On Thu, Jun 23, 2011 at 04:36:31PM +0100, Alan Cox wrote:
> > +
> > +
> > +What: /sys/bus/i2c/devices/<busnum>-<devaddr>/value
> > +Date: May 2011
> > +Contact: Eric Andersson <eric.andersson@xxxxxxxxxxxxx>
> > +Description: This is used to get the current acceleration values for each
> > + axis. The values are represented as (x,y,z), where each axis can
> > + hold a value between -512 and 511.
> > +
> > + Reading: returns the current acceleration values.
>
> This was nacked in the bma023 driver by the IIO folks - and Dmitry
> pointed out you can do this without a sysfs hack. The trick is to do an
> initial poll in input_open at which point the ioctl query for the
> position will have data that is current and open/ioctl/close works and
> providing we go nail that into other drivers that need that kind of use
> the API is generic and input event based.
>
Right, I think the patch below will do what is needed for all polled
devices.
Thanks.
--
Dmitry
Input: polldev - immediately poll device upon opening
To allow open/ioctl(EVIOCGABS)/close use pattern for polled devices read
the device in context of open() call instead of offloading the first read
to a workqueue. This will ensure that once call to open() returns device
would have cached reasonably recent axis values that can be retrieved via
appropriate ioctl.
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---
drivers/input/input-polldev.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/input/input-polldev.c b/drivers/input/input-polldev.c
index b1aabde..b253973 100644
--- a/drivers/input/input-polldev.c
+++ b/drivers/input/input-polldev.c
@@ -49,8 +49,10 @@ static int input_open_polled_device(struct input_dev *input)
dev->open(dev);
/* Only start polling if polling is enabled */
- if (dev->poll_interval > 0)
- queue_delayed_work(system_freezable_wq, &dev->work, 0);
+ if (dev->poll_interval > 0) {
+ dev->poll(dev);
+ input_polldev_queue_work(dev);
+ }
return 0;
}
--
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