Re: [PATCH v5 1/8] i2c: core: let adapters be notified of client attach/detach

Andy Shevchenko
2022-12-19T09:49:05Z

On Mon, Dec 19, 2022 at 09:51:43AM +0100, Luca Ceresoli wrote:
> On Sun, 11 Dec 2022 18:55:39 +0200
> Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote:
> > On Thu, Dec 08, 2022 at 12:39:59PM +0200, Tomi Valkeinen wrote:

...

> > This may be a stupid question, but couldn't you instead use the
> > BUS_NOTIFY_ADD_DEVICE and BUS_NOTIFY_DEL_DEVICE bus notifiers ?
>
> I'm not sure they would be the correct tool for this task. Bus
> notifiers inform about new events on the 'struct bus_type, i.e. any
> event on the global i2c bus type. In the i2c world this means being
> notified about new _adapters_, which is exactly what
> drivers/i2c/i2c-dev.c does.
>
> Here, however, we need to be informed about new _clients_ being added
> under a specific adapter.

This is for example exactly what ACPI integration in I2C framework does. But...

> I'm not sure whether the bus notifiers can
> inform about new clients in addition of new adapters, but they at least
> seem unable to provide per-adapter notification.

...personally I don't like notifiers, they looks like overkill for this task.

> Does that seem correct?

--
With Best Regards,
Andy Shevchenko