i2c: cp2615: Fix 'assignment to __be16' warning

While the preamble field _is_ technically big-endian, its value is always 0x2A2A,
which is the same in either endianness. However, to avoid generating a warning,
we should still call `htons()` explicitly.

Signed-off-by: Bence Csókás <bence98@sch.bme.hu>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: cp2615: replace deprecated strncpy with strscpy

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We should prefer more robust and less ambiguous string interfaces.

We expect name to be NUL-terminated based on its numerous uses with
functions that expect NUL-terminated strings.

For example in i2c-core-base.c +1533:
| dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

NUL-padding is not required as `adap` is already zero-alloacted with:
| adap = devm_kzalloc(&usbif->dev, sizeof(struct i2c_adapter), GFP_KERNEL);

With the above in mind, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: cp2615: check for allocation failure in cp2615_i2c_recv()

We need to add a check for if the kzalloc() fails.

Fixes: 4a7695429ead ("i2c: cp2615: add i2c driver for Silicon Labs' CP2615 Digital Audio Bridge")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Bence Csókás <bence98@sch.bme.hu>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: cp2615: add i2c driver for Silicon Labs' CP2615 Digital Audio Bridge

Create an i2c_adapter for CP2615's I2C master interface

Signed-off-by: Bence Csókás <bence98@sch.bme.hu>
[wsa: switched to '__packed', added some 'static' and an include]
Signed-off-by: Wolfram Sang <wsa@kernel.org>