Re: [PATCH v8 1/6] i2c: core: Setup i2c_adapter runtime-pm before calling device_add()

Wolfram Sang
2024-08-16T14:38:46Z

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On Mon, Aug 12, 2024 at 10:39:47PM +0200, Hans de Goede 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.
>
> Reviewed-by: Pali Rohár <pali@kernel.org>
> Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

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