On 2019-06-08 12:55, Wolfram Sang wrote:

While preparing a refactoring series, I noticed that some drivers use a
complicated way of determining the adapter of a client. The easy way is
to use the intended pointer: client->adapter

These drivers do:
	to_i2c_adapter(client->dev.parent);

The I2C core populates the parent pointer as:
	client->dev.parent = &client->adapter->dev;

Now take into consideration that
	to_i2c_adapter(&adapter->dev);

is a complicated way of saying 'adapter', then we can even formally
prove that the complicated expression can be simplified by using
client->adapter.

The conversion was done using a coccinelle script with some manual
indentation fixes applied on top.

To avoid a brown paper bag mistake, I double checked this on a Renesas
Salvator-XS board (R-Car M3N) and verified both expression result in the
same pointer. Other than that, the series is only build tested.

Similar things go on in:

drivers/hwmon/lm90.c
drivers/leds/leds-is31fl319x.c
drivers/of/unittest.c

Those have this pattern:

	struct device *dev = &client->dev;
	struct i2c_adapter *adapter = to_i2c_adapter(dev->parent);

And drivers/rtc/rtc-fm3130.c has a couple of these:

	tmp = i2c_transfer(to_i2c_adapter(fm3130->client->dev.parent),
			...);

where fm3130->client is of type "struct i2c_client *"

Cheers,
Peter
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