These series of patches try to add support for testing of gpio
subsystem based on the proposal from Linus Walleij.
The basic idea is implement a virtual gpio device(gpio-mockup) base
on gpiolib. Tester could test the gpiolib by manipulating gpio-mockup
device through sysfs and check the result from debugfs. Both sysfs
and debugfs are provided by gpiolib. Reference the following figure:
sysfs debugfs
| |
gpiolib---/
|
gpio-mockup
Find two issues with my patch series[1]
Futher work and discussion:
1. Test other code path(if exists).
2 Add pinctrl and interrupt support(Linus suggest trying the
eventfd) in next steps.
3. I feel that we could rework the debugfs in other gpiolib based
drivers to the code in gpiolib.c with generic gpiolib_dbg_show or
chip->dbg_show.
4. Currently, gpio-mockup does not support the device tree. There are
pros and cons if we do not support device tree:
Pros: do not need to mix with the real hardware dts.
Cons: could not test the dt_gpio_count, of_find_gpio which rely on
device tree. And other function such like gpiod_get_index which
rely on the correctness of the above functions.
If we want to test the above functions, we could provide a
dedicated device tree for gpio-mockup device which could be
included by other device tree. And we could use device tree
overlay to provide multiple device tree testcases.
5. Given that this gpio test framework is based on sysfs and debugfs.
I feel that it could be a generic gpio test script other then a
dedicated script for gpio-mockup driver. Although, my script only
support gpio-mockup driver at this monment.
[1] http://article.gmane.org/gmane.linux.kernel.gpio/11878
Bamvor Jian Zhang (3):
gpio/mockup: add virtual gpio device
selftest/gpio: add gpio test case
gpio: MAINTAINERS: Add an entry for GPIO mockup driver
MAINTAINERS | 9 ++
drivers/gpio/Kconfig | 9 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-mockup.c | 216 +++++++++++++++++++++++++++++++
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/gpio/gpio.sh | 238 +++++++++++++++++++++++++++++++++++
6 files changed, 474 insertions(+)
create mode 100644 drivers/gpio/gpio-mockup.c
create mode 100755 tools/testing/selftests/gpio/gpio.sh
--
2.1.4
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