staging: pi433: Added information about bit_rate configuration

Information in the TODO file for bit_rate configuration is
insufficient.

This patch adds information on how to approach when considering
to modify bit_rate to support upto 300kbps.

Signed-off-by: Guru Mehar Rachaputi <gurumeharrachaputi@gmail.com>
Acked-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/Y9laj+z0TuasBRx5@combine-ThinkPad-S1-Yoga
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: pi433: remove TODOs-related item from the TODO file

All occurences of code annotated with TODO in this driver have been
addressed in the last couple of years by the community. The last
occurrence of the word "TODO" was in the form of a multi-line comment in
the header file intended to be exposed to userspace once this driver
moves away from the staging folder.

This patch removes that TODO as well as the TODO-related item from the
driver's TODO file

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Link: https://lore.kernel.org/r/YhmyK1Utaoj924im@mail.google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: pi433: remove coding style item from the TODO file

After several patches sent by the community along the last couple of
years, it's possible to remove the coding style item from the TODO file
in the driver's folder.

This patch addresses the last code formatting inconsistences and remove
the coding style item from the TODO file.

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Link: https://lore.kernel.org/r/YfYdVokxsQ+Adl+T@mail.google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: pi433: validate max bit_rate based on modulation used

Max bit rate is dependent on which modulation is used. Previous
validation routine only took into consideration min bit rate which can
lead a misconfiguration of the rf69 chip causing the packets not to be
sent/read.

This patch enhances that input check in set_bit_rate to account for
modulation values and their respective max bit rate

Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Link: https://lore.kernel.org/r/20220118230555.GA4961@mail.google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: pi433: New driver

Added a driver for the pi433 radio module
(see https://www.pi433.de/en.html for details).

Signed-off-by: Marcus Wolf <linux@Wolf-Entwicklungen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>