staging: rtl8723bs: refactor rtw_ch2freq()

Convert the array ch_freq_map to a simple integer array and use
the indices as channel numbers. This simplifies the code and avoids
looping through the array to get the frequency. To avoid out of
bounds array access return a default value for invalid channel values,
like the original code did.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220331214146.15161-3-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: rtl8723bs: remove 5 GHz channels from ch_freq_map

According to the Realtek documentation the chips this driver supports
are 2.4 GHz only chips. Frequencies for 5 GHz channels can be removed
from the ch_freq_map array.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220331214146.15161-2-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: rtl8723bs: remove unused macros

remove unused macros detected by -Wunused-macros
gcc option.

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/20210801134629.23433-1-fabioaiuto83@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: rtl8723bs: Replace license boilerplate with SPDX identifiers

This satisfies a checkpatch.pl warning and is the preferred method for
notating the license due to its lack of ambiguity.

Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: rtl8723bs: use ARRAY_SIZE

Using the ARRAY_SIZE macro improves the readability of the code. Also,
it is not always useful to use a variable to store this constant
calculated at compile time.

Found with Coccinelle with the following semantic patch:
@r depends on (org || report)@
type T;
T[] E;
position p;
@@
(
(sizeof(E)@p /sizeof(*E))
|
(sizeof(E)@p /sizeof(E[...]))
|
(sizeof(E)@p /sizeof(T))
)

Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: Add rtl8723bs sdio wifi driver

The rtl8723bs is found on quite a few systems used by Linux users,
such as on Atom systems (Intel Computestick and various other
Atom based devices) and on many (budget) ARM boards such as
the CHIP.

The plan moving forward with this is for the new clean,
written from scratch, rtl8xxxu driver to eventually gain
support for sdio devices. But there is no clear timeline
for that, so lets add this driver included in staging for now.

Cc: Bastien Nocera <hadess@hadess.net>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Jes Sorensen <jes.sorensen@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>