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i2c: core: Setup i2c_adapter runtime-pm before calling device_add()

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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>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
This commit is contained in:
Hans de Goede 2024-08-12 22:39:47 +02:00 • committed by Andi Shyti
parent 15b882c6c8
commit 60f6859702
1 changed files with 12 additions and 6 deletions
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18
drivers/i2c/i2c-core-base.c
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@ -1524,7 +1524,18 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
adap->dev.bus = &i2c_bus_type;
adap->dev.type = &i2c_adapter_type;
res = device_register(&adap->dev);
device_initialize(&adap->dev);
/*
* This adapter can be used as a parent immediately after device_add(),
* setup runtime-pm (especially ignore-children) before hand.
*/
device_enable_async_suspend(&adap->dev);
pm_runtime_no_callbacks(&adap->dev);
pm_suspend_ignore_children(&adap->dev, true);
pm_runtime_enable(&adap->dev);
res = device_add(&adap->dev);
if (res) {
pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
goto out_list;
@ -1536,11 +1547,6 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
if (res)
goto out_reg;
device_enable_async_suspend(&adap->dev);
pm_runtime_no_callbacks(&adap->dev);
pm_suspend_ignore_children(&adap->dev, true);
pm_runtime_enable(&adap->dev);
res = i2c_init_recovery(adap);
if (res == -EPROBE_DEFER)
goto out_reg;