On Fri, Jun 21, 2024 at 2:25 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> Platform glue code, which is not build into the kernel and thus cannot
> use i2c_register_board_info() may want to use bus_register_notifier()
> to listen for i2c-adapters to show up on which the platform code needs
> to manually instantiate platform specific i2c_clients.
>
> This results in calling i2c_new_client_device() from the bus notifier
> which happens near the device_add() call.
>
> If the i2c-core has not yet setup runtime-pm (specifically the
> no-callbacks and ignore-children flags) for the device embedded
> inside struct i2c_adapter and the driver for the i2c_client
> calls pm_runtime_set_active() this will trigger the following
> error inside __pm_runtime_set_status():
>
> "runtime PM trying to activate child device %s but parent (%s) is not active\n"
>
> and the i2c_client's runtime-status will not be updated.
>
> Split the device_register() call for the adapter into device_initialize()
> and device_add() and move the pm-runtime init calls inbetween these 2 calls
> so that the runtime-status can be correctly set when a driver binds from
> the bus-notifier.
>
> Note the moved pm-runtime init calls just override the initial value of
> some flags in struct device set by device_initialize() and calling these
> before device_add() is safe.
LGTM, but this is non-trivial (I think) for the usual cases, can you
add a comment on top of the code you modified?
...
...somewhere here?
> + res = device_add(&adap->dev);
> if (res) {
> pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
> goto out_list;
--
With Best Regards,
Andy Shevchenko
