Re: [RFC PATCH 0/7] IIO: Reduce to 1 the number of chrdevs per device

[Jonathan Cameron <jic23@cam.ac.uk>]

I forgot to mention that this series also thoroughly breaks the sca3000.
I'll fix that one up before reposting.

> This is another of Arnd's suggestions.
> 
> Some of the patches here are just pre conversion reworks to make the important
> bit easier and some are cleanups of headers etc as a result of things not
> being needed any more.
> 
> One little change I slipped in here:
> 
> devices now have iio:deviceX as their name so that we have something
> sensibly named under /dev/
> 
> The important patches are 4 and 6.
> 
> 4 uses Arnd's suggestion of an annon_fd obtained via ioctl on the buffer
> chrdev to get a file for easy use for reading events.  This is a very neat
> solution that lets us keep the actual event system separate from the data
> stream without two chrdevs.
> 
> 6. Moves the remaining single chrdev so it associated with the iio_dev rather
> than the buffer.  This means we now only have two types of device (other than
> weird ones like the sysfs trigger management node), triggers and devices.
> Given either can exist independently, those two don't make sense to merge.
> 
> Anyhow, I'm far from convinced that the allocation / deallocation is now
> correct and that there aren't any race conditions on removal od devices.
> (then again I'm not convinced there weren't any of those before.)
> 
> Note I haven't ammended the nature of either 'chrdev' at all. There
> is more to be done there.
> 
> Note, this is 3.2 material so no particular rush for comments.
> Having said that, please do pull it into local trees and hammer it
> nice and hard to see where I messed up.
> 
> For reference a minimal test app is:
> 
> #include <stdio.h>
> /* little dirty test prog */
>  #include <sys/ioctl.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <stdint.h>
> 
> struct iio_event_data {
> 	int	id;
> 	int64_t	timestamp;
> };
> 
> 
> int main(int argc, char **argv)
> {
> 	int ret;
> 	int fp;
> 	int data;
> 	int i = 0;
> 	FILE *evfp;
> 	struct iio_event_data ev;
> 	fp = open(argv[1], O_RDONLY);
> 	ret = ioctl(fp, 0, &data);
> 	/* So we have the fd (in theory) of the anon file */
> 	evfp = fdopen(data, "r");
> 
> 	if (evfp)
> 		for (i = 0; i < 100; i++) {
> 			ret = fread( &ev, sizeof(ev), 1, evfp);
> 			printf("%d %lld\n", ev.id, ev.timestamp);
> 		}
> 	return 0;
> }
> 
> Jonathan
> 
> Jonathan Cameron (7):
>   staging:iio:trigger push functions that don't need to be generaly
>     available down into the core.
>   staging:iio:kfifo buffer - push structure definition down into
>     implementation.
>   staging:iio:chrdev.h rationalization.
>   staging:iio: remove specific chrdev for event reading. Get fd from
>     ioctl on buffer.
>   staging:iio: squash chrdev handler remains into users.
>   staging:iio: push the main buffer chrdev down to the top level.
>   staging:iio: remove now defunct header definitions and add some
>     statics
> 
>  drivers/staging/iio/Documentation/generic_buffer.c |   11 +-
>  drivers/staging/iio/Documentation/iio_utils.h      |    2 +-
>  drivers/staging/iio/accel/adis16201_core.c         |    6 +-
>  drivers/staging/iio/accel/adis16203_core.c         |    6 +-
>  drivers/staging/iio/accel/adis16204_core.c         |    6 +-
>  drivers/staging/iio/accel/adis16209_core.c         |    6 +-
>  drivers/staging/iio/accel/adis16240_core.c         |    6 +-
>  drivers/staging/iio/accel/lis3l02dq_core.c         |    6 +-
>  drivers/staging/iio/accel/sca3000_core.c           |    4 +-
>  drivers/staging/iio/adc/ad7298_core.c              |    4 +-
>  drivers/staging/iio/adc/ad7476_core.c              |    4 +-
>  drivers/staging/iio/adc/ad7606_core.c              |    4 +-
>  drivers/staging/iio/adc/ad7793.c                   |    6 +-
>  drivers/staging/iio/adc/ad7887_core.c              |    4 +-
>  drivers/staging/iio/adc/ad799x_core.c              |    4 +-
>  drivers/staging/iio/adc/max1363_core.c             |    6 +-
>  drivers/staging/iio/chrdev.h                       |   51 ----
>  drivers/staging/iio/gyro/adis16260_core.c          |    6 +-
>  drivers/staging/iio/iio.h                          |    4 +-
>  drivers/staging/iio/iio_core.h                     |   39 +++-
>  drivers/staging/iio/imu/adis16400_core.c           |    6 +-
>  drivers/staging/iio/industrialio-core.c            |  273 +++++++++++---------
>  drivers/staging/iio/industrialio-ring.c            |  220 ++++++-----------
>  drivers/staging/iio/industrialio-trigger.c         |   30 ++-
>  drivers/staging/iio/kfifo_buf.c                    |   43 ++--
>  drivers/staging/iio/kfifo_buf.h                    |    8 -
>  drivers/staging/iio/meter/ade7758_core.c           |    2 +-
>  drivers/staging/iio/ring_generic.h                 |   28 +--
>  drivers/staging/iio/ring_sw.c                      |   23 +--
>  drivers/staging/iio/trigger.h                      |   39 ---
>  30 files changed, 368 insertions(+), 489 deletions(-)
>