FIQ (was Motion Sensor Status)

Andy Green andy at
Sat Jan 26 17:00:16 CET 2008

Hash: SHA1

Somebody in the thread at some point said:
> Somebody in the thread at some point said:
>> I made a start on this tonight and have a basically empty but working C
>> FIQ ISR now off timer 3, seems to have inherited a rate of something
>> like ~20K FIQ a second (~50us period) which doesn't make problems.
> This stuff has now replaced the Vibrator PWM implementation for GTA02
> successfully here using FIQ... the FIQs only run for as long as they
> have a task and turn themselves off automatically until a new task
> comes.  Vibrator has the same interface, but is now done using PWM in
> the FIQ ISR and with GPIO controlling the output.  GTA-01 should go on
> as before.
> I'm going to start on implementing the SPI bitbang to the motion sensors
> in FIQ now, so I won't post the patches here yet since I will probably

The motion sensors are now handled by FIQ when someone has the
/dev/input/event<n> node open.

I can see the event timestamps with hexdump /dev/input/event2 for
example but I can't see the X Y Z data due to needing an IOCTL, but I
have separately printk()'d the data from the motion sensor irq service
and it looked okay.

Maybe someone better placed to examine /dev/input/event<n> from usermode
in there (Mickey?) can check if the data is good using a current git
kernel off the "andy" branch.

Don't forget neod holds these guys open.  You can still see the count of
FIQ services by

$ cat /sys/devices/platform/spi_s3c24xx_gpio.1/spi0.1/fiq_count

and... it's definitely beer o'clock now :-)

- -Andy
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