Mentors: [http://kernelnewbies.org/OctavianPurdila Octavian Purdila], [http://kernelnewbies.org/DanielBaluta Daniel Baluta]

checkpatch.pl cleanups

Use scripts/checkpatch.pl to align code in staging/drivers/iio to Linux kernel coding style.

• accel/

  • status: clean - resolved by Tapasweni Pathak (irc: tapasweni)

• adc/

  • status: clean - resolved by Vaishali Thakkar (irc: vaishu)

• addac/

  • status: clean - resolved by Roxana Blaj (irc: roxana)

• cdc/

  • status: clean

• Documentation/

  • status: clean - resolved by Heena Sirwani (irc: heena) [one patch in review]

• frequency/

  • status: clean - resolved by Roxana Blaj (irc: roxana)

• gyro/

  • status: clean - resolved by Heena Sirwani (irc: heena)

• impedance-analyzer/

  • status: clean

• light/

  • status: clean - resolved by to Roberta Dobrescu (irc: roberta) [dt patch in review]

• magnetometer/

  • status: clean (there is one line over 80 chars but we won't fix it because it makes code harder to read)

• meter/

  • status: clean - resolved by Darshana Padmadas (irc: darshana) [one patch pending review]

• resolver/

  • status: clean - resolved by Roberta Dobrescu (irc: roberta)

• trigger/

  • status: clean - resolved by Darshana Padmadas (irc: darshana)

A directory (e.g. accel) is considered clean in the context of checkpatch.pl if running the following commands results in no warnings or errors:

• scripts/checkpatch.pl -f drivers/staging/iio/accel/*.c

• scripts/checkpatch.pl -f drivers/staging/iio/accel/*.h

• scripts/checkpatch.pl -f drivers/staging/iio/accel/Kconfig

Please send us an email with the directory you want to work on. Don't forget to specify your full name and IRC handle.

Experimenting with IIO subsystem

For this we will use two kernel modules found in drivers/staging/iio:

• iio_dummy_evgen.ko - generates fake events interrupts to be used by the iio_dummy example driver

  • implementation for this module is in iio_dummy_evgen.c

• iio_dummy.ko - example IIO driver to demonstrate existing functionality

  • core implementation can be found in iio_simple_dummy.c

  • buffer functionality is implemented in iio_simple_dummy_buffer.c

  • events functionality is implemented in iio_simple_dummy_events.c

Dummy modules compilation

You need to select the following config options:

• CONFIG_IIO_DUMMY_EVGEN - for building iio_dummy_evgen kernel module

• CONFIG_IIO_SIMPLE_DUMMY - for building iio_dummy kernel module

  • CONFIG_IIO_SIMPLE_DUMMY_EVENTS, CONFIG_IIO_SIMPLE_DUMMY_BUFFER should be selected for events and buffer functionality.

Use the following commands for modules compilation:

• $ make drivers/staging/iio/iio_dummy_evgen.ko

• $ make drivers/staging/iio/iio_dummy.ko

Use the following commands for module loading:

• $ insmod iio_dummy_evgen.ko

• $ insmod iio_dummy.ko

Task 01:

• Show that the modules were successfully loaded . Send an email to mentors listed at the top of the page, with the output of the following commands
  • lsmod
  • ls -l /sys/bus/iio/devices/
  • ls -l /sys/bus/iio/devices/iio:device0/
  • ls -l /sys/bus/iio/devices/iio_evgen/

IIO event monitor

IIO event monitor is an user space example application which reads events from IIO layer and pretty prints the results. Implementation can be found in iio_event_monitor.c under iio/drivers/staging/iio/Documentation. BR

Task 02:

• compile iio_event_monitor.c to obtain an executable called iio_event_monitor. Send an email with the command used for compilation to mentors listed at the top of the page.

IIO sysfs attributes

IIO sysfs attributes should all be documented in Documentation/ABI/testing/sysfs-bus-iio. Have a look at this file, with a focus on the following entries:

• /sys/bus/iio/devices/iio:deviceX
• /sys/bus/iio/devices/triggerX
• /sys/bus/iio/devices/iio:deviceX/buffer
• /sys/bus/iio/devices/iio:deviceX/events

Task 03: Add missing ABI Documentation

• this task asks you to find missing ABI documentation in Documentation/ABI/testing/sysfs-bus-iio (for example look at this [http://www.spinics.net/lists/linux-iio/msg15203.html patch])

• the key structure to be analyzed is [http://lxr.free-electrons.com/source/include/linux/iio/iio.h#L217 struct iio_chan_spec]

• use drivers/staging/iio/iio_simple_dummy.c for testing adding new channels to iio_dummy_channels[] array. Then look for the attributes names in /sys/bus/iio/devices/iio:device0 and check to see if they

are documented in Documentation/ABI/testing/sysfs-bus-iio

• make sure that the undocumented ABI has at least one user driver in drivers/iio/ or drivers/staging/iio/