diff options
| author | Michael Hanselmann <[email protected]> | 2020-07-04 20:25:03 +0200 |
|---|---|---|
| committer | Johan Hovold <[email protected]> | 2020-07-06 11:25:07 +0200 |
| commit | 0580baa46ef67069217bfeabd511ea036e58c1c0 (patch) | |
| tree | 601313691266c6c25a6a054b06c9740a0f024055 /drivers/fpga/fpga-bridge.c | |
| parent | cabe0785ff14e944ab1d828bed64e796e8f96594 (diff) | |
USB: serial: ch341: simulate break condition if not supported
A subset of all CH341 devices don't support a real break condition. This
fact is already used in the "ch341_detect_quirks" function. With this
change a quirk is implemented to simulate a break condition by
temporarily lowering the baud rate and sending a NUL byte.
The primary drawbacks of this approach are that the duration of the
break can't be controlled by userland and that data incoming during
a simulated break is corrupted.
The "TTY_DRIVER_HARDWARE_BREAK" serial driver flag was investigated as
an alternative. It's a driver-wide flag and would've required
significant changes to the serial and USB-serial driver frameworks to
expose it for individual USB-serial adapters.
Tested by sending a break condition and watching the TX pin using an
oscilloscope.
Signed-off-by: Michael Hanselmann <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ johan: condense info message ]
Signed-off-by: Johan Hovold <[email protected]>
Diffstat (limited to 'drivers/fpga/fpga-bridge.c')
0 files changed, 0 insertions, 0 deletions