A rounding error was causing comedi_nsamples_left to
return the wrong value when nsamples was not a multiple
of the scan length.

Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Frank Mori Hess <fmh6jj@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that the SPDX tag is in all comedi files, that identifies the
license in a specific and legally-defined manner.  So the extra GPL text
wording can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/staging/comedi files files with the correct SPDX
license identifier based on the license text in the file itself.  The
SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The patch removes "WARNING: Prefer using '"%s...", __func__'
to using 'xxxxxxxx', this function's name, in a string" warnings
reported by checkpatch.pl script.

Signed-off-by: Simo Koskinen <koskisoft@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Align the * on each line of block comments as reported by checkpatch

Signed-off-by: Ramiro Oliveira <roliveir@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This function assumes that the async subdevice has a cancel() function.
It looks like all the current comedi drivers implement a cancel() for
the async subdevices except for the dt2814 analog input usbdevice.

Fix comedi_handle_events() so it does not try to call a non-existent
cancel() function.

Add a dev_warn() to __comedi_device_postconfig_async() so that any new
driver authors will be reminded to implement the cancel().

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>

Tidy up this function and fix the checkpatch.pl issues:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'

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>

`comedi_nsamples_left(s, nsamples)` returns the number of samples
remaining to complete an asynchronous command or the passed in
`nsamples`, whichever is lower.  However, it goes wrong in the extreme
case of setting the `nsamples` parameter to `UINT_MAX` when the number
of conversions per "scan" (`s->async->cmd.scan_end_arg`) is 1.  It uses
`comedi_nscans_remaining(s, nscans)` to determine the number of scans
remaining, or the parameter `nscans`, whichever is lower.  To determine
the parameter `nscans`, it divides `nsamples` by the number of
conversions per scan and adds 1.  The addition of 1 is to avoid setting
the parameter `nscans` to 0, as `comedi_nscans_remaining(s, nscans)`
treats that value specially.  However in the extreme case where
`nsamples` is `UINT_MAX` and the number of samples per scan is 1, the
addition of 1 to `nscans` overflows, producing the unwanted 0.

Fix it by refactoring new a function `__comedi_nscans_remaining(s,
nscans)` out of `comedi_nscans_remaining(s, nscans)`.  The new function
does everything except the special handling when `nscans` is 0.  Change
`comedi_nsamples_remaining()` to call the new function without adding 1
to `nscans` to avoid the overflow.

This overflow bug doesn't affect any of the current COMEDI drivers.  I
stumbled across it while changing to one of the drivers.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add missing kernel-doc to the low-level COMEDI driver API functions
exported from "drivers.c" and tart up some of the existing kernel-doc
comments for consistency.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Comedi's "drivers.c" doesn't use anything from `<linux/dma-mapping.h>`,
but it does use `DMA_NONE` from `<linux/dma-direction.h>`, so replace
the appropriate `#include` directive.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>