[PATCH v2] treewide, serdev: change receive_buf() return type to size_t

[Johan Hovold]

On Mon, Jan 22, 2024 at 07:05:51PM +0100, Francesco Dolcini wrote:
> From: Francesco Dolcini <francesco.dolcini at toradex.com>
> 
> receive_buf() is called from ttyport_receive_buf() that expects values
> ">= 0" from serdev_controller_receive_buf(), change its return type from
> ssize_t to size_t.
> 
> The need for this clean-up was noticed while fixing a warning, see
> commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value").
> Changing the callback prototype to return an unsigned seems the best way
> to document the API and ensure that is properly used.
> 
> GNSS drivers implementation of serdev receive_buf() callback return
> directly the return value of gnss_insert_raw(). gnss_insert_raw()
> returns a signed int, however this is not an issue since the value
> returned is always positive, because of the kfifo_in() implementation.
> gnss_insert_raw() could be changed to return also an unsigned, however
> this is not implemented here as request by the GNSS maintainer Johan
> Hovold.
> 
> Suggested-by: Jiri Slaby <jirislaby at kernel.org>
> Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/
> Signed-off-by: Francesco Dolcini <francesco.dolcini at toradex.com>
> Acked-by: Jonathan Cameron <Jonathan.Cameron at huawei.com> #for-iio
> ---
> v1:
>  - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/
> v2:
>  - rebased on 6.8-rc1
>  - add acked-by Jonathan
>  - do not change gnss_insert_raw()
>  - do not change the code style of the gnss code
>  - commit message improvements, explain the reasons for doing only minimal
>    changes on the GNSS part

Looks good to me now:

Reviewed-by: Johan Hovold <johan at kernel.org>