On 4/15/20 3:56 PM, Ardelean, Alexandru wrote:
On Tue, 2020-04-14 at 19:06 +0100, Jonathan Cameron wrote:
[External]
On Tue, 14 Apr 2020 11:36:56 +0300
Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:
The final intent is to localize all buffer ops into the
industrialio-buffer.c file, to be able to add support for multiple buffers
per IIO device.
We only need a chardev if we need to support buffers and/or events.
With this change, a chardev will be created:
1. if there is an IIO buffer attached OR
2. if there is an event_interface configured
Otherwise, no chardev will be created.
Quite a lot of IIO devices don't really need a chardev, so this is a minor
improvement to the IIO core, as the IIO device will take up fewer
resources.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
Changelog v1 -> v2:
* split away from series 'iio: core,buffer: re-organize chardev creation';
i'm getting the feeling that this has some value on it's own;
no idea if it needs 'Fixes' tag; it is a bit fuzzy to point to a patch
which this would be fixed by this; i'm guessing it would be fine
without one
I'd argue it's an 'optimization' rather than a fix :)
Still looks good to me but I'd like it to sit for a little while to
see if anyone points out something we are both missing!
This is not good.
It seems that I did not properly test all cases.
I had to break a device to not have an event_interface to notice that the sysfs
doesn't get instantiated either because device_add is missing.
Will do another try.
I think you also have to make the `indio_dev->dev.devt = ...`
conditional. Or conditionally use device_add() instead of device_add_cdev().
If you go for the former you need to call cdev_device_del()
unconditionally, for the latter call device_del() or cdev_device_del()
depending on whether the cdev was registered.
- Lars
