedi.h
comedi_buf.c staging: comedi: use dma_mmap_coherent for DMA-able buffer mmap 2019-06-26 09:32:13 +08:00
comedi_compat32.c
comedi_compat32.h
comedi_fops.c staging: comedi: Fix comedi_device refcnt leak in comedi_open 2020-04-29 16:33:20 +02:00
comedi_internal.h
comedi_pci.c
comedi_pci.h
comedi_pcmcia.c
comedi_pcmcia.h
comedi_usb.c
comedi_usb.h
comedidev.h
comedilib.h
drivers.c
proc.c
range.c