Add a new driver for Bicker DC UPS systems based on the PSZ-1063
extension module. This includes UPSIC-1205, UPSIC-2403 and
DC2412-UPS(LD) models.

Signed-off-by: Nicola Fontana <[email protected]>

The protocol supports shutdown after a custom delay settable between 0
and 255 seconds. Unfortunately the real device (UPSIC-2403D) seems to
always enforce a 2 seconds delay.

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

Bicker told me to refer to the UPS Gen software's user manual for more
details on their protocol, and in fact that manual contains much more
info. Added a summary of available commands to the comments, as a quick
reference for feature implementation.

Signed-off-by: Nicola Fontana <[email protected]>

In the previous implementation the command index was always '\x03', as
stated by the UPSIC manual. After new evidence has been found (UPS-Gen2
software user manual), it came out there are much more commands grouped
in different indexes.

Signed-off-by: Nicola Fontana <[email protected]>

I'm planning to add functions for reading strings, i.e. without knowing
beforehand the size of the response packets. This required some
refactoring of the receiving functions.

Also, while at it, added docblocks to many Bicker functions, hopefully
easing the maintenance in the future.

Signed-off-by: Nicola Fontana <[email protected]>

Identification fields are now queried from the device. Also
"battery.charge" is now set properly.

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

Added the needed infrastructure for getting and setting parameters.
Actually the only parameter that is surely working is "ups.delay.start".

Signed-off-by: Nicola Fontana <[email protected]>

When a command is unsupported, the "\x01\x03\xEE\x07\x04" response
packet is returned. This is different from a response packet with a
wrong command index.

WARNING: the "unsupported" packet has been found sperimentally and it is
an undocumented feature.

Signed-off-by: Nicola Fontana <[email protected]>

User provided strings could contain printf special sequences and as such
they should never be used in the format argument of dstate_setinfo().

Signed-off-by: Nicola Fontana <[email protected]>

Accessing an uint16_t on odd addresses is not portable. Avoid having to
deal with that issue by always constructing words mathematically from
single bytes. This also solves any endianness difference.

Signed-off-by: Nicola Fontana <[email protected]>

Signed-off-by: Nicola Fontana <[email protected]>

`char` is by default signed and (as the name implies) designed to access
string characters. For accessing bytes, the `uint8_t` type is more
appropriate.

Signed-off-by: Nicola Fontana <[email protected]>

Ensure the format string in logging messages is the correct one without
subcasting. Furthermore, due to the promotion rules of the C language
(where any given type, even unsigned, is promoted to int when possible),
explicitly cast to unsigned where required.

Signed-off-by: Nicola Fontana <[email protected]>

Change BICKER_PACKET from a constant value to a macro that depends on
the data length. This should make clear that the packet size depends
directly from the data size.

Refactored some code here and there trying to minimize the presence of
magic numbers and clarify the intentions.

Signed-off-by: Nicola Fontana <[email protected]>

Using an in/out struct and making some specific field mandatory is
cumbersome and error prone. Now the data needed for setting or getting
parameters is explicitly required by the arguments.

Signed-off-by: Nicola Fontana <[email protected]>

These devices seem to be picky on what you use to set parameters.

Signed-off-by: Nicola Fontana <[email protected]>

Every Bicker parameter that has a correspondence in nut-names.txt has
been mapped. If the parameter is disabled on the device, no NUT variable
is created. If the NUT variable is set to an empty string, the parameter
is reset and disabled on the device and that NUT variable is removed.

Signed-off-by: Nicola Fontana <[email protected]>