In the case of USB drivers, a driver's dev_acquisition_stop() cannot
simply remove its fd sources from the session and close its devices:
a USB transfer might still be underway, and it needs to be finished
(and its memory freed) properly.
An sr_dev_inst->status value is added: SR_ST_STOPPING, which should
be set when the driver's dev_acquisition_stop() is called, and acts
as a marker for the USB event handler to wind up its operations.
In order for dev_acquisition_stop() to be able to set the sdi status,
however, it needs to be unconstified.
While testing the new radioshack-dmm driver with pulseview, I found
a few inconvenients.
1. Print an info message when a port is probed, and when a device is
found. This makes it easy to tell if and where the driver is looking.
2. num_samples was not reset after the first aquisition, so the
second aquisition would quit right away. Reset num_samples at start
of a new aquisition.
3. There's no need to open the serial port RW, so change O_RDWR to
O_RDONLY when opening the port.
These changes are too trivial to split into different patches.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Uwe Hermann
Bert Vermeulen
Alexandru Gagniuc