[Note: This patch is basically a squashed version of the initial driver
commits by Andreas Zschunke <andreas.zschunke@gmx.net>, two fixes by
Andrej Valek <andy@skyrain.eu>, and various coding style / cosmetic
fixes by Uwe Hermann <uwe@hermann-uwe.de> to make the driver a lot more
consistent with the rest of the libsigrok code-base.]

When refactoring the code, some places where sr_scpi_send was replaced
by rigol_ds_config_set the first argument was not changed from sdi->conn
to sdi. Fix the remaining ones.

Fix: https://sigrok.org/bug/1073Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>

According to a vendor software screenshot of a user on IRC, this
device is detected as having 200MHz max. samplerate and 128kBit
memory per channel.

Untested yet, but pretty likely to work.

This regression was introduced in f1ba6b4b.

Due to how the sysclk-lwla driver does up to 3 open/close operations in
one dev_open() API callback we cannot rely on the sr_dev_open() and
sr_dev_close() wrappers setting the sdi->status variable in this case.

Tested on LWLA1034.

When processing of large VCD input files was spread across multiple
parse_contents() invocations, the resulting sigrok stream of sample data
had gaps in them and total timing was off. For instance 74ms of input
data were interpreted as spanning some 600ms or 300ms, depending on the
number of channels in the input stream.

Move the "previous timestamp" variable to the input module context. This
eliminates the inappropriate gaps and fixes the translation of VCD file
timestamps to sigrok sample numbers.

This fixes bug #1075.

Untested, so we don't know for sure it'll work.

This fixes bug #1045.

This fixes bug #883.

Remove vague statements from the README. On all current distributions,
the udev paths are identical, anyone deliberately deviating from the
defaults should be able to handle it by themselves.

Rules in /etc/udev/rules.d/ should only be used for customization, or
for locally built packages.

Split the distribution independent database from the access policy rules.
This avoids warnings due to granting permissions to the commonly unknown
plugdev group, and allows simple overrides of the used access policy.

The "uaccess" tag has to be added before the "seat" rule is evaluated.
The upstream default for the seat rule is "71-seat.rules", so use
60-libsigrok.rules for appropriate lexicographical sorting.

Also use a dash instead of underscore, the latter is commonly used as a
replacement character of unsafe characters in autogenerated identifiers.

This fixes bug #1059.

Some drivers used locale dependent functions for converting strings
to float/double values. These functions fail when the decimal mark
is a "," in the locale settings but the string contains a ".".

This fixes bug #1064.

conrad-digi-35-cpu: Add SR_CONF_LIST for voltage_target and current_limit. Change current_limit lower limit.

A "low samplerate" in this case means anything where
samples_todo is less than SAMPLES_PER_FRAME. This case
wasn't handled properly before, resulting in wrong
amounts of data being sent out.

We can't use the memory size command because it returns
the *maximum* memory used, not the *actual* memory used.
Hence, we only know the number of samples per div once
sample data actually comes in.

WinUSB seems to have a maximum size of 2M, reads of a larger size fail.

This fixes bug #1048.

As there is a huge range of supported LeCroy scopes, naming
the IDN response for every single one of them is going to be
impossible. Hence, it makes more sense to treat all LeCroy
devices as if they were scopes and supported. This approach
lets users try to see how far they get and if they run into
issues, they can then be treated separately - e.g. by creating
a custom device profile.
Unless we do this, the vast majority of LeCroy scopes will
not be recognized by the driver.