mirror of https://gitee.com/openkylin/linux.git
0cf55bbef2
Implement COMEDI asynchronous commands on the fake analog output subdevice. This is useful for testing asynchronous commands in the "write" direction when no real hardware is available. A normal kernel timer is used to drive the command. The new timer expiry function `waveform_ao_timer()` handles whole "scans" at a time according to the number of scan period that have elapsed since the last scan. Data for each channel in the scan is written to the internal loopback array `devpriv->ao_loopbacks[]` and can be read back on the analog input channels. However, if several scan periods are outstanding in the timer expiry function, only the latest available scan data is written to the loopback array in order to save processing time. The expiry function also checks for underrun conditions, and checks for normal termination of the asynchronous command when a "stop" scan count is reached. After the command is tested by `waveform_ao_cmdtest()` and set up by `waveform_ao_cmd()`, it is not started until an internal trigger function `waveform_ao_inttrig_start()` is called as a result of the user performing an `INSN_INTTRIG` instruction on the subdevice. The command is stopped when the "cancel" handler `waveform_ao_cancel()` is called. This may be due to the command terminating due to completion or an error, or as a result of the user cancelling the command. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| drivers | ||
| kcomedilib | ||
| Kconfig | ||
| Makefile | ||
| TODO | ||
| comedi.h | ||
| comedi_buf.c | ||
| comedi_compat32.c | ||
| comedi_compat32.h | ||
| comedi_fops.c | ||
| 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 | ||