This driver can acquire analog input samples during the async command with
DMA, by using the FIFO, or sample-by-sample using the End-Of-Conversion
interrupt. All three methods do the following sequence:
1) check for channel dropout
2) add the sample to the async buffer
3) advance the channel dropout detection and detect the end of the command
Merge this sequence into a new helper function.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>