On Mon, Jun 25, 2018 at 05:50:11PM +0200, Bartosz Golaszewski wrote:

From: Bartosz Golaszewski <redacted>

Since I took over maintainership of the at24 driver I've been working
towards removing at24_platform_data in favor for device properties.

DaVinci is the only platform that's still using it - all other users
have already been converted.

One of the obstacles in case of DaVinci is removing the setup() callback
from the pdata struct, the only user of which are some davinci boards.

Hi Bartosz

Nice code.

I've got a platform i want to add sometime soon using the at24. I
noticed you doing the cleanup, so i avoided the setup() call. But
using it would of helped...

My platform is x86 based, so no device tree. I instantiate a number of
AT24 devices from a platform driver, and then add nvmem cells so i can
access data in these eeproms. This new code will make this simpler.

The only board that's still using this callback is now mityomapl138.
Unfortunately it stores more info in EEPROM than just the MAC address
and will require some more work. Unfortunately I don't have access
to this board so I can't test any actual solutions on a live hardware.

Depending on what i find in the EEPROM, i need to instantiate other
i2c devices. So i have the problem of knowing when the EEPROM has
actually probed and i can use the nvmem API to retrieve the contents.

What i have done so far, is registers a bus notifier on i2c_bus_type,
and look for BUS_NOTIFY_BOUND_DRIVER. I can then check if the i2c
client in the notifier is the at24 client. But when i then add more
i2c clients from inside the notifier i get lockdep splats. They are
false positives, but it does suggest it is not a good idea to do this.

So it would be good to have some sort of recommended alternative to
the setup() callback. Ideally it would be specific to a particular
at24, and safe to call other i2c functions from.

Do you have any ideas?

   Andrew